Adding upstream version 1.23.0.upstream/1.23.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

105 files changed, 55894 insertions, 0 deletions

diff --git a/src/preproc/eqn/TODO b/src/preproc/eqn/TODO
new file mode 100644
index 0000000..2a22183
--- /dev/null
+++ b/src/preproc/eqn/TODO
@@ -0,0 +1,49 @@
+Use the same size increases for sum prod int as eqn does.
+
+Perhaps chartype should be renamed.
+
+TeX makes {sub,super}script on a single character with an accent
+into an accent onto the (character with the script). Should we do this?
+
+Implement mark and lineups within scripts, matrices and piles, and accents.
+(Why would this be useful?)
+
+Perhaps push hmotions down through lists to avoid upsetting spacing
+adjustments.
+
+Possibly generate .lf commands during compute_metrics phase.
+
+Consider whether there should be extra space at the side of piles.
+
+Provide scriptstyle displaystyle etc.
+
+Provide a nicer matrix syntax, e.g.,
+matrix ccc {
+a then b then c above
+e then f then g above
+h then i then k
+}
+
+Perhaps generate syntax error messages using the style of gpic.
+
+Wide accents.
+
+More use of \Z.
+
+Extensible square roots.
+
+Vphantom
+
+Smash.
+
+Provide a variant of vec that extends over the length of the accentee.
+
+Support vertical arrow delimiters.
+
+Make the following work:
+.EQ
+delim @@
+.EN
+.EQ @<-@
+some equation
+.EN
diff --git a/src/preproc/eqn/box.cpp b/src/preproc/eqn/box.cpp
new file mode 100644
index 0000000..5f6343e
--- /dev/null
+++ b/src/preproc/eqn/box.cpp
@@ -0,0 +1,651 @@
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <assert.h>
+
+#include "eqn.h"
+#include "pbox.h"
+
+const char *current_roman_font;
+
+char *gfont = 0;
+char *grfont = 0;
+char *gbfont = 0;
+int gsize = 0;
+
+int script_size_reduction = -1;	// negative means reduce by a percentage 
+
+int positive_space = -1;
+int negative_space = -1;
+
+int minimum_size = 5;
+
+int fat_offset = 4;
+int body_height = 85;
+int body_depth = 35;
+
+int over_hang = 0;
+int accent_width = 31;
+int delimiter_factor = 900;
+int delimiter_shortfall = 50;
+
+int null_delimiter_space = 12;
+int script_space = 5;
+int thin_space = 17;
+int medium_space = 22;
+int thick_space = 28;
+
+int num1 = 70;
+int num2 = 40;
+// we don't use num3, because we don't have \atop
+int denom1 = 70;
+int denom2 = 36;
+int axis_height = 26;		// in 100ths of an em
+int sup1 = 42;
+int sup2 = 37;
+int sup3 = 28;
+int default_rule_thickness = 4;
+int sub1 = 20;
+int sub2 = 23;
+int sup_drop = 38;
+int sub_drop = 5;
+int x_height = 45;
+int big_op_spacing1 = 11;
+int big_op_spacing2 = 17;
+int big_op_spacing3 = 20;
+int big_op_spacing4 = 60;
+int big_op_spacing5 = 10;
+
+// These are for piles and matrices.
+
+int baseline_sep = 140;		// = num1 + denom1
+int shift_down = 26;		// = axis_height
+int column_sep = 100;		// = em space
+int matrix_side_sep = 17;	// = thin space
+
+int nroff = 0;			// should we grok ndefine or tdefine?
+
+struct S {
+  const char *name;
+  int *ptr;
+} param_table[] = {
+  { "fat_offset", &fat_offset },
+  { "over_hang", &over_hang },
+  { "accent_width", &accent_width },
+  { "delimiter_factor", &delimiter_factor },
+  { "delimiter_shortfall", &delimiter_shortfall },
+  { "null_delimiter_space", &null_delimiter_space },
+  { "script_space", &script_space },
+  { "thin_space", &thin_space },
+  { "medium_space", &medium_space },
+  { "thick_space", &thick_space },
+  { "num1", &num1 },
+  { "num2", &num2 },
+  { "denom1", &denom1 },
+  { "denom2", &denom2 },
+  { "axis_height", &axis_height },
+  { "sup1", &sup1 },
+  { "sup2", &sup2 },
+  { "sup3", &sup3 },
+  { "default_rule_thickness", &default_rule_thickness },
+  { "sub1", &sub1 },
+  { "sub2", &sub2 },
+  { "sup_drop", &sup_drop },
+  { "sub_drop", &sub_drop },
+  { "x_height", &x_height },
+  { "big_op_spacing1", &big_op_spacing1 },
+  { "big_op_spacing2", &big_op_spacing2 },
+  { "big_op_spacing3", &big_op_spacing3 },
+  { "big_op_spacing4", &big_op_spacing4 },
+  { "big_op_spacing5", &big_op_spacing5 },
+  { "minimum_size", &minimum_size },
+  { "baseline_sep", &baseline_sep },
+  { "shift_down", &shift_down },
+  { "column_sep", &column_sep },
+  { "matrix_side_sep", &matrix_side_sep },
+  { "draw_lines", &draw_flag },
+  { "body_height", &body_height },
+  { "body_depth", &body_depth },
+  { "nroff", &nroff },
+  { 0, 0 }
+};
+
+void set_param(const char *name, int value)
+{
+  for (int i = 0; param_table[i].name != 0; i++)
+    if (strcmp(param_table[i].name, name) == 0) {
+      *param_table[i].ptr = value;
+      return;
+    }
+  error("unrecognised parameter '%1'", name);
+}
+
+int script_style(int style)
+{
+  return style > SCRIPT_STYLE ? style - 2 : style;
+}
+
+int cramped_style(int style)
+{
+  return (style & 1) ? style - 1 : style;
+}
+
+void set_space(int n)
+{
+  if (n < 0)
+    negative_space = -n;
+  else
+    positive_space = n;
+}
+
+// Return 0 if the specified size is bad.
+// The caller is responsible for giving the error message.
+
+int set_gsize(const char *s)
+{
+  const char *p = (*s == '+' || *s == '-') ? s + 1 : s;
+  char *end;
+  long n = strtol(p, &end, 10);
+  if (n <= 0 || *end != '\0' || n > INT_MAX)
+    return 0;
+  if (p > s) {
+    if (!gsize)
+      gsize = 10;
+    if (*s == '+') {
+      if (gsize > INT_MAX - n)
+	return 0;
+      gsize += int(n);
+    }
+    else {
+      if (gsize - n <= 0)
+	return 0;
+      gsize -= int(n);
+    }
+  }
+  else
+    gsize = int(n);
+  return 1;
+}
+
+void set_script_reduction(int n)
+{
+  script_size_reduction = n;
+}
+
+const char *get_gfont()
+{
+  return gfont ? gfont : "I";
+}
+
+const char *get_grfont()
+{
+  return grfont ? grfont : "R";
+}
+
+const char *get_gbfont()
+{
+  return gbfont ? gbfont : "B";
+}
+
+void set_gfont(const char *s)
+{
+  delete[] gfont;
+  gfont = strsave(s);
+}
+
+void set_grfont(const char *s)
+{
+  delete[] grfont;
+  grfont = strsave(s);
+}
+
+void set_gbfont(const char *s)
+{
+  delete[] gbfont;
+  gbfont = strsave(s);
+}
+
+// this must be precisely 2 characters in length
+#define COMPATIBLE_REG "0C"
+
+void start_string()
+{
+  if (output_format == troff) {
+    printf(".nr " COMPATIBLE_REG " \\n(.C\n");
+    printf(".cp 0\n");
+    printf(".ds " LINE_STRING "\n");
+  }
+}
+
+void output_string()
+{
+  if (output_format == troff)
+    printf("\\*(" LINE_STRING "\n");
+  else if (output_format == mathml && !xhtml)
+    putchar('\n');
+}
+
+void restore_compatibility()
+{
+  if (output_format == troff)
+    printf(".cp \\n(" COMPATIBLE_REG "\n");
+}
+
+void do_text(const char *s)
+{
+  if (output_format == troff) {
+    printf(".eo\n");
+    printf(".as " LINE_STRING " \"%s\n", s);
+    printf(".ec\n");
+  }
+  else if (output_format == mathml) {
+    fputs(s, stdout);
+    if (xhtml && strlen(s) > 0)
+      printf("\n");
+  }
+}
+
+void set_minimum_size(int n)
+{
+  minimum_size = n;
+}
+
+void set_script_size()
+{
+  if (minimum_size < 0)
+    minimum_size = 0;
+  if (script_size_reduction >= 0)
+    printf(".ps \\n[.s]-%d>?%d\n", script_size_reduction, minimum_size);
+  else
+    printf(".ps (u;\\n[.ps]*7+5/10>?%dz)\n", minimum_size);
+}
+
+int box::next_uid = 0;
+
+box::box() : spacing_type(ORDINARY_TYPE), uid(next_uid++)
+{
+}
+
+box::~box()
+{
+}
+
+void box::top_level()
+{
+  box *b = this;
+  if (output_format == troff) {
+    // debug_print();
+    // putc('\n', stderr);
+    printf(".nr " SAVED_FONT_REG " \\n[.f]\n");
+    printf(".ft\n");
+    printf(".nr " SAVED_PREV_FONT_REG " \\n[.f]\n");
+    printf(".ft %s\n", get_gfont());
+    printf(".nr " SAVED_SIZE_REG " \\n[.ps]\n");
+    if (gsize > 0) {
+      char buf[INT_DIGITS + 1];
+      sprintf(buf, "%d", gsize);
+      b = new size_box(strsave(buf), b);
+    }
+    current_roman_font = get_grfont();
+    // This catches tabs used within \Z (which aren't allowed).
+    b->check_tabs(0);
+    int r = b->compute_metrics(DISPLAY_STYLE);
+    printf(".ft \\n[" SAVED_PREV_FONT_REG "]\n");
+    printf(".ft \\n[" SAVED_FONT_REG "]\n");
+    printf(".nr " MARK_OR_LINEUP_FLAG_REG " %d\n", r);
+    if (r == FOUND_MARK) {
+      printf(".nr " SAVED_MARK_REG " \\n[" MARK_REG "]\n");
+      printf(".nr " MARK_WIDTH_REG " 0\\n[" WIDTH_FORMAT "]\n", b->uid);
+    }
+    else if (r == FOUND_LINEUP)
+      printf(".if r" SAVED_MARK_REG " .as1 " LINE_STRING " \\h'\\n["
+	     SAVED_MARK_REG "]u-\\n[" MARK_REG "]u'\n");
+    else
+      assert(r == FOUND_NOTHING);
+    // If we use \R directly, the space will prevent it working in a
+    // macro argument; so we hide it in a string instead.
+    printf(".ds " SAVE_FONT_STRING " "
+	   "\\R'" SAVED_INLINE_FONT_REG " \\En[.f]'"
+	   "\\fP"
+	   "\\R'" SAVED_INLINE_PREV_FONT_REG " \\En[.f]'"
+	   "\\R'" SAVED_INLINE_SIZE_REG " \\En[.ps]'"
+	   "\\s0"
+	   "\\R'" SAVED_INLINE_PREV_SIZE_REG " \\En[.ps]'"
+	   "\n"
+	   ".ds " RESTORE_FONT_STRING " "
+	   "\\f[\\En[" SAVED_INLINE_PREV_FONT_REG "]]"
+	   "\\f[\\En[" SAVED_INLINE_FONT_REG "]]"
+	   "\\s'\\En[" SAVED_INLINE_PREV_SIZE_REG "]u'"
+	   "\\s'\\En[" SAVED_INLINE_SIZE_REG "]u'"
+	   "\n");
+    printf(".as1 " LINE_STRING " \\&\\E*[" SAVE_FONT_STRING "]");
+    printf("\\f[%s]", get_gfont());
+    printf("\\s'\\En[" SAVED_SIZE_REG "]u'");
+    current_roman_font = get_grfont();
+    b->output();
+    printf("\\E*[" RESTORE_FONT_STRING "]\n");
+    if (r == FOUND_LINEUP)
+      printf(".if r" SAVED_MARK_REG " .as1 " LINE_STRING " \\h'\\n["
+	     MARK_WIDTH_REG "]u-\\n[" SAVED_MARK_REG "]u-(\\n["
+	     WIDTH_FORMAT "]u-\\n[" MARK_REG "]u)'\n",
+	     b->uid);
+    b->extra_space();
+    if (!inline_flag)
+      printf(".ne \\n[" HEIGHT_FORMAT "]u-%dM>?0+(\\n["
+	     DEPTH_FORMAT "]u-%dM>?0)\n",
+	     b->uid, body_height, b->uid, body_depth);
+  }
+  else if (output_format == mathml) {
+    if (xhtml)
+      printf(".MATHML ");
+    printf("<math>");
+    b->output();
+    printf("</math>");
+  }
+  delete b;
+  next_uid = 0;
+}
+
+// gpic defines this register so as to make geqn not produce '\x's
+#define EQN_NO_EXTRA_SPACE_REG "0x"
+
+void box::extra_space()
+{
+  printf(".if !r" EQN_NO_EXTRA_SPACE_REG " "
+	 ".nr " EQN_NO_EXTRA_SPACE_REG " 0\n");
+  if (positive_space >= 0 || negative_space >= 0) {
+    if (positive_space > 0)
+      printf(".if !\\n[" EQN_NO_EXTRA_SPACE_REG "] "
+	     ".as1 " LINE_STRING " \\x'-%dM'\n", positive_space);
+    if (negative_space > 0)
+      printf(".if !\\n[" EQN_NO_EXTRA_SPACE_REG "] "
+	     ".as1 " LINE_STRING " \\x'%dM'\n", negative_space);
+    positive_space = negative_space = -1;
+  }
+  else {
+    printf(".if !\\n[" EQN_NO_EXTRA_SPACE_REG "] "
+	   ".if \\n[" HEIGHT_FORMAT "]>%dM .as1 " LINE_STRING
+	   " \\x'-(\\n[" HEIGHT_FORMAT
+	   "]u-%dM)'\n",
+	   uid, body_height, uid, body_height);
+    printf(".if !\\n[" EQN_NO_EXTRA_SPACE_REG "] "
+	   ".if \\n[" DEPTH_FORMAT "]>%dM .as1 " LINE_STRING
+	   " \\x'\\n[" DEPTH_FORMAT
+	   "]u-%dM'\n",
+	   uid, body_depth, uid, body_depth);
+  }
+}
+
+int box::compute_metrics(int)
+{
+  printf(".nr " WIDTH_FORMAT " 0\n", uid);
+  printf(".nr " HEIGHT_FORMAT " 0\n", uid);
+  printf(".nr " DEPTH_FORMAT " 0\n", uid);
+  return FOUND_NOTHING;
+}
+
+void box::compute_subscript_kern()
+{
+  printf(".nr " SUB_KERN_FORMAT " 0\n", uid);
+}
+
+void box::compute_skew()
+{
+  printf(".nr " SKEW_FORMAT " 0\n", uid);
+}
+
+void box::output()
+{
+}
+
+void box::check_tabs(int)
+{
+}
+
+int box::is_char()
+{
+  return 0;
+}
+
+int box::left_is_italic()
+{
+  return 0;
+}
+
+int box::right_is_italic()
+{
+  return 0;
+}
+
+void box::hint(unsigned)
+{
+}
+  
+void box::handle_char_type(int, int)
+{
+}
+
+
+box_list::box_list(box *pp)
+{
+  p = new box*[10];
+  for (int i = 0; i < 10; i++)
+    p[i] = 0;
+  maxlen = 10;
+  len = 1;
+  p[0] = pp;
+}
+
+void box_list::append(box *pp)
+{
+  if (len + 1 > maxlen) {
+    box **oldp = p;
+    maxlen *= 2;
+    p = new box*[maxlen];
+    memcpy(p, oldp, sizeof(box*)*len);
+    delete[] oldp;
+  }
+  p[len++] = pp;
+}
+
+box_list::~box_list()
+{
+  for (int i = 0; i < len; i++)
+    delete p[i];
+  delete[] p;
+}
+
+void box_list::list_check_tabs(int level)
+{
+  for (int i = 0; i < len; i++)
+    p[i]->check_tabs(level);
+}
+
+
+pointer_box::pointer_box(box *pp) : p(pp)
+{
+  spacing_type = p->spacing_type;
+}
+
+pointer_box::~pointer_box()
+{
+  delete p;
+}
+
+int pointer_box::compute_metrics(int style)
+{
+  int r = p->compute_metrics(style);
+  printf(".nr " WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]\n", uid, p->uid);
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]\n", uid, p->uid);
+  printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]\n", uid, p->uid);
+  return r;
+}
+
+void pointer_box::compute_subscript_kern()
+{
+  p->compute_subscript_kern();
+  printf(".nr " SUB_KERN_FORMAT " \\n[" SUB_KERN_FORMAT "]\n", uid, p->uid);
+}
+
+void pointer_box::compute_skew()
+{
+  p->compute_skew();
+  printf(".nr " SKEW_FORMAT " 0\\n[" SKEW_FORMAT "]\n",
+	 uid, p->uid);
+}
+
+void pointer_box::check_tabs(int level)
+{
+  p->check_tabs(level);
+}
+
+int simple_box::compute_metrics(int)
+{
+  printf(".nr " WIDTH_FORMAT " 0\\w" DELIMITER_CHAR, uid);
+  output();
+  printf(DELIMITER_CHAR "\n");
+  printf(".nr " HEIGHT_FORMAT " 0>?\\n[rst]\n", uid);
+  printf(".nr " DEPTH_FORMAT " 0-\\n[rsb]>?0\n", uid);
+  printf(".nr " SUB_KERN_FORMAT " 0-\\n[ssc]>?0\n", uid);
+  printf(".nr " SKEW_FORMAT " 0\\n[skw]\n", uid);
+  return FOUND_NOTHING;
+}
+
+void simple_box::compute_subscript_kern()
+{
+  // do nothing, we already computed it in do_metrics
+}
+
+void simple_box::compute_skew()
+{
+  // do nothing, we already computed it in do_metrics
+}
+
+int box::is_simple()
+{
+  return 0;
+}
+
+int simple_box::is_simple()
+{
+  return 1;
+}
+
+quoted_text_box::quoted_text_box(char *s) : text(s)
+{
+}
+
+quoted_text_box::~quoted_text_box()
+{
+  free(text);
+}
+
+void quoted_text_box::output()
+{
+  if (text) {
+    if (output_format == troff)
+      fputs(text, stdout);
+    else if (output_format == mathml) {
+      fputs("<mtext>", stdout);
+      fputs(text, stdout);
+      fputs("</mtext>", stdout);
+    }
+  }
+}
+
+tab_box::tab_box() : disabled(0)
+{
+}
+
+// We treat a tab_box as having width 0 for width computations.
+
+void tab_box::output()
+{
+  if (!disabled)
+    printf("\\t");
+}
+
+void tab_box::check_tabs(int level)
+{
+  if (level > 0) {
+    error("tabs allowed only at outermost level");
+    disabled = 1;
+  }
+}
+
+space_box::space_box()
+{
+  spacing_type = SUPPRESS_TYPE;
+}
+
+void space_box::output()
+{
+  if (output_format == troff)
+    printf("\\h'%dM'", thick_space);
+  else if (output_format == mathml)
+    // &ThickSpace; doesn't display right under Firefox 1.5.
+    printf("<mtext>&ensp;</mtext>");
+}
+
+half_space_box::half_space_box()
+{
+  spacing_type = SUPPRESS_TYPE;
+}
+
+void half_space_box::output()
+{
+  if (output_format == troff)
+    printf("\\h'%dM'", thin_space);
+  else if (output_format == mathml)
+    printf("<mtext>&ThinSpace;</mtext>");
+}
+
+void box_list::list_debug_print(const char *sep)
+{
+  p[0]->debug_print();
+  for (int i = 1; i < len; i++) {
+    fprintf(stderr, "%s", sep);
+    p[i]->debug_print();
+  }
+}
+
+void quoted_text_box::debug_print()
+{
+  fprintf(stderr, "\"%s\"", (text ? text : ""));
+}
+
+void half_space_box::debug_print()
+{
+  fprintf(stderr, "^");
+}
+
+void space_box::debug_print()
+{
+  fprintf(stderr, "~");
+}
+
+void tab_box::debug_print()
+{
+  fprintf(stderr, "<tab>");
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/eqn/box.h b/src/preproc/eqn/box.h
new file mode 100644
index 0000000..981b464
--- /dev/null
+++ b/src/preproc/eqn/box.h
@@ -0,0 +1,278 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+class list_box;
+
+class box {
+private:
+  static int next_uid;
+public:
+  int spacing_type;
+  const int uid;
+  box();
+  virtual void debug_print() = 0;
+  virtual ~box();
+  void top_level();
+  virtual int compute_metrics(int);
+  virtual void compute_subscript_kern();
+  virtual void compute_skew();
+  virtual void output();
+  void extra_space();
+  virtual list_box *to_list_box();
+  virtual int is_simple();
+  virtual int is_char();
+  virtual int left_is_italic();
+  virtual int right_is_italic();
+  virtual void handle_char_type(int, int);
+  enum { FOUND_NOTHING = 0, FOUND_MARK = 1, FOUND_LINEUP = 2 };
+  void set_spacing_type(char *type);
+  virtual void hint(unsigned);
+  virtual void check_tabs(int);
+};
+
+class box_list {
+private:
+  int maxlen;
+public:
+  box **p;
+  int len;
+
+  box_list(box *);
+  ~box_list();
+  void append(box *);
+  void list_check_tabs(int);
+  void list_debug_print(const char *sep);
+  friend class list_box;
+};
+
+// declarations to avoid friend name injection problems
+box *make_script_box(box *, box *, box *);
+box *make_mark_box(box *);
+box *make_lineup_box(box *);
+
+class list_box : public box {
+  int is_script;
+  box_list list;
+  int sty;
+public:
+  list_box(box *);
+  void debug_print();
+  int compute_metrics(int);
+  void compute_subscript_kern();
+  void output();
+  void check_tabs(int);
+  void append(box *);
+  list_box *to_list_box();
+  void handle_char_type(int, int);
+  void compute_sublist_width(int n);
+  friend box *make_script_box(box *, box *, box *);
+  friend box *make_mark_box(box *);
+  friend box *make_lineup_box(box *);
+};
+
+enum alignment { LEFT_ALIGN, RIGHT_ALIGN, CENTER_ALIGN };
+
+class column : public box_list {
+  alignment align;
+  int space;
+public:
+  column(box *);
+  void set_alignment(alignment);
+  void set_space(int);
+  void debug_print(const char *);
+
+  friend class matrix_box;
+  friend class pile_box;
+};
+
+class pile_box : public box {
+  column col;
+public:
+  pile_box(box *);
+  int compute_metrics(int);
+  void output();
+  void debug_print();
+  void check_tabs(int);
+  void set_alignment(alignment a) { col.set_alignment(a); }
+  void set_space(int n) { col.set_space(n); }
+  void append(box *p) { col.append(p); }
+};
+
+class matrix_box : public box {
+private:
+  int len;
+  int maxlen;
+  column **p;
+public:
+  matrix_box(column *);
+  ~matrix_box();
+  void append(column *);
+  int compute_metrics(int);
+  void output();
+  void check_tabs(int);
+  void debug_print();
+};
+
+class pointer_box : public box {
+protected:
+  box *p;
+public:
+  pointer_box(box *);
+  ~pointer_box();
+  int compute_metrics(int);
+  void compute_subscript_kern();
+  void compute_skew();
+  void debug_print() = 0;
+  void check_tabs(int);
+};
+
+class vcenter_box : public pointer_box {
+public:
+  vcenter_box(box *);
+  int compute_metrics(int);
+  void output();
+  void debug_print();
+};
+
+class simple_box : public box {
+public:
+  int compute_metrics(int);
+  void compute_subscript_kern();
+  void compute_skew();
+  void output() = 0;
+  void debug_print() = 0;
+  int is_simple();
+};
+
+class quoted_text_box : public simple_box {
+  char *text;
+public:
+  quoted_text_box(char *);
+  ~quoted_text_box();
+  void debug_print();
+  void output();
+};
+
+class half_space_box : public simple_box {
+public:
+  half_space_box();
+  void output();
+  void debug_print();
+};
+
+class space_box : public simple_box {
+public:
+  space_box();
+  void output();
+  void debug_print();
+};
+
+class tab_box : public box {
+  int disabled;
+public:
+  tab_box();
+  void output();
+  void debug_print();
+  void check_tabs(int);
+};
+
+class size_box : public pointer_box {
+private:
+  char *size;
+public:
+  size_box(char *, box *);
+  ~size_box();
+  int compute_metrics(int);
+  void output();
+  void debug_print();
+};
+
+class font_box : public pointer_box {
+private:
+  char *f;
+public:
+  font_box(char *, box *);
+  ~font_box();
+  int compute_metrics(int);
+  void output();
+  void debug_print();
+};
+
+class fat_box : public pointer_box {
+public:
+  fat_box(box *);
+  int compute_metrics(int);
+  void output();
+  void debug_print();
+};
+
+class vmotion_box : public pointer_box {
+private:
+  int n;			// up is >= 0
+public:
+  vmotion_box(int, box *);
+  int compute_metrics(int);
+  void output();
+  void debug_print();
+};
+
+class hmotion_box : public pointer_box {
+  int n;
+public:
+  hmotion_box(int, box *);
+  int compute_metrics(int);
+  void output();
+  void debug_print();
+};
+
+box *split_text(char *);
+box *make_delim_box(char *, box *, char *);
+box *make_sqrt_box(box *);
+box *make_prime_box(box *);
+box *make_over_box(box *, box *);
+box *make_small_over_box(box *, box *);
+box *make_limit_box(box *, box *, box *);
+box *make_accent_box(box *, box *);
+box *make_uaccent_box(box *, box *);
+box *make_overline_box(box *);
+box *make_underline_box(box *);
+box *make_special_box(char *, box *);
+
+void set_space(int);
+int set_gsize(const char *);
+void set_gfont(const char *);
+void set_grfont(const char *);
+void set_gbfont(const char *);
+const char *get_gfont();
+const char *get_grfont();
+const char *get_gbfont();
+void start_string();
+void output_string();
+void do_text(const char *);
+void restore_compatibility();
+void set_script_reduction(int n);
+void set_minimum_size(int n);
+void set_param(const char *name, int value);
+
+void set_char_type(const char *type, char *ch);
+
+void init_char_table();
+void init_extensible();
+void define_extensible(const char *name, const char *ext, const char *top = 0,
+		       const char *mid = 0, const char *bot = 0);
diff --git a/src/preproc/eqn/delim.cpp b/src/preproc/eqn/delim.cpp
new file mode 100644
index 0000000..01557c5
--- /dev/null
+++ b/src/preproc/eqn/delim.cpp
@@ -0,0 +1,418 @@
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <assert.h>
+
+#include "eqn.h"
+#include "pbox.h"
+
+enum left_or_right_t { LEFT_DELIM = 01, RIGHT_DELIM = 02 };
+
+// Small must be none-zero and must exist in each device.
+// Small will be put in the roman font, others are assumed to be
+// on the special font (so no font change will be necessary.)
+
+struct delimiter {
+  const char *name;
+  int flags;
+  const char *small;
+  const char *chain_format;
+  const char *ext;
+  const char *top;
+  const char *mid;
+  const char *bot;
+} delim_table[] = {
+  {
+    "(", LEFT_DELIM|RIGHT_DELIM, "(", "\\[parenleft%s]",
+    "\\[parenleftex]",
+    "\\[parenlefttp]",
+    0,
+    "\\[parenleftbt]",
+  },
+  {
+    ")", LEFT_DELIM|RIGHT_DELIM, ")", "\\[parenright%s]",
+    "\\[parenrightex]",
+    "\\[parenrighttp]",
+    0,
+    "\\[parenrightbt]",
+  },
+  {
+    "[", LEFT_DELIM|RIGHT_DELIM, "[", "\\[bracketleft%s]",
+    "\\[bracketleftex]",
+    "\\[bracketlefttp]",
+    0,
+    "\\[bracketleftbt]",
+  },
+  {
+    "]", LEFT_DELIM|RIGHT_DELIM, "]", "\\[bracketright%s]",
+    "\\[bracketrightex]",
+    "\\[bracketrighttp]",
+    0,
+    "\\[bracketrightbt]",
+  },
+  {
+    "{", LEFT_DELIM|RIGHT_DELIM, "{", "\\[braceleft%s]",
+    "\\[braceleftex]",
+    "\\[bracelefttp]",
+    "\\[braceleftmid]",
+    "\\[braceleftbt]",
+  },
+  {
+    "}", LEFT_DELIM|RIGHT_DELIM, "}", "\\[braceright%s]",
+    "\\[bracerightex]",
+    "\\[bracerighttp]",
+    "\\[bracerightmid]",
+    "\\[bracerightbt]",
+  },
+  {
+    "|", LEFT_DELIM|RIGHT_DELIM, "|", "\\[bar%s]",
+    "\\[barex]",
+    0,
+    0,
+    0,
+  },
+  {
+    "floor", LEFT_DELIM, "\\(lf", "\\[floorleft%s]",
+    "\\[bracketleftex]",
+    0,
+    0,
+    "\\[bracketleftbt]",
+  },
+  {
+    "floor", RIGHT_DELIM, "\\(rf", "\\[floorright%s]",
+    "\\[bracketrightex]",
+    0,
+    0,
+    "\\[bracketrightbt]",
+  },
+  {
+    "ceiling", LEFT_DELIM, "\\(lc", "\\[ceilingleft%s]",
+    "\\[bracketleftex]",
+    "\\[bracketlefttp]",
+    0,
+    0,
+  },
+  {
+    "ceiling", RIGHT_DELIM, "\\(rc", "\\[ceilingright%s]",
+    "\\[bracketrightex]",
+    "\\[bracketrighttp]",
+    0,
+    0,
+  },
+  {
+    "||", LEFT_DELIM|RIGHT_DELIM, "|", "\\[bar%s]",
+    "\\[bardblex]",
+    0,
+    0,
+    0,
+  },
+  {
+    "<", LEFT_DELIM|RIGHT_DELIM, "\\(la", "\\[angleleft%s]",
+    0,
+    0,
+    0,
+    0,
+  },
+  {
+    ">", LEFT_DELIM|RIGHT_DELIM, "\\(ra", "\\[angleright%s]",
+    0,
+    0,
+    0,
+    0,
+  },
+  {
+    "uparrow", LEFT_DELIM|RIGHT_DELIM, "\\(ua", "\\[arrowup%s]",
+    "\\[arrowvertex]",
+    "\\[arrowverttp]",
+    0,
+    0,
+  },
+  {
+    "downarrow", LEFT_DELIM|RIGHT_DELIM, "\\(da", "\\[arrowdown%s]",
+    "\\[arrowvertex]",
+    0,
+    0,
+    "\\[arrowvertbt]",
+  },
+  {
+    "updownarrow", LEFT_DELIM|RIGHT_DELIM, "\\(va", "\\[arrowupdown%s]",
+    "\\[arrowvertex]",
+    "\\[arrowverttp]",
+    0,
+    "\\[arrowvertbt]",
+  },
+};
+
+const int DELIM_TABLE_SIZE = int(sizeof(delim_table)/sizeof(delim_table[0]));
+
+class delim_box : public box {
+private:
+  char *left;
+  char *right;
+  box *p;
+public:
+  delim_box(char *, box *, char *);
+  ~delim_box();
+  int compute_metrics(int);
+  void output();
+  void check_tabs(int);
+  void debug_print();
+};
+
+box *make_delim_box(char *l, box *pp, char *r)
+{
+  if (l != 0 && *l == '\0') {
+    delete[] l;
+    l = 0;
+  }
+  if (r != 0 && *r == '\0') {
+    delete[] r;
+    r = 0;
+  }
+  return new delim_box(l, pp, r);
+}
+
+delim_box::delim_box(char *l, box *pp, char *r)
+: left(l), right(r), p(pp)
+{
+}
+
+delim_box::~delim_box()
+{
+  delete[] left;
+  delete[] right;
+  delete p;
+}
+
+static void build_extensible(const char *ext, const char *top, const char *mid,
+			     const char *bot)
+{
+  assert(ext != 0);
+  printf(".nr " DELIM_WIDTH_REG " 0\\w" DELIMITER_CHAR "%s" DELIMITER_CHAR "\n",
+	 ext);
+  printf(".nr " EXT_HEIGHT_REG " 0\\n[rst]\n");
+  printf(".nr " EXT_DEPTH_REG " 0-\\n[rsb]\n");
+  if (top) {
+    printf(".nr " DELIM_WIDTH_REG " 0\\n[" DELIM_WIDTH_REG "]"
+	   ">?\\w" DELIMITER_CHAR "%s" DELIMITER_CHAR "\n",
+	   top);
+    printf(".nr " TOP_HEIGHT_REG " 0\\n[rst]\n");
+    printf(".nr " TOP_DEPTH_REG " 0-\\n[rsb]\n");
+  }
+  if (mid) {
+    printf(".nr " DELIM_WIDTH_REG " 0\\n[" DELIM_WIDTH_REG "]"
+	   ">?\\w" DELIMITER_CHAR "%s" DELIMITER_CHAR "\n",
+	   mid);
+    printf(".nr " MID_HEIGHT_REG " 0\\n[rst]\n");
+    printf(".nr " MID_DEPTH_REG " 0-\\n[rsb]\n");
+  }
+  if (bot) {
+    printf(".nr " DELIM_WIDTH_REG " 0\\n[" DELIM_WIDTH_REG "]"
+	   ">?\\w" DELIMITER_CHAR "%s" DELIMITER_CHAR "\n",
+	   bot);
+    printf(".nr " BOT_HEIGHT_REG " 0\\n[rst]\n");
+    printf(".nr " BOT_DEPTH_REG " 0-\\n[rsb]\n");
+  }
+  printf(".nr " TOTAL_HEIGHT_REG " 0");
+  if (top)
+    printf("+\\n[" TOP_HEIGHT_REG "]+\\n[" TOP_DEPTH_REG "]");
+  if (bot)
+    printf("+\\n[" BOT_HEIGHT_REG "]+\\n[" BOT_DEPTH_REG "]");
+  if (mid)
+    printf("+\\n[" MID_HEIGHT_REG "]+\\n[" MID_DEPTH_REG "]");
+  printf("\n");
+  // determine how many extensible characters we need
+  printf(".nr " TEMP_REG " \\n[" DELTA_REG "]-\\n[" TOTAL_HEIGHT_REG "]");
+  if (mid)
+    printf("/2");
+  printf(">?0+\\n[" EXT_HEIGHT_REG "]+\\n[" EXT_DEPTH_REG "]-1/(\\n["
+	 EXT_HEIGHT_REG "]+\\n[" EXT_DEPTH_REG "])\n");
+  
+  printf(".nr " TOTAL_HEIGHT_REG " +(\\n[" EXT_HEIGHT_REG "]+\\n["
+	 EXT_DEPTH_REG "]*\\n[" TEMP_REG "]");
+  if (mid)
+    printf("*2");
+  printf(")\n");
+  printf(".ds " DELIM_STRING " \\Z" DELIMITER_CHAR
+	 "\\v'-%dM-(\\n[" TOTAL_HEIGHT_REG "]u/2u)'\n",
+	 axis_height);
+  if (top)
+    printf(".as " DELIM_STRING " \\v'\\n[" TOP_HEIGHT_REG "]u'"
+	   "\\Z" DELIMITER_CHAR "%s" DELIMITER_CHAR
+	   "\\v'\\n[" TOP_DEPTH_REG "]u'\n",
+	   top);
+
+  // this macro appends $2 copies of $3 to string $1
+  printf(".de " REPEAT_APPEND_STRING_MACRO "\n"
+	 ".if \\\\$2 \\{.as \\\\$1 \"\\\\$3\n"
+	 "." REPEAT_APPEND_STRING_MACRO " \\\\$1 \\\\$2-1 \"\\\\$3\"\n"
+	 ".\\}\n"
+	 "..\n");
+
+  printf("." REPEAT_APPEND_STRING_MACRO " " DELIM_STRING " \\n[" TEMP_REG "] "
+	 "\\v'\\n[" EXT_HEIGHT_REG "]u'"
+	 "\\Z" DELIMITER_CHAR "%s" DELIMITER_CHAR 
+	 "\\v'\\n[" EXT_DEPTH_REG "]u'\n",
+	 ext);
+
+  if (mid) {
+    printf(".as " DELIM_STRING " \\v'\\n[" MID_HEIGHT_REG "]u'"
+	   "\\Z" DELIMITER_CHAR "%s" DELIMITER_CHAR
+	   "\\v'\\n[" MID_DEPTH_REG "]u'\n",
+	   mid);
+    printf("." REPEAT_APPEND_STRING_MACRO " " DELIM_STRING 
+	   " \\n[" TEMP_REG "] "
+	   "\\v'\\n[" EXT_HEIGHT_REG "]u'"
+	   "\\Z" DELIMITER_CHAR "%s" DELIMITER_CHAR
+	   "\\v'\\n[" EXT_DEPTH_REG "]u'\n",
+	   ext);
+  }
+  if (bot)
+    printf(".as " DELIM_STRING " \\v'\\n[" BOT_HEIGHT_REG "]u'"
+	   "\\Z" DELIMITER_CHAR "%s" DELIMITER_CHAR
+	   "\\v'\\n[" BOT_DEPTH_REG "]u'\n",
+	   bot);
+  printf(".as " DELIM_STRING " " DELIMITER_CHAR "\n");
+}
+
+static void define_extensible_string(char *delim, int uid,
+				     left_or_right_t left_or_right)
+{
+  printf(".ds " DELIM_STRING "\n");
+  delimiter *d = delim_table;
+  int delim_len = strlen(delim);
+  int i;
+  for (i = 0; i < DELIM_TABLE_SIZE; i++, d++)
+    if (strncmp(delim, d->name, delim_len) == 0 
+	&& (left_or_right & d->flags) != 0)
+      break;
+  if (i >= DELIM_TABLE_SIZE) {
+    error("there is no '%1' delimiter", delim);
+    printf(".nr " DELIM_WIDTH_REG " 0\n");
+    return;
+  }
+
+  printf(".nr " DELIM_WIDTH_REG " 0\\w" DELIMITER_CHAR "\\f[%s]%s\\fP" DELIMITER_CHAR "\n"
+	 ".ds " DELIM_STRING " \\Z" DELIMITER_CHAR
+	   "\\v'\\n[rsb]u+\\n[rst]u/2u-%dM'\\f[%s]%s\\fP" DELIMITER_CHAR "\n"
+	 ".nr " TOTAL_HEIGHT_REG " \\n[rst]-\\n[rsb]\n"
+	 ".if \\n[" TOTAL_HEIGHT_REG "]<\\n[" DELTA_REG "] "
+	 "\\{",
+	 current_roman_font, d->small, axis_height,
+	 current_roman_font, d->small);
+
+  char buf[256];
+// The format string in the sprintf below comes from a struct
+// initializer above, and is not subject to external influence.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wformat-nonliteral"
+  sprintf(buf, d->chain_format, "\\\\n[" INDEX_REG "]");
+#pragma GCC diagnostic pop
+  printf(".nr " INDEX_REG " 0\n"
+	 ".de " TEMP_MACRO "\n"
+	 ".ie c%s \\{\\\n"
+	 ".nr " DELIM_WIDTH_REG " 0\\w" DELIMITER_CHAR "%s" DELIMITER_CHAR "\n"
+	 ".ds " DELIM_STRING " \\Z" DELIMITER_CHAR
+	   "\\v'\\\\n[rsb]u+\\\\n[rst]u/2u-%dM'%s" DELIMITER_CHAR "\n"
+	 ".nr " TOTAL_HEIGHT_REG " \\\\n[rst]-\\\\n[rsb]\n"
+	 ".if \\\\n[" TOTAL_HEIGHT_REG "]<\\n[" DELTA_REG "] "
+	 "\\{.nr " INDEX_REG " +1\n"
+	 "." TEMP_MACRO "\n"
+	 ".\\}\\}\n"
+	 ".el .nr " INDEX_REG " 0-1\n"
+	 "..\n"
+	 "." TEMP_MACRO "\n",
+	 buf, buf, axis_height, buf);
+  if (d->ext) {
+    printf(".if \\n[" INDEX_REG "]<0 \\{.if c%s \\{\\\n", d->ext);
+    build_extensible(d->ext, d->top, d->mid, d->bot);
+    printf(".\\}\\}\n");
+  }
+  printf(".\\}\n");
+  printf(".as " DELIM_STRING " \\h'\\n[" DELIM_WIDTH_REG "]u'\n");
+  printf(".nr " WIDTH_FORMAT " +\\n[" DELIM_WIDTH_REG "]\n", uid);
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]"
+	 ">?(\\n[" TOTAL_HEIGHT_REG "]/2+%dM)\n",
+	 uid, uid, axis_height);
+  printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]"
+	 ">?(\\n[" TOTAL_HEIGHT_REG "]/2-%dM)\n",
+	 uid, uid, axis_height);
+}
+
+int delim_box::compute_metrics(int style)
+{
+  int r = p->compute_metrics(style);
+  printf(".nr " WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]\n", uid, p->uid);
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]\n", uid, p->uid);
+  printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]\n", uid, p->uid);
+  printf(".nr " DELTA_REG " \\n[" HEIGHT_FORMAT "]-%dM"
+	 ">?(\\n[" DEPTH_FORMAT "]+%dM)\n",
+	 p->uid, axis_height, p->uid, axis_height);
+  printf(".nr " DELTA_REG " 0\\n[" DELTA_REG "]*%d/500"
+	 ">?(\\n[" DELTA_REG "]*2-%dM)\n",
+	 delimiter_factor, delimiter_shortfall);
+  if (left) {
+    define_extensible_string(left, uid, LEFT_DELIM);
+    printf(".rn " DELIM_STRING " " LEFT_DELIM_STRING_FORMAT "\n",
+	   uid);
+    if (r)
+      printf(".nr " MARK_REG " +\\n[" DELIM_WIDTH_REG "]\n");
+  }
+  if (right) {
+    define_extensible_string(right, uid, RIGHT_DELIM);
+    printf(".rn " DELIM_STRING " " RIGHT_DELIM_STRING_FORMAT "\n",
+	   uid);
+  }
+  return r;
+}
+
+void delim_box::output()
+{
+  if (output_format == troff) {
+    if (left)
+      printf("\\*[" LEFT_DELIM_STRING_FORMAT "]", uid);
+    p->output();
+    if (right)
+      printf("\\*[" RIGHT_DELIM_STRING_FORMAT "]", uid);
+  }
+  else if (output_format == mathml) {
+    printf("<mrow><mo>%s</mo>", left);
+    p->output();
+    printf("<mo>%s</mo></mrow>", right);
+  }
+}
+
+void delim_box::check_tabs(int level)
+{
+  p->check_tabs(level);
+}
+
+void delim_box::debug_print()
+{
+  fprintf(stderr, "left \"%s\" { ", left ? left : "");
+  p->debug_print();
+  fprintf(stderr, " }");
+  if (right)
+    fprintf(stderr, " right \"%s\"", right);
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/eqn/eqn.1.man b/src/preproc/eqn/eqn.1.man
new file mode 100644
index 0000000..9c3d43c
--- /dev/null
+++ b/src/preproc/eqn/eqn.1.man
@@ -0,0 +1,2240 @@
+'\" et
+.TH @g@eqn @MAN1EXT@ "@MDATE@" "groff @VERSION@"
+.SH Name
+@g@eqn \- format mathematics (equations) for
+.I groff
+or MathML
+.
+.
+.\" ====================================================================
+.\" Legal Terms
+.\" ====================================================================
+.\"
+.\" Copyright (C) 1989-2023 Free Software Foundation, Inc.
+.\"
+.\" Permission is granted to make and distribute verbatim copies of this
+.\" manual provided the copyright notice and this permission notice are
+.\" preserved on all copies.
+.\"
+.\" Permission is granted to copy and distribute modified versions of
+.\" this manual under the conditions for verbatim copying, provided that
+.\" the entire resulting derived work is distributed under the terms of
+.\" a permission notice identical to this one.
+.\"
+.\" Permission is granted to copy and distribute translations of this
+.\" manual into another language, under the above conditions for
+.\" modified versions, except that this permission notice may be
+.\" included in translations approved by the Free Software Foundation
+.\" instead of in the original English.
+.
+.
+.\" Save and disable compatibility mode (for, e.g., Solaris 10/11).
+.do nr *groff_eqn_1_man_C \n[.cp]
+.cp 0
+.
+.\" Define fallback for groff 1.23's MR macro if the system lacks it.
+.nr do-fallback 0
+.if !\n(.f           .nr do-fallback 1 \" mandoc
+.if  \n(.g .if !d MR .nr do-fallback 1 \" older groff
+.if !\n(.g           .nr do-fallback 1 \" non-groff *roff
+.if \n[do-fallback]  \{\
+.  de MR
+.    ie \\n(.$=1 \
+.      I \%\\$1
+.    el \
+.      IR \%\\$1 (\\$2)\\$3
+.  .
+.\}
+.rr do-fallback
+.
+.
+.ie \n(.V<\n(.v \
+.  ds tx T\h'-.1667m'\v'.224m'E\v'-.224m'\h'-.125m'X
+.el \
+.  ds tx TeX
+.
+.
+.\" ====================================================================
+.SH Synopsis
+.\" ====================================================================
+.
+.SY @g@eqn
+.RB [ \-CNrR ]
+.RB [ \- d
+.IR xy ]
+.RB [ \-f
+.IR F ]
+.RB [ \-m
+.IR n ]
+.RB [ \-M
+.IR dir ]
+.RB [ \-p
+.IR n ]
+.RB [ \-s
+.IR n ]
+.RB [ \-T
+.IR dev ]
+.RI [ file\~ .\|.\|.]
+.YS
+.
+.
+.SY @g@eqn
+.B \-\-help
+.YS
+.
+.
+.SY @g@eqn
+.B \-v
+.
+.SY @g@eqn
+.B \-\-version
+.YS
+.
+.
+.\" ====================================================================
+.SH Description
+.\" ====================================================================
+.
+The GNU implementation of
+.I eqn \" GNU
+is part of the
+.MR groff @MAN7EXT@
+document formatting system.
+.
+.I @g@eqn
+is a
+.MR @g@troff @MAN1EXT@
+preprocessor that translates expressions in its own language,
+embedded in
+.MR roff @MAN7EXT@
+input files,
+into mathematical notation typeset by
+.MR @g@troff @MAN1EXT@ .
+.
+It copies each
+.IR file 's
+contents to the standard output stream,
+translating each
+.I equation
+between lines starting with
+.B .EQ
+and
+.BR .EN ,
+or within a pair of user-specified delimiters.
+.
+Normally,
+.I @g@eqn
+is not executed directly by the user,
+but invoked by specifying the
+.B \-e
+option to
+.MR groff @MAN1EXT@ .
+.
+While GNU
+.IR eqn 's \" GNU
+input syntax is highly compatible with AT&T
+.IR eqn , \" AT&T
+the output
+.I @g@eqn
+produces cannot be processed by AT&T
+.IR troff ; \" AT&T
+GNU
+.I troff \" GNU
+(or a
+.I troff \" generic
+implementing relevant GNU extensions)
+must be used.
+.
+If no
+.I file
+operands are given on the command line,
+or if
+.I file
+is
+.RB \[lq] \- \[rq],
+.I @g@eqn
+reads the standard input stream.
+.
+.
+.P
+Unless the
+.B \-R
+option is used,
+.I @g@eqn
+searches for the file
+.I eqnrc
+in the directories given with the
+.B \-M
+option first,
+then in
+.if !'@COMPATIBILITY_WRAPPERS@'no' .IR @SYSTEMMACRODIR@ ,
+.IR @LOCALMACRODIR@ ,
+and finally in the standard macro directory
+.IR @MACRODIR@ .
+.
+If it exists and is readable,
+.I @g@eqn
+processes it before any input files.
+.
+.
+.P
+This man page primarily discusses the differences between GNU
+.I eqn \" GNU
+and AT&T
+.IR eqn .\" AT&T
+.
+Most of the new features of the GNU
+.I eqn \" GNU
+input language are based on \*[tx].
+.
+There are some references to the differences between \*[tx] and GNU
+.I eqn \" GNU
+below;
+these may safely be ignored if you do not know \*[tx].
+.
+.
+.P
+Three points are worth special note. \" good, bad, and different
+.
+.
+.IP \[bu] 2n
+GNU
+.I eqn \" GNU
+emits Presentation MathML output when invoked with the
+.RB \[lq] "\-T\~MathML" \[rq]
+option.
+.
+.
+.IP \[bu]
+GNU
+.I eqn \" GNU
+does not support terminal devices well,
+though it may suffice for simple inputs.
+.
+.
+.IP \[bu]
+GNU
+.I eqn
+sets the input token
+.RB \[lq] .\|.\|.\& \[rq]
+as an ellipsis on the text baseline,
+not the three centered dots of AT&T
+.IR eqn . \" AT&T
+.
+Set an ellipsis on the math axis with the GNU extension macro
+.BR cdots .
+.
+.
+.\" ====================================================================
+.SS "Anatomy of an equation"
+.\" ====================================================================
+.
+.I eqn
+input consists of tokens.
+.
+Consider a form of Newton's second law of motion.
+.
+The input
+.
+.
+.P
+.RS
+.EX
+\&.EQ
+F =
+m a
+\&.EN
+.EE
+.RE
+.
+.
+.P
+becomes
+.EQ
+F =
+m a.
+.EN
+.
+Each of
+.BR F ,
+.BR = ,
+.BR m ,
+and
+.B a
+is a token.
+.
+.
+Spaces and newlines are interchangeable;
+they separate tokens but do not break lines or produce space in
+the output.
+.
+.
+.P
+The following input characters not only separate tokens,
+but manage their grouping and spacing as well.
+.
+.
+.TP
+.B "{ }"
+Braces perform grouping.
+.
+Whereas
+.RB \[lq] "e sup a b" \[rq]
+expresses
+.ie n .RI \[lq]( e "\~to the\~" a )\~times\~ b \[rq],
+.el \{\
+.EQ
+e sup a b ,
+.EN
+.\}
+.RB \[lq] "e sup { a b }" \[rq]
+means
+.ie n .RI \[lq] e "\~to the\~(" a \~times\~ b )\[rq].
+.el \{\
+.EQ
+e sup { a b } .
+.EN
+.\}
+.
+When immediately preceded by a
+.RB \[lq] left \[rq]
+or
+.RB \[lq] right \[rq]
+primitive,
+a brace loses its special meaning.
+.
+.
+.TP
+.B "\[ha] \[ti]
+are the
+.I "half space"
+and
+.I "full space,"
+respectively.
+.
+Use them to tune the appearance of the output.
+.
+.
+.P
+Tab and leader characters separate tokens as well as advancing the
+drawing position to the next tab stop,
+but are seldom used in
+.I eqn
+input.
+.
+When they occur,
+they must appear at the outermost lexical scope.
+.
+This roughly means that they can't appear within braces that are
+necessary to disambiguate the input;
+.I @g@eqn
+will diagnose an error in this event.
+.
+(See subsection \[lq]Macros\[rq] below for additional token separation
+rules.)
+.
+.
+.P
+Other tokens are primitives,
+macros,
+an argument to either of the foregoing,
+or components of an equation.
+.
+.
+.br
+.ne 4v
+.P
+.I Primitives
+are fundamental keywords of the
+.I eqn
+language.
+.
+They can configure an aspect of the preprocessor's state,
+as when setting a \[lq]global\[rq] font selection or type size
+.RB ( gfont
+and
+.BR gsize ),
+or declaring or deleting macros
+.RB \%(\[lq] define \[rq]
+and
+.BR undef );
+these are termed
+.I commands.
+.
+Other primitives perform formatting operations on the tokens after them
+(as with
+.BR fat ,
+.BR over ,
+.BR sqrt ,
+or
+.BR up ).
+.
+.
+.P
+Equation
+.I components
+include mathematical variables,
+constants,
+numeric literals,
+and operators.
+.
+.I @g@eqn
+remaps some input character sequences to
+.I groff
+special character escape sequences for economy in equation entry and to
+ensure that glyphs from an unstyled font are used;
+see
+.MR groff_char @MAN7EXT@ .
+.
+.
+.P
+.RS
+.TS
+tab(@);
+Lf(CR) Lf(CR) Lw(1i) Lf(CR) Lf(CR).
++@\[rs][pl]@\&@\[aq]@\[rs][fm]
+-@\[rs][mi]@\&@<=@\[rs][<=]
+\&=@\[rs][eq]@\&@>=@\[rs][>=]
+.TE
+.RE
+.
+.
+.P
+.I Macros
+permit primitives,
+components,
+and other macros to be collected and referred to by a single token.
+.
+Predefined macros make convenient the preparation of
+.I eqn
+input in a form resembling its spoken expression;
+for example,
+consider
+.BR cos ,
+.BR hat ,
+.BR inf ,
+and
+.BR lim .
+.
+.
+.\" ====================================================================
+.SS "Spacing and typeface"
+.\" ====================================================================
+.
+GNU
+.I eqn
+imputes types to the components of an equation,
+adjusting the spacing between them accordingly.
+.
+Recognized types are as follows;
+most affect spacing only,
+whereas the
+.RB \%\[lq] letter \[rq]
+subtype of
+.RB \%\[lq] ordinary \[rq]
+also assigns a style.
+.
+.
+.RS 2n \" we need quite a bit of horizontal space for this table
+.P
+.TS
+Lf(CR) Lx
+Af(CR) Lx
+Af(CR) Lx
+Lf(CR) Lx.
+ordinary	T{
+character such as \[lq]1\[rq],
+\[lq]a\[rq],
+or
+\[lq]!\&\[rq]
+T}
+letter	character to be italicized by default
+digit	\f[I]n/a\f[]
+operator	T{
+large operator such as
+.ds Su \[lq]\s+5\[*S]\s0\[rq]
+.if \n(.g .if !c\[*S] .ds Su the summation operator
+\*[Su]
+.rm Su
+T}
+binary	binary operator such as \[lq]\[pl]\[rq]
+relation	relational operator such as \[lq]=\[rq]
+opening	opening bracket such as \[lq](\[rq]
+closing	closing bracket such as \[lq])\[rq]
+punctuation	punctuation character such as \[lq],\[rq]
+inner	sub-formula contained within brackets
+suppress	component to which automatic spacing is not applied
+.TE
+.RE
+.
+.
+.P
+Two primitives apply types to equation components.
+.
+.
+.TP
+.BI type\~ "t e"
+Apply
+.RI type\~ t
+to
+.RI expression\~ e .
+.
+.
+.TP
+.BI chartype\~ "t text"
+Assign each character in (unquoted)
+.I text
+.RI type\~ t ,
+persistently.
+.
+.
+.P
+.I @g@eqn \" GNU
+sets up spacings and styles as if by the following commands.
+.
+.P
+.RS
+.TS
+tab(@);
+Lf(CR)1 Lf(CR).
+chartype \[dq]letter\[dq]@abcdefghiklmnopqrstuvwxyz
+chartype \[dq]letter\[dq]@ABCDEFGHIKLMNOPQRSTUVWXYZ
+chartype \[dq]letter\[dq]@\[rs][*a]\[rs][*b]\[rs][*g]\[rs][*d]\[rs][*e]\
+\[rs][*z]
+chartype \[dq]letter\[dq]@\[rs][*y]\[rs][*h]\[rs][*i]\[rs][*k]\[rs][*l]\
+\[rs][*m]
+chartype \[dq]letter\[dq]@\[rs][*n]\[rs][*c]\[rs][*o]\[rs][*p]\[rs][*r]\
+\[rs][*s]
+chartype \[dq]letter\[dq]@\[rs][*t]\[rs][*u]\[rs][*f]\[rs][*x]\[rs][*q]\
+\[rs][*w]
+chartype \[dq]binary\[dq]@*\[rs][pl]\[rs][mi]
+chartype \[dq]relation\[dq]@<>\[rs][eq]\[rs][<=]\[rs][>=]
+chartype \[dq]opening\[dq]@{([
+chartype \[dq]closing\[dq]@})]
+chartype \[dq]punctuation\[dq]@,;:.
+chartype \[dq]suppress\[dq]@\[ha]\[ti]
+.TE
+.RE
+.
+.
+.P
+.I @g@eqn
+assigns all other ordinary and special
+.I roff
+characters,
+including numerals 0\[en]9,
+the
+.RB \%\[lq] ordinary \[rq]
+type.
+.
+(The
+.RB \[lq] digit \[rq]
+type is not used,
+but is available for customization.)
+.\" XXX: How would you actually customize it, though?  There doesn't
+.\" seem to be a means of replacing the font associated with a type.
+.\" Is the "digit" type just cruft?
+.
+In keeping with common practice in mathematical typesetting,
+lowercase,
+but not uppercase,
+Greek letters are assigned the
+.RB \%\[lq] letter \[rq]
+type to style them in italics.
+.
+The macros for producing ellipses,
+.RB \[lq] .\|.\|. \[rq],
+.BR cdots ,
+and
+.BR ldots ,
+use the
+.RB \%\[lq] inner \[rq]
+type.
+.
+.
+.\" ====================================================================
+.SS Primitives
+.\" ====================================================================
+.
+.I @g@eqn
+supports without alteration the AT&T
+.I eqn \" AT&T
+primitives
+.BR above ,
+.BR back ,
+.BR bar ,
+.BR bold ,
+.BR \%define ,
+.BR down ,
+.BR fat ,
+.BR font ,
+.BR from ,
+.BR fwd ,
+.BR gfont ,
+.BR gsize ,
+.BR italic ,
+.BR left ,
+.BR lineup ,
+.BR mark ,
+.BR \%matrix ,
+.BR \%ndefine ,
+.BR over ,
+.BR right ,
+.BR roman ,
+.BR size ,
+.BR sqrt ,
+.BR sub ,
+.BR sup ,
+.BR \%tdefine ,
+.BR to ,
+.BR \%under ,
+and
+.BR up .
+.
+.
+.\" ====================================================================
+.SS "New primitives"
+.\" ====================================================================
+.
+The GNU extension primitives
+.RB \[lq] type \[rq]
+and
+.B \%chartype
+are discussed in subsection \[lq]Spacing and typeface\[rq] above;
+.RB \[lq] set \[rq]
+in subsection \[lq]Customization\[rq] below;
+and
+.B grfont
+and
+.B gbfont
+in subsection \[lq]Fonts\[rq] below.
+.
+In the following synopses,
+.I X
+can be any character not appearing in the parameter thus bracketed.
+.
+.
+.TP
+.IB e1 \~accent\~ e2
+Set
+.I e2
+as an accent over
+.IR e1 .
+.
+.I e2
+is assumed to be at the appropriate height for a lowercase letter
+without an ascender;
+.I @g@ eqn
+vertically shifts it depending on
+.IR e1 's
+height.
+.
+For example,
+.B hat
+is defined as follows.
+.
+.
+.RS
+.IP
+.EX
+accent { "\[ha]" }
+.EE
+.RE
+.
+.
+.IP
+.BR dotdot ,
+.BR dot ,
+.BR tilde ,
+.BR vec ,
+and
+.B dyad
+are also defined using the
+.B \%accent
+primitive.
+.
+.
+.TP
+.BI big\~ e
+Enlarge the expression
+.IR e ;
+semantics like those of CSS \[lq]large\[rq] are intended.
+.
+In
+.I @g@troff
+output,
+the type size is increased by\~5 scaled points.
+.
+MathML output emits the following.
+.
+.
+.RS
+.IP
+.EX
+<mstyle \%mathsize=\[aq]big\[aq]>
+.EE
+.RE
+.
+.
+.TP
+.BI copy\~ file
+.TQ
+.BI include\~ file
+Interpolate the contents of
+.IR file ,
+omitting lines
+beginning with
+.B .EQ
+or
+.BR .EN .
+.
+If a relative path name,
+.I file
+is sought relative to the current working directory.
+.
+.
+.TP
+.BI ifdef\~ "name X anything X"
+If
+.I name
+is defined as a primitive or macro,
+interpret
+.IR anything .
+.
+.
+.TP
+.BI nosplit\~ text
+As
+.RI \[dq] text \[dq],
+but since
+.I text
+is not quoted it is subject to macro expansion;
+it is not split up and the spacing between characters not adjusted per
+subsection \[lq]Spacing and typeface\[rq] above.
+.
+.
+.TP
+.IB e\~ opprime
+As
+.BR prime ,
+but set the prime symbol as an operator
+.RI on\~ e .
+.
+In the input
+.RB \[lq] "A opprime sub 1" \[rq],
+the\~\[lq]1\[rq] is tucked under the prime as a subscript to
+the\~\[lq]A\[rq]
+(as is conventional in mathematical typesetting),
+whereas when
+.B prime
+is used,
+the\~\[lq]1\[rq] is a subscript to the prime character.
+.
+The precedence of
+.B \%opprime
+is the same as that of
+.B bar
+and
+.RB \%\[lq] under \[rq],
+and higher than that of other primitives except
+.B \%accent
+and
+.BR uaccent .
+.
+In unquoted text,
+a neutral apostrophe
+.RB ( \[aq] )
+that is not the first character on the input line is treated like
+.BR \%opprime .
+.
+.
+.TP
+.BI sdefine\~ "name X anything X"
+As
+.RB \%\[lq] define \[rq],
+but
+.I name
+is not recognized as a macro if called with arguments.
+.
+.
+.TP
+.IB e1 \~smallover\~ e2
+As
+.BR over ,
+but reduces the type size of
+.I e1
+and
+.IR e2 ,
+and puts less vertical space between
+.I e1
+and
+.I e2
+and the fraction bar.
+.
+The
+.B over
+primitive corresponds to the \*[tx]
+.B \[rs]over
+primitive in displayed equation styles;
+.B smallover
+corresponds to
+.B \[rs]over
+in non-display (\[lq]inline\[rq]) styles.
+.
+.
+.br
+.ne 5v
+.TP
+.BI space\~ n
+Set extra vertical spacing around the equation,
+replacing the default values,
+where
+.IR n \~is
+an integer in hundredths of an em.
+.
+If positive,
+.IR n \~increases
+vertical spacing before the equation;
+if negative,
+it does so after the equation.
+.
+This primitive provides an interface to
+.IR groff 's
+.B \[rs]x
+escape sequence,
+but with the opposite sign convention.
+.
+It has no effect if the equation is part of a
+.MR @g@pic @MAN1EXT@
+picture.
+.
+.
+.TP
+.BI special\~ "troff-macro e"
+Construct an object by calling
+.I troff-macro
+.RI on\~ e .
+.
+The
+.I troff \" generic
+string
+.B 0s
+contains the
+.I eqn \" generic
+output
+.RI for\~ e ,
+and the registers
+.BR 0w ,
+.BR 0h ,
+.BR 0d ,
+.BR 0skern ,
+and
+.B 0skew
+the width,
+height,
+depth,
+subscript kern,
+and skew
+.RI of\~ e ,
+respectively.
+.
+(The
+.I subscript kern
+of an object indicates how much a subscript on that object should be
+\[lq]tucked in\[rq],
+or placed to the left relative to a non-subscripted glyph of the same
+size.
+.
+The
+.I skew
+of an object is how far to the right of the center of the object an
+accent over it should be placed.)
+.
+The macro must modify
+.B 0s
+so that it outputs the desired result,
+returns the drawing position to the text baseline at the beginning of
+.IR e ,
+and updates the foregoing registers to correspond to the new dimensions
+of the result.
+.
+.
+.IP
+Suppose you want a construct that \[lq]cancels\[rq] an expression by
+drawing a diagonal line through it.
+.
+.
+.br
+.ne 11v
+.RS
+.IP
+.EX
+\&.de Ca
+\&.  ds 0s \[rs]
+\[rs]Z\[aq]\[rs]\[rs]*(0s\[aq]\[rs]
+\[rs]v\[aq]\[rs]\[rs]n(0du\[aq]\[rs]
+\[rs]D\[aq]l \[rs]\[rs]n(0wu \-\[rs]\[rs]n(0hu\-\[rs]\
+\[rs]n(0du\[aq]\[rs]
+\[rs]v\[aq]\[rs]\[rs]n(0hu\[aq]
+\&..
+\&.EQ
+special Ca "x \[rs][mi] 3 \[rs][pl] x" \[ti] 3
+\&.EN
+.EE
+.RE
+.
+.
+.IP
+We use the
+.B \[rs][mi]
+and
+.B \[rs][pl]
+special characters instead of + and \-
+because they are part of the argument to a
+.I @g@troff
+macro,
+so
+.I @g@eqn
+does not transform them to mathematical glyphs for us.
+.
+Here's a more complicated construct that draws a box around an
+expression;
+the bottom of the box rests on the text baseline.
+.
+We define the
+.I eqn \" generic
+macro
+.B box
+to wrap the call of the
+.I @g@troff
+macro
+.BR Bx .
+.
+.
+.br
+.ne 17v
+.RS
+.IP
+.EX
+\&.de Bx
+\&.ds 0s \[rs]
+\[rs]Z\[aq]\[rs]\[rs]h\[aq]1n\[aq]\[rs]\[rs]*[0s]\[aq]\[rs]
+\[rs]v\[aq]\[rs]\[rs]n(0du+1n\[aq]\[rs]
+\[rs]D\[aq]l \[rs]\[rs]n(0wu+2n 0\[aq]\[rs]
+\[rs]D\[aq]l 0 \-\[rs]\[rs]n(0hu\-\[rs]\[rs]n(0du\-2n\[aq]\[rs]
+\[rs]D\[aq]l \-\[rs]\[rs]n(0wu\-2n 0\[aq]\[rs]
+\[rs]D\[aq]l 0 \[rs]\[rs]n(0hu+\[rs]\[rs]n(0du+2n\[aq]\[rs]
+\[rs]h\[aq]\[rs]\[rs]n(0wu+2n\[aq]
+\&.nr 0w +2n
+\&.nr 0d +1n
+\&.nr 0h +1n
+\&..
+\&.EQ
+define box \[aq] special Bx $1 \[aq]
+box(foo) \[ti] "bar"
+\&.EN
+.EE
+.RE
+.
+.
+.TP
+.BI "split \[dq]" text \[dq]
+As
+.IR text ,
+but since
+.I text
+is quoted,
+it is not subject to macro expansion;
+it is split up and the spacing between characters adjusted per
+subsection \[lq]Spacing and typeface\[rq] above.
+.
+.
+.TP
+.IB e1 \~uaccent\~ e2
+Set
+.I e2
+as an accent under
+.IR e1 .
+.
+.I e2
+is assumed to be at the appropriate height for a letter without a
+descender;
+.I @g@ eqn
+vertically shifts it depending on whether
+.I e1
+has a descender.
+.
+.B utilde
+is predefined using
+.B uaccent
+as a tilde accent below the baseline.
+.
+.
+.TP
+.BI undef\~ name
+Remove definition of macro or primitive
+.IR name ,
+making it undefined.
+.
+.
+.TP
+.BI vcenter\~ e
+Vertically center
+.I e
+about the
+.IR "math axis" ,
+a horizontal line upon which fraction bars and characters such as
+\[lq]\[pl]\[rq] and \[lq]\[mi]\[rq] are aligned.
+.
+MathML already behaves this way,
+so
+.I @g@eqn
+ignores this primitive when producing that output format.
+.
+The built-in
+.B sum
+macro is defined as if by the following.
+.
+.RS
+.IP
+.EX
+define sum ! { type "operator" vcenter size +5 \[rs](*S } !
+.EE
+.RE
+.
+.
+.br
+.ne 8v
+.\" ====================================================================
+.SS "Extended primitives"
+.\" ====================================================================
+.
+GNU
+.I eqn \" GNU
+extends the syntax of some AT&T
+.I eqn \" AT&T
+primitives,
+introducing one deliberate incompatibility.
+.
+.
+.TP
+.B "delim on"
+.I @g@eqn
+recognizes an
+.RB \[lq] on \[rq]
+argument to the
+.B \%delim
+primitive specially,
+restoring any delimiters previously disabled with
+.RB \%\[lq] "delim off" \[rq].
+.
+If delimiters haven't been specified,
+neither command has effect.
+.
+Few
+.I eqn \" generic
+documents are expected to use \[lq]o\[rq] and \[lq]n\[rq] as left and
+right delimiters,
+respectively.
+.
+If yours does,
+consider swapping them,
+or select others.
+.
+.
+.TP
+.BI col\~ n\~\c
+.BR {\~ .\|.\|.\& \~}
+.TQ
+.BI ccol\~ n\~\c
+.BR {\~ .\|.\|.\& \~}
+.TQ
+.BI lcol\~ n\~\c
+.BR {\~ .\|.\|.\& \~}
+.TQ
+.BI rcol\~ n\~\c
+.BR {\~ .\|.\|.\& \~}
+.TQ
+.BI pile\~ n\~\c
+.BR {\~ .\|.\|.\& \~}
+.TQ
+.BI cpile\~ n\~\c
+.BR {\~ .\|.\|.\& \~}
+.TQ
+.BI lpile\~ n\~\c
+.BR {\~ .\|.\|.\& \~}
+.TQ
+.BI rpile\~ n\~\c
+.BR {\~ .\|.\|.\& \~}
+The integer
+.RI value\~ n
+(in hundredths of an em)
+increases the vertical spacing between rows,
+using
+.IR groff 's
+.B \[rs]x
+escape sequence
+(the value has no effect in MathML mode).
+.
+Negative values are accepted but have no effect.
+.
+If more than one
+.I n
+occurs in a matrix or pile,
+the largest is used.
+.
+.
+.\" ====================================================================
+.SS Customization
+.\" ====================================================================
+.
+When
+.I @g@eqn
+generates
+.I @g@troff
+input,
+the appearance of equations is controlled by a large number of
+parameters.
+.
+They have no effect when generating MathML,
+which delegates typesetting to a MathML rendering engine.
+.
+Configure these parameters with the
+.B set
+primitive.
+.
+.
+.TP
+.BI set\~ "p n"
+assigns
+.RI parameter\~ p
+the integer
+.RI value\~ n ;
+.IR n \~is
+interpreted in units of hundredths of an em unless otherwise stated.
+.
+For example,
+.
+.
+.RS
+.IP
+.EX
+set x_height 45
+.EE
+.RE
+.
+.
+.IP
+says that
+.I @g@eqn
+should assume that the font's x-height is 0.45\~ems.
+.
+.
+.RS
+.P
+Available parameters are as follows;
+defaults are shown in parentheses.
+.
+We intend these descriptions to be expository rather than rigorous.
+.
+.
+.TP 17n
+.B minimum_size
+sets a floor for the type size
+(in scaled points)
+at which equations are set
+.RB ( 5 ).
+.
+.
+.TP
+.B fat_offset
+The
+.B fat
+primitive emboldens an equation by overprinting two copies of the
+equation horizontally offset by this amount
+.RB ( 4 ).
+.
+In MathML mode,
+components to which
+.B \%fat_offset
+applies instead use the following.
+.
+.RS
+.RS
+.EX
+<mstyle mathvariant=\[aq]double\-struck\[aq]>
+.EE
+.RE
+.RE
+.
+.
+.TP
+.B over_hang
+A fraction bar is longer by twice this amount than
+the maximum of the widths of the numerator and denominator;
+in other words,
+it overhangs the numerator and denominator by at least this amount
+.RB ( 0 ).
+.
+.
+.TP
+.B accent_width
+When
+.B bar
+or
+.B \%under
+is applied to a single character,
+the line is this long
+.RB ( 31 ).
+.
+Normally,
+.B bar
+or
+.B \%under
+produces a line whose length is the width of the object to which it
+applies;
+in the case of a single character,
+this tends to produce a line that looks too long.
+.
+.
+.TP
+.B delimiter_factor
+Extensible delimiters produced with the
+.B left
+and
+.B right
+primitives have a combined height and depth of at least this many
+thousandths of twice the maximum amount by which the sub-equation that
+the delimiters enclose extends away from the axis
+.RB ( 900 ).
+.
+.
+.TP
+.B delimiter_shortfall
+Extensible delimiters produced with the
+.B left
+and
+.B right
+primitives have a combined height and depth not less than the
+difference of twice the maximum amount by which the sub-equation that
+the delimiters enclose extends away from the axis and this amount
+.RB ( 50 ).
+.
+.
+.TP
+.B null_delimiter_space
+This much horizontal space is inserted on each side of a fraction
+.RB ( 12 ).
+.
+.
+.TP
+.B script_space
+The width of subscripts and superscripts is increased by this amount
+.RB ( 5 ).
+.
+.
+.TP
+.B thin_space
+This amount of space is automatically inserted after punctuation
+characters.
+.
+It also configures the width of the space produced by the
+.B \[ha]
+token
+.RB ( 17 ).
+.
+.
+.TP
+.B medium_space
+This amount of space is automatically inserted on either side of
+binary operators
+.RB ( 22 ).
+.
+.
+.TP
+.B thick_space
+This amount of space is automatically inserted on either side of
+relations.
+.
+It also configures the width of the space produced by the
+.B \[ti]
+token
+.RB ( 28 ).
+.
+.
+.TP
+.B x_height
+The height of lowercase letters without ascenders such as \[lq]x\[rq]
+.RB ( 45 ).
+.
+.
+.TP
+.B axis_height
+The height above the baseline of the center of characters such as
+\[lq]\[pl]\[rq] and \[lq]\[mi]\[rq]
+.RB ( 26 ).
+.
+It is important that this value is correct for the font
+you are using.
+.
+.
+.TP
+.B default_rule_thickness
+This should be set to the thickness of the
+.B \[rs][ru]
+character,
+or the thickness of horizontal lines produced with the
+.B \[rs]D
+escape sequence
+.RB ( 4 ).
+.
+.
+.TP
+.B num1
+The
+.B over
+primitive shifts up the numerator by at least this amount
+.RB ( 70 ).
+.
+.
+.TP
+.B num2
+The
+.B smallover
+primitive shifts up the numerator by at least this amount
+.RB ( 36 ).
+.
+.
+.TP
+.B denom1
+The
+.B over
+primitive shifts down the denominator by at least this amount
+.RB ( 70 ).
+.
+.
+.TP
+.B denom2
+The
+.B smallover
+primitive shifts down the denominator by at least this amount
+.RB ( 36 ).
+.
+.
+.TP
+.B sup1
+Normally superscripts are shifted up by at least this amount
+.RB ( 42 ).
+.
+.
+.TP
+.B sup2
+Superscripts within superscripts or upper limits
+or numerators of
+.B smallover
+fractions are shifted up by at least this amount
+.RB ( 37 ).
+.
+Conventionally,
+this is less than
+.BR sup1 .
+.
+.
+.TP
+.B sup3
+Superscripts within denominators or square roots
+or subscripts or lower limits are shifted up by at least
+this amount
+.RB ( 28 ).
+.
+Conventionally,
+this is less than
+.BR sup2 .
+.
+.
+.TP
+.B sub1
+Subscripts are normally shifted down by at least this amount
+.RB ( 20 ).
+.
+.
+.TP
+.B sub2
+When there is both a subscript and a superscript,
+the subscript is shifted down by at least this amount
+.RB ( 23 ).
+.
+.
+.TP
+.B sup_drop
+The baseline of a superscript is no more than this much below the top of
+the object on which the superscript is set
+.RB ( 38 ).
+.
+.
+.TP
+.B sub_drop
+The baseline of a subscript is at least this much below the bottom of
+the object on which the subscript is set
+.RB ( 5 ).
+.
+.
+.TP
+.B big_op_spacing1
+The baseline of an upper limit is at least this much above the top of
+the object on which the limit is set
+.RB ( 11 ).
+.
+.
+.TP
+.B big_op_spacing2
+The baseline of a lower limit is at least this much below the bottom
+of the object on which the limit is set
+.RB ( 17 ).
+.
+.
+.TP
+.B big_op_spacing3
+The bottom of an upper limit is at least this much above the top of
+the object on which the limit is set
+.RB ( 20 ).
+.
+.
+.TP
+.B big_op_spacing4
+The top of a lower limit is at least this much below the bottom of the
+object on which the limit is set
+.RB ( 60 ).
+.
+.
+.TP
+.B big_op_spacing5
+This much vertical space is added above and below limits
+.RB ( 10 ).
+.
+.
+.TP
+.B baseline_sep
+The baselines of the rows in a pile or matrix are normally this far
+apart
+.RB ( 140 ).
+.
+Usually equal to the sum of
+.B num1
+and
+.BR denom1 .
+.
+.
+.TP
+.B shift_down
+The midpoint between the top baseline and the bottom baseline in a
+matrix or pile is shifted down by this much from the axis
+.RB ( 26 ).
+.
+Usually equal to
+.BR axis_height .
+.
+.
+.TP
+.B column_sep
+This much space is added between columns in a matrix
+.RB ( 100 ).
+.
+.
+.TP
+.B matrix_side_sep
+This much space is added at each side of a matrix
+.RB ( 17 ).
+.
+.
+.br
+.ne 4v
+.TP
+.B draw_lines
+If non-zero,
+.I @g@eqn
+draws lines using the
+.I troff \" generic
+.B \[rs]D
+escape sequence,
+rather than the
+.B \[rs]l
+escape sequence and the
+.B \[rs][ru]
+special character.
+.
+The
+.I eqnrc
+file sets the default:
+.BR 1 \~on
+.BR ps ,
+.BR html ,
+and the X11 devices,
+.RB otherwise\~ 0 .
+.
+.
+.TP
+.B body_height
+is the presumed height of an equation above the text baseline;
+.I @g@eqn
+adds any excess as extra pre-vertical line spacing with
+.IR troff 's\" generic
+.B \[rs]x
+escape sequence
+.RB ( 85 ).
+.
+.
+.TP
+.B body_depth
+is the presumed depth of an equation below the text baseline;
+.I @g@eqn
+adds any excess as extra post-vertical line spacing with
+.IR troff 's\" generic
+.B \[rs]x
+escape sequence
+.RB ( 35 ).
+.
+.
+.TP
+.B nroff
+If non-zero,
+then
+.B \%ndefine
+behaves like
+.B \%define
+and
+.B \%tdefine
+is ignored,
+otherwise
+.B \%tdefine
+behaves like
+.B \%define
+and
+.B \%ndefine
+is ignored.
+.
+The
+.I eqnrc
+file sets the default:
+.BR 1 \~on
+.BR ascii ,
+.BR latin1 ,
+.BR utf8 ,
+and
+.B cp1047
+devices,
+.RB otherwise\~ 0 .
+.RE
+.
+.
+.\" ====================================================================
+.SS Macros
+.\" ====================================================================
+.
+In GNU
+.IR eqn , \" GNU
+macros can take arguments.
+.
+A word defined by any of the
+.BR \%define ,
+.BR \%ndefine ,
+or
+.B \%tdefine
+primitives followed immediately by a left parenthesis is treated as a
+.I "parameterized macro call:"
+subsequent tokens up to a matching right parenthesis are treated as
+comma-separated arguments.
+.
+In this context only,
+commas and parentheses also serve as token separators.
+.
+A macro argument is not terminated by a comma inside parentheses nested
+within it.
+.
+In a macro definition,
+.BI $ n\c
+,
+where
+.I n
+is between 1 and\~9 inclusive,
+is replaced by the
+.IR n th
+argument;
+if there are fewer than
+.IR n \~arguments,
+it is replaced by nothing.
+.
+.
+.\" ====================================================================
+.SS "Predefined macros"
+.\" ====================================================================
+.
+GNU
+.I eqn \" GNU
+supports the predefined macros offered by AT&T
+.IR eqn : \" AT&T
+.BR and ,
+.BR \%approx ,
+.BR arc ,
+.BR cos ,
+.BR cosh ,
+.BR del ,
+.BR det ,
+.BR dot ,
+.BR \%dotdot ,
+.BR dyad ,
+.BR exp ,
+.BR for ,
+.BR grad ,
+.BR half ,
+.BR hat ,
+.BR if ,
+.BR \%inter ,
+.BR Im ,
+.BR inf ,
+.BR int ,
+.BR lim ,
+.BR ln ,
+.BR log ,
+.BR max ,
+.BR min ,
+.BR \%nothing ,
+.BR \%partial ,
+.BR prime ,
+.BR prod ,
+.BR Re ,
+.BR sin ,
+.BR sinh ,
+.BR sum ,
+.BR tan ,
+.BR tanh ,
+.BR tilde ,
+.BR times ,
+.BR union ,
+.BR vec ,
+.BR == ,
+.BR != ,
+.BR += ,
+.BR \-> ,
+.BR <\- ,
+.BR << ,
+.BR >> ,
+and
+.RB \[lq] .\|.\|. \[rq].
+.
+The lowercase classical Greek letters are available as
+.BR \%alpha ,
+.BR beta ,
+.BR chi ,
+.BR delta ,
+.BR \%epsilon ,
+.BR eta ,
+.BR gamma ,
+.BR iota ,
+.BR kappa ,
+.BR lambda ,
+.BR mu ,
+.BR nu ,
+.BR omega ,
+.BR \%omicron ,
+.BR phi ,
+.BR pi ,
+.BR psi ,
+.BR rho ,
+.BR sigma ,
+.BR tau ,
+.BR theta ,
+.BR \%upsilon ,
+.BR xi ,
+and
+.BR zeta .
+.
+Spell them with an initial capital letter
+.RB \%( Alpha )
+or in full capitals
+.RB \%( ALPHA )
+to obtain uppercase forms.
+.
+.
+.P
+GNU
+.I eqn \" GNU
+further defines the macros
+.BR cdot ,
+.BR cdots ,
+and
+.B utilde
+(all discussed above),
+.BR \%dollar ,
+which sets a dollar sign,
+and
+.BR ldots ,
+which sets an ellipsis on the text baseline.
+.
+.
+.\" ====================================================================
+.SS Fonts
+.\" ====================================================================
+.
+.I @g@eqn
+uses up to three typefaces to set an equation:
+italic (oblique),
+roman (upright),
+and bold.
+.
+Assign each a
+.I groff
+typeface with the primitives
+.BR gfont ,
+.BR \%grfont ,
+and
+.B \%gbfont.
+.
+The defaults are the styles
+.BR I ,
+.BR R ,
+and
+.B B
+(applied to the current font family).
+.
+The
+.B \%chartype
+primitive
+(see above)
+sets a character's type,
+which determines the face used to set it.
+.
+The
+.RB \%\[lq] letter \[rq]
+type is set in italics;
+others are set in roman.
+.
+Use the
+.B bold
+primitive to select an (upright) bold style.
+.
+.
+.TP
+.BI gbfont\~ f
+.RI Select\~ f
+as the bold font.
+.
+This is a GNU extension.
+.
+.
+.TP
+.BI gfont\~ f
+.RI Select\~ f
+as the italic font.
+.
+.
+.TP
+.BI grfont\~ f
+.RI Select\~ f
+as the roman font.
+.
+This is a GNU extension.
+.
+.
+.br
+.ne 4v
+.\" ====================================================================
+.SH Options
+.\" ====================================================================
+.
+.B \-\-help
+displays a usage message,
+while
+.B \-v
+and
+.B \-\-version
+show version information;
+all exit afterward.
+.
+.
+.TP
+.B \-C
+Recognize
+.B .EQ
+and
+.B .EN
+even when followed by a character other than space or newline.
+.
+.
+.TP
+.BI \-d\~ xy
+Specify delimiters
+.I x
+for left
+.RI and\~ y
+for right ends
+of equations not bracketed by
+.BR .EQ / .EN .
+.
+.I x
+and
+.I y
+need not be distinct.
+.
+Any
+.RB \%\[lq] delim
+.IR xy \[rq]
+statements in the source file override this option.
+.
+.
+.TP
+.BI \-f\~ F
+is equivalent to
+.RB \[lq] gfont
+.IR F \[rq].
+.
+.
+.TP
+.BI \-m\~ n
+is equivalent to
+.RB \[lq] "set \%minimum_size"
+.IR n \[rq].
+.
+.
+.TP
+.BI \-M\~ dir
+Search
+.I dir
+for
+.I eqnrc
+before those listed in section \[lq]Description\[rq] above.
+.
+.
+.TP
+.B \-N
+Prohibit newlines within delimiters.
+.
+This option allows
+.I @g@eqn
+to recover better from missing closing delimiters.
+.
+.
+.TP
+.BI \-p\~ n
+Set sub- and superscripts
+.IR n \~points
+smaller than the surrounding text.
+.
+This option is deprecated.
+.
+.I @g@eqn
+normally sets sub- and superscripts at 70% of the type size of the
+surrounding text.
+.
+.
+.TP
+.B \-r
+Reduce the type size of subscripts at most once relative to the base
+type size for the equation.
+.
+.
+.TP
+.B \-R
+Don't load
+.IR eqnrc .
+.
+.
+.TP
+.BI \-s\~ n
+is equivalent to
+.RB \[lq] gsize
+.IR n \[rq].
+.
+This option is deprecated.
+.
+.
+.TP
+.BI \-T\~ dev
+Prepare output for the device
+.IR dev .
+.
+In most cases,
+the effect of this is to define a macro
+.I dev
+with a value
+.RB of\~ 1 ;
+.I eqnrc
+uses this to provide definitions appropriate for the device.
+.
+However,
+if the specified driver is \[lq]MathML\[rq],
+the output is MathML markup rather than
+.I @g@troff
+input,
+and
+.I eqnrc
+is not loaded at all.
+.
+The default output device is
+.BR @DEVICE@ .
+.
+.
+.\" ====================================================================
+.SH Files
+.\" ====================================================================
+.
+.TP
+.I @MACRODIR@/\:\%eqnrc
+Initialization file.
+.
+.
+.\" ====================================================================
+.SH "MathML mode limitations"
+.\" ====================================================================
+.
+MathML is designed on the assumption that it cannot know the exact
+physical characteristics of the media and devices on which it will
+be rendered.
+.
+It does not support control of motions and sizes to the same
+degree
+.I @g@troff
+does.
+.
+.
+.IP \[bu] 2n
+.I @g@eqn
+customization parameters have no effect on generated MathML.
+.
+.
+.IP \[bu]
+The
+.BR \%special ,
+.BR up ,
+.BR down ,
+.BR fwd ,
+and
+.B back
+primitives cannot be implemented,
+and yield a MathML \%\[lq]<merror>\[rq] message instead.
+.
+.
+.IP \[bu]
+The
+.B vcenter
+primitive is silently ignored,
+as centering on the math axis is the MathML default.
+.
+.
+.IP \[bu]
+Characters that
+.I @g@eqn
+sets extra large in
+.I troff \" mode
+mode\[em]notably the integral sign\[em]may appear too small and need to
+have their \[lq]<mstyle>\[rq] wrappers adjusted by hand.
+.
+.
+.P
+As in its
+.I troff \" mode
+mode,
+.I @g@eqn
+in MathML mode leaves the
+.B .EQ
+and
+.B .EN
+tokens in place,
+but emits nothing corresponding to
+.B \%delim
+delimiters.
+.
+They can,
+however,
+be recognized as character sequences that begin with \[lq]<math>\[rq],
+end with \[lq]</math>\[rq],
+and do not cross line boundaries.
+.
+.
+.\" ====================================================================
+.SH Caveats
+.\" ====================================================================
+.
+Tokens must be double-quoted in
+.I eqn \" generic
+input if they are not to be recognized as names of macros or primitives,
+or if they are to be interpreted by
+.IR troff . \" generic
+.
+In particular,
+short ones,
+like
+.RB \[lq] pi \[rq]
+and
+.RB \[lq] PI \[rq],
+can collide with
+.I troff \" generic
+identifiers.
+.
+For instance,
+the
+.I eqn \" generic
+command
+.RB \%\[lq]\^ "gfont PI" \^\[rq]
+does not select
+.IR groff 's
+Palatino italic font for the global italic face;
+you must use
+.RB \%\[lq]\^ "gfont \[dq]PI\[dq]" \^\[rq]
+instead.
+.
+.
+.P
+Delimited equations are set at the type size current at the beginning of
+the input line,
+not necessarily that immediately preceding the opening delimiter.
+.
+.
+.P
+Unlike \*[tx],
+.I eqn \" generic
+does not inherently distinguish displayed and inline equation styles;
+see the
+.B smallover
+primitive above.
+.
+However,
+macro packages frequently define
+.B EQ
+and
+.B EN
+macros such that the equation within is displayed.
+.
+These macros may accept arguments permitting the equation to be labeled
+or captioned;
+see the package's documentation.
+.
+.
+.\" ====================================================================
+.SH Bugs
+.\" ====================================================================
+.
+.I eqn \" generic
+abuses terminology\[em]its
+\[lq]equations\[rq]
+can be inequalities,
+bare expressions,
+or unintelligible gibberish.
+.
+But there's no changing it now.
+.
+.
+.P
+In
+.I nroff \" mode
+mode,
+lowercase Greek letters are rendered in roman instead of italic style.
+.
+.
+.P
+In MathML mode,
+the
+.B mark
+and
+.B lineup
+features don't work.
+.
+These could,
+in theory,
+be implemented with \%\[lq]<maligngroup>\[rq] elements.
+.
+.
+.P
+In MathML mode,
+each digit of a numeric literal gets a separate \[lq]<mn>\:</mn>\[rq]
+pair,
+and decimal points are tagged with \[lq]<mo>\:</mo>\[rq].
+.
+This is allowed by the specification,
+but inefficient.
+.
+.
+.\" ====================================================================
+.SH Examples
+.\" ====================================================================
+.
+We first illustrate
+.I @g@eqn
+usage with a trigonometric identity.
+.
+.
+.RS
+.P
+.EX
+\&.EQ
+sin ( alpha + beta ) = sin alpha cos beta + cos alpha sin beta
+\&.EN
+.EE
+.if t \{\
+.
+.
+.P
+.RS
+.EQ
+sin ( alpha + beta ) = sin alpha cos beta + cos alpha sin beta
+.EN
+.RE
+.\}
+.RE
+.
+.
+.P
+It can be convenient to set up delimiters if mathematical content will
+appear frequently in running text.
+.
+.
+.RS
+.P
+.EX
+\&.EQ
+delim $$
+\&.EN
+.
+Having cached a table of logarithms,
+the property $ln ( x y ) = ln x + ln y$ sped calculations.
+.EE
+.if t \{\
+.
+.
+.P
+.RS
+.EQ
+delim $$
+.EN
+.
+Having cached a table of logarithms,
+the property $ln ( x y ) = ln x + ln y$ sped calculations.
+.
+.\" We _must_ shut delimiters back off when serially processing man
+.\" pages, or subsequent documents cannot safely use those characters.
+.EQ
+delim off
+.EN
+.RE
+.\}
+.RE
+.
+.
+.P
+The quadratic formula illustrates use of fractions and radicals,
+and affords an opportunity to use the full space token
+.BR \[ti] .
+.
+.
+.RS
+.P
+.EX
+\&.EQ
+x = { \- b \[ti] \[rs][+\-] \[ti] sqrt { b sup 2 \- 4 a c } } \
+over { 2 a }
+\&.EN
+.EE
+.if t \{\
+.
+.
+.P
+.RS
+.EQ
+x = { - b ~ \[+-] ~ sqrt { b sup 2 - 4 a c } } over { 2 a }
+.EN
+.RE
+.\}
+.RE
+.
+.
+.P
+Alternatively,
+we could define the plus-minus sign as a binary operator.
+.
+Automatic spacing puts 0.06\~em less space on either side of the
+plus-minus than \[ti] does,
+this being the difference between the widths of the
+.B medium_space
+parameter used by binary operators and that of the full space.
+.
+Independently,
+we can define a macro \[lq]frac\[rq] for setting fractions.
+.
+.
+.RS
+.P
+.EX
+\&.EQ
+chartype "binary" \[rs][+\-]
+define frac ! { $1 } over { $2 } !
+x = frac(\- b \[rs][+\-] sqrt { b sup 2 \- 4 a c }, 2 a)
+\&.EN
+.EE
+.if t \{\
+.
+.
+.P
+.RS
+.EQ
+chartype "binary" \[+-]
+define frac ! { $1 } over { $2 } !
+x = frac(- b \[+-] sqrt { b sup 2 - 4 a c }, 2 a)
+.EN
+.RE
+.\}
+.RE
+.
+.
+.\" ====================================================================
+.SH "See also"
+.\" ====================================================================
+.
+\[lq]Typesetting Mathematics\[em]User's Guide\[rq]
+(2nd edition),
+by Brian W.\& Kernighan
+and Lorinda L.\& Cherry,
+1978,
+AT&T Bell Laboratories Computing Science Technical Report No.\& 17.
+.
+.
+.P
+.IR The\~\*[tx]book ,
+by Donald E.\& Knuth,
+1984,
+Addison-Wesley Professional.
+.
+Appendix\~G
+discusses many of the parameters from section \[lq]Customization\[rq]
+above in greater detail.
+.
+.
+.P
+.MR groff_char @MAN7EXT@ ,
+particularly subsections \[lq]Logical symbols\[rq],
+\[lq]Mathematical symbols\[rq],
+and \[lq]Greek glyphs\[rq],
+documents a variety of special character escape sequences useful in
+mathematical typesetting.
+.
+.
+.P
+.MR groff @MAN1EXT@ ,
+.MR @g@troff @MAN1EXT@ ,
+.MR @g@pic @MAN1EXT@ ,
+.MR groff_font @MAN5EXT@
+.
+.
+.\" Clean up.
+.rm tx
+.
+.\" Restore compatibility mode (for, e.g., Solaris 10/11).
+.cp \n[*groff_eqn_1_man_C]
+.do rr *groff_eqn_1_man_C
+.
+.
+.\" Local Variables:
+.\" fill-column: 72
+.\" mode: nroff
+.\" tab-width: 12
+.\" End:
+.\" vim: set filetype=groff tabstop=12 textwidth=72:
diff --git a/src/preproc/eqn/eqn.am b/src/preproc/eqn/eqn.am
new file mode 100644
index 0000000..e32bfb5
--- /dev/null
+++ b/src/preproc/eqn/eqn.am
@@ -0,0 +1,79 @@
+# Copyright (C) 2014-2020 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or (at your
+# option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+prefixexecbin_PROGRAMS += eqn
+prefixexecbin_SCRIPTS += neqn
+eqn_CPPFLAGS = \
+  $(AM_CPPFLAGS) \
+  -I $(top_srcdir)/src/preproc/eqn \
+  -I $(top_builddir)/src/preproc/eqn
+eqn_LDADD = $(LIBM) libgroff.a lib/libgnu.a
+eqn_SOURCES = \
+  src/preproc/eqn/main.cpp \
+  src/preproc/eqn/lex.cpp \
+  src/preproc/eqn/box.cpp \
+  src/preproc/eqn/limit.cpp \
+  src/preproc/eqn/list.cpp \
+  src/preproc/eqn/over.cpp \
+  src/preproc/eqn/text.cpp \
+  src/preproc/eqn/script.cpp \
+  src/preproc/eqn/mark.cpp \
+  src/preproc/eqn/other.cpp \
+  src/preproc/eqn/delim.cpp \
+  src/preproc/eqn/sqrt.cpp \
+  src/preproc/eqn/pile.cpp \
+  src/preproc/eqn/special.cpp \
+  src/preproc/eqn/eqn.ypp \
+  src/preproc/eqn/box.h \
+  src/preproc/eqn/pbox.h \
+  src/preproc/eqn/eqn.h
+
+PREFIXMAN1 += src/preproc/eqn/eqn.1 src/preproc/eqn/neqn.1
+EXTRA_DIST += \
+  src/preproc/eqn/TODO \
+  src/preproc/eqn/eqn.1.man \
+  src/preproc/eqn/neqn.1.man \
+  src/preproc/eqn/neqn.sh
+
+# Since eqn_CPPFLAGS was set, all .o files have an 'eqn-' prefix.
+src/preproc/eqn/eqn-lex.$(OBJEXT): src/preproc/eqn/eqn.hpp
+
+MAINTAINERCLEANFILES += \
+  src/preproc/eqn/eqn.hpp \
+  src/preproc/eqn/eqn.cpp \
+  src/preproc/eqn/eqn.output
+
+neqn: $(top_srcdir)/src/preproc/eqn/neqn.sh $(SH_DEPS_SED_SCRIPT)
+	$(AM_V_GEN)sed -e 's/[@]g[@]/$(g)/g' \
+	       -f $(SH_DEPS_SED_SCRIPT) \
+	       -e $(SH_SCRIPT_SED_CMD) \
+	       $(top_srcdir)/src/preproc/eqn/neqn.sh \
+	       >$@.tmp \
+	&& chmod +x $@.tmp \
+	&& mv $@.tmp $@
+
+eqn_TESTS = \
+  src/preproc/eqn/tests/diagnostics-report-correct-line-numbers.sh
+TESTS += $(eqn_TESTS)
+EXTRA_DIST += $(eqn_TESTS)
+
+
+# Local Variables:
+# fill-column: 72
+# mode: makefile-automake
+# End:
+# vim: set autoindent filetype=automake textwidth=72:
diff --git a/src/preproc/eqn/eqn.cpp b/src/preproc/eqn/eqn.cpp
new file mode 100644
index 0000000..6756b9e
--- /dev/null
+++ b/src/preproc/eqn/eqn.cpp
@@ -0,0 +1,2112 @@
+/* A Bison parser, made by GNU Bison 3.8.2.  */
+
+/* Bison implementation for Yacc-like parsers in C
+
+   Copyright (C) 1984, 1989-1990, 2000-2015, 2018-2021 Free Software Foundation,
+   Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* As a special exception, you may create a larger work that contains
+   part or all of the Bison parser skeleton and distribute that work
+   under terms of your choice, so long as that work isn't itself a
+   parser generator using the skeleton or a modified version thereof
+   as a parser skeleton.  Alternatively, if you modify or redistribute
+   the parser skeleton itself, you may (at your option) remove this
+   special exception, which will cause the skeleton and the resulting
+   Bison output files to be licensed under the GNU General Public
+   License without this special exception.
+
+   This special exception was added by the Free Software Foundation in
+   version 2.2 of Bison.  */
+
+/* C LALR(1) parser skeleton written by Richard Stallman, by
+   simplifying the original so-called "semantic" parser.  */
+
+/* DO NOT RELY ON FEATURES THAT ARE NOT DOCUMENTED in the manual,
+   especially those whose name start with YY_ or yy_.  They are
+   private implementation details that can be changed or removed.  */
+
+/* All symbols defined below should begin with yy or YY, to avoid
+   infringing on user name space.  This should be done even for local
+   variables, as they might otherwise be expanded by user macros.
+   There are some unavoidable exceptions within include files to
+   define necessary library symbols; they are noted "INFRINGES ON
+   USER NAME SPACE" below.  */
+
+/* Identify Bison output, and Bison version.  */
+#define YYBISON 30802
+
+/* Bison version string.  */
+#define YYBISON_VERSION "3.8.2"
+
+/* Skeleton name.  */
+#define YYSKELETON_NAME "yacc.c"
+
+/* Pure parsers.  */
+#define YYPURE 0
+
+/* Push parsers.  */
+#define YYPUSH 0
+
+/* Pull parsers.  */
+#define YYPULL 1
+
+
+
+
+/* First part of user prologue.  */
+#line 18 "../src/preproc/eqn/eqn.ypp"
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "lib.h"
+#include "box.h"
+extern int non_empty_flag;
+int yylex();
+void yyerror(const char *);
+
+#line 87 "src/preproc/eqn/eqn.cpp"
+
+# ifndef YY_CAST
+#  ifdef __cplusplus
+#   define YY_CAST(Type, Val) static_cast<Type> (Val)
+#   define YY_REINTERPRET_CAST(Type, Val) reinterpret_cast<Type> (Val)
+#  else
+#   define YY_CAST(Type, Val) ((Type) (Val))
+#   define YY_REINTERPRET_CAST(Type, Val) ((Type) (Val))
+#  endif
+# endif
+# ifndef YY_NULLPTR
+#  if defined __cplusplus
+#   if 201103L <= __cplusplus
+#    define YY_NULLPTR nullptr
+#   else
+#    define YY_NULLPTR 0
+#   endif
+#  else
+#   define YY_NULLPTR ((void*)0)
+#  endif
+# endif
+
+/* Use api.header.include to #include this header
+   instead of duplicating it here.  */
+#ifndef YY_YY_SRC_PREPROC_EQN_EQN_HPP_INCLUDED
+# define YY_YY_SRC_PREPROC_EQN_EQN_HPP_INCLUDED
+/* Debug traces.  */
+#ifndef YYDEBUG
+# define YYDEBUG 0
+#endif
+#if YYDEBUG
+extern int yydebug;
+#endif
+
+/* Token kinds.  */
+#ifndef YYTOKENTYPE
+# define YYTOKENTYPE
+  enum yytokentype
+  {
+    YYEMPTY = -2,
+    YYEOF = 0,                     /* "end of file"  */
+    YYerror = 256,                 /* error  */
+    YYUNDEF = 257,                 /* "invalid token"  */
+    OVER = 258,                    /* OVER  */
+    SMALLOVER = 259,               /* SMALLOVER  */
+    SQRT = 260,                    /* SQRT  */
+    SUB = 261,                     /* SUB  */
+    SUP = 262,                     /* SUP  */
+    LPILE = 263,                   /* LPILE  */
+    RPILE = 264,                   /* RPILE  */
+    CPILE = 265,                   /* CPILE  */
+    PILE = 266,                    /* PILE  */
+    LEFT = 267,                    /* LEFT  */
+    RIGHT = 268,                   /* RIGHT  */
+    TO = 269,                      /* TO  */
+    FROM = 270,                    /* FROM  */
+    SIZE = 271,                    /* SIZE  */
+    FONT = 272,                    /* FONT  */
+    ROMAN = 273,                   /* ROMAN  */
+    BOLD = 274,                    /* BOLD  */
+    ITALIC = 275,                  /* ITALIC  */
+    FAT = 276,                     /* FAT  */
+    ACCENT = 277,                  /* ACCENT  */
+    BAR = 278,                     /* BAR  */
+    UNDER = 279,                   /* UNDER  */
+    ABOVE = 280,                   /* ABOVE  */
+    TEXT = 281,                    /* TEXT  */
+    QUOTED_TEXT = 282,             /* QUOTED_TEXT  */
+    FWD = 283,                     /* FWD  */
+    BACK = 284,                    /* BACK  */
+    DOWN = 285,                    /* DOWN  */
+    UP = 286,                      /* UP  */
+    MATRIX = 287,                  /* MATRIX  */
+    COL = 288,                     /* COL  */
+    LCOL = 289,                    /* LCOL  */
+    RCOL = 290,                    /* RCOL  */
+    CCOL = 291,                    /* CCOL  */
+    MARK = 292,                    /* MARK  */
+    LINEUP = 293,                  /* LINEUP  */
+    TYPE = 294,                    /* TYPE  */
+    VCENTER = 295,                 /* VCENTER  */
+    PRIME = 296,                   /* PRIME  */
+    SPLIT = 297,                   /* SPLIT  */
+    NOSPLIT = 298,                 /* NOSPLIT  */
+    UACCENT = 299,                 /* UACCENT  */
+    SPECIAL = 300,                 /* SPECIAL  */
+    SPACE = 301,                   /* SPACE  */
+    GFONT = 302,                   /* GFONT  */
+    GSIZE = 303,                   /* GSIZE  */
+    DEFINE = 304,                  /* DEFINE  */
+    NDEFINE = 305,                 /* NDEFINE  */
+    TDEFINE = 306,                 /* TDEFINE  */
+    SDEFINE = 307,                 /* SDEFINE  */
+    UNDEF = 308,                   /* UNDEF  */
+    IFDEF = 309,                   /* IFDEF  */
+    INCLUDE = 310,                 /* INCLUDE  */
+    DELIM = 311,                   /* DELIM  */
+    CHARTYPE = 312,                /* CHARTYPE  */
+    SET = 313,                     /* SET  */
+    GRFONT = 314,                  /* GRFONT  */
+    GBFONT = 315                   /* GBFONT  */
+  };
+  typedef enum yytokentype yytoken_kind_t;
+#endif
+/* Token kinds.  */
+#define YYEMPTY -2
+#define YYEOF 0
+#define YYerror 256
+#define YYUNDEF 257
+#define OVER 258
+#define SMALLOVER 259
+#define SQRT 260
+#define SUB 261
+#define SUP 262
+#define LPILE 263
+#define RPILE 264
+#define CPILE 265
+#define PILE 266
+#define LEFT 267
+#define RIGHT 268
+#define TO 269
+#define FROM 270
+#define SIZE 271
+#define FONT 272
+#define ROMAN 273
+#define BOLD 274
+#define ITALIC 275
+#define FAT 276
+#define ACCENT 277
+#define BAR 278
+#define UNDER 279
+#define ABOVE 280
+#define TEXT 281
+#define QUOTED_TEXT 282
+#define FWD 283
+#define BACK 284
+#define DOWN 285
+#define UP 286
+#define MATRIX 287
+#define COL 288
+#define LCOL 289
+#define RCOL 290
+#define CCOL 291
+#define MARK 292
+#define LINEUP 293
+#define TYPE 294
+#define VCENTER 295
+#define PRIME 296
+#define SPLIT 297
+#define NOSPLIT 298
+#define UACCENT 299
+#define SPECIAL 300
+#define SPACE 301
+#define GFONT 302
+#define GSIZE 303
+#define DEFINE 304
+#define NDEFINE 305
+#define TDEFINE 306
+#define SDEFINE 307
+#define UNDEF 308
+#define IFDEF 309
+#define INCLUDE 310
+#define DELIM 311
+#define CHARTYPE 312
+#define SET 313
+#define GRFONT 314
+#define GBFONT 315
+
+/* Value type.  */
+#if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
+union YYSTYPE
+{
+#line 34 "../src/preproc/eqn/eqn.ypp"
+
+	char *str;
+	box *b;
+	pile_box *pb;
+	matrix_box *mb;
+	int n;
+	column *col;
+
+#line 269 "src/preproc/eqn/eqn.cpp"
+
+};
+typedef union YYSTYPE YYSTYPE;
+# define YYSTYPE_IS_TRIVIAL 1
+# define YYSTYPE_IS_DECLARED 1
+#endif
+
+
+extern YYSTYPE yylval;
+
+
+int yyparse (void);
+
+
+#endif /* !YY_YY_SRC_PREPROC_EQN_EQN_HPP_INCLUDED  */
+/* Symbol kind.  */
+enum yysymbol_kind_t
+{
+  YYSYMBOL_YYEMPTY = -2,
+  YYSYMBOL_YYEOF = 0,                      /* "end of file"  */
+  YYSYMBOL_YYerror = 1,                    /* error  */
+  YYSYMBOL_YYUNDEF = 2,                    /* "invalid token"  */
+  YYSYMBOL_OVER = 3,                       /* OVER  */
+  YYSYMBOL_SMALLOVER = 4,                  /* SMALLOVER  */
+  YYSYMBOL_SQRT = 5,                       /* SQRT  */
+  YYSYMBOL_SUB = 6,                        /* SUB  */
+  YYSYMBOL_SUP = 7,                        /* SUP  */
+  YYSYMBOL_LPILE = 8,                      /* LPILE  */
+  YYSYMBOL_RPILE = 9,                      /* RPILE  */
+  YYSYMBOL_CPILE = 10,                     /* CPILE  */
+  YYSYMBOL_PILE = 11,                      /* PILE  */
+  YYSYMBOL_LEFT = 12,                      /* LEFT  */
+  YYSYMBOL_RIGHT = 13,                     /* RIGHT  */
+  YYSYMBOL_TO = 14,                        /* TO  */
+  YYSYMBOL_FROM = 15,                      /* FROM  */
+  YYSYMBOL_SIZE = 16,                      /* SIZE  */
+  YYSYMBOL_FONT = 17,                      /* FONT  */
+  YYSYMBOL_ROMAN = 18,                     /* ROMAN  */
+  YYSYMBOL_BOLD = 19,                      /* BOLD  */
+  YYSYMBOL_ITALIC = 20,                    /* ITALIC  */
+  YYSYMBOL_FAT = 21,                       /* FAT  */
+  YYSYMBOL_ACCENT = 22,                    /* ACCENT  */
+  YYSYMBOL_BAR = 23,                       /* BAR  */
+  YYSYMBOL_UNDER = 24,                     /* UNDER  */
+  YYSYMBOL_ABOVE = 25,                     /* ABOVE  */
+  YYSYMBOL_TEXT = 26,                      /* TEXT  */
+  YYSYMBOL_QUOTED_TEXT = 27,               /* QUOTED_TEXT  */
+  YYSYMBOL_FWD = 28,                       /* FWD  */
+  YYSYMBOL_BACK = 29,                      /* BACK  */
+  YYSYMBOL_DOWN = 30,                      /* DOWN  */
+  YYSYMBOL_UP = 31,                        /* UP  */
+  YYSYMBOL_MATRIX = 32,                    /* MATRIX  */
+  YYSYMBOL_COL = 33,                       /* COL  */
+  YYSYMBOL_LCOL = 34,                      /* LCOL  */
+  YYSYMBOL_RCOL = 35,                      /* RCOL  */
+  YYSYMBOL_CCOL = 36,                      /* CCOL  */
+  YYSYMBOL_MARK = 37,                      /* MARK  */
+  YYSYMBOL_LINEUP = 38,                    /* LINEUP  */
+  YYSYMBOL_TYPE = 39,                      /* TYPE  */
+  YYSYMBOL_VCENTER = 40,                   /* VCENTER  */
+  YYSYMBOL_PRIME = 41,                     /* PRIME  */
+  YYSYMBOL_SPLIT = 42,                     /* SPLIT  */
+  YYSYMBOL_NOSPLIT = 43,                   /* NOSPLIT  */
+  YYSYMBOL_UACCENT = 44,                   /* UACCENT  */
+  YYSYMBOL_SPECIAL = 45,                   /* SPECIAL  */
+  YYSYMBOL_SPACE = 46,                     /* SPACE  */
+  YYSYMBOL_GFONT = 47,                     /* GFONT  */
+  YYSYMBOL_GSIZE = 48,                     /* GSIZE  */
+  YYSYMBOL_DEFINE = 49,                    /* DEFINE  */
+  YYSYMBOL_NDEFINE = 50,                   /* NDEFINE  */
+  YYSYMBOL_TDEFINE = 51,                   /* TDEFINE  */
+  YYSYMBOL_SDEFINE = 52,                   /* SDEFINE  */
+  YYSYMBOL_UNDEF = 53,                     /* UNDEF  */
+  YYSYMBOL_IFDEF = 54,                     /* IFDEF  */
+  YYSYMBOL_INCLUDE = 55,                   /* INCLUDE  */
+  YYSYMBOL_DELIM = 56,                     /* DELIM  */
+  YYSYMBOL_CHARTYPE = 57,                  /* CHARTYPE  */
+  YYSYMBOL_SET = 58,                       /* SET  */
+  YYSYMBOL_GRFONT = 59,                    /* GRFONT  */
+  YYSYMBOL_GBFONT = 60,                    /* GBFONT  */
+  YYSYMBOL_61_ = 61,                       /* '^'  */
+  YYSYMBOL_62_ = 62,                       /* '~'  */
+  YYSYMBOL_63_t_ = 63,                     /* '\t'  */
+  YYSYMBOL_64_ = 64,                       /* '{'  */
+  YYSYMBOL_65_ = 65,                       /* '}'  */
+  YYSYMBOL_YYACCEPT = 66,                  /* $accept  */
+  YYSYMBOL_top = 67,                       /* top  */
+  YYSYMBOL_equation = 68,                  /* equation  */
+  YYSYMBOL_mark = 69,                      /* mark  */
+  YYSYMBOL_from_to = 70,                   /* from_to  */
+  YYSYMBOL_sqrt_over = 71,                 /* sqrt_over  */
+  YYSYMBOL_script = 72,                    /* script  */
+  YYSYMBOL_nonsup = 73,                    /* nonsup  */
+  YYSYMBOL_simple = 74,                    /* simple  */
+  YYSYMBOL_number = 75,                    /* number  */
+  YYSYMBOL_pile_element_list = 76,         /* pile_element_list  */
+  YYSYMBOL_pile_arg = 77,                  /* pile_arg  */
+  YYSYMBOL_column_list = 78,               /* column_list  */
+  YYSYMBOL_column_element_list = 79,       /* column_element_list  */
+  YYSYMBOL_column_arg = 80,                /* column_arg  */
+  YYSYMBOL_column = 81,                    /* column  */
+  YYSYMBOL_text = 82,                      /* text  */
+  YYSYMBOL_delim = 83                      /* delim  */
+};
+typedef enum yysymbol_kind_t yysymbol_kind_t;
+
+
+
+
+#ifdef short
+# undef short
+#endif
+
+/* On compilers that do not define __PTRDIFF_MAX__ etc., make sure
+   <limits.h> and (if available) <stdint.h> are included
+   so that the code can choose integer types of a good width.  */
+
+#ifndef __PTRDIFF_MAX__
+# include <limits.h> /* INFRINGES ON USER NAME SPACE */
+# if defined __STDC_VERSION__ && 199901 <= __STDC_VERSION__
+#  include <stdint.h> /* INFRINGES ON USER NAME SPACE */
+#  define YY_STDINT_H
+# endif
+#endif
+
+/* Narrow types that promote to a signed type and that can represent a
+   signed or unsigned integer of at least N bits.  In tables they can
+   save space and decrease cache pressure.  Promoting to a signed type
+   helps avoid bugs in integer arithmetic.  */
+
+#ifdef __INT_LEAST8_MAX__
+typedef __INT_LEAST8_TYPE__ yytype_int8;
+#elif defined YY_STDINT_H
+typedef int_least8_t yytype_int8;
+#else
+typedef signed char yytype_int8;
+#endif
+
+#ifdef __INT_LEAST16_MAX__
+typedef __INT_LEAST16_TYPE__ yytype_int16;
+#elif defined YY_STDINT_H
+typedef int_least16_t yytype_int16;
+#else
+typedef short yytype_int16;
+#endif
+
+/* Work around bug in HP-UX 11.23, which defines these macros
+   incorrectly for preprocessor constants.  This workaround can likely
+   be removed in 2023, as HPE has promised support for HP-UX 11.23
+   (aka HP-UX 11i v2) only through the end of 2022; see Table 2 of
+   <https://h20195.www2.hpe.com/V2/getpdf.aspx/4AA4-7673ENW.pdf>.  */
+#ifdef __hpux
+# undef UINT_LEAST8_MAX
+# undef UINT_LEAST16_MAX
+# define UINT_LEAST8_MAX 255
+# define UINT_LEAST16_MAX 65535
+#endif
+
+#if defined __UINT_LEAST8_MAX__ && __UINT_LEAST8_MAX__ <= __INT_MAX__
+typedef __UINT_LEAST8_TYPE__ yytype_uint8;
+#elif (!defined __UINT_LEAST8_MAX__ && defined YY_STDINT_H \
+       && UINT_LEAST8_MAX <= INT_MAX)
+typedef uint_least8_t yytype_uint8;
+#elif !defined __UINT_LEAST8_MAX__ && UCHAR_MAX <= INT_MAX
+typedef unsigned char yytype_uint8;
+#else
+typedef short yytype_uint8;
+#endif
+
+#if defined __UINT_LEAST16_MAX__ && __UINT_LEAST16_MAX__ <= __INT_MAX__
+typedef __UINT_LEAST16_TYPE__ yytype_uint16;
+#elif (!defined __UINT_LEAST16_MAX__ && defined YY_STDINT_H \
+       && UINT_LEAST16_MAX <= INT_MAX)
+typedef uint_least16_t yytype_uint16;
+#elif !defined __UINT_LEAST16_MAX__ && USHRT_MAX <= INT_MAX
+typedef unsigned short yytype_uint16;
+#else
+typedef int yytype_uint16;
+#endif
+
+#ifndef YYPTRDIFF_T
+# if defined __PTRDIFF_TYPE__ && defined __PTRDIFF_MAX__
+#  define YYPTRDIFF_T __PTRDIFF_TYPE__
+#  define YYPTRDIFF_MAXIMUM __PTRDIFF_MAX__
+# elif defined PTRDIFF_MAX
+#  ifndef ptrdiff_t
+#   include <stddef.h> /* INFRINGES ON USER NAME SPACE */
+#  endif
+#  define YYPTRDIFF_T ptrdiff_t
+#  define YYPTRDIFF_MAXIMUM PTRDIFF_MAX
+# else
+#  define YYPTRDIFF_T long
+#  define YYPTRDIFF_MAXIMUM LONG_MAX
+# endif
+#endif
+
+#ifndef YYSIZE_T
+# ifdef __SIZE_TYPE__
+#  define YYSIZE_T __SIZE_TYPE__
+# elif defined size_t
+#  define YYSIZE_T size_t
+# elif defined __STDC_VERSION__ && 199901 <= __STDC_VERSION__
+#  include <stddef.h> /* INFRINGES ON USER NAME SPACE */
+#  define YYSIZE_T size_t
+# else
+#  define YYSIZE_T unsigned
+# endif
+#endif
+
+#define YYSIZE_MAXIMUM                                  \
+  YY_CAST (YYPTRDIFF_T,                                 \
+           (YYPTRDIFF_MAXIMUM < YY_CAST (YYSIZE_T, -1)  \
+            ? YYPTRDIFF_MAXIMUM                         \
+            : YY_CAST (YYSIZE_T, -1)))
+
+#define YYSIZEOF(X) YY_CAST (YYPTRDIFF_T, sizeof (X))
+
+
+/* Stored state numbers (used for stacks). */
+typedef yytype_uint8 yy_state_t;
+
+/* State numbers in computations.  */
+typedef int yy_state_fast_t;
+
+#ifndef YY_
+# if defined YYENABLE_NLS && YYENABLE_NLS
+#  if ENABLE_NLS
+#   include <libintl.h> /* INFRINGES ON USER NAME SPACE */
+#   define YY_(Msgid) dgettext ("bison-runtime", Msgid)
+#  endif
+# endif
+# ifndef YY_
+#  define YY_(Msgid) Msgid
+# endif
+#endif
+
+
+#ifndef YY_ATTRIBUTE_PURE
+# if defined __GNUC__ && 2 < __GNUC__ + (96 <= __GNUC_MINOR__)
+#  define YY_ATTRIBUTE_PURE __attribute__ ((__pure__))
+# else
+#  define YY_ATTRIBUTE_PURE
+# endif
+#endif
+
+#ifndef YY_ATTRIBUTE_UNUSED
+# if defined __GNUC__ && 2 < __GNUC__ + (7 <= __GNUC_MINOR__)
+#  define YY_ATTRIBUTE_UNUSED __attribute__ ((__unused__))
+# else
+#  define YY_ATTRIBUTE_UNUSED
+# endif
+#endif
+
+/* Suppress unused-variable warnings by "using" E.  */
+#if ! defined lint || defined __GNUC__
+# define YY_USE(E) ((void) (E))
+#else
+# define YY_USE(E) /* empty */
+#endif
+
+/* Suppress an incorrect diagnostic about yylval being uninitialized.  */
+#if defined __GNUC__ && ! defined __ICC && 406 <= __GNUC__ * 100 + __GNUC_MINOR__
+# if __GNUC__ * 100 + __GNUC_MINOR__ < 407
+#  define YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN                           \
+    _Pragma ("GCC diagnostic push")                                     \
+    _Pragma ("GCC diagnostic ignored \"-Wuninitialized\"")
+# else
+#  define YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN                           \
+    _Pragma ("GCC diagnostic push")                                     \
+    _Pragma ("GCC diagnostic ignored \"-Wuninitialized\"")              \
+    _Pragma ("GCC diagnostic ignored \"-Wmaybe-uninitialized\"")
+# endif
+# define YY_IGNORE_MAYBE_UNINITIALIZED_END      \
+    _Pragma ("GCC diagnostic pop")
+#else
+# define YY_INITIAL_VALUE(Value) Value
+#endif
+#ifndef YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+# define YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+# define YY_IGNORE_MAYBE_UNINITIALIZED_END
+#endif
+#ifndef YY_INITIAL_VALUE
+# define YY_INITIAL_VALUE(Value) /* Nothing. */
+#endif
+
+#if defined __cplusplus && defined __GNUC__ && ! defined __ICC && 6 <= __GNUC__
+# define YY_IGNORE_USELESS_CAST_BEGIN                          \
+    _Pragma ("GCC diagnostic push")                            \
+    _Pragma ("GCC diagnostic ignored \"-Wuseless-cast\"")
+# define YY_IGNORE_USELESS_CAST_END            \
+    _Pragma ("GCC diagnostic pop")
+#endif
+#ifndef YY_IGNORE_USELESS_CAST_BEGIN
+# define YY_IGNORE_USELESS_CAST_BEGIN
+# define YY_IGNORE_USELESS_CAST_END
+#endif
+
+
+#define YY_ASSERT(E) ((void) (0 && (E)))
+
+#if !defined yyoverflow
+
+/* The parser invokes alloca or malloc; define the necessary symbols.  */
+
+# ifdef YYSTACK_USE_ALLOCA
+#  if YYSTACK_USE_ALLOCA
+#   ifdef __GNUC__
+#    define YYSTACK_ALLOC __builtin_alloca
+#   elif defined __BUILTIN_VA_ARG_INCR
+#    include <alloca.h> /* INFRINGES ON USER NAME SPACE */
+#   elif defined _AIX
+#    define YYSTACK_ALLOC __alloca
+#   elif defined _MSC_VER
+#    include <malloc.h> /* INFRINGES ON USER NAME SPACE */
+#    define alloca _alloca
+#   else
+#    define YYSTACK_ALLOC alloca
+#    if ! defined _ALLOCA_H && ! defined EXIT_SUCCESS
+#     include <stdlib.h> /* INFRINGES ON USER NAME SPACE */
+      /* Use EXIT_SUCCESS as a witness for stdlib.h.  */
+#     ifndef EXIT_SUCCESS
+#      define EXIT_SUCCESS 0
+#     endif
+#    endif
+#   endif
+#  endif
+# endif
+
+# ifdef YYSTACK_ALLOC
+   /* Pacify GCC's 'empty if-body' warning.  */
+#  define YYSTACK_FREE(Ptr) do { /* empty */; } while (0)
+#  ifndef YYSTACK_ALLOC_MAXIMUM
+    /* The OS might guarantee only one guard page at the bottom of the stack,
+       and a page size can be as small as 4096 bytes.  So we cannot safely
+       invoke alloca (N) if N exceeds 4096.  Use a slightly smaller number
+       to allow for a few compiler-allocated temporary stack slots.  */
+#   define YYSTACK_ALLOC_MAXIMUM 4032 /* reasonable circa 2006 */
+#  endif
+# else
+#  define YYSTACK_ALLOC YYMALLOC
+#  define YYSTACK_FREE YYFREE
+#  ifndef YYSTACK_ALLOC_MAXIMUM
+#   define YYSTACK_ALLOC_MAXIMUM YYSIZE_MAXIMUM
+#  endif
+#  if (defined __cplusplus && ! defined EXIT_SUCCESS \
+       && ! ((defined YYMALLOC || defined malloc) \
+             && (defined YYFREE || defined free)))
+#   include <stdlib.h> /* INFRINGES ON USER NAME SPACE */
+#   ifndef EXIT_SUCCESS
+#    define EXIT_SUCCESS 0
+#   endif
+#  endif
+#  ifndef YYMALLOC
+#   define YYMALLOC malloc
+#   if ! defined malloc && ! defined EXIT_SUCCESS
+void *malloc (YYSIZE_T); /* INFRINGES ON USER NAME SPACE */
+#   endif
+#  endif
+#  ifndef YYFREE
+#   define YYFREE free
+#   if ! defined free && ! defined EXIT_SUCCESS
+void free (void *); /* INFRINGES ON USER NAME SPACE */
+#   endif
+#  endif
+# endif
+#endif /* !defined yyoverflow */
+
+#if (! defined yyoverflow \
+     && (! defined __cplusplus \
+         || (defined YYSTYPE_IS_TRIVIAL && YYSTYPE_IS_TRIVIAL)))
+
+/* A type that is properly aligned for any stack member.  */
+union yyalloc
+{
+  yy_state_t yyss_alloc;
+  YYSTYPE yyvs_alloc;
+};
+
+/* The size of the maximum gap between one aligned stack and the next.  */
+# define YYSTACK_GAP_MAXIMUM (YYSIZEOF (union yyalloc) - 1)
+
+/* The size of an array large to enough to hold all stacks, each with
+   N elements.  */
+# define YYSTACK_BYTES(N) \
+     ((N) * (YYSIZEOF (yy_state_t) + YYSIZEOF (YYSTYPE)) \
+      + YYSTACK_GAP_MAXIMUM)
+
+# define YYCOPY_NEEDED 1
+
+/* Relocate STACK from its old location to the new one.  The
+   local variables YYSIZE and YYSTACKSIZE give the old and new number of
+   elements in the stack, and YYPTR gives the new location of the
+   stack.  Advance YYPTR to a properly aligned location for the next
+   stack.  */
+# define YYSTACK_RELOCATE(Stack_alloc, Stack)                           \
+    do                                                                  \
+      {                                                                 \
+        YYPTRDIFF_T yynewbytes;                                         \
+        YYCOPY (&yyptr->Stack_alloc, Stack, yysize);                    \
+        Stack = &yyptr->Stack_alloc;                                    \
+        yynewbytes = yystacksize * YYSIZEOF (*Stack) + YYSTACK_GAP_MAXIMUM; \
+        yyptr += yynewbytes / YYSIZEOF (*yyptr);                        \
+      }                                                                 \
+    while (0)
+
+#endif
+
+#if defined YYCOPY_NEEDED && YYCOPY_NEEDED
+/* Copy COUNT objects from SRC to DST.  The source and destination do
+   not overlap.  */
+# ifndef YYCOPY
+#  if defined __GNUC__ && 1 < __GNUC__
+#   define YYCOPY(Dst, Src, Count) \
+      __builtin_memcpy (Dst, Src, YY_CAST (YYSIZE_T, (Count)) * sizeof (*(Src)))
+#  else
+#   define YYCOPY(Dst, Src, Count)              \
+      do                                        \
+        {                                       \
+          YYPTRDIFF_T yyi;                      \
+          for (yyi = 0; yyi < (Count); yyi++)   \
+            (Dst)[yyi] = (Src)[yyi];            \
+        }                                       \
+      while (0)
+#  endif
+# endif
+#endif /* !YYCOPY_NEEDED */
+
+/* YYFINAL -- State number of the termination state.  */
+#define YYFINAL  72
+/* YYLAST -- Last index in YYTABLE.  */
+#define YYLAST   379
+
+/* YYNTOKENS -- Number of terminals.  */
+#define YYNTOKENS  66
+/* YYNNTS -- Number of nonterminals.  */
+#define YYNNTS  18
+/* YYNRULES -- Number of rules.  */
+#define YYNRULES  75
+/* YYNSTATES -- Number of states.  */
+#define YYNSTATES  142
+
+/* YYMAXUTOK -- Last valid token kind.  */
+#define YYMAXUTOK   315
+
+
+/* YYTRANSLATE(TOKEN-NUM) -- Symbol number corresponding to TOKEN-NUM
+   as returned by yylex, with out-of-bounds checking.  */
+#define YYTRANSLATE(YYX)                                \
+  (0 <= (YYX) && (YYX) <= YYMAXUTOK                     \
+   ? YY_CAST (yysymbol_kind_t, yytranslate[YYX])        \
+   : YYSYMBOL_YYUNDEF)
+
+/* YYTRANSLATE[TOKEN-NUM] -- Symbol number corresponding to TOKEN-NUM
+   as returned by yylex.  */
+static const yytype_int8 yytranslate[] =
+{
+       0,     2,     2,     2,     2,     2,     2,     2,     2,    63,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,    61,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,    64,     2,    65,    62,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     1,     2,     3,     4,
+       5,     6,     7,     8,     9,    10,    11,    12,    13,    14,
+      15,    16,    17,    18,    19,    20,    21,    22,    23,    24,
+      25,    26,    27,    28,    29,    30,    31,    32,    33,    34,
+      35,    36,    37,    38,    39,    40,    41,    42,    43,    44,
+      45,    46,    47,    48,    49,    50,    51,    52,    53,    54,
+      55,    56,    57,    58,    59,    60
+};
+
+#if YYDEBUG
+/* YYRLINE[YYN] -- Source line where rule number YYN was defined.  */
+static const yytype_int16 yyrline[] =
+{
+       0,   125,   125,   127,   132,   134,   145,   147,   149,   154,
+     156,   158,   160,   162,   167,   169,   171,   173,   178,   180,
+     185,   187,   189,   194,   196,   198,   200,   202,   204,   206,
+     208,   210,   212,   214,   216,   218,   220,   222,   224,   226,
+     228,   230,   232,   234,   236,   238,   240,   242,   244,   246,
+     248,   250,   252,   254,   256,   258,   263,   273,   275,   280,
+     282,   287,   289,   294,   296,   301,   303,   308,   310,   312,
+     314,   318,   320,   325,   327,   329
+};
+#endif
+
+/** Accessing symbol of state STATE.  */
+#define YY_ACCESSING_SYMBOL(State) YY_CAST (yysymbol_kind_t, yystos[State])
+
+#if YYDEBUG || 0
+/* The user-facing name of the symbol whose (internal) number is
+   YYSYMBOL.  No bounds checking.  */
+static const char *yysymbol_name (yysymbol_kind_t yysymbol) YY_ATTRIBUTE_UNUSED;
+
+/* YYTNAME[SYMBOL-NUM] -- String name of the symbol SYMBOL-NUM.
+   First, the terminals, then, starting at YYNTOKENS, nonterminals.  */
+static const char *const yytname[] =
+{
+  "\"end of file\"", "error", "\"invalid token\"", "OVER", "SMALLOVER",
+  "SQRT", "SUB", "SUP", "LPILE", "RPILE", "CPILE", "PILE", "LEFT", "RIGHT",
+  "TO", "FROM", "SIZE", "FONT", "ROMAN", "BOLD", "ITALIC", "FAT", "ACCENT",
+  "BAR", "UNDER", "ABOVE", "TEXT", "QUOTED_TEXT", "FWD", "BACK", "DOWN",
+  "UP", "MATRIX", "COL", "LCOL", "RCOL", "CCOL", "MARK", "LINEUP", "TYPE",
+  "VCENTER", "PRIME", "SPLIT", "NOSPLIT", "UACCENT", "SPECIAL", "SPACE",
+  "GFONT", "GSIZE", "DEFINE", "NDEFINE", "TDEFINE", "SDEFINE", "UNDEF",
+  "IFDEF", "INCLUDE", "DELIM", "CHARTYPE", "SET", "GRFONT", "GBFONT",
+  "'^'", "'~'", "'\\t'", "'{'", "'}'", "$accept", "top", "equation",
+  "mark", "from_to", "sqrt_over", "script", "nonsup", "simple", "number",
+  "pile_element_list", "pile_arg", "column_list", "column_element_list",
+  "column_arg", "column", "text", "delim", YY_NULLPTR
+};
+
+static const char *
+yysymbol_name (yysymbol_kind_t yysymbol)
+{
+  return yytname[yysymbol];
+}
+#endif
+
+#define YYPACT_NINF (-76)
+
+#define yypact_value_is_default(Yyn) \
+  ((Yyn) == YYPACT_NINF)
+
+#define YYTABLE_NINF (-1)
+
+#define yytable_value_is_error(Yyn) \
+  0
+
+/* YYPACT[STATE-NUM] -- Index in YYTABLE of the portion describing
+   STATE-NUM.  */
+static const yytype_int16 yypact[] =
+{
+     230,   269,     6,     6,     6,     6,     2,    14,    14,   308,
+     308,   308,   308,   -76,   -76,    14,    14,    14,    14,   -50,
+     230,   230,    14,   308,     4,    23,    14,   -76,   -76,   -76,
+     230,    24,   230,   -76,   -76,    70,   -76,   -76,    20,   -76,
+     -76,   -76,   230,   -44,   -76,   -76,   -76,   -76,   -76,   -76,
+     -76,   -76,   230,   308,   308,    57,    57,    57,    57,   308,
+     308,   308,   308,     3,   -76,   -76,   308,    57,   -76,   -76,
+     308,   130,   -76,   -76,   269,   269,   269,   269,   308,   308,
+     308,   -76,   -76,   -76,   308,   230,   -12,   230,   191,    57,
+      57,    57,    57,    57,    57,     8,     8,     8,     8,    12,
+     -76,    57,    57,   -76,   -76,   -76,   -76,    79,   -76,   335,
+     -76,   -76,   -76,   230,   -76,    -6,     2,   230,    28,   -76,
+     -76,   -76,   -76,   -76,   -76,   269,   269,   308,   230,   -76,
+     -76,   230,    -3,   230,   -76,   -76,   -76,   230,   -76,    -2,
+     230,   -76
+};
+
+/* YYDEFACT[STATE-NUM] -- Default reduction number in state STATE-NUM.
+   Performed when YYTABLE does not specify something else to do.  Zero
+   means the default is an error.  */
+static const yytype_int8 yydefact[] =
+{
+       2,     0,     0,     0,     0,     0,     0,     0,     0,     0,
+       0,     0,     0,    23,    24,     0,     0,     0,     0,     0,
+       0,     0,     0,     0,     0,     0,     0,    27,    28,    29,
+       0,     0,     3,     4,     6,     9,    14,    18,    20,    15,
+      71,    72,     0,     0,    32,    56,    33,    34,    31,    74,
+      75,    73,     0,     0,     0,    43,    44,    45,    46,     0,
+       0,     0,     0,     0,     7,     8,     0,    54,    25,    26,
+       0,     0,     1,     5,     0,     0,     0,     0,     0,     0,
+       0,    38,    39,    40,     0,    57,     0,     0,    37,    48,
+      47,    49,    50,    52,    51,     0,     0,     0,     0,     0,
+      61,    53,    55,    30,    16,    17,    10,    11,    21,    20,
+      19,    41,    42,     0,    59,     0,     0,     0,     0,    67,
+      68,    69,    70,    35,    62,     0,     0,     0,    58,    60,
+      36,    63,     0,     0,    12,    13,    22,     0,    65,     0,
+      64,    66
+};
+
+/* YYPGOTO[NTERM-NUM].  */
+static const yytype_int8 yypgoto[] =
+{
+     -76,   -76,     0,   -17,   -75,     1,   -67,   -13,    46,    -7,
+       9,    13,   -76,   -47,    22,    -4,    -1,   -29
+};
+
+/* YYDEFGOTO[NTERM-NUM].  */
+static const yytype_uint8 yydefgoto[] =
+{
+       0,    31,    85,    33,    34,    35,    36,    37,    38,    43,
+      86,    44,    99,   132,   119,   100,    45,    52
+};
+
+/* YYTABLE[YYPACT[STATE-NUM]] -- What to do in state STATE-NUM.  If
+   positive, shift that token.  If negative, reduce the rule whose
+   number is the opposite.  If YYTABLE_NINF, syntax error.  */
+static const yytype_uint8 yytable[] =
+{
+      32,   106,    39,    64,    65,    51,    53,    54,    59,    60,
+      61,    62,   110,   113,    63,    73,    46,    47,    48,   113,
+      87,    66,   137,   137,    72,    70,    78,    79,    40,    41,
+      71,    68,    40,    41,    40,    41,    95,    96,    97,    98,
+      40,    41,    80,    81,    82,    95,    96,    97,    98,    69,
+     134,   135,    88,   114,    73,    55,    56,    57,    58,   129,
+     136,    83,   138,   141,    84,   108,    49,    50,    73,    67,
+      42,    73,   117,    74,    75,   104,   105,   123,   107,    80,
+      81,    82,    74,    75,    76,    77,   139,   130,   118,   118,
+     118,   118,   133,   125,   126,   124,   115,     0,    83,    89,
+      90,    84,     0,     0,     0,    91,    92,    93,    94,     0,
+       0,    73,   101,   128,    73,    51,   102,   131,   120,   121,
+     122,     0,     0,    73,   109,     0,   111,     0,     0,     0,
+     112,     0,     0,   131,     0,     1,     0,   140,     2,     3,
+       4,     5,     6,     0,     0,     0,     7,     8,     9,    10,
+      11,    12,     0,     0,     0,     0,    13,    14,    15,    16,
+      17,    18,    19,     0,     0,     0,     0,    20,    21,    22,
+      23,     0,    24,    25,     0,    26,     0,     0,     0,     0,
+       0,     0,     0,     0,     0,     0,     0,     0,     0,     0,
+       0,    27,    28,    29,    30,   103,     1,     0,     0,     2,
+       3,     4,     5,     6,   116,     0,     0,     7,     8,     9,
+      10,    11,    12,     0,     0,     0,     0,    13,    14,    15,
+      16,    17,    18,    19,     0,     0,     0,     0,    20,    21,
+      22,    23,     0,    24,    25,     1,    26,     0,     2,     3,
+       4,     5,     6,     0,     0,     0,     7,     8,     9,    10,
+      11,    12,    27,    28,    29,    30,    13,    14,    15,    16,
+      17,    18,    19,     0,     0,     0,     0,    20,    21,    22,
+      23,     0,    24,    25,     1,    26,     0,     2,     3,     4,
+       5,     6,     0,     0,     0,     7,     8,     9,    10,    11,
+      12,    27,    28,    29,    30,    13,    14,    15,    16,    17,
+      18,    19,     0,     0,     0,     0,     0,     0,    22,    23,
+       0,    24,    25,     0,    26,     0,     2,     3,     4,     5,
+       6,     0,     0,     0,     7,     8,     9,    10,    11,    12,
+      27,    28,    29,    30,    13,    14,    15,    16,    17,    18,
+      19,    78,   127,     0,     0,     0,     0,    22,    23,     0,
+      24,    25,     0,    26,     0,     0,     0,    80,    81,    82,
+       0,     0,     0,     0,     0,     0,     0,     0,     0,    27,
+      28,    29,    30,     0,     0,     0,    83,     0,     0,    84
+};
+
+static const yytype_int16 yycheck[] =
+{
+       0,    76,     1,    20,    21,     6,     7,     8,    15,    16,
+      17,    18,    79,    25,    64,    32,     3,     4,     5,    25,
+      64,    22,    25,    25,     0,    26,     6,     7,    26,    27,
+      30,    27,    26,    27,    26,    27,    33,    34,    35,    36,
+      26,    27,    22,    23,    24,    33,    34,    35,    36,    26,
+     125,   126,    52,    65,    71,     9,    10,    11,    12,    65,
+     127,    41,    65,    65,    44,    78,    64,    65,    85,    23,
+      64,    88,    64,     3,     4,    74,    75,    65,    77,    22,
+      23,    24,     3,     4,    14,    15,   133,   116,    95,    96,
+      97,    98,    64,    14,    15,    99,    87,    -1,    41,    53,
+      54,    44,    -1,    -1,    -1,    59,    60,    61,    62,    -1,
+      -1,   128,    66,   113,   131,   116,    70,   117,    96,    97,
+      98,    -1,    -1,   140,    78,    -1,    80,    -1,    -1,    -1,
+      84,    -1,    -1,   133,    -1,     5,    -1,   137,     8,     9,
+      10,    11,    12,    -1,    -1,    -1,    16,    17,    18,    19,
+      20,    21,    -1,    -1,    -1,    -1,    26,    27,    28,    29,
+      30,    31,    32,    -1,    -1,    -1,    -1,    37,    38,    39,
+      40,    -1,    42,    43,    -1,    45,    -1,    -1,    -1,    -1,
+      -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,
+      -1,    61,    62,    63,    64,    65,     5,    -1,    -1,     8,
+       9,    10,    11,    12,    13,    -1,    -1,    16,    17,    18,
+      19,    20,    21,    -1,    -1,    -1,    -1,    26,    27,    28,
+      29,    30,    31,    32,    -1,    -1,    -1,    -1,    37,    38,
+      39,    40,    -1,    42,    43,     5,    45,    -1,     8,     9,
+      10,    11,    12,    -1,    -1,    -1,    16,    17,    18,    19,
+      20,    21,    61,    62,    63,    64,    26,    27,    28,    29,
+      30,    31,    32,    -1,    -1,    -1,    -1,    37,    38,    39,
+      40,    -1,    42,    43,     5,    45,    -1,     8,     9,    10,
+      11,    12,    -1,    -1,    -1,    16,    17,    18,    19,    20,
+      21,    61,    62,    63,    64,    26,    27,    28,    29,    30,
+      31,    32,    -1,    -1,    -1,    -1,    -1,    -1,    39,    40,
+      -1,    42,    43,    -1,    45,    -1,     8,     9,    10,    11,
+      12,    -1,    -1,    -1,    16,    17,    18,    19,    20,    21,
+      61,    62,    63,    64,    26,    27,    28,    29,    30,    31,
+      32,     6,     7,    -1,    -1,    -1,    -1,    39,    40,    -1,
+      42,    43,    -1,    45,    -1,    -1,    -1,    22,    23,    24,
+      -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,    61,
+      62,    63,    64,    -1,    -1,    -1,    41,    -1,    -1,    44
+};
+
+/* YYSTOS[STATE-NUM] -- The symbol kind of the accessing symbol of
+   state STATE-NUM.  */
+static const yytype_int8 yystos[] =
+{
+       0,     5,     8,     9,    10,    11,    12,    16,    17,    18,
+      19,    20,    21,    26,    27,    28,    29,    30,    31,    32,
+      37,    38,    39,    40,    42,    43,    45,    61,    62,    63,
+      64,    67,    68,    69,    70,    71,    72,    73,    74,    71,
+      26,    27,    64,    75,    77,    82,    77,    77,    77,    64,
+      65,    82,    83,    82,    82,    74,    74,    74,    74,    75,
+      75,    75,    75,    64,    69,    69,    82,    74,    27,    26,
+      82,    68,     0,    69,     3,     4,    14,    15,     6,     7,
+      22,    23,    24,    41,    44,    68,    76,    64,    68,    74,
+      74,    74,    74,    74,    74,    33,    34,    35,    36,    78,
+      81,    74,    74,    65,    71,    71,    70,    71,    73,    74,
+      72,    74,    74,    25,    65,    76,    13,    64,    75,    80,
+      80,    80,    80,    65,    81,    14,    15,     7,    68,    65,
+      83,    68,    79,    64,    70,    70,    72,    25,    65,    79,
+      68,    65
+};
+
+/* YYR1[RULE-NUM] -- Symbol kind of the left-hand side of rule RULE-NUM.  */
+static const yytype_int8 yyr1[] =
+{
+       0,    66,    67,    67,    68,    68,    69,    69,    69,    70,
+      70,    70,    70,    70,    71,    71,    71,    71,    72,    72,
+      73,    73,    73,    74,    74,    74,    74,    74,    74,    74,
+      74,    74,    74,    74,    74,    74,    74,    74,    74,    74,
+      74,    74,    74,    74,    74,    74,    74,    74,    74,    74,
+      74,    74,    74,    74,    74,    74,    75,    76,    76,    77,
+      77,    78,    78,    79,    79,    80,    80,    81,    81,    81,
+      81,    82,    82,    83,    83,    83
+};
+
+/* YYR2[RULE-NUM] -- Number of symbols on the right-hand side of rule RULE-NUM.  */
+static const yytype_int8 yyr2[] =
+{
+       0,     2,     0,     1,     1,     2,     1,     2,     2,     1,
+       3,     3,     5,     5,     1,     2,     3,     3,     1,     3,
+       1,     3,     5,     1,     1,     2,     2,     1,     1,     1,
+       3,     2,     2,     2,     2,     4,     5,     3,     2,     2,
+       2,     3,     3,     2,     2,     2,     2,     3,     3,     3,
+       3,     3,     3,     3,     2,     3,     1,     1,     3,     3,
+       4,     1,     2,     1,     3,     3,     4,     2,     2,     2,
+       2,     1,     1,     1,     1,     1
+};
+
+
+enum { YYENOMEM = -2 };
+
+#define yyerrok         (yyerrstatus = 0)
+#define yyclearin       (yychar = YYEMPTY)
+
+#define YYACCEPT        goto yyacceptlab
+#define YYABORT         goto yyabortlab
+#define YYERROR         goto yyerrorlab
+#define YYNOMEM         goto yyexhaustedlab
+
+
+#define YYRECOVERING()  (!!yyerrstatus)
+
+#define YYBACKUP(Token, Value)                                    \
+  do                                                              \
+    if (yychar == YYEMPTY)                                        \
+      {                                                           \
+        yychar = (Token);                                         \
+        yylval = (Value);                                         \
+        YYPOPSTACK (yylen);                                       \
+        yystate = *yyssp;                                         \
+        goto yybackup;                                            \
+      }                                                           \
+    else                                                          \
+      {                                                           \
+        yyerror (YY_("syntax error: cannot back up")); \
+        YYERROR;                                                  \
+      }                                                           \
+  while (0)
+
+/* Backward compatibility with an undocumented macro.
+   Use YYerror or YYUNDEF. */
+#define YYERRCODE YYUNDEF
+
+
+/* Enable debugging if requested.  */
+#if YYDEBUG
+
+# ifndef YYFPRINTF
+#  include <stdio.h> /* INFRINGES ON USER NAME SPACE */
+#  define YYFPRINTF fprintf
+# endif
+
+# define YYDPRINTF(Args)                        \
+do {                                            \
+  if (yydebug)                                  \
+    YYFPRINTF Args;                             \
+} while (0)
+
+
+
+
+# define YY_SYMBOL_PRINT(Title, Kind, Value, Location)                    \
+do {                                                                      \
+  if (yydebug)                                                            \
+    {                                                                     \
+      YYFPRINTF (stderr, "%s ", Title);                                   \
+      yy_symbol_print (stderr,                                            \
+                  Kind, Value); \
+      YYFPRINTF (stderr, "\n");                                           \
+    }                                                                     \
+} while (0)
+
+
+/*-----------------------------------.
+| Print this symbol's value on YYO.  |
+`-----------------------------------*/
+
+static void
+yy_symbol_value_print (FILE *yyo,
+                       yysymbol_kind_t yykind, YYSTYPE const * const yyvaluep)
+{
+  FILE *yyoutput = yyo;
+  YY_USE (yyoutput);
+  if (!yyvaluep)
+    return;
+  YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+  YY_USE (yykind);
+  YY_IGNORE_MAYBE_UNINITIALIZED_END
+}
+
+
+/*---------------------------.
+| Print this symbol on YYO.  |
+`---------------------------*/
+
+static void
+yy_symbol_print (FILE *yyo,
+                 yysymbol_kind_t yykind, YYSTYPE const * const yyvaluep)
+{
+  YYFPRINTF (yyo, "%s %s (",
+             yykind < YYNTOKENS ? "token" : "nterm", yysymbol_name (yykind));
+
+  yy_symbol_value_print (yyo, yykind, yyvaluep);
+  YYFPRINTF (yyo, ")");
+}
+
+/*------------------------------------------------------------------.
+| yy_stack_print -- Print the state stack from its BOTTOM up to its |
+| TOP (included).                                                   |
+`------------------------------------------------------------------*/
+
+static void
+yy_stack_print (yy_state_t *yybottom, yy_state_t *yytop)
+{
+  YYFPRINTF (stderr, "Stack now");
+  for (; yybottom <= yytop; yybottom++)
+    {
+      int yybot = *yybottom;
+      YYFPRINTF (stderr, " %d", yybot);
+    }
+  YYFPRINTF (stderr, "\n");
+}
+
+# define YY_STACK_PRINT(Bottom, Top)                            \
+do {                                                            \
+  if (yydebug)                                                  \
+    yy_stack_print ((Bottom), (Top));                           \
+} while (0)
+
+
+/*------------------------------------------------.
+| Report that the YYRULE is going to be reduced.  |
+`------------------------------------------------*/
+
+static void
+yy_reduce_print (yy_state_t *yyssp, YYSTYPE *yyvsp,
+                 int yyrule)
+{
+  int yylno = yyrline[yyrule];
+  int yynrhs = yyr2[yyrule];
+  int yyi;
+  YYFPRINTF (stderr, "Reducing stack by rule %d (line %d):\n",
+             yyrule - 1, yylno);
+  /* The symbols being reduced.  */
+  for (yyi = 0; yyi < yynrhs; yyi++)
+    {
+      YYFPRINTF (stderr, "   $%d = ", yyi + 1);
+      yy_symbol_print (stderr,
+                       YY_ACCESSING_SYMBOL (+yyssp[yyi + 1 - yynrhs]),
+                       &yyvsp[(yyi + 1) - (yynrhs)]);
+      YYFPRINTF (stderr, "\n");
+    }
+}
+
+# define YY_REDUCE_PRINT(Rule)          \
+do {                                    \
+  if (yydebug)                          \
+    yy_reduce_print (yyssp, yyvsp, Rule); \
+} while (0)
+
+/* Nonzero means print parse trace.  It is left uninitialized so that
+   multiple parsers can coexist.  */
+int yydebug;
+#else /* !YYDEBUG */
+# define YYDPRINTF(Args) ((void) 0)
+# define YY_SYMBOL_PRINT(Title, Kind, Value, Location)
+# define YY_STACK_PRINT(Bottom, Top)
+# define YY_REDUCE_PRINT(Rule)
+#endif /* !YYDEBUG */
+
+
+/* YYINITDEPTH -- initial size of the parser's stacks.  */
+#ifndef YYINITDEPTH
+# define YYINITDEPTH 200
+#endif
+
+/* YYMAXDEPTH -- maximum size the stacks can grow to (effective only
+   if the built-in stack extension method is used).
+
+   Do not make this value too large; the results are undefined if
+   YYSTACK_ALLOC_MAXIMUM < YYSTACK_BYTES (YYMAXDEPTH)
+   evaluated with infinite-precision integer arithmetic.  */
+
+#ifndef YYMAXDEPTH
+# define YYMAXDEPTH 10000
+#endif
+
+
+
+
+
+
+/*-----------------------------------------------.
+| Release the memory associated to this symbol.  |
+`-----------------------------------------------*/
+
+static void
+yydestruct (const char *yymsg,
+            yysymbol_kind_t yykind, YYSTYPE *yyvaluep)
+{
+  YY_USE (yyvaluep);
+  if (!yymsg)
+    yymsg = "Deleting";
+  YY_SYMBOL_PRINT (yymsg, yykind, yyvaluep, yylocationp);
+
+  YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+  YY_USE (yykind);
+  YY_IGNORE_MAYBE_UNINITIALIZED_END
+}
+
+
+/* Lookahead token kind.  */
+int yychar;
+
+/* The semantic value of the lookahead symbol.  */
+YYSTYPE yylval;
+/* Number of syntax errors so far.  */
+int yynerrs;
+
+
+
+
+/*----------.
+| yyparse.  |
+`----------*/
+
+int
+yyparse (void)
+{
+    yy_state_fast_t yystate = 0;
+    /* Number of tokens to shift before error messages enabled.  */
+    int yyerrstatus = 0;
+
+    /* Refer to the stacks through separate pointers, to allow yyoverflow
+       to reallocate them elsewhere.  */
+
+    /* Their size.  */
+    YYPTRDIFF_T yystacksize = YYINITDEPTH;
+
+    /* The state stack: array, bottom, top.  */
+    yy_state_t yyssa[YYINITDEPTH];
+    yy_state_t *yyss = yyssa;
+    yy_state_t *yyssp = yyss;
+
+    /* The semantic value stack: array, bottom, top.  */
+    YYSTYPE yyvsa[YYINITDEPTH];
+    YYSTYPE *yyvs = yyvsa;
+    YYSTYPE *yyvsp = yyvs;
+
+  int yyn;
+  /* The return value of yyparse.  */
+  int yyresult;
+  /* Lookahead symbol kind.  */
+  yysymbol_kind_t yytoken = YYSYMBOL_YYEMPTY;
+  /* The variables used to return semantic value and location from the
+     action routines.  */
+  YYSTYPE yyval;
+
+
+
+#define YYPOPSTACK(N)   (yyvsp -= (N), yyssp -= (N))
+
+  /* The number of symbols on the RHS of the reduced rule.
+     Keep to zero when no symbol should be popped.  */
+  int yylen = 0;
+
+  YYDPRINTF ((stderr, "Starting parse\n"));
+
+  yychar = YYEMPTY; /* Cause a token to be read.  */
+
+  goto yysetstate;
+
+
+/*------------------------------------------------------------.
+| yynewstate -- push a new state, which is found in yystate.  |
+`------------------------------------------------------------*/
+yynewstate:
+  /* In all cases, when you get here, the value and location stacks
+     have just been pushed.  So pushing a state here evens the stacks.  */
+  yyssp++;
+
+
+/*--------------------------------------------------------------------.
+| yysetstate -- set current state (the top of the stack) to yystate.  |
+`--------------------------------------------------------------------*/
+yysetstate:
+  YYDPRINTF ((stderr, "Entering state %d\n", yystate));
+  YY_ASSERT (0 <= yystate && yystate < YYNSTATES);
+  YY_IGNORE_USELESS_CAST_BEGIN
+  *yyssp = YY_CAST (yy_state_t, yystate);
+  YY_IGNORE_USELESS_CAST_END
+  YY_STACK_PRINT (yyss, yyssp);
+
+  if (yyss + yystacksize - 1 <= yyssp)
+#if !defined yyoverflow && !defined YYSTACK_RELOCATE
+    YYNOMEM;
+#else
+    {
+      /* Get the current used size of the three stacks, in elements.  */
+      YYPTRDIFF_T yysize = yyssp - yyss + 1;
+
+# if defined yyoverflow
+      {
+        /* Give user a chance to reallocate the stack.  Use copies of
+           these so that the &'s don't force the real ones into
+           memory.  */
+        yy_state_t *yyss1 = yyss;
+        YYSTYPE *yyvs1 = yyvs;
+
+        /* Each stack pointer address is followed by the size of the
+           data in use in that stack, in bytes.  This used to be a
+           conditional around just the two extra args, but that might
+           be undefined if yyoverflow is a macro.  */
+        yyoverflow (YY_("memory exhausted"),
+                    &yyss1, yysize * YYSIZEOF (*yyssp),
+                    &yyvs1, yysize * YYSIZEOF (*yyvsp),
+                    &yystacksize);
+        yyss = yyss1;
+        yyvs = yyvs1;
+      }
+# else /* defined YYSTACK_RELOCATE */
+      /* Extend the stack our own way.  */
+      if (YYMAXDEPTH <= yystacksize)
+        YYNOMEM;
+      yystacksize *= 2;
+      if (YYMAXDEPTH < yystacksize)
+        yystacksize = YYMAXDEPTH;
+
+      {
+        yy_state_t *yyss1 = yyss;
+        union yyalloc *yyptr =
+          YY_CAST (union yyalloc *,
+                   YYSTACK_ALLOC (YY_CAST (YYSIZE_T, YYSTACK_BYTES (yystacksize))));
+        if (! yyptr)
+          YYNOMEM;
+        YYSTACK_RELOCATE (yyss_alloc, yyss);
+        YYSTACK_RELOCATE (yyvs_alloc, yyvs);
+#  undef YYSTACK_RELOCATE
+        if (yyss1 != yyssa)
+          YYSTACK_FREE (yyss1);
+      }
+# endif
+
+      yyssp = yyss + yysize - 1;
+      yyvsp = yyvs + yysize - 1;
+
+      YY_IGNORE_USELESS_CAST_BEGIN
+      YYDPRINTF ((stderr, "Stack size increased to %ld\n",
+                  YY_CAST (long, yystacksize)));
+      YY_IGNORE_USELESS_CAST_END
+
+      if (yyss + yystacksize - 1 <= yyssp)
+        YYABORT;
+    }
+#endif /* !defined yyoverflow && !defined YYSTACK_RELOCATE */
+
+
+  if (yystate == YYFINAL)
+    YYACCEPT;
+
+  goto yybackup;
+
+
+/*-----------.
+| yybackup.  |
+`-----------*/
+yybackup:
+  /* Do appropriate processing given the current state.  Read a
+     lookahead token if we need one and don't already have one.  */
+
+  /* First try to decide what to do without reference to lookahead token.  */
+  yyn = yypact[yystate];
+  if (yypact_value_is_default (yyn))
+    goto yydefault;
+
+  /* Not known => get a lookahead token if don't already have one.  */
+
+  /* YYCHAR is either empty, or end-of-input, or a valid lookahead.  */
+  if (yychar == YYEMPTY)
+    {
+      YYDPRINTF ((stderr, "Reading a token\n"));
+      yychar = yylex ();
+    }
+
+  if (yychar <= YYEOF)
+    {
+      yychar = YYEOF;
+      yytoken = YYSYMBOL_YYEOF;
+      YYDPRINTF ((stderr, "Now at end of input.\n"));
+    }
+  else if (yychar == YYerror)
+    {
+      /* The scanner already issued an error message, process directly
+         to error recovery.  But do not keep the error token as
+         lookahead, it is too special and may lead us to an endless
+         loop in error recovery. */
+      yychar = YYUNDEF;
+      yytoken = YYSYMBOL_YYerror;
+      goto yyerrlab1;
+    }
+  else
+    {
+      yytoken = YYTRANSLATE (yychar);
+      YY_SYMBOL_PRINT ("Next token is", yytoken, &yylval, &yylloc);
+    }
+
+  /* If the proper action on seeing token YYTOKEN is to reduce or to
+     detect an error, take that action.  */
+  yyn += yytoken;
+  if (yyn < 0 || YYLAST < yyn || yycheck[yyn] != yytoken)
+    goto yydefault;
+  yyn = yytable[yyn];
+  if (yyn <= 0)
+    {
+      if (yytable_value_is_error (yyn))
+        goto yyerrlab;
+      yyn = -yyn;
+      goto yyreduce;
+    }
+
+  /* Count tokens shifted since error; after three, turn off error
+     status.  */
+  if (yyerrstatus)
+    yyerrstatus--;
+
+  /* Shift the lookahead token.  */
+  YY_SYMBOL_PRINT ("Shifting", yytoken, &yylval, &yylloc);
+  yystate = yyn;
+  YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+  *++yyvsp = yylval;
+  YY_IGNORE_MAYBE_UNINITIALIZED_END
+
+  /* Discard the shifted token.  */
+  yychar = YYEMPTY;
+  goto yynewstate;
+
+
+/*-----------------------------------------------------------.
+| yydefault -- do the default action for the current state.  |
+`-----------------------------------------------------------*/
+yydefault:
+  yyn = yydefact[yystate];
+  if (yyn == 0)
+    goto yyerrlab;
+  goto yyreduce;
+
+
+/*-----------------------------.
+| yyreduce -- do a reduction.  |
+`-----------------------------*/
+yyreduce:
+  /* yyn is the number of a rule to reduce with.  */
+  yylen = yyr2[yyn];
+
+  /* If YYLEN is nonzero, implement the default value of the action:
+     '$$ = $1'.
+
+     Otherwise, the following line sets YYVAL to garbage.
+     This behavior is undocumented and Bison
+     users should not rely upon it.  Assigning to YYVAL
+     unconditionally makes the parser a bit smaller, and it avoids a
+     GCC warning that YYVAL may be used uninitialized.  */
+  yyval = yyvsp[1-yylen];
+
+
+  YY_REDUCE_PRINT (yyn);
+  switch (yyn)
+    {
+  case 3: /* top: equation  */
+#line 128 "../src/preproc/eqn/eqn.ypp"
+                { (yyvsp[0].b)->top_level(); non_empty_flag = 1; }
+#line 1472 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 4: /* equation: mark  */
+#line 133 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = (yyvsp[0].b); }
+#line 1478 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 5: /* equation: equation mark  */
+#line 135 "../src/preproc/eqn/eqn.ypp"
+                {
+		  list_box *lb = (yyvsp[-1].b)->to_list_box();
+		  if (!lb)
+		    lb = new list_box((yyvsp[-1].b));
+		  lb->append((yyvsp[0].b));
+		  (yyval.b) = lb;
+		}
+#line 1490 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 6: /* mark: from_to  */
+#line 146 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = (yyvsp[0].b); }
+#line 1496 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 7: /* mark: MARK mark  */
+#line 148 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_mark_box((yyvsp[0].b)); }
+#line 1502 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 8: /* mark: LINEUP mark  */
+#line 150 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_lineup_box((yyvsp[0].b)); }
+#line 1508 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 9: /* from_to: sqrt_over  */
+#line 155 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = (yyvsp[0].b); }
+#line 1514 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 10: /* from_to: sqrt_over TO from_to  */
+#line 157 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_limit_box((yyvsp[-2].b), 0, (yyvsp[0].b)); }
+#line 1520 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 11: /* from_to: sqrt_over FROM sqrt_over  */
+#line 159 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_limit_box((yyvsp[-2].b), (yyvsp[0].b), 0); }
+#line 1526 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 12: /* from_to: sqrt_over FROM sqrt_over TO from_to  */
+#line 161 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_limit_box((yyvsp[-4].b), (yyvsp[-2].b), (yyvsp[0].b)); }
+#line 1532 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 13: /* from_to: sqrt_over FROM sqrt_over FROM from_to  */
+#line 163 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_limit_box((yyvsp[-4].b), make_limit_box((yyvsp[-2].b), (yyvsp[0].b), 0), 0); }
+#line 1538 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 14: /* sqrt_over: script  */
+#line 168 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = (yyvsp[0].b); }
+#line 1544 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 15: /* sqrt_over: SQRT sqrt_over  */
+#line 170 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_sqrt_box((yyvsp[0].b)); }
+#line 1550 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 16: /* sqrt_over: sqrt_over OVER sqrt_over  */
+#line 172 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_over_box((yyvsp[-2].b), (yyvsp[0].b)); }
+#line 1556 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 17: /* sqrt_over: sqrt_over SMALLOVER sqrt_over  */
+#line 174 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_small_over_box((yyvsp[-2].b), (yyvsp[0].b)); }
+#line 1562 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 18: /* script: nonsup  */
+#line 179 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = (yyvsp[0].b); }
+#line 1568 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 19: /* script: simple SUP script  */
+#line 181 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_script_box((yyvsp[-2].b), 0, (yyvsp[0].b)); }
+#line 1574 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 20: /* nonsup: simple  */
+#line 186 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = (yyvsp[0].b); }
+#line 1580 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 21: /* nonsup: simple SUB nonsup  */
+#line 188 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_script_box((yyvsp[-2].b), (yyvsp[0].b), 0); }
+#line 1586 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 22: /* nonsup: simple SUB simple SUP script  */
+#line 190 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_script_box((yyvsp[-4].b), (yyvsp[-2].b), (yyvsp[0].b)); }
+#line 1592 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 23: /* simple: TEXT  */
+#line 195 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = split_text((yyvsp[0].str)); }
+#line 1598 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 24: /* simple: QUOTED_TEXT  */
+#line 197 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = new quoted_text_box((yyvsp[0].str)); }
+#line 1604 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 25: /* simple: SPLIT QUOTED_TEXT  */
+#line 199 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = split_text((yyvsp[0].str)); }
+#line 1610 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 26: /* simple: NOSPLIT TEXT  */
+#line 201 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = new quoted_text_box((yyvsp[0].str)); }
+#line 1616 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 27: /* simple: '^'  */
+#line 203 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = new half_space_box; }
+#line 1622 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 28: /* simple: '~'  */
+#line 205 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = new space_box; }
+#line 1628 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 29: /* simple: '\t'  */
+#line 207 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = new tab_box; }
+#line 1634 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 30: /* simple: '{' equation '}'  */
+#line 209 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = (yyvsp[-1].b); }
+#line 1640 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 31: /* simple: PILE pile_arg  */
+#line 211 "../src/preproc/eqn/eqn.ypp"
+                { (yyvsp[0].pb)->set_alignment(CENTER_ALIGN); (yyval.b) = (yyvsp[0].pb); }
+#line 1646 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 32: /* simple: LPILE pile_arg  */
+#line 213 "../src/preproc/eqn/eqn.ypp"
+                { (yyvsp[0].pb)->set_alignment(LEFT_ALIGN); (yyval.b) = (yyvsp[0].pb); }
+#line 1652 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 33: /* simple: RPILE pile_arg  */
+#line 215 "../src/preproc/eqn/eqn.ypp"
+                { (yyvsp[0].pb)->set_alignment(RIGHT_ALIGN); (yyval.b) = (yyvsp[0].pb); }
+#line 1658 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 34: /* simple: CPILE pile_arg  */
+#line 217 "../src/preproc/eqn/eqn.ypp"
+                { (yyvsp[0].pb)->set_alignment(CENTER_ALIGN); (yyval.b) = (yyvsp[0].pb); }
+#line 1664 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 35: /* simple: MATRIX '{' column_list '}'  */
+#line 219 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = (yyvsp[-1].mb); }
+#line 1670 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 36: /* simple: LEFT delim equation RIGHT delim  */
+#line 221 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_delim_box((yyvsp[-3].str), (yyvsp[-2].b), (yyvsp[0].str)); }
+#line 1676 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 37: /* simple: LEFT delim equation  */
+#line 223 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_delim_box((yyvsp[-1].str), (yyvsp[0].b), 0); }
+#line 1682 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 38: /* simple: simple BAR  */
+#line 225 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_overline_box((yyvsp[-1].b)); }
+#line 1688 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 39: /* simple: simple UNDER  */
+#line 227 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_underline_box((yyvsp[-1].b)); }
+#line 1694 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 40: /* simple: simple PRIME  */
+#line 229 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_prime_box((yyvsp[-1].b)); }
+#line 1700 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 41: /* simple: simple ACCENT simple  */
+#line 231 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_accent_box((yyvsp[-2].b), (yyvsp[0].b)); }
+#line 1706 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 42: /* simple: simple UACCENT simple  */
+#line 233 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_uaccent_box((yyvsp[-2].b), (yyvsp[0].b)); }
+#line 1712 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 43: /* simple: ROMAN simple  */
+#line 235 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = new font_box(strsave(get_grfont()), (yyvsp[0].b)); }
+#line 1718 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 44: /* simple: BOLD simple  */
+#line 237 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = new font_box(strsave(get_gbfont()), (yyvsp[0].b)); }
+#line 1724 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 45: /* simple: ITALIC simple  */
+#line 239 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = new font_box(strsave(get_gfont()), (yyvsp[0].b)); }
+#line 1730 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 46: /* simple: FAT simple  */
+#line 241 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = new fat_box((yyvsp[0].b)); }
+#line 1736 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 47: /* simple: FONT text simple  */
+#line 243 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = new font_box((yyvsp[-1].str), (yyvsp[0].b)); }
+#line 1742 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 48: /* simple: SIZE text simple  */
+#line 245 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = new size_box((yyvsp[-1].str), (yyvsp[0].b)); }
+#line 1748 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 49: /* simple: FWD number simple  */
+#line 247 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = new hmotion_box((yyvsp[-1].n), (yyvsp[0].b)); }
+#line 1754 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 50: /* simple: BACK number simple  */
+#line 249 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = new hmotion_box(-(yyvsp[-1].n), (yyvsp[0].b)); }
+#line 1760 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 51: /* simple: UP number simple  */
+#line 251 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = new vmotion_box((yyvsp[-1].n), (yyvsp[0].b)); }
+#line 1766 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 52: /* simple: DOWN number simple  */
+#line 253 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = new vmotion_box(-(yyvsp[-1].n), (yyvsp[0].b)); }
+#line 1772 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 53: /* simple: TYPE text simple  */
+#line 255 "../src/preproc/eqn/eqn.ypp"
+                { (yyvsp[0].b)->set_spacing_type((yyvsp[-1].str)); (yyval.b) = (yyvsp[0].b); }
+#line 1778 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 54: /* simple: VCENTER simple  */
+#line 257 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = new vcenter_box((yyvsp[0].b)); }
+#line 1784 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 55: /* simple: SPECIAL text simple  */
+#line 259 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.b) = make_special_box((yyvsp[-1].str), (yyvsp[0].b)); }
+#line 1790 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 56: /* number: text  */
+#line 264 "../src/preproc/eqn/eqn.ypp"
+                {
+		  int n;
+		  if (sscanf((yyvsp[0].str), "%d", &n) == 1)
+		    (yyval.n) = n;
+		  delete[] (yyvsp[0].str);
+		}
+#line 1801 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 57: /* pile_element_list: equation  */
+#line 274 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.pb) = new pile_box((yyvsp[0].b)); }
+#line 1807 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 58: /* pile_element_list: pile_element_list ABOVE equation  */
+#line 276 "../src/preproc/eqn/eqn.ypp"
+                { (yyvsp[-2].pb)->append((yyvsp[0].b)); (yyval.pb) = (yyvsp[-2].pb); }
+#line 1813 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 59: /* pile_arg: '{' pile_element_list '}'  */
+#line 281 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.pb) = (yyvsp[-1].pb); }
+#line 1819 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 60: /* pile_arg: number '{' pile_element_list '}'  */
+#line 283 "../src/preproc/eqn/eqn.ypp"
+                { (yyvsp[-1].pb)->set_space((yyvsp[-3].n)); (yyval.pb) = (yyvsp[-1].pb); }
+#line 1825 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 61: /* column_list: column  */
+#line 288 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.mb) = new matrix_box((yyvsp[0].col)); }
+#line 1831 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 62: /* column_list: column_list column  */
+#line 290 "../src/preproc/eqn/eqn.ypp"
+                { (yyvsp[-1].mb)->append((yyvsp[0].col)); (yyval.mb) = (yyvsp[-1].mb); }
+#line 1837 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 63: /* column_element_list: equation  */
+#line 295 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.col) = new column((yyvsp[0].b)); }
+#line 1843 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 64: /* column_element_list: column_element_list ABOVE equation  */
+#line 297 "../src/preproc/eqn/eqn.ypp"
+                { (yyvsp[-2].col)->append((yyvsp[0].b)); (yyval.col) = (yyvsp[-2].col); }
+#line 1849 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 65: /* column_arg: '{' column_element_list '}'  */
+#line 302 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.col) = (yyvsp[-1].col); }
+#line 1855 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 66: /* column_arg: number '{' column_element_list '}'  */
+#line 304 "../src/preproc/eqn/eqn.ypp"
+                { (yyvsp[-1].col)->set_space((yyvsp[-3].n)); (yyval.col) = (yyvsp[-1].col); }
+#line 1861 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 67: /* column: COL column_arg  */
+#line 309 "../src/preproc/eqn/eqn.ypp"
+                { (yyvsp[0].col)->set_alignment(CENTER_ALIGN); (yyval.col) = (yyvsp[0].col); }
+#line 1867 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 68: /* column: LCOL column_arg  */
+#line 311 "../src/preproc/eqn/eqn.ypp"
+                { (yyvsp[0].col)->set_alignment(LEFT_ALIGN); (yyval.col) = (yyvsp[0].col); }
+#line 1873 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 69: /* column: RCOL column_arg  */
+#line 313 "../src/preproc/eqn/eqn.ypp"
+                { (yyvsp[0].col)->set_alignment(RIGHT_ALIGN); (yyval.col) = (yyvsp[0].col); }
+#line 1879 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 70: /* column: CCOL column_arg  */
+#line 315 "../src/preproc/eqn/eqn.ypp"
+                { (yyvsp[0].col)->set_alignment(CENTER_ALIGN); (yyval.col) = (yyvsp[0].col); }
+#line 1885 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 71: /* text: TEXT  */
+#line 319 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.str) = (yyvsp[0].str); }
+#line 1891 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 72: /* text: QUOTED_TEXT  */
+#line 321 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.str) = (yyvsp[0].str); }
+#line 1897 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 73: /* delim: text  */
+#line 326 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.str) = (yyvsp[0].str); }
+#line 1903 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 74: /* delim: '{'  */
+#line 328 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.str) = strsave("{"); }
+#line 1909 "src/preproc/eqn/eqn.cpp"
+    break;
+
+  case 75: /* delim: '}'  */
+#line 330 "../src/preproc/eqn/eqn.ypp"
+                { (yyval.str) = strsave("}"); }
+#line 1915 "src/preproc/eqn/eqn.cpp"
+    break;
+
+
+#line 1919 "src/preproc/eqn/eqn.cpp"
+
+      default: break;
+    }
+  /* User semantic actions sometimes alter yychar, and that requires
+     that yytoken be updated with the new translation.  We take the
+     approach of translating immediately before every use of yytoken.
+     One alternative is translating here after every semantic action,
+     but that translation would be missed if the semantic action invokes
+     YYABORT, YYACCEPT, or YYERROR immediately after altering yychar or
+     if it invokes YYBACKUP.  In the case of YYABORT or YYACCEPT, an
+     incorrect destructor might then be invoked immediately.  In the
+     case of YYERROR or YYBACKUP, subsequent parser actions might lead
+     to an incorrect destructor call or verbose syntax error message
+     before the lookahead is translated.  */
+  YY_SYMBOL_PRINT ("-> $$ =", YY_CAST (yysymbol_kind_t, yyr1[yyn]), &yyval, &yyloc);
+
+  YYPOPSTACK (yylen);
+  yylen = 0;
+
+  *++yyvsp = yyval;
+
+  /* Now 'shift' the result of the reduction.  Determine what state
+     that goes to, based on the state we popped back to and the rule
+     number reduced by.  */
+  {
+    const int yylhs = yyr1[yyn] - YYNTOKENS;
+    const int yyi = yypgoto[yylhs] + *yyssp;
+    yystate = (0 <= yyi && yyi <= YYLAST && yycheck[yyi] == *yyssp
+               ? yytable[yyi]
+               : yydefgoto[yylhs]);
+  }
+
+  goto yynewstate;
+
+
+/*--------------------------------------.
+| yyerrlab -- here on detecting error.  |
+`--------------------------------------*/
+yyerrlab:
+  /* Make sure we have latest lookahead translation.  See comments at
+     user semantic actions for why this is necessary.  */
+  yytoken = yychar == YYEMPTY ? YYSYMBOL_YYEMPTY : YYTRANSLATE (yychar);
+  /* If not already recovering from an error, report this error.  */
+  if (!yyerrstatus)
+    {
+      ++yynerrs;
+      yyerror (YY_("syntax error"));
+    }
+
+  if (yyerrstatus == 3)
+    {
+      /* If just tried and failed to reuse lookahead token after an
+         error, discard it.  */
+
+      if (yychar <= YYEOF)
+        {
+          /* Return failure if at end of input.  */
+          if (yychar == YYEOF)
+            YYABORT;
+        }
+      else
+        {
+          yydestruct ("Error: discarding",
+                      yytoken, &yylval);
+          yychar = YYEMPTY;
+        }
+    }
+
+  /* Else will try to reuse lookahead token after shifting the error
+     token.  */
+  goto yyerrlab1;
+
+
+/*---------------------------------------------------.
+| yyerrorlab -- error raised explicitly by YYERROR.  |
+`---------------------------------------------------*/
+yyerrorlab:
+  /* Pacify compilers when the user code never invokes YYERROR and the
+     label yyerrorlab therefore never appears in user code.  */
+  if (0)
+    YYERROR;
+  ++yynerrs;
+
+  /* Do not reclaim the symbols of the rule whose action triggered
+     this YYERROR.  */
+  YYPOPSTACK (yylen);
+  yylen = 0;
+  YY_STACK_PRINT (yyss, yyssp);
+  yystate = *yyssp;
+  goto yyerrlab1;
+
+
+/*-------------------------------------------------------------.
+| yyerrlab1 -- common code for both syntax error and YYERROR.  |
+`-------------------------------------------------------------*/
+yyerrlab1:
+  yyerrstatus = 3;      /* Each real token shifted decrements this.  */
+
+  /* Pop stack until we find a state that shifts the error token.  */
+  for (;;)
+    {
+      yyn = yypact[yystate];
+      if (!yypact_value_is_default (yyn))
+        {
+          yyn += YYSYMBOL_YYerror;
+          if (0 <= yyn && yyn <= YYLAST && yycheck[yyn] == YYSYMBOL_YYerror)
+            {
+              yyn = yytable[yyn];
+              if (0 < yyn)
+                break;
+            }
+        }
+
+      /* Pop the current state because it cannot handle the error token.  */
+      if (yyssp == yyss)
+        YYABORT;
+
+
+      yydestruct ("Error: popping",
+                  YY_ACCESSING_SYMBOL (yystate), yyvsp);
+      YYPOPSTACK (1);
+      yystate = *yyssp;
+      YY_STACK_PRINT (yyss, yyssp);
+    }
+
+  YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+  *++yyvsp = yylval;
+  YY_IGNORE_MAYBE_UNINITIALIZED_END
+
+
+  /* Shift the error token.  */
+  YY_SYMBOL_PRINT ("Shifting", YY_ACCESSING_SYMBOL (yyn), yyvsp, yylsp);
+
+  yystate = yyn;
+  goto yynewstate;
+
+
+/*-------------------------------------.
+| yyacceptlab -- YYACCEPT comes here.  |
+`-------------------------------------*/
+yyacceptlab:
+  yyresult = 0;
+  goto yyreturnlab;
+
+
+/*-----------------------------------.
+| yyabortlab -- YYABORT comes here.  |
+`-----------------------------------*/
+yyabortlab:
+  yyresult = 1;
+  goto yyreturnlab;
+
+
+/*-----------------------------------------------------------.
+| yyexhaustedlab -- YYNOMEM (memory exhaustion) comes here.  |
+`-----------------------------------------------------------*/
+yyexhaustedlab:
+  yyerror (YY_("memory exhausted"));
+  yyresult = 2;
+  goto yyreturnlab;
+
+
+/*----------------------------------------------------------.
+| yyreturnlab -- parsing is finished, clean up and return.  |
+`----------------------------------------------------------*/
+yyreturnlab:
+  if (yychar != YYEMPTY)
+    {
+      /* Make sure we have latest lookahead translation.  See comments at
+         user semantic actions for why this is necessary.  */
+      yytoken = YYTRANSLATE (yychar);
+      yydestruct ("Cleanup: discarding lookahead",
+                  yytoken, &yylval);
+    }
+  /* Do not reclaim the symbols of the rule whose action triggered
+     this YYABORT or YYACCEPT.  */
+  YYPOPSTACK (yylen);
+  YY_STACK_PRINT (yyss, yyssp);
+  while (yyssp != yyss)
+    {
+      yydestruct ("Cleanup: popping",
+                  YY_ACCESSING_SYMBOL (+*yyssp), yyvsp);
+      YYPOPSTACK (1);
+    }
+#ifndef yyoverflow
+  if (yyss != yyssa)
+    YYSTACK_FREE (yyss);
+#endif
+
+  return yyresult;
+}
+
+#line 333 "../src/preproc/eqn/eqn.ypp"
+
diff --git a/src/preproc/eqn/eqn.h b/src/preproc/eqn/eqn.h
new file mode 100644
index 0000000..a4143cb
--- /dev/null
+++ b/src/preproc/eqn/eqn.h
@@ -0,0 +1,57 @@
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "lib.h"
+
+#include <stdlib.h>
+#include <errno.h>
+#include "cset.h"
+#include "errarg.h"
+#include "error.h"
+
+#include "box.h"
+
+typedef enum {troff, mathml} eqnmode_t;
+
+extern char start_delim;
+extern char end_delim;
+extern int non_empty_flag;
+extern int inline_flag;
+extern int draw_flag;
+extern int one_size_reduction_flag;
+extern int compatible_flag;
+extern int nroff;
+extern eqnmode_t output_format;
+extern int xhtml;
+
+void init_lex(const char *str, const char *filename, int lineno);
+void lex_error(const char *message,
+	       const errarg &arg1 = empty_errarg,
+	       const errarg &arg2 = empty_errarg,
+	       const errarg &arg3 = empty_errarg);
+
+void init_table(const char *device);
+
+// prefix for all registers, strings, macros
+#define PREFIX "0"
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/eqn/eqn.hpp b/src/preproc/eqn/eqn.hpp
new file mode 100644
index 0000000..de02d7c
--- /dev/null
+++ b/src/preproc/eqn/eqn.hpp
@@ -0,0 +1,210 @@
+/* A Bison parser, made by GNU Bison 3.8.2.  */
+
+/* Bison interface for Yacc-like parsers in C
+
+   Copyright (C) 1984, 1989-1990, 2000-2015, 2018-2021 Free Software Foundation,
+   Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* As a special exception, you may create a larger work that contains
+   part or all of the Bison parser skeleton and distribute that work
+   under terms of your choice, so long as that work isn't itself a
+   parser generator using the skeleton or a modified version thereof
+   as a parser skeleton.  Alternatively, if you modify or redistribute
+   the parser skeleton itself, you may (at your option) remove this
+   special exception, which will cause the skeleton and the resulting
+   Bison output files to be licensed under the GNU General Public
+   License without this special exception.
+
+   This special exception was added by the Free Software Foundation in
+   version 2.2 of Bison.  */
+
+/* DO NOT RELY ON FEATURES THAT ARE NOT DOCUMENTED in the manual,
+   especially those whose name start with YY_ or yy_.  They are
+   private implementation details that can be changed or removed.  */
+
+#ifndef YY_YY_SRC_PREPROC_EQN_EQN_HPP_INCLUDED
+# define YY_YY_SRC_PREPROC_EQN_EQN_HPP_INCLUDED
+/* Debug traces.  */
+#ifndef YYDEBUG
+# define YYDEBUG 0
+#endif
+#if YYDEBUG
+extern int yydebug;
+#endif
+
+/* Token kinds.  */
+#ifndef YYTOKENTYPE
+# define YYTOKENTYPE
+  enum yytokentype
+  {
+    YYEMPTY = -2,
+    YYEOF = 0,                     /* "end of file"  */
+    YYerror = 256,                 /* error  */
+    YYUNDEF = 257,                 /* "invalid token"  */
+    OVER = 258,                    /* OVER  */
+    SMALLOVER = 259,               /* SMALLOVER  */
+    SQRT = 260,                    /* SQRT  */
+    SUB = 261,                     /* SUB  */
+    SUP = 262,                     /* SUP  */
+    LPILE = 263,                   /* LPILE  */
+    RPILE = 264,                   /* RPILE  */
+    CPILE = 265,                   /* CPILE  */
+    PILE = 266,                    /* PILE  */
+    LEFT = 267,                    /* LEFT  */
+    RIGHT = 268,                   /* RIGHT  */
+    TO = 269,                      /* TO  */
+    FROM = 270,                    /* FROM  */
+    SIZE = 271,                    /* SIZE  */
+    FONT = 272,                    /* FONT  */
+    ROMAN = 273,                   /* ROMAN  */
+    BOLD = 274,                    /* BOLD  */
+    ITALIC = 275,                  /* ITALIC  */
+    FAT = 276,                     /* FAT  */
+    ACCENT = 277,                  /* ACCENT  */
+    BAR = 278,                     /* BAR  */
+    UNDER = 279,                   /* UNDER  */
+    ABOVE = 280,                   /* ABOVE  */
+    TEXT = 281,                    /* TEXT  */
+    QUOTED_TEXT = 282,             /* QUOTED_TEXT  */
+    FWD = 283,                     /* FWD  */
+    BACK = 284,                    /* BACK  */
+    DOWN = 285,                    /* DOWN  */
+    UP = 286,                      /* UP  */
+    MATRIX = 287,                  /* MATRIX  */
+    COL = 288,                     /* COL  */
+    LCOL = 289,                    /* LCOL  */
+    RCOL = 290,                    /* RCOL  */
+    CCOL = 291,                    /* CCOL  */
+    MARK = 292,                    /* MARK  */
+    LINEUP = 293,                  /* LINEUP  */
+    TYPE = 294,                    /* TYPE  */
+    VCENTER = 295,                 /* VCENTER  */
+    PRIME = 296,                   /* PRIME  */
+    SPLIT = 297,                   /* SPLIT  */
+    NOSPLIT = 298,                 /* NOSPLIT  */
+    UACCENT = 299,                 /* UACCENT  */
+    SPECIAL = 300,                 /* SPECIAL  */
+    SPACE = 301,                   /* SPACE  */
+    GFONT = 302,                   /* GFONT  */
+    GSIZE = 303,                   /* GSIZE  */
+    DEFINE = 304,                  /* DEFINE  */
+    NDEFINE = 305,                 /* NDEFINE  */
+    TDEFINE = 306,                 /* TDEFINE  */
+    SDEFINE = 307,                 /* SDEFINE  */
+    UNDEF = 308,                   /* UNDEF  */
+    IFDEF = 309,                   /* IFDEF  */
+    INCLUDE = 310,                 /* INCLUDE  */
+    DELIM = 311,                   /* DELIM  */
+    CHARTYPE = 312,                /* CHARTYPE  */
+    SET = 313,                     /* SET  */
+    GRFONT = 314,                  /* GRFONT  */
+    GBFONT = 315                   /* GBFONT  */
+  };
+  typedef enum yytokentype yytoken_kind_t;
+#endif
+/* Token kinds.  */
+#define YYEMPTY -2
+#define YYEOF 0
+#define YYerror 256
+#define YYUNDEF 257
+#define OVER 258
+#define SMALLOVER 259
+#define SQRT 260
+#define SUB 261
+#define SUP 262
+#define LPILE 263
+#define RPILE 264
+#define CPILE 265
+#define PILE 266
+#define LEFT 267
+#define RIGHT 268
+#define TO 269
+#define FROM 270
+#define SIZE 271
+#define FONT 272
+#define ROMAN 273
+#define BOLD 274
+#define ITALIC 275
+#define FAT 276
+#define ACCENT 277
+#define BAR 278
+#define UNDER 279
+#define ABOVE 280
+#define TEXT 281
+#define QUOTED_TEXT 282
+#define FWD 283
+#define BACK 284
+#define DOWN 285
+#define UP 286
+#define MATRIX 287
+#define COL 288
+#define LCOL 289
+#define RCOL 290
+#define CCOL 291
+#define MARK 292
+#define LINEUP 293
+#define TYPE 294
+#define VCENTER 295
+#define PRIME 296
+#define SPLIT 297
+#define NOSPLIT 298
+#define UACCENT 299
+#define SPECIAL 300
+#define SPACE 301
+#define GFONT 302
+#define GSIZE 303
+#define DEFINE 304
+#define NDEFINE 305
+#define TDEFINE 306
+#define SDEFINE 307
+#define UNDEF 308
+#define IFDEF 309
+#define INCLUDE 310
+#define DELIM 311
+#define CHARTYPE 312
+#define SET 313
+#define GRFONT 314
+#define GBFONT 315
+
+/* Value type.  */
+#if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
+union YYSTYPE
+{
+#line 34 "../src/preproc/eqn/eqn.ypp"
+
+	char *str;
+	box *b;
+	pile_box *pb;
+	matrix_box *mb;
+	int n;
+	column *col;
+
+#line 196 "src/preproc/eqn/eqn.hpp"
+
+};
+typedef union YYSTYPE YYSTYPE;
+# define YYSTYPE_IS_TRIVIAL 1
+# define YYSTYPE_IS_DECLARED 1
+#endif
+
+
+extern YYSTYPE yylval;
+
+
+int yyparse (void);
+
+
+#endif /* !YY_YY_SRC_PREPROC_EQN_EQN_HPP_INCLUDED  */
diff --git a/src/preproc/eqn/eqn.ypp b/src/preproc/eqn/eqn.ypp
new file mode 100644
index 0000000..a22ad59
--- /dev/null
+++ b/src/preproc/eqn/eqn.ypp
@@ -0,0 +1,333 @@
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+%{
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "lib.h"
+#include "box.h"
+extern int non_empty_flag;
+int yylex();
+void yyerror(const char *);
+%}
+
+%union {
+	char *str;
+	box *b;
+	pile_box *pb;
+	matrix_box *mb;
+	int n;
+	column *col;
+}
+
+%token OVER
+%token SMALLOVER
+%token SQRT
+%token SUB
+%token SUP
+%token LPILE
+%token RPILE
+%token CPILE
+%token PILE
+%token LEFT
+%token RIGHT
+%token TO
+%token FROM
+%token SIZE
+%token FONT
+%token ROMAN
+%token BOLD
+%token ITALIC
+%token FAT
+%token ACCENT
+%token BAR
+%token UNDER
+%token ABOVE
+%token <str> TEXT
+%token <str> QUOTED_TEXT
+%token FWD
+%token BACK
+%token DOWN
+%token UP
+%token MATRIX
+%token COL
+%token LCOL
+%token RCOL
+%token CCOL
+%token MARK
+%token LINEUP
+%token TYPE
+%token VCENTER
+%token PRIME
+%token SPLIT
+%token NOSPLIT
+%token UACCENT
+%token SPECIAL
+
+/* these are handled in the lexer */
+%token SPACE
+%token GFONT
+%token GSIZE
+%token DEFINE
+%token NDEFINE
+%token TDEFINE
+%token SDEFINE
+%token UNDEF
+%token IFDEF
+%token INCLUDE
+%token DELIM
+%token CHARTYPE
+%token SET
+%token GRFONT
+%token GBFONT
+
+/* The original eqn manual says that 'left' is right associative. It's lying.
+Consider 'left ( ~ left ( ~ right ) right )'. */
+
+%right LEFT
+%left RIGHT
+%right LPILE RPILE CPILE PILE TEXT QUOTED_TEXT MATRIX MARK LINEUP '^' '~' '\t' '{' SPLIT NOSPLIT
+%right FROM TO
+%left SQRT OVER SMALLOVER
+%right SUB SUP
+%right ROMAN BOLD ITALIC FAT FONT SIZE FWD BACK DOWN UP TYPE VCENTER SPECIAL
+%right BAR UNDER PRIME
+%left ACCENT UACCENT
+
+%type <b> mark from_to sqrt_over script simple equation nonsup
+%type <n> number
+%type <str> text delim
+%type <pb> pile_element_list pile_arg
+%type <mb> column_list
+%type <col> column column_arg column_element_list
+
+%%
+top:
+	/* empty */
+	| equation
+		{ $1->top_level(); non_empty_flag = 1; }
+	;
+
+equation:
+	mark
+		{ $$ = $1; }
+	| equation mark
+		{
+		  list_box *lb = $1->to_list_box();
+		  if (!lb)
+		    lb = new list_box($1);
+		  lb->append($2);
+		  $$ = lb;
+		}
+	;
+
+mark:
+	from_to
+		{ $$ = $1; }
+	| MARK mark
+		{ $$ = make_mark_box($2); }
+	| LINEUP mark
+		{ $$ = make_lineup_box($2); }
+	;
+
+from_to:
+	sqrt_over  %prec FROM
+		{ $$ = $1; }
+	| sqrt_over TO from_to
+		{ $$ = make_limit_box($1, 0, $3); }
+	| sqrt_over FROM sqrt_over
+		{ $$ = make_limit_box($1, $3, 0); }
+	| sqrt_over FROM sqrt_over TO from_to
+		{ $$ = make_limit_box($1, $3, $5); }
+	| sqrt_over FROM sqrt_over FROM from_to
+		{ $$ = make_limit_box($1, make_limit_box($3, $5, 0), 0); }
+	;
+
+sqrt_over:
+	script
+		{ $$ = $1; }
+	| SQRT sqrt_over
+		{ $$ = make_sqrt_box($2); }
+	| sqrt_over OVER sqrt_over
+		{ $$ = make_over_box($1, $3); }
+	| sqrt_over SMALLOVER sqrt_over
+		{ $$ = make_small_over_box($1, $3); }
+	;
+
+script:
+	nonsup
+		{ $$ = $1; }
+	| simple SUP script
+		{ $$ = make_script_box($1, 0, $3); }
+	;
+
+nonsup:
+	simple  %prec SUP
+		{ $$ = $1; }
+	| simple SUB nonsup
+		{ $$ = make_script_box($1, $3, 0); }
+	| simple SUB simple SUP script
+		{ $$ = make_script_box($1, $3, $5); }
+	;
+
+simple:
+	TEXT
+		{ $$ = split_text($1); }
+	| QUOTED_TEXT
+		{ $$ = new quoted_text_box($1); }
+	| SPLIT QUOTED_TEXT
+		{ $$ = split_text($2); }
+	| NOSPLIT TEXT
+		{ $$ = new quoted_text_box($2); }
+	| '^'
+		{ $$ = new half_space_box; }
+	| '~'
+		{ $$ = new space_box; }
+	| '\t'
+		{ $$ = new tab_box; }
+	| '{' equation '}'
+		{ $$ = $2; }
+	| PILE pile_arg
+		{ $2->set_alignment(CENTER_ALIGN); $$ = $2; }
+	| LPILE pile_arg
+		{ $2->set_alignment(LEFT_ALIGN); $$ = $2; }
+	| RPILE pile_arg
+		{ $2->set_alignment(RIGHT_ALIGN); $$ = $2; }
+	| CPILE pile_arg
+		{ $2->set_alignment(CENTER_ALIGN); $$ = $2; }
+	| MATRIX '{' column_list '}'
+		{ $$ = $3; }
+	| LEFT delim equation RIGHT delim
+		{ $$ = make_delim_box($2, $3, $5); }
+	| LEFT delim equation
+		{ $$ = make_delim_box($2, $3, 0); }
+	| simple BAR
+		{ $$ = make_overline_box($1); }
+	| simple UNDER
+		{ $$ = make_underline_box($1); }
+	| simple PRIME
+		{ $$ = make_prime_box($1); }
+	| simple ACCENT simple
+		{ $$ = make_accent_box($1, $3); }
+	| simple UACCENT simple
+		{ $$ = make_uaccent_box($1, $3); }
+	| ROMAN simple
+		{ $$ = new font_box(strsave(get_grfont()), $2); }
+	| BOLD simple
+		{ $$ = new font_box(strsave(get_gbfont()), $2); }
+	| ITALIC simple
+		{ $$ = new font_box(strsave(get_gfont()), $2); }
+	| FAT simple
+		{ $$ = new fat_box($2); }
+	| FONT text simple
+		{ $$ = new font_box($2, $3); }
+	| SIZE text simple
+		{ $$ = new size_box($2, $3); }
+	| FWD number simple
+		{ $$ = new hmotion_box($2, $3); }
+	| BACK number simple
+		{ $$ = new hmotion_box(-$2, $3); }
+	| UP number simple
+		{ $$ = new vmotion_box($2, $3); }
+	| DOWN number simple
+		{ $$ = new vmotion_box(-$2, $3); }
+	| TYPE text simple
+		{ $3->set_spacing_type($2); $$ = $3; }
+	| VCENTER simple
+		{ $$ = new vcenter_box($2); }
+	| SPECIAL text simple
+		{ $$ = make_special_box($2, $3); }
+	;
+	
+number:
+	text
+		{
+		  int n;
+		  if (sscanf($1, "%d", &n) == 1)
+		    $$ = n;
+		  delete[] $1;
+		}
+	;
+
+pile_element_list:
+	equation
+		{ $$ = new pile_box($1); }
+	| pile_element_list ABOVE equation
+		{ $1->append($3); $$ = $1; }
+	;
+
+pile_arg:
+  	'{' pile_element_list '}'
+		{ $$ = $2; }
+	| number '{' pile_element_list '}'
+		{ $3->set_space($1); $$ = $3; }
+	;
+
+column_list:
+	column
+		{ $$ = new matrix_box($1); }
+	| column_list column
+		{ $1->append($2); $$ = $1; }
+	;
+
+column_element_list:
+	equation
+		{ $$ = new column($1); }
+	| column_element_list ABOVE equation
+		{ $1->append($3); $$ = $1; }
+	;
+
+column_arg:
+  	'{' column_element_list '}'
+		{ $$ = $2; }
+	| number '{' column_element_list '}'
+		{ $3->set_space($1); $$ = $3; }
+	;
+
+column:
+	COL column_arg
+		{ $2->set_alignment(CENTER_ALIGN); $$ = $2; }
+	| LCOL column_arg
+		{ $2->set_alignment(LEFT_ALIGN); $$ = $2; }
+	| RCOL column_arg
+		{ $2->set_alignment(RIGHT_ALIGN); $$ = $2; }
+	| CCOL column_arg
+		{ $2->set_alignment(CENTER_ALIGN); $$ = $2; }
+	;
+
+text:	TEXT
+		{ $$ = $1; }
+	| QUOTED_TEXT
+		{ $$ = $1; }
+	;
+
+delim:
+	text
+		{ $$ = $1; }
+	| '{'
+		{ $$ = strsave("{"); }
+	| '}'
+		{ $$ = strsave("}"); }
+	;
+
+%%
diff --git a/src/preproc/eqn/lex.cpp b/src/preproc/eqn/lex.cpp
new file mode 100644
index 0000000..e38a486
--- /dev/null
+++ b/src/preproc/eqn/lex.cpp
@@ -0,0 +1,1236 @@
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "eqn.h"
+#include "eqn.hpp"
+#include "stringclass.h"
+#include "ptable.h"
+
+
+// declarations to avoid friend name injection problems
+int get_char();
+int peek_char();
+int get_location(char **, int *);
+
+struct definition {
+  char is_macro;
+  char is_simple;
+  union {
+    int tok;
+    char *contents;
+  };
+  definition();
+  ~definition();
+};
+
+definition::definition() : is_macro(1), is_simple(0)
+{
+  contents = 0;
+}
+
+definition::~definition()
+{
+  if (is_macro)
+    free(contents);
+}
+
+declare_ptable(definition)
+implement_ptable(definition)
+
+PTABLE(definition) macro_table;
+
+static struct {
+  const char *name;
+  int token;
+} token_table[] = {
+  { "over", OVER },
+  { "smallover", SMALLOVER },
+  { "sqrt", SQRT },
+  { "sub", SUB },
+  { "sup", SUP },
+  { "lpile", LPILE },
+  { "rpile", RPILE },
+  { "cpile", CPILE },
+  { "pile", PILE },
+  { "left", LEFT },
+  { "right", RIGHT },
+  { "to", TO },
+  { "from", FROM },
+  { "size", SIZE },
+  { "font", FONT },
+  { "roman", ROMAN },
+  { "bold", BOLD },
+  { "italic", ITALIC },
+  { "fat", FAT },
+  { "bar", BAR },
+  { "under", UNDER },
+  { "accent", ACCENT },
+  { "uaccent", UACCENT },
+  { "above", ABOVE },
+  { "fwd", FWD },
+  { "back", BACK },
+  { "down", DOWN },
+  { "up", UP },
+  { "matrix", MATRIX },
+  { "col", COL },
+  { "lcol", LCOL },
+  { "rcol", RCOL },
+  { "ccol", CCOL },
+  { "mark", MARK },
+  { "lineup", LINEUP },
+  { "space", SPACE },
+  { "gfont", GFONT },
+  { "gsize", GSIZE },
+  { "define", DEFINE },
+  { "sdefine", SDEFINE },
+  { "ndefine", NDEFINE },
+  { "tdefine", TDEFINE },
+  { "undef", UNDEF },
+  { "ifdef", IFDEF },
+  { "include", INCLUDE },
+  { "copy", INCLUDE },
+  { "delim", DELIM },
+  { "chartype", CHARTYPE },
+  { "type", TYPE },
+  { "vcenter", VCENTER },
+  { "set", SET },
+  { "opprime", PRIME },
+  { "grfont", GRFONT },
+  { "gbfont", GBFONT },
+  { "split", SPLIT },
+  { "nosplit", NOSPLIT },
+  { "special", SPECIAL },
+};
+
+struct builtin_def {
+  const char *name;
+  const char *def;
+};
+
+static struct builtin_def common_defs[] = {
+  { "ALPHA", "\\(*A" },
+  { "BETA", "\\(*B" },
+  { "CHI", "\\(*X" },
+  { "DELTA", "\\(*D" },
+  { "EPSILON", "\\(*E" },
+  { "ETA", "\\(*Y" },
+  { "GAMMA", "\\(*G" },
+  { "IOTA", "\\(*I" },
+  { "KAPPA", "\\(*K" },
+  { "LAMBDA", "\\(*L" },
+  { "MU", "\\(*M" },
+  { "NU", "\\(*N" },
+  { "OMEGA", "\\(*W" },
+  { "OMICRON", "\\(*O" },
+  { "PHI", "\\(*F" },
+  { "PI", "\\(*P" },
+  { "PSI", "\\(*Q" },
+  { "RHO", "\\(*R" },
+  { "SIGMA", "\\(*S" },
+  { "TAU", "\\(*T" },
+  { "THETA", "\\(*H" },
+  { "UPSILON", "\\(*U" },
+  { "XI", "\\(*C" },
+  { "ZETA", "\\(*Z" },
+  { "Alpha", "\\(*A" },
+  { "Beta", "\\(*B" },
+  { "Chi", "\\(*X" },
+  { "Delta", "\\(*D" },
+  { "Epsilon", "\\(*E" },
+  { "Eta", "\\(*Y" },
+  { "Gamma", "\\(*G" },
+  { "Iota", "\\(*I" },
+  { "Kappa", "\\(*K" },
+  { "Lambda", "\\(*L" },
+  { "Mu", "\\(*M" },
+  { "Nu", "\\(*N" },
+  { "Omega", "\\(*W" },
+  { "Omicron", "\\(*O" },
+  { "Phi", "\\(*F" },
+  { "Pi", "\\(*P" },
+  { "Psi", "\\(*Q" },
+  { "Rho", "\\(*R" },
+  { "Sigma", "\\(*S" },
+  { "Tau", "\\(*T" },
+  { "Theta", "\\(*H" },
+  { "Upsilon", "\\(*U" },
+  { "Xi", "\\(*C" },
+  { "Zeta", "\\(*Z" },
+  { "alpha", "\\(*a" },
+  { "beta", "\\(*b" },
+  { "chi", "\\(*x" },
+  { "delta", "\\(*d" },
+  { "epsilon", "\\(*e" },
+  { "eta", "\\(*y" },
+  { "gamma", "\\(*g" },
+  { "iota", "\\(*i" },
+  { "kappa", "\\(*k" },
+  { "lambda", "\\(*l" },
+  { "mu", "\\(*m" },
+  { "nu", "\\(*n" },
+  { "omega", "\\(*w" },
+  { "omicron", "\\(*o" },
+  { "phi", "\\(*f" },
+  { "pi", "\\(*p" },
+  { "psi", "\\(*q" },
+  { "rho", "\\(*r" },
+  { "sigma", "\\(*s" },
+  { "tau", "\\(*t" },
+  { "theta", "\\(*h" },
+  { "upsilon", "\\(*u" },
+  { "xi", "\\(*c" },
+  { "zeta", "\\(*z" },
+  { "max", "{type \"operator\" roman \"max\"}" },
+  { "min", "{type \"operator\" roman \"min\"}" },
+  { "lim", "{type \"operator\" roman \"lim\"}" },
+  { "sin", "{type \"operator\" roman \"sin\"}" },
+  { "cos", "{type \"operator\" roman \"cos\"}" },
+  { "tan", "{type \"operator\" roman \"tan\"}" },
+  { "sinh", "{type \"operator\" roman \"sinh\"}" },
+  { "cosh", "{type \"operator\" roman \"cosh\"}" },
+  { "tanh", "{type \"operator\" roman \"tanh\"}" },
+  { "arc", "{type \"operator\" roman \"arc\"}" },
+  { "log", "{type \"operator\" roman \"log\"}" },
+  { "ln", "{type \"operator\" roman \"ln\"}" },
+  { "exp", "{type \"operator\" roman \"exp\"}" },
+  { "Re", "{type \"operator\" roman \"Re\"}" },
+  { "Im", "{type \"operator\" roman \"Im\"}" },
+  { "det", "{type \"operator\" roman \"det\"}" },
+  { "and", "{roman \"and\"}" },
+  { "if", "{roman \"if\"}" },
+  { "for", "{roman \"for\"}" },
+  { "times", "type \"binary\" \\(mu" },
+  { "ldots", "type \"inner\" { . . . }" },
+  { "inf", "\\(if" },
+  { "partial", "\\(pd" },
+  { "nothing", "\"\"" },
+  { "half", "{1 smallover 2}" },
+  { "hat_def", "roman \"^\"" },
+  { "hat", "accent { hat_def }" },
+  { "tilde_def", "\"~\"" },
+  { "tilde", "accent { tilde_def }" },
+  { "==", "type \"relation\" \\(==" },
+  { "!=", "type \"relation\" \\(!=" },
+  { "+-", "type \"binary\" \\(+-" },
+  { "->", "type \"relation\" \\(->" },
+  { "<-", "type \"relation\" \\(<-" },
+  { "<<", "type \"relation\" \\(<<" },
+  { ">>", "type \"relation\" \\(>>" },
+  { "prime", "'" },
+  { "approx", "type \"relation\" \"\\(~=\"" },
+  { "grad", "\\(gr" },
+  { "del", "\\(gr" },
+  { "cdot", "type \"binary\" \\(md" },
+  { "cdots", "type \"inner\" { \\(md \\(md \\(md }" },
+  { "dollar", "$" },
+};  
+
+/* composite definitions that require troff size and motion operators */
+static struct builtin_def troff_defs[] = {
+  { "sum", "{type \"operator\" vcenter size +5 \\(*S}" },
+  { "prod", "{type \"operator\" vcenter size +5 \\(*P}" },
+  { "int", "{type \"operator\" vcenter size +8 \\(is}" },
+  { "union", "{type \"operator\" vcenter size +5 \\(cu}" },
+  { "inter", "{type \"operator\" vcenter size +5 \\(ca}" },
+  { "dot_def", "up 52 back 15 \".\"" },
+  { "dot", "accent { dot_def }" },
+  { "dotdot_def", "up 52 back 25 \"..\"" },
+  { "dotdot", "accent { dotdot_def }" },
+  { "utilde_def", "down 75 \"~\"" },
+  { "utilde", "uaccent { utilde_def }" },
+  { "vec_def", "up 52 size -5 \\(->" },
+  { "vec", "accent { vec_def }" },
+  { "dyad_def", "up 52 size -5 { \\(<> }" },
+  { "dyad", "accent { dyad_def }" },
+  { "...", "type \"inner\" { . . . }" },
+};
+
+/* equivalent definitions for MathML mode */
+static struct builtin_def mathml_defs[] = {
+  { "sum", "{type \"operator\" size big \\(*S}" },
+  { "prod", "{type \"operator\" size big \\(*P}" },
+  { "int", "{type \"operator\" size big \\(is}" },
+  { "union", "{type \"operator\" size big \\(cu}" },
+  { "inter", "{type \"operator\" size big \\(ca}" },
+  { "dot", "accent { \".\" }" },
+  { "dotdot", "accent { \"..\" }" },
+  { "utilde", "uaccent { \"~\" }" },
+  { "vec", "accent { \\(-> }" },
+  { "dyad", "accent { \\(<> }" },
+  { "...", "type \"inner\" { . . . }" },
+};
+
+void init_table(const char *device)
+{
+  unsigned int i;
+  for (i = 0; i < sizeof(token_table)/sizeof(token_table[0]); i++) {
+    definition *def = new definition[1];
+    def->is_macro = 0;
+    def->tok = token_table[i].token;
+    macro_table.define(token_table[i].name, def);
+  }
+  for (i = 0; i < sizeof(common_defs)/sizeof(common_defs[0]); i++) {
+    definition *def = new definition[1];
+    def->is_macro = 1;
+    def->contents = strsave(common_defs[i].def);
+    def->is_simple = 1;
+    macro_table.define(common_defs[i].name, def);
+  }
+  if (output_format == troff) {
+    for (i = 0; i < sizeof(troff_defs)/sizeof(troff_defs[0]); i++) {
+      definition *def = new definition[1];
+      def->is_macro = 1;
+      def->contents = strsave(troff_defs[i].def);
+      def->is_simple = 1;
+      macro_table.define(troff_defs[i].name, def);
+    }
+  }
+  else if (output_format == mathml) {
+    for (i = 0; i < sizeof(mathml_defs)/sizeof(mathml_defs[0]); i++) {
+      definition *def = new definition[1];
+      def->is_macro = 1;
+      def->contents = strsave(mathml_defs[i].def);
+      def->is_simple = 1;
+      macro_table.define(mathml_defs[i].name, def);
+    }
+  }
+  definition *def = new definition[1];
+  def->is_macro = 1;
+  def->contents = strsave("1");
+  macro_table.define(device, def);
+}
+
+class input {
+  input *next;
+public:
+  input(input *p);
+  virtual ~input();
+  virtual int get() = 0;
+  virtual int peek() = 0;
+  virtual int get_location(char **, int *);
+
+  friend int get_char();
+  friend int peek_char();
+  friend int get_location(char **, int *);
+  friend void init_lex(const char *str, const char *filename, int lineno);
+};
+
+class file_input : public input {
+  FILE *fp;
+  char *filename;
+  int lineno;
+  string line;
+  const char *ptr;
+  int read_line();
+public:
+  file_input(FILE *, const char *, input *);
+  ~file_input();
+  int get();
+  int peek();
+  int get_location(char **, int *);
+};
+
+
+class macro_input : public input {
+  char *s;
+  char *p;
+public:
+  macro_input(const char *, input *);
+  ~macro_input();
+  int get();
+  int peek();
+};
+
+class top_input : public macro_input {
+  char *filename;
+  int lineno;
+ public:
+  top_input(const char *, const char *, int, input *);
+  ~top_input();
+  int get();
+  int get_location(char **, int *);
+};
+
+class argument_macro_input: public input {
+  char *s;
+  char *p;
+  char *ap;
+  int argc;
+  char *argv[9];
+public:
+  argument_macro_input(const char *, int, char **, input *);
+  ~argument_macro_input();
+  int get();
+  int peek();
+};
+
+input::input(input *x) : next(x)
+{
+}
+
+input::~input()
+{
+}
+
+int input::get_location(char **, int *)
+{
+  return 0;
+}
+
+file_input::file_input(FILE *f, const char *fn, input *p)
+: input(p), lineno(0), ptr("")
+{
+  fp = f;
+  filename = strsave(fn);
+}
+
+file_input::~file_input()
+{
+  if (fclose(fp) < 0)
+    fatal("unable to close '%1': %2", filename, strerror(errno));
+  delete[] filename;
+}
+
+int file_input::read_line()
+{
+  for (;;) {
+    line.clear();
+    lineno++;
+    for (;;) {
+      int c = getc(fp);
+      if (c == '\r') {
+	c = getc(fp);
+	if (c != '\n')
+	  lex_error("invalid input character code %1", '\r');
+      }
+      if (c == EOF)
+	break;
+      else if (is_invalid_input_char(c))
+	lex_error("invalid input character code %1", c);
+      else {
+	line += char(c);
+	if (c == '\n') 
+	  break;
+      }
+    }
+    if (line.length() == 0)
+      return 0;
+    if (!(line.length() >= 3 && line[0] == '.' && line[1] == 'E'
+	  && (line[2] == 'Q' || line[2] == 'N')
+	  && (line.length() == 3 || line[3] == ' ' || line[3] == '\n'
+	      || compatible_flag))) {
+      line += '\0';
+      ptr = line.contents();
+      return 1;
+    }
+  }
+}
+
+int file_input::get()
+{
+  if (*ptr != '\0' || read_line())
+    return *ptr++ & 0377;
+  else
+    return EOF;
+}
+
+int file_input::peek()
+{
+  if (*ptr != '\0' || read_line())
+    return *ptr;
+  else
+    return EOF;
+}
+
+int file_input::get_location(char **fnp, int *lnp)
+{
+  *fnp = filename;
+  *lnp = lineno;
+  return 1;
+}
+
+macro_input::macro_input(const char *str, input *x) : input(x)
+{
+  p = s = strsave(str);
+}
+
+macro_input::~macro_input()
+{
+  free(s);
+}
+
+int macro_input::get()
+{
+  if (p == 0 || *p == '\0')
+    return EOF;
+  else
+    return *p++ & 0377;
+}
+
+int macro_input::peek()
+{
+  if (p == 0 || *p == '\0')
+    return EOF;
+  else
+    return *p & 0377;
+}
+
+top_input::top_input(const char *str, const char *fn, int ln, input *x)
+: macro_input(str, x), lineno(ln)
+{
+  filename = strsave(fn);
+}
+
+top_input::~top_input()
+{
+  free(filename);
+}
+
+int top_input::get()
+{
+  int c = macro_input::get();
+  if (c == '\n')
+    lineno++;
+  return c;
+}
+
+int top_input::get_location(char **fnp, int *lnp)
+{
+  *fnp = filename;
+  *lnp = lineno;
+  return 1;
+}
+
+// Character representing $1.  Must be invalid input character.
+#define ARG1 14
+
+argument_macro_input::argument_macro_input(const char *body, int ac, 
+					   char **av, input *x)
+: input(x), ap(0), argc(ac)
+{
+  int i;
+  for (i = 0; i < argc; i++)
+    argv[i] = av[i];
+  p = s = strsave(body);
+  int j = 0;
+  for (i = 0; s[i] != '\0'; i++)
+    if (s[i] == '$' && s[i+1] >= '0' && s[i+1] <= '9') {
+      if (s[i+1] != '0')
+	s[j++] = ARG1 + s[++i] - '1';
+    }
+    else
+      s[j++] = s[i];
+  s[j] = '\0';
+}
+
+
+argument_macro_input::~argument_macro_input()
+{
+  for (int i = 0; i < argc; i++)
+    delete[] argv[i];
+  delete[] s;
+}
+
+int argument_macro_input::get()
+{
+  if (ap) {
+    if (*ap != '\0')
+      return *ap++ & 0377;
+    ap = 0;
+  }
+  if (p == 0)
+    return EOF;
+  while (*p >= ARG1 && *p <= ARG1 + 8) {
+    int i = *p++ - ARG1;
+    if (i < argc && argv[i] != 0 && argv[i][0] != '\0') {
+      ap = argv[i];
+      return *ap++ & 0377;
+    }
+  }
+  if (*p == '\0')
+    return EOF;
+  return *p++ & 0377;
+}
+
+int argument_macro_input::peek()
+{
+  if (ap) {
+    if (*ap != '\0')
+      return *ap & 0377;
+    ap = 0;
+  }
+  if (p == 0)
+    return EOF;
+  while (*p >= ARG1 && *p <= ARG1 + 8) {
+    int i = *p++ - ARG1;
+    if (i < argc && argv[i] != 0 && argv[i][0] != '\0') {
+      ap = argv[i];
+      return *ap & 0377;
+    }
+  }
+  if (*p == '\0')
+    return EOF;
+  return *p & 0377;
+}
+
+static input *current_input = 0;
+
+/* we insert a newline between input from different levels */
+
+int get_char()
+{
+  if (current_input == 0)
+    return EOF;
+  else {
+    int c = current_input->get();
+    if (c != EOF)
+      return c;
+    else {
+      input *tem = current_input;
+      current_input = current_input->next;
+      delete tem;
+      return '\n';
+    }
+  }
+}
+
+int peek_char()
+{
+  if (current_input == 0)
+    return EOF;
+  else {
+    int c = current_input->peek();
+    if (c != EOF)
+      return c;
+    else
+      return '\n';
+  }
+}
+
+int get_location(char **fnp, int *lnp)
+{
+  for (input *p = current_input; p; p = p->next)
+    if (p->get_location(fnp, lnp))
+      return 1;
+  return 0;
+}
+
+string token_buffer;
+const int NCONTEXT = 4;
+string context_ring[NCONTEXT];
+int context_index = 0;
+
+void flush_context()
+{
+  for (int i = 0; i < NCONTEXT; i++)
+    context_ring[i] = "";
+  context_index = 0;
+}
+
+void show_context()
+{
+  int i = context_index;
+  fputs(" context is\n\t", stderr);
+  for (;;) {
+    int j = (i + 1) % NCONTEXT;
+    if (j == context_index) {
+      fputs(">>> ", stderr);
+      put_string(context_ring[i], stderr);
+      fputs(" <<<", stderr);
+      break;
+    }
+    else if (context_ring[i].length() > 0) {
+      put_string(context_ring[i], stderr);
+      putc(' ', stderr);
+    }
+    i = j;
+  }
+  putc('\n', stderr);
+}
+
+void add_context(const string &s)
+{
+  context_ring[context_index] = s;
+  context_index = (context_index + 1) % NCONTEXT;
+}
+
+void add_context(char c)
+{
+  context_ring[context_index] = c;
+  context_index = (context_index + 1) % NCONTEXT;
+}
+
+void add_quoted_context(const string &s)
+{
+  string &r = context_ring[context_index];
+  r = '"';
+  for (int i = 0; i < s.length(); i++)
+    if (s[i] == '"')
+      r += "\\\"";
+    else
+      r += s[i];
+  r += '"';
+  context_index = (context_index + 1) % NCONTEXT;
+}
+
+void init_lex(const char *str, const char *filename, int lineno)
+{
+  while (current_input != 0) {
+    input *tem = current_input;
+    current_input = current_input->next;
+    delete tem;
+  }
+  current_input = new top_input(str, filename, lineno, 0);
+  flush_context();
+}
+
+
+void get_delimited_text()
+{
+  char *filename, *last_seen_filename;
+  int lineno;
+  int got_location = get_location(&filename, &lineno);
+  // `filename` gets invalidated if we iterate off the end of the file.
+  last_seen_filename = strdup(filename);
+  int start = get_char();
+  while (start == ' ' || start == '\t' || start == '\n')
+    start = get_char();
+  token_buffer.clear();
+  if (start == EOF) {
+    current_lineno = 0;
+    if (got_location)
+      error_with_file_and_line(last_seen_filename, lineno,
+			       "end of input while defining macro");
+    else
+      error("end of input while defining macro");
+    free(last_seen_filename);
+    return;
+  }
+  for (;;) {
+    int c = get_char();
+    if (c == EOF) {
+      current_lineno = 0;
+      if (got_location)
+	error_with_file_and_line(last_seen_filename, lineno,
+				 "end of input while defining macro");
+      else
+	error("end of input while defining macro");
+      add_context(start + token_buffer);
+      free(last_seen_filename);
+      return;
+    }
+    if (c == start)
+      break;
+    token_buffer += char(c);
+  }
+  add_context(start + token_buffer + start);
+  free(last_seen_filename);
+}
+
+void interpolate_macro_with_args(const char *body)
+{
+  char *argv[9];
+  int argc = 0;
+  int i;
+  for (i = 0; i < 9; i++)
+    argv[i] = 0;
+  int level = 0;
+  int c;
+  do {
+    token_buffer.clear();
+    for (;;) {
+      c = get_char();
+      if (c == EOF) {
+	lex_error("end of input while scanning macro arguments");
+	break;
+      }
+      if (level == 0 && (c == ',' || c == ')')) {
+	if (token_buffer.length() > 0) {
+	  token_buffer +=  '\0';
+	  argv[argc] = strsave(token_buffer.contents());
+	}
+	// for 'foo()', argc = 0
+	if (argc > 0 || c != ')' || i > 0)
+	  argc++;
+	break;
+      }
+      token_buffer += char(c);
+      if (c == '(')
+	level++;
+      else if (c == ')')
+	level--;
+    }
+  } while (c != ')' && c != EOF);
+  current_input = new argument_macro_input(body, argc, argv, current_input);
+}
+
+/* If lookup flag is non-zero the token will be looked up to see
+if it is macro. If it's 1, it will looked up to see if it's a token.
+*/
+
+int get_token(int lookup_flag = 0)
+{
+  for (;;) {
+    int c = get_char();
+    while (c == ' ' || c == '\n')
+      c = get_char();
+    switch (c) {
+    case EOF:
+      {
+	add_context("end of input");
+      }
+      return 0;
+    case '"':
+      {
+	int quoted = 0;
+	token_buffer.clear();
+	for (;;) {
+	  c = get_char();
+	  if (c == EOF) {
+	    lex_error("missing \"");
+	    break;
+	  }
+	  else if (c == '\n') {
+	    lex_error("newline before end of quoted text");
+	    break;
+	  }
+	  else if (c == '"') {
+	    if (!quoted)
+	      break;
+	    token_buffer[token_buffer.length() - 1] = '"';
+	    quoted = 0;
+	  }
+	  else {
+	    token_buffer += c;
+	    quoted = quoted ? 0 : c == '\\';
+	  }
+	}
+      }
+      add_quoted_context(token_buffer);
+      return QUOTED_TEXT;
+    case '{':
+    case '}':
+    case '^':
+    case '~':
+    case '\t':
+      add_context(c);
+      return c;
+    default:
+      {
+	int break_flag = 0;
+	int quoted = 0;
+	token_buffer.clear();
+	if (c == '\\')
+	  quoted = 1;
+	else
+	  token_buffer += c;
+	int done = 0;
+	while (!done) {
+	  c = peek_char();
+	  if (!quoted && lookup_flag != 0 && c == '(') {
+	    token_buffer += '\0';
+	    definition *def = macro_table.lookup(token_buffer.contents());
+	    if (def && def->is_macro && !def->is_simple) {
+	      (void)get_char();	// skip initial '('
+	      interpolate_macro_with_args(def->contents);
+	      break_flag = 1;
+	      break;
+	    }
+	    token_buffer.set_length(token_buffer.length() - 1);
+	  }
+	  if (quoted) {
+	    quoted = 0;
+	    switch (c) {
+	    case EOF:
+	      lex_error("'\\' ignored at end of equation");
+	      done = 1;
+	      break;
+	    case '\n':
+	      lex_error("'\\' ignored because followed by newline");
+	      done = 1;
+	      break;
+	    case '\t':
+	      lex_error("'\\' ignored because followed by tab");
+	      done = 1;
+	      break;
+	    case '"':
+	      (void)get_char();
+	      token_buffer += '"';
+	      break;
+	    default:
+	      (void)get_char();
+	      token_buffer += '\\';
+	      token_buffer += c;
+	      break;
+	    }
+	  }
+	  else {
+	    switch (c) {
+	    case EOF:
+	    case '{':
+	    case '}':
+	    case '^':
+	    case '~':
+	    case '"':
+	    case ' ':
+	    case '\t':
+	    case '\n':
+	      done = 1;
+	      break;
+	    case '\\':
+	      (void)get_char();
+	      quoted = 1;
+	      break;
+	    default:
+	      (void)get_char();
+	      token_buffer += char(c);
+	      break;
+	    }
+	  }
+	}
+	if (break_flag || token_buffer.length() == 0)
+	  break;
+	if (lookup_flag != 0) {
+	  token_buffer += '\0';
+	  definition *def = macro_table.lookup(token_buffer.contents());
+	  token_buffer.set_length(token_buffer.length() - 1);
+	  if (def) {
+	    if (def->is_macro) {
+	      current_input = new macro_input(def->contents, current_input);
+	      break;
+	    }
+	    else if (lookup_flag == 1) {
+	      add_context(token_buffer);
+	      return def->tok;
+	    }
+	  }
+	}
+	add_context(token_buffer);
+	return TEXT;
+      }
+    }
+  }
+}
+
+void do_include()
+{
+  int t = get_token(2);
+  if (t != TEXT && t != QUOTED_TEXT) {
+    lex_error("bad filename for include");
+    return;
+  }
+  token_buffer += '\0';
+  const char *filename = token_buffer.contents();
+  errno = 0;
+  FILE *fp = fopen(filename, "r");
+  if (fp == 0) {
+    lex_error("can't open included file '%1'", filename);
+    return;
+  }
+  current_input = new file_input(fp, filename, current_input);
+}
+
+void ignore_definition()
+{
+  int t = get_token();
+  if (t != TEXT) {
+    lex_error("bad definition");
+    return;
+  }
+  get_delimited_text();
+}
+
+void do_definition(int is_simple)
+{
+  int t = get_token();
+  if (t != TEXT) {
+    lex_error("bad definition");
+    return;
+  }
+  token_buffer += '\0';
+  const char *name = token_buffer.contents();
+  definition *def = macro_table.lookup(name);
+  if (def == 0) {
+    def = new definition[1];
+    macro_table.define(name, def);
+  }
+  else if (def->is_macro) {
+    free(def->contents);
+  }
+  get_delimited_text();
+  token_buffer += '\0';
+  def->is_macro = 1;
+  def->contents = strsave(token_buffer.contents());
+  def->is_simple = is_simple;
+}
+
+void do_undef()
+{
+  int t = get_token();
+  if (t != TEXT) {
+    lex_error("bad undef command");
+    return;
+  }
+  token_buffer += '\0';
+  macro_table.define(token_buffer.contents(), 0);
+}
+
+void do_gsize()
+{
+  int t = get_token(2);
+  if (t != TEXT && t != QUOTED_TEXT) {
+    lex_error("bad argument to gsize command");
+    return;
+  }
+  token_buffer += '\0';
+  if (!set_gsize(token_buffer.contents()))
+    lex_error("invalid size '%1'", token_buffer.contents());
+}
+
+void do_gfont()
+{
+  int t = get_token(2);
+  if (t != TEXT && t != QUOTED_TEXT) {
+    lex_error("bad argument to gfont command");
+    return;
+  }
+  token_buffer += '\0';
+  set_gfont(token_buffer.contents());
+}
+
+void do_grfont()
+{
+  int t = get_token(2);
+  if (t != TEXT && t != QUOTED_TEXT) {
+    lex_error("bad argument to grfont command");
+    return;
+  }
+  token_buffer += '\0';
+  set_grfont(token_buffer.contents());
+}
+
+void do_gbfont()
+{
+  int t = get_token(2);
+  if (t != TEXT && t != QUOTED_TEXT) {
+    lex_error("bad argument to gbfont command");
+    return;
+  }
+  token_buffer += '\0';
+  set_gbfont(token_buffer.contents());
+}
+
+void do_space()
+{
+  int t = get_token(2);
+  if (t != TEXT && t != QUOTED_TEXT) {
+    lex_error("bad argument to space command");
+    return;
+  }
+  token_buffer += '\0';
+  char *ptr;
+  long n = strtol(token_buffer.contents(), &ptr, 10);
+  if (n == 0 && ptr == token_buffer.contents())
+    lex_error("bad argument '%1' to space command", token_buffer.contents());
+  else
+    set_space(int(n));
+}
+
+void do_ifdef()
+{
+  int t = get_token();
+  if (t != TEXT) {
+    lex_error("bad ifdef");
+    return;
+  }
+  token_buffer += '\0';
+  definition *def = macro_table.lookup(token_buffer.contents());
+  int result = def && def->is_macro && !def->is_simple;
+  get_delimited_text();
+  if (result) {
+    token_buffer += '\0';
+    current_input = new macro_input(token_buffer.contents(), current_input);
+  }
+}
+
+char start_delim_saved = '\0';
+char end_delim_saved = '\0';
+
+void do_delim()
+{
+  int c = get_char();
+  while (c == ' ' || c == '\n')
+    c = get_char();
+  int d;
+  if (c == EOF || (d = get_char()) == EOF)
+    lex_error("end of file while reading argument to 'delim'");
+  else {
+    if (c == 'o' && d == 'f' && peek_char() == 'f') {
+      (void)get_char();
+      start_delim_saved = start_delim;
+      end_delim_saved = end_delim;
+      start_delim = end_delim = '\0';
+    }
+    else if (c == 'o' && d == 'n') {
+      start_delim = start_delim_saved;
+      end_delim = end_delim_saved;
+    }
+    else {
+      start_delim = c;
+      end_delim = d;
+    }
+  }
+}
+
+void do_chartype()
+{
+  int t = get_token(2);
+  if (t != TEXT && t != QUOTED_TEXT) {
+    lex_error("bad chartype");
+    return;
+  }
+  token_buffer += '\0';
+  string type = token_buffer;
+  t = get_token();
+  if (t != TEXT && t != QUOTED_TEXT) {
+    lex_error("bad chartype");
+    return;
+  }
+  token_buffer += '\0';
+  set_char_type(type.contents(), strsave(token_buffer.contents()));
+}
+
+void do_set()
+{
+  int t = get_token(2);
+  if (t != TEXT && t != QUOTED_TEXT) {
+    lex_error("bad set");
+    return;
+  }
+  token_buffer += '\0';
+  string param = token_buffer;
+  t = get_token();
+  if (t != TEXT && t != QUOTED_TEXT) {
+    lex_error("bad set");
+    return;
+  }
+  token_buffer += '\0';
+  int n;
+  if (sscanf(&token_buffer[0], "%d", &n) != 1) {
+    lex_error("bad number '%1'", token_buffer.contents());
+    return;
+  }
+  set_param(param.contents(), n);
+}
+
+int yylex()
+{
+  for (;;) {
+    int tk = get_token(1);
+    switch(tk) {
+    case UNDEF:
+      do_undef();
+      break;
+    case SDEFINE:
+      do_definition(1);
+      break;
+    case DEFINE:
+      do_definition(0);
+      break;
+    case TDEFINE:
+      if (!nroff)
+	do_definition(0);
+      else
+	ignore_definition();
+      break;
+    case NDEFINE:
+      if (nroff)
+	do_definition(0);
+      else
+	ignore_definition();
+      break;
+    case GSIZE:
+      do_gsize();
+      break;
+    case GFONT:
+      do_gfont();
+      break;
+    case GRFONT:
+      do_grfont();
+      break;
+    case GBFONT:
+      do_gbfont();
+      break;
+    case SPACE:
+      do_space();
+      break;
+    case INCLUDE:
+      do_include();
+      break;
+    case IFDEF:
+      do_ifdef();
+      break;
+    case DELIM:
+      do_delim();
+      break;
+    case CHARTYPE:
+      do_chartype();
+      break;
+    case SET:
+      do_set();
+      break;
+    case QUOTED_TEXT:
+    case TEXT:
+      token_buffer += '\0';
+      yylval.str = strsave(token_buffer.contents());
+      // fall through
+    default:
+      return tk;
+    }
+  }
+}
+
+void lex_error(const char *message,
+	       const errarg &arg1,
+	       const errarg &arg2,
+	       const errarg &arg3)
+{
+  char *filename;
+  int lineno;
+  if (!get_location(&filename, &lineno))
+    error(message, arg1, arg2, arg3);
+  else
+    error_with_file_and_line(filename, lineno, message, arg1, arg2, arg3);
+}
+
+void yyerror(const char *s)
+{
+  char *filename;
+  int lineno;
+  if (!get_location(&filename, &lineno))
+    error(s);
+  else
+    error_with_file_and_line(filename, lineno, s);
+  show_context();
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/eqn/limit.cpp b/src/preproc/eqn/limit.cpp
new file mode 100644
index 0000000..bf64a04
--- /dev/null
+++ b/src/preproc/eqn/limit.cpp
@@ -0,0 +1,217 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "eqn.h"
+#include "pbox.h"
+
+class limit_box : public box {
+private:
+  box *p;
+  box *from;
+  box *to;
+public:
+  limit_box(box *, box *, box *);
+  ~limit_box();
+  int compute_metrics(int);
+  void output();
+  void debug_print();
+  void check_tabs(int);
+};
+
+box *make_limit_box(box *pp, box *qq, box *rr)
+{
+  return new limit_box(pp, qq, rr);
+}
+
+limit_box::limit_box(box *pp, box *qq, box *rr)
+: p(pp), from(qq), to(rr)
+{
+  spacing_type = p->spacing_type;
+}
+
+limit_box::~limit_box()
+{
+  delete p;
+  delete from;
+  delete to;
+}
+
+int limit_box::compute_metrics(int style)
+{
+  printf(".nr " SIZE_FORMAT " \\n[.ps]\n", uid);
+  if (!(style <= SCRIPT_STYLE && one_size_reduction_flag))
+    set_script_size();
+  printf(".nr " SMALL_SIZE_FORMAT " \\n[.ps]\n", uid);
+  int res = 0;
+  int mark_uid = -1;
+  if (from != 0) {
+    res = from->compute_metrics(cramped_style(script_style(style)));
+    if (res)
+      mark_uid = from->uid;
+  }
+  if (to != 0) {
+    int r = to->compute_metrics(script_style(style));
+    if (res && r)
+      error("multiple marks and lineups");
+    else  {
+      mark_uid = to->uid;
+      res = r;
+    }
+  }
+  printf(".ps \\n[" SIZE_FORMAT "]u\n", uid);
+  int r = p->compute_metrics(style);
+  p->compute_subscript_kern();
+  if (res && r)
+    error("multiple marks and lineups");
+  else {
+    mark_uid = p->uid;
+    res = r;
+  }
+  printf(".nr " LEFT_WIDTH_FORMAT " "
+	 "0\\n[" WIDTH_FORMAT "]",
+	 uid, p->uid);
+  if (from != 0)
+    printf(">?(\\n[" SUB_KERN_FORMAT "]+\\n[" WIDTH_FORMAT "])",
+	   p->uid, from->uid);
+  if (to != 0)
+    printf(">?(-\\n[" SUB_KERN_FORMAT "]+\\n[" WIDTH_FORMAT "])",
+	   p->uid, to->uid);
+  printf("/2\n");
+  printf(".nr " WIDTH_FORMAT " "
+	 "0\\n[" WIDTH_FORMAT "]",
+	 uid, p->uid);
+  if (from != 0)
+    printf(">?(-\\n[" SUB_KERN_FORMAT "]+\\n[" WIDTH_FORMAT "])",
+	   p->uid, from->uid);
+  if (to != 0)
+    printf(">?(\\n[" SUB_KERN_FORMAT "]+\\n[" WIDTH_FORMAT "])",
+	   p->uid, to->uid);
+  printf("/2+\\n[" LEFT_WIDTH_FORMAT "]\n", uid);
+  printf(".nr " WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]", uid, p->uid);
+  if (to != 0)
+    printf(">?\\n[" WIDTH_FORMAT "]", to->uid);
+  if (from != 0)
+    printf(">?\\n[" WIDTH_FORMAT "]", from->uid);
+  printf("\n");
+  if (res)
+    printf(".nr " MARK_REG " +(\\n[" LEFT_WIDTH_FORMAT "]"
+	   "-(\\n[" WIDTH_FORMAT "]/2))\n",
+	   uid, mark_uid);
+  if (to != 0) {
+    printf(".nr " SUP_RAISE_FORMAT " %dM+\\n[" DEPTH_FORMAT
+	   "]>?%dM+\\n[" HEIGHT_FORMAT "]\n",
+	   uid, big_op_spacing1, to->uid, big_op_spacing3, p->uid);
+    printf(".nr " HEIGHT_FORMAT " \\n[" SUP_RAISE_FORMAT "]+\\n["
+	   HEIGHT_FORMAT "]+%dM\n",
+	   uid, uid, to->uid, big_op_spacing5);
+  }
+  else
+    printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]\n", uid, p->uid);
+  if (from != 0) {
+    printf(".nr " SUB_LOWER_FORMAT " %dM+\\n[" HEIGHT_FORMAT
+	   "]>?%dM+\\n[" DEPTH_FORMAT "]\n",
+	   uid, big_op_spacing2, from->uid, big_op_spacing4, p->uid);
+    printf(".nr " DEPTH_FORMAT " \\n[" SUB_LOWER_FORMAT "]+\\n["
+	   DEPTH_FORMAT "]+%dM\n",
+	   uid, uid, from->uid, big_op_spacing5);
+  }
+  else
+    printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]\n", uid, p->uid);
+  return res;
+}
+
+void limit_box::output()
+{
+  if (output_format == troff) {
+    printf("\\s[\\n[" SMALL_SIZE_FORMAT "]u]", uid);
+    if (to != 0) {
+      printf("\\Z" DELIMITER_CHAR);
+      printf("\\v'-\\n[" SUP_RAISE_FORMAT "]u'", uid);
+      printf("\\h'\\n[" LEFT_WIDTH_FORMAT "]u"
+	     "+(-\\n[" WIDTH_FORMAT "]u+\\n[" SUB_KERN_FORMAT "]u/2u)'",
+	     uid, to->uid, p->uid);
+      to->output();
+      printf(DELIMITER_CHAR);
+    }
+    if (from != 0) {
+      printf("\\Z" DELIMITER_CHAR);
+      printf("\\v'\\n[" SUB_LOWER_FORMAT "]u'", uid);
+      printf("\\h'\\n[" LEFT_WIDTH_FORMAT "]u"
+	     "+(-\\n[" SUB_KERN_FORMAT "]u-\\n[" WIDTH_FORMAT "]u/2u)'",
+	     uid, p->uid, from->uid);
+      from->output();
+      printf(DELIMITER_CHAR);
+    }
+    printf("\\s[\\n[" SIZE_FORMAT "]u]", uid);
+    printf("\\Z" DELIMITER_CHAR);
+    printf("\\h'\\n[" LEFT_WIDTH_FORMAT "]u"
+	   "-(\\n[" WIDTH_FORMAT "]u/2u)'",
+	   uid, p->uid);
+    p->output();
+    printf(DELIMITER_CHAR);
+    printf("\\h'\\n[" WIDTH_FORMAT "]u'", uid);
+  }
+  else if (output_format == mathml) {
+    if (from != 0 && to != 0) {
+      printf("<munderover>");
+      p->output();
+      from->output();
+      to->output();
+      printf("</munderover>");
+    }
+    else if (from != 0) {
+      printf("<munder>");
+      p->output();
+      from->output();
+      printf("</munder>");
+    }
+    else if (to != 0) {
+      printf("<mover>");
+      p->output();
+      to->output();
+      printf("</mover>");
+    }
+  }
+}
+
+void limit_box::debug_print()
+{
+  fprintf(stderr, "{ ");
+  p->debug_print();
+  fprintf(stderr, " }");
+  if (from) {
+    fprintf(stderr, " from { ");
+    from->debug_print();
+    fprintf(stderr, " }");
+  }
+  if (to) {
+    fprintf(stderr, " to { ");
+    to->debug_print();
+    fprintf(stderr, " }");
+  }
+}
+
+void limit_box::check_tabs(int level)
+{
+  if (to)
+    to->check_tabs(level + 1);
+  if (from)
+    from->check_tabs(level + 1);
+  p->check_tabs(level + 1);
+}
diff --git a/src/preproc/eqn/list.cpp b/src/preproc/eqn/list.cpp
new file mode 100644
index 0000000..52644c5
--- /dev/null
+++ b/src/preproc/eqn/list.cpp
@@ -0,0 +1,241 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "eqn.h"
+#include "pbox.h"
+
+list_box *box::to_list_box()
+{
+  return 0;
+}
+
+list_box *list_box::to_list_box()
+{
+  return this;
+}
+
+void list_box::append(box *pp)
+{
+  list_box *q = pp->to_list_box();
+  if (q == 0)
+    list.append(pp);
+  else {
+    for (int i = 0; i < q->list.len; i++) {
+      list.append(q->list.p[i]);
+      q->list.p[i] = 0;
+    }
+    q->list.len = 0;
+    delete q;
+  }
+}
+
+list_box::list_box(box *pp) : list(pp), sty(-1)
+{
+  list_box *q = pp->to_list_box();
+  if (q != 0) {
+    // flatten it
+    list.p[0] = q->list.p[0];
+    for (int i = 1; i < q->list.len; i++) {
+      list.append(q->list.p[i]);
+      q->list.p[i] = 0;
+    }
+    q->list.len = 0;
+    delete q;
+  }
+}
+
+static int compute_spacing(int is_script, int left, int right)
+{
+  if (left == SUPPRESS_TYPE || right == SUPPRESS_TYPE)
+    return 0;
+  if (left == PUNCTUATION_TYPE)
+    return is_script ? 0 : thin_space;
+  if (left == OPENING_TYPE || right == CLOSING_TYPE)
+    return 0;
+  if (right == BINARY_TYPE || left == BINARY_TYPE)
+    return is_script ? 0 : medium_space;
+  if (right == RELATION_TYPE) {
+    if (left == RELATION_TYPE)
+      return 0;
+    else
+      return is_script ? 0 : thick_space;
+  }
+  if (left == RELATION_TYPE)
+    return is_script ? 0 : thick_space;
+  if (right == OPERATOR_TYPE)
+    return thin_space;
+  if (left == INNER_TYPE || right == INNER_TYPE)
+    return is_script ? 0 : thin_space;
+  if (left == OPERATOR_TYPE && right == ORDINARY_TYPE)
+    return thin_space;
+  return 0;
+}
+
+int list_box::compute_metrics(int style)
+{
+  sty = style;
+  int i;
+  for (i = 0; i < list.len; i++) {
+    int t = list.p[i]->spacing_type; 
+    // 5
+    if (t == BINARY_TYPE) {
+      int prevt;
+      if (i == 0
+	  || (prevt = list.p[i-1]->spacing_type) == BINARY_TYPE
+	  || prevt == OPERATOR_TYPE
+	  || prevt == RELATION_TYPE
+	  || prevt == OPENING_TYPE
+	  || prevt == SUPPRESS_TYPE
+	  || prevt == PUNCTUATION_TYPE)
+	list.p[i]->spacing_type = ORDINARY_TYPE;
+    }
+    // 7
+    else if ((t == RELATION_TYPE || t == CLOSING_TYPE 
+	      || t == PUNCTUATION_TYPE)
+	     && i > 0 && list.p[i-1]->spacing_type == BINARY_TYPE)
+      list.p[i-1]->spacing_type = ORDINARY_TYPE;
+  }
+  for (i = 0; i < list.len; i++) {
+    unsigned flags = 0;
+    if (i - 1 >= 0 && list.p[i - 1]->right_is_italic())
+      flags |= HINT_PREV_IS_ITALIC;
+    if (i + 1 < list.len && list.p[i + 1]->left_is_italic())
+      flags |= HINT_NEXT_IS_ITALIC;
+    if (flags)
+      list.p[i]->hint(flags);
+  }
+  is_script = (style <= SCRIPT_STYLE);
+  int total_spacing = 0;
+  for (i = 1; i < list.len; i++)
+    total_spacing += compute_spacing(is_script, list.p[i-1]->spacing_type,
+				     list.p[i]->spacing_type);
+  int res = 0;
+  for (i = 0; i < list.len; i++)
+    if (!list.p[i]->is_simple()) {
+      int r = list.p[i]->compute_metrics(style);
+      if (r) {
+	if (res)
+	  error("multiple marks and lineups");
+	else {
+	  compute_sublist_width(i);
+	  printf(".nr " MARK_REG " +\\n[" TEMP_REG"]\n");
+	  res = r;
+	}
+      }
+    }
+  printf(".nr " WIDTH_FORMAT " %dM", uid, total_spacing);
+  for (i = 0; i < list.len; i++)
+    if (!list.p[i]->is_simple())
+      printf("+\\n[" WIDTH_FORMAT "]", list.p[i]->uid);
+  printf("\n");
+  printf(".nr " HEIGHT_FORMAT " 0", uid);
+  for (i = 0; i < list.len; i++)
+    if (!list.p[i]->is_simple())
+      printf(">?\\n[" HEIGHT_FORMAT "]", list.p[i]->uid);
+  printf("\n");
+  printf(".nr " DEPTH_FORMAT " 0", uid);
+  for (i = 0; i < list.len; i++)
+    if (!list.p[i]->is_simple())
+      printf(">?\\n[" DEPTH_FORMAT "]", list.p[i]->uid);
+  printf("\n");
+  int have_simple = 0;
+  for (i = 0; i < list.len && !have_simple; i++)
+    have_simple = list.p[i]->is_simple();
+  if (have_simple) {
+    printf(".nr " WIDTH_FORMAT " +\\w" DELIMITER_CHAR, uid);
+    for (i = 0; i < list.len; i++)
+      if (list.p[i]->is_simple())
+	list.p[i]->output();
+    printf(DELIMITER_CHAR "\n");
+    printf(".nr " HEIGHT_FORMAT " \\n[rst]>?\\n[" HEIGHT_FORMAT "]\n",
+	   uid, uid);
+    printf(".nr " DEPTH_FORMAT " 0-\\n[rsb]>?\\n[" DEPTH_FORMAT "]\n",
+	   uid, uid);
+  }
+  return res;
+}
+
+void list_box::compute_sublist_width(int n)
+{
+  int total_spacing = 0;
+  int i;
+  for (i = 1; i < n + 1 && i < list.len; i++)
+    total_spacing += compute_spacing(is_script, list.p[i-1]->spacing_type,
+				     list.p[i]->spacing_type);
+  printf(".nr " TEMP_REG " %dM", total_spacing);
+  for (i = 0; i < n; i++)
+    if (!list.p[i]->is_simple())
+      printf("+\\n[" WIDTH_FORMAT "]", list.p[i]->uid);
+  int have_simple = 0;
+  for (i = 0; i < n && !have_simple; i++)
+    have_simple = list.p[i]->is_simple();
+  if (have_simple) {
+    printf("+\\w" DELIMITER_CHAR);
+    for (i = 0; i < n; i++)
+      if (list.p[i]->is_simple())
+	list.p[i]->output();
+    printf(DELIMITER_CHAR);
+  }
+  printf("\n");
+}
+
+void list_box::compute_subscript_kern()
+{
+  // We can only call compute_subscript_kern if we have called
+  // compute_metrics first.
+  if (list.p[list.len-1]->is_simple())
+    list.p[list.len-1]->compute_metrics(sty);
+  list.p[list.len-1]->compute_subscript_kern();
+  printf(".nr " SUB_KERN_FORMAT " \\n[" SUB_KERN_FORMAT "]\n",
+	 uid, list.p[list.len-1]->uid);
+}
+
+void list_box::output()
+{
+  if (output_format == mathml)
+    printf("<mrow>");
+  for (int i = 0; i < list.len; i++) {
+    if (output_format == troff && i > 0) {
+      int n = compute_spacing(is_script,
+			      list.p[i-1]->spacing_type,
+			      list.p[i]->spacing_type);
+      if (n > 0)
+	printf("\\h'%dM'", n);
+    }
+    list.p[i]->output();
+  }
+  if (output_format == mathml)
+    printf("</mrow>");
+}
+
+void list_box::handle_char_type(int st, int ft)
+{
+  for (int i = 0; i < list.len; i++)
+    list.p[i]->handle_char_type(st, ft);
+}
+
+void list_box::debug_print()
+{
+  list.list_debug_print(" ");
+}
+
+void list_box::check_tabs(int level)
+{
+  list.list_check_tabs(level);
+}
diff --git a/src/preproc/eqn/main.cpp b/src/preproc/eqn/main.cpp
new file mode 100644
index 0000000..81d5184
--- /dev/null
+++ b/src/preproc/eqn/main.cpp
@@ -0,0 +1,485 @@
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "eqn.h"
+#include "stringclass.h"
+#include "device.h"
+#include "searchpath.h"
+#include "macropath.h"
+#include "htmlhint.h"
+#include "pbox.h"
+#include "ctype.h"
+#include "lf.h"
+
+#define STARTUP_FILE "eqnrc"
+
+extern int yyparse();
+extern "C" const char *Version_string;
+
+static char *delim_search    (char *, int);
+static int   inline_equation (FILE *, string &, string &);
+
+char start_delim = '\0';
+char end_delim = '\0';
+int non_empty_flag;
+int inline_flag;
+int draw_flag = 0;
+int one_size_reduction_flag = 0;
+int compatible_flag = 0;
+int no_newline_in_delim_flag = 0;
+int html = 0;
+int xhtml = 0;
+eqnmode_t output_format;
+
+static const char *input_char_description(int c)
+{
+  switch (c) {
+  case '\001':
+    return "a leader character";
+  case '\n':
+    return "a newline character";
+  case '\b':
+    return "a backspace character";
+  case '\t':
+    return "a tab character";
+  case ' ':
+    return "a space character";
+  case '\177':
+    return "a delete character";
+  }
+  size_t bufsz = sizeof "character code " + INT_DIGITS + 1;
+  // repeat expression; no VLAs in ISO C++
+  static char buf[sizeof "character code " + INT_DIGITS + 1];
+  (void) memset(buf, 0, bufsz);
+  if (csprint(c)) {
+    buf[0] = '\'';
+    buf[1] = c;
+    buf[2] = '\'';
+    return buf;
+  }
+  (void) sprintf(buf, "character code %d", c);
+  return buf;
+}
+
+static bool read_line(FILE *fp, string *p)
+{
+  p->clear();
+  int c = -1;
+  while ((c = getc(fp)) != EOF) {
+    if (!is_invalid_input_char(c))
+      *p += char(c);
+    else
+      error("invalid input (%1)", input_char_description(c));
+    if (c == '\n')
+      break;
+  }
+  return (p->length() > 0);
+}
+
+void do_file(FILE *fp, const char *filename)
+{
+  string linebuf;
+  string str;
+  string fn(filename);
+  fn += '\0';
+  normalize_for_lf(fn);
+  current_filename = fn.contents();
+  if (output_format == troff)
+    printf(".lf 1 %s\n", current_filename);
+  current_lineno = 1;
+  while (read_line(fp, &linebuf)) {
+    if (linebuf.length() >= 4
+	&& linebuf[0] == '.' && linebuf[1] == 'l' && linebuf[2] == 'f'
+	&& (linebuf[3] == ' ' || linebuf[3] == '\n' || compatible_flag))
+    {
+      put_string(linebuf, stdout);
+      linebuf += '\0';
+      // In GNU roff, `lf` assigns the number of the _next_ line.
+      if (interpret_lf_args(linebuf.contents() + 3))
+	current_lineno--;
+    }
+    else if (linebuf.length() >= 4
+	     && linebuf[0] == '.'
+	     && linebuf[1] == 'E'
+	     && linebuf[2] == 'Q'
+	     && (linebuf[3] == ' ' || linebuf[3] == '\n'
+		 || compatible_flag)) {
+      put_string(linebuf, stdout);
+      int start_lineno = current_lineno + 1;
+      str.clear();
+      for (;;) {
+	if (!read_line(fp, &linebuf)) {
+	  current_lineno = 0; // suppress report of line number
+	  fatal("end of file before .EN");
+	}
+	if (linebuf.length() >= 3
+	    && linebuf[0] == '.'
+	    && linebuf[1] == 'E') {
+	  if (linebuf[2] == 'N'
+	      && (linebuf.length() == 3 || linebuf[3] == ' '
+		  || linebuf[3] == '\n' || compatible_flag))
+	    break;
+	  else if (linebuf[2] == 'Q' && linebuf.length() > 3
+		   && (linebuf[3] == ' ' || linebuf[3] == '\n'
+		       || compatible_flag)) {
+	    current_lineno++; // We just read another line.
+	    fatal("equations cannot be nested (.EQ within .EQ)");
+	  }
+	}
+	str += linebuf;
+      }
+      str += '\0';
+      start_string();
+      init_lex(str.contents(), current_filename, start_lineno);
+      non_empty_flag = 0;
+      inline_flag = 0;
+      yyparse();
+      restore_compatibility();
+      if (non_empty_flag) {
+	if (output_format == mathml)
+	  putchar('\n');
+        else {
+	  current_lineno++;
+	  printf(".lf %d\n", current_lineno);
+	  output_string();
+	}
+      }
+      if (output_format == troff) {
+	current_lineno++;
+	printf(".lf %d\n", current_lineno);
+      }
+      put_string(linebuf, stdout);
+    }
+    else if (start_delim != '\0' && linebuf.search(start_delim) >= 0
+	     && inline_equation(fp, linebuf, str))
+      ;
+    else
+      put_string(linebuf, stdout);
+    current_lineno++;
+  }
+  current_filename = 0;
+  current_lineno = 0;
+}
+
+// Handle an inline equation.  Return 1 if it was an inline equation,
+// otherwise.
+static int inline_equation(FILE *fp, string &linebuf, string &str)
+{
+  linebuf += '\0';
+  char *ptr = &linebuf[0];
+  char *start = delim_search(ptr, start_delim);
+  if (!start) {
+    // It wasn't a delimiter after all.
+    linebuf.set_length(linebuf.length() - 1); // strip the '\0'
+    return 0;
+  }
+  start_string();
+  inline_flag = 1;
+  for (;;) {
+    if (no_newline_in_delim_flag && strchr(start + 1, end_delim) == 0) {
+      error("unterminated inline equation; started with %1,"
+	    " expecting %2", input_char_description(start_delim),
+	    input_char_description(end_delim));
+      char *nl = strchr(start + 1, '\n');
+      if (nl != 0)
+	*nl = '\0';
+      do_text(ptr);
+      break;
+    }
+    int start_lineno = current_lineno;
+    *start = '\0';
+    do_text(ptr);
+    ptr = start + 1;
+    str.clear();
+    for (;;) {
+      char *end = strchr(ptr, end_delim);
+      if (end != 0) {
+	*end = '\0';
+	str += ptr;
+	ptr = end + 1;
+	break;
+      }
+      str += ptr;
+      if (!read_line(fp, &linebuf))
+	fatal("unterminated inline equation; started with %1,"
+	      " expecting %2", input_char_description(start_delim),
+	      input_char_description(end_delim));
+      linebuf += '\0';
+      ptr = &linebuf[0];
+    }
+    str += '\0';
+    if (output_format == troff && html) {
+      printf(".as1 %s ", LINE_STRING);
+      html_begin_suppress();
+      printf("\n");
+    }
+    init_lex(str.contents(), current_filename, start_lineno);
+    yyparse();
+    if (output_format == troff && html) {
+      printf(".as1 %s ", LINE_STRING);
+      html_end_suppress();
+      printf("\n");
+    }
+    if (output_format == mathml)
+      printf("\n");
+    if (xhtml) {
+      /* skip leading spaces */
+      while ((*ptr != '\0') && (*ptr == ' '))
+	ptr++;
+    }
+    start = delim_search(ptr, start_delim);
+    if (start == 0) {
+      char *nl = strchr(ptr, '\n');
+      if (nl != 0)
+	*nl = '\0';
+      do_text(ptr);
+      break;
+    }
+  }
+  restore_compatibility();
+  if (output_format == troff)
+    printf(".lf %d\n", current_lineno);
+  output_string();
+  if (output_format == troff)
+    printf(".lf %d\n", current_lineno + 1);
+  return 1;
+}
+
+/* Search for delim.  Skip over number register and string names etc. */
+
+static char *delim_search(char *ptr, int delim)
+{
+  while (*ptr) {
+    if (*ptr == delim)
+      return ptr;
+    if (*ptr++ == '\\') {
+      switch (*ptr) {
+      case 'n':
+      case '*':
+      case 'f':
+      case 'g':
+      case 'k':
+	switch (*++ptr) {
+	case '\0':
+	case '\\':
+	  break;
+	case '(':
+	  if (*++ptr != '\\' && *ptr != '\0'
+	      && *++ptr != '\\' && *ptr != '\0')
+	      ptr++;
+	  break;
+	case '[':
+	  while (*++ptr != '\0')
+	    if (*ptr == ']') {
+	      ptr++;
+	      break;
+	    }
+	  break;
+	default:
+	  ptr++;
+	  break;
+	}
+	break;
+      case '\\':
+      case '\0':
+	break;
+      default:
+	ptr++;
+	break;
+      }
+    }
+  }
+  return 0;
+}
+
+void usage(FILE *stream)
+{
+  fprintf(stream,
+    "usage: %s [-CNrR] [-d xy] [-f font] [-m n] [-M dir] [-p n] [-s n]"
+    " [-T name] [file ...]\n"
+    "usage: %s {-v | --version}\n"
+    "usage: %s --help\n",
+    program_name, program_name, program_name);
+}
+
+int main(int argc, char **argv)
+{
+  program_name = argv[0];
+  static char stderr_buf[BUFSIZ];
+  setbuf(stderr, stderr_buf);
+  int opt;
+  int load_startup_file = 1;
+  static const struct option long_options[] = {
+    { "help", no_argument, 0, CHAR_MAX + 1 },
+    { "version", no_argument, 0, 'v' },
+    { NULL, 0, 0, 0 }
+  };
+  while ((opt = getopt_long(argc, argv, "CNrRd:f:m:M:p:s:T:v",
+			    long_options, NULL))
+	 != EOF)
+    switch (opt) {
+    case 'C':
+      compatible_flag = 1;
+      break;
+    case 'R':			// don't load eqnrc
+      load_startup_file = 0;
+      break;
+    case 'M':
+      config_macro_path.command_line_dir(optarg);
+      break;
+    case 'v':
+      printf("GNU eqn (groff) version %s\n", Version_string);
+      exit(EXIT_SUCCESS);
+      break;
+    case 'd':
+      if (optarg[0] == '\0' || optarg[1] == '\0')
+	error("'-d' option requires a two-character argument");
+      else if (is_invalid_input_char(optarg[0]))
+	error("invalid delimiter (%1) in '-d' option argument",
+	      input_char_description(optarg[0]));
+      else if (is_invalid_input_char(optarg[1]))
+	error("invalid delimiter (%1) in '-d' option argument",
+	      input_char_description(optarg[1]));
+      else {
+	start_delim = optarg[0];
+	end_delim = optarg[1];
+      }
+      break;
+    case 'f':
+      set_gfont(optarg);
+      break;
+    case 'T':
+      device = optarg;
+      if (strcmp(device, "ps:html") == 0) {
+	device = "ps";
+	html = 1;
+      }
+      else if (strcmp(device, "MathML") == 0) {
+	output_format = mathml;
+	load_startup_file = 0;
+      }
+      else if (strcmp(device, "mathml:xhtml") == 0) {
+	device = "MathML";
+	output_format = mathml;
+	load_startup_file = 0;
+	xhtml = 1;
+      }
+      break;
+    case 's':
+      if (set_gsize(optarg))
+	warning("option '-s' is deprecated");
+      else
+	error("invalid size '%1' in '-s' option argument ", optarg);
+      break;
+    case 'p':
+      {
+	int n;
+	if (sscanf(optarg, "%d", &n) == 1) {
+	  warning("option '-p' is deprecated");
+	  set_script_reduction(n);
+	}
+	else
+	  error("invalid size '%1' in '-p' option argument ", optarg);
+      }
+      break;
+    case 'm':
+      {
+	int n;
+	if (sscanf(optarg, "%d", &n) == 1)
+	  set_minimum_size(n);
+	else
+	  error("invalid size '%1' in '-n' option argument", optarg);
+      }
+      break;
+    case 'r':
+      one_size_reduction_flag = 1;
+      break;
+    case 'N':
+      no_newline_in_delim_flag = 1;
+      break;
+    case CHAR_MAX + 1: // --help
+      usage(stdout);
+      exit(EXIT_SUCCESS);
+      break;
+    case '?':
+      usage(stderr);
+      exit(EXIT_FAILURE);
+      break;
+    default:
+      assert(0 == "unhandled getopt_long return value");
+    }
+  init_table(device);
+  init_char_table();
+  printf(".do if !dEQ .ds EQ\n"
+	 ".do if !dEN .ds EN\n");
+  if (output_format == troff) {
+    printf(".if !'\\*(.T'%s' "
+	   ".if !'\\*(.T'html' "	// the html device uses '-Tps' to render
+				  // equations as images
+	   ".tm warning: %s should have been given a '-T\\*(.T' option\n",
+	   device, program_name);
+    printf(".if '\\*(.T'html' "
+	   ".if !'%s'ps' "
+	   ".tm warning: %s should have been given a '-Tps' option\n",
+	   device, program_name);
+    printf(".if '\\*(.T'html' "
+	   ".if !'%s'ps' "
+	   ".tm warning: (it is advisable to invoke groff via: groff -Thtml -e)\n",
+	   device);
+  }
+  if (load_startup_file) {
+    char *path;
+    FILE *fp = config_macro_path.open_file(STARTUP_FILE, &path);
+    if (fp) {
+      do_file(fp, path);
+      if (fclose(fp) < 0)
+	fatal("unable to close '%1': %2", STARTUP_FILE,
+	      strerror(errno));
+      free(path);
+    }
+  }
+  if (optind >= argc)
+    do_file(stdin, "-");
+  else
+    for (int i = optind; i < argc; i++)
+      if (strcmp(argv[i], "-") == 0)
+	do_file(stdin, "-");
+      else {
+	errno = 0;
+	FILE *fp = fopen(argv[i], "r");
+	if (!fp)
+	  fatal("unable to open '%1': %2", argv[i], strerror(errno));
+	else {
+	  do_file(fp, argv[i]);
+	  if (fclose(fp) < 0)
+	    fatal("unable to close '%1': %2", argv[i], strerror(errno));
+	}
+      }
+  if (ferror(stdout))
+    fatal("standard output stream is in an error state");
+  if (fflush(stdout) < 0)
+    fatal("unable to flush standard output stream: %1",
+	  strerror(errno));
+  exit(EXIT_SUCCESS);
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/eqn/mark.cpp b/src/preproc/eqn/mark.cpp
new file mode 100644
index 0000000..9427b10
--- /dev/null
+++ b/src/preproc/eqn/mark.cpp
@@ -0,0 +1,120 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "eqn.h"
+#include "pbox.h"
+
+class mark_box : public pointer_box {
+public:
+  mark_box(box *);
+  int compute_metrics(int);
+  void output();
+  void debug_print();
+};
+
+// we push down marks so that they don't interfere with spacing
+
+box *make_mark_box(box *p)
+{
+  list_box *b = p->to_list_box();
+  if (b != 0) {
+    b->list.p[0] = make_mark_box(b->list.p[0]);
+    return b;
+  }
+  else
+    return new mark_box(p);
+}
+
+mark_box::mark_box(box *pp) : pointer_box(pp)
+{
+}
+
+void mark_box::output()
+{
+  p->output();
+}
+
+int mark_box::compute_metrics(int style)
+{
+  int res = p->compute_metrics(style);
+  if (res)
+    error("multiple marks and lineups");
+  printf(".nr " WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]\n", uid, p->uid);
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]\n", uid, p->uid);
+  printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]\n", uid, p->uid);
+  printf(".nr " MARK_REG " 0\n");
+  return FOUND_MARK;
+}
+
+void mark_box::debug_print()
+{
+  fprintf(stderr, "mark { ");
+  p->debug_print();
+  fprintf(stderr, " }");
+}
+
+
+class lineup_box : public pointer_box {
+public:
+  lineup_box(box *);
+  void output();
+  int compute_metrics(int style);
+  void debug_print();
+};
+
+// we push down lineups so that they don't interfere with spacing
+
+box *make_lineup_box(box *p)
+{
+  list_box *b = p->to_list_box();
+  if (b != 0) {
+    b->list.p[0] = make_lineup_box(b->list.p[0]);
+    return b;
+  }
+  else
+    return new lineup_box(p);
+}
+
+lineup_box::lineup_box(box *pp) : pointer_box(pp)
+{
+}
+
+void lineup_box::output()
+{
+  p->output();
+}
+
+int lineup_box::compute_metrics(int style)
+{
+  int res = p->compute_metrics(style);
+  if (res)
+    error("multiple marks and lineups");
+  printf(".nr " WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]\n", uid, p->uid);
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]\n", uid, p->uid);
+  printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]\n", uid, p->uid);
+  printf(".nr " MARK_REG " 0\n");
+  return FOUND_LINEUP;
+}
+
+void lineup_box::debug_print()
+{
+  fprintf(stderr, "lineup { ");
+  p->debug_print();
+  fprintf(stderr, " }");
+}
diff --git a/src/preproc/eqn/neqn.1.man b/src/preproc/eqn/neqn.1.man
new file mode 100644
index 0000000..758a150
--- /dev/null
+++ b/src/preproc/eqn/neqn.1.man
@@ -0,0 +1,92 @@
+.TH @g@neqn @MAN1EXT@ "@MDATE@" "groff @VERSION@"
+.SH Name
+@g@neqn \- format equations for character-cell terminal output
+.
+.
+.\" ====================================================================
+.\" Legal Terms
+.\" ====================================================================
+.\"
+.\" Copyright (C) 2001-2020 Free Software Foundation, Inc.
+.\"
+.\" Permission is granted to make and distribute verbatim copies of this
+.\" manual provided the copyright notice and this permission notice are
+.\" preserved on all copies.
+.\"
+.\" Permission is granted to copy and distribute modified versions of
+.\" this manual under the conditions for verbatim copying, provided that
+.\" the entire resulting derived work is distributed under the terms of
+.\" a permission notice identical to this one.
+.\"
+.\" Permission is granted to copy and distribute translations of this
+.\" manual into another language, under the above conditions for
+.\" modified versions, except that this permission notice may be
+.\" included in translations approved by the Free Software Foundation
+.\" instead of in the original English.
+.
+.
+.\" Save and disable compatibility mode (for, e.g., Solaris 10/11).
+.do nr *groff_neqn_1_man_C \n[.cp]
+.cp 0
+.
+.\" Define fallback for groff 1.23's MR macro if the system lacks it.
+.nr do-fallback 0
+.if !\n(.f           .nr do-fallback 1 \" mandoc
+.if  \n(.g .if !d MR .nr do-fallback 1 \" older groff
+.if !\n(.g           .nr do-fallback 1 \" non-groff *roff
+.if \n[do-fallback]  \{\
+.  de MR
+.    ie \\n(.$=1 \
+.      I \%\\$1
+.    el \
+.      IR \%\\$1 (\\$2)\\$3
+.  .
+.\}
+.rr do-fallback
+.
+.
+.\" ====================================================================
+.SH Synopsis
+.\" ====================================================================
+.
+.SY @g@neqn
+.RI [ @g@eqn-argument \~.\|.\|.]
+.YS
+.
+.
+.\" ====================================================================
+.SH Description
+.\" ====================================================================
+.
+.I @g@neqn
+invokes the
+.MR @g@eqn @MAN1EXT@
+command with the
+.B ascii
+output device.
+.
+.
+.LP
+.I @g@eqn
+does not support low-resolution,
+typewriter-like devices,
+although it may work adequately for very simple input.
+.
+.
+.\" ====================================================================
+.SH "See also"
+.\" ====================================================================
+.
+.MR @g@eqn @MAN1EXT@
+.
+.
+.\" Restore compatibility mode (for, e.g., Solaris 10/11).
+.cp \n[*groff_neqn_1_man_C]
+.do rr *groff_neqn_1_man_C
+.
+.
+.\" Local Variables:
+.\" fill-column: 72
+.\" mode: nroff
+.\" End:
+.\" vim: set filetype=nroff textwidth=72:
diff --git a/src/preproc/eqn/neqn.sh b/src/preproc/eqn/neqn.sh
new file mode 100644
index 0000000..fb8d616
--- /dev/null
+++ b/src/preproc/eqn/neqn.sh
@@ -0,0 +1,26 @@
+#! /bin/sh
+# Copyright (C) 2014-2020 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+# 
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 2 of the License (GPL2).
+# 
+# groff is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+# 
+# The GPL2 license text is available in the internet at
+# <http://www.gnu.org/licenses/gpl-2.0.txt>.
+
+# Provision of this shell script should not be taken to imply that use of
+# GNU eqn with groff -Tascii|-Tlatin1|-Tutf8|-Tcp1047 is supported.
+
+@GROFF_BIN_PATH_SETUP@
+PATH="$GROFF_RUNTIME$PATH"
+export PATH
+exec @g@eqn -Tascii ${1+"$@"}
+
+# eof
diff --git a/src/preproc/eqn/other.cpp b/src/preproc/eqn/other.cpp
new file mode 100644
index 0000000..1ddc8fb
--- /dev/null
+++ b/src/preproc/eqn/other.cpp
@@ -0,0 +1,706 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdlib.h>
+
+#include "eqn.h"
+#include "pbox.h"
+
+class accent_box : public pointer_box {
+private:
+  box *ab;
+public:
+  accent_box(box *, box *);
+  ~accent_box();
+  int compute_metrics(int);
+  void output();
+  void debug_print();
+  void check_tabs(int);
+};
+
+box *make_accent_box(box *p, box *q)
+{
+  return new accent_box(p, q);
+}
+
+accent_box::accent_box(box *pp, box *qq) : pointer_box(pp), ab(qq)
+{
+}
+
+accent_box::~accent_box()
+{
+  delete ab;
+}
+
+#if 0
+int accent_box::compute_metrics(int style)
+{
+  int r = p->compute_metrics(style);
+  p->compute_skew();
+  ab->compute_metrics(style);
+  printf(".nr " WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]\n", uid, p->uid);
+  printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]\n", uid, p->uid);
+  printf(".nr " SUP_RAISE_FORMAT " \\n[" HEIGHT_FORMAT "]-%dM>?0\n",
+	 uid, p->uid, x_height);
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]+\\n["
+	 SUP_RAISE_FORMAT "]\n",
+	 uid, ab->uid, uid);
+  return r;
+}
+
+void accent_box::output()
+{
+  if (output_format == troff) {
+    printf("\\h'\\n[" WIDTH_FORMAT "]u-\\n[" WIDTH_FORMAT "]u/2u+\\n["
+	   SKEW_FORMAT "]u'",
+	   p->uid, ab->uid, p->uid);
+    printf("\\v'-\\n[" SUP_RAISE_FORMAT "]u'", uid); 
+    ab->output();
+    printf("\\h'-\\n[" WIDTH_FORMAT "]u'", ab->uid);
+    printf("\\v'\\n[" SUP_RAISE_FORMAT "]u'", uid);
+    printf("\\h'-(\\n[" WIDTH_FORMAT "]u-\\n[" WIDTH_FORMAT "]u/2u+\\n["
+	   SKEW_FORMAT "]u)'",
+	   p->uid, ab->uid, p->uid);
+    p->output();
+  }
+  else if (output_format == mathml) {
+    printf("<mover accent='true'>");
+    p->output();
+    ab->output();
+    printf("</mover>")
+  }
+}
+#endif
+
+/* This version copes with the possibility of an accent's being wider
+than its accentee.  LEFT_WIDTH_FORMAT gives the distance from the
+left edge of the resulting box to the middle of the accentee's box.*/
+
+int accent_box::compute_metrics(int style)
+{
+  int r = p->compute_metrics(style);
+  p->compute_skew();
+  ab->compute_metrics(style);
+  printf(".nr " LEFT_WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]/2"
+	 ">?(\\n[" WIDTH_FORMAT "]/2-\\n[" SKEW_FORMAT "])\n",
+	 uid, p->uid, ab->uid, p->uid);
+  printf(".nr " WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]/2"
+	 ">?(\\n[" WIDTH_FORMAT "]/2+\\n[" SKEW_FORMAT "])"
+	 "+\\n[" LEFT_WIDTH_FORMAT "]\n",
+	 uid, p->uid, ab->uid, p->uid, uid);
+  printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]\n", uid, p->uid);
+  printf(".nr " SUP_RAISE_FORMAT " \\n[" HEIGHT_FORMAT "]-%dM>?0\n",
+	 uid, p->uid, x_height);
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]+\\n["
+	 SUP_RAISE_FORMAT "]\n",
+	 uid, ab->uid, uid);
+  if (r)
+    printf(".nr " MARK_REG " +\\n[" LEFT_WIDTH_FORMAT "]"
+	   "-(\\n[" WIDTH_FORMAT "]/2)'\n",
+	   uid, p->uid);
+  return r;
+}
+
+void accent_box::output()
+{
+  if (output_format == troff) {
+    printf("\\Z" DELIMITER_CHAR);
+    printf("\\h'\\n[" LEFT_WIDTH_FORMAT "]u+\\n[" SKEW_FORMAT "]u"
+	   "-(\\n[" WIDTH_FORMAT "]u/2u)'",
+	   uid, p->uid, ab->uid);
+    printf("\\v'-\\n[" SUP_RAISE_FORMAT "]u'", uid); 
+    ab->output();
+    printf(DELIMITER_CHAR);
+    printf("\\Z" DELIMITER_CHAR);
+    printf("\\h'\\n[" LEFT_WIDTH_FORMAT "]u-(\\n[" WIDTH_FORMAT "]u/2u)'",
+	   uid, p->uid);
+    p->output();
+    printf(DELIMITER_CHAR);
+    printf("\\h'\\n[" WIDTH_FORMAT "]u'", uid);
+  }
+  else if (output_format == mathml) {
+    printf("<mover accent='true'>");
+    p->output();
+    ab->output();
+    printf("</mover>");
+  }
+}
+
+void accent_box::check_tabs(int level)
+{
+  ab->check_tabs(level + 1);
+  p->check_tabs(level + 1);
+}
+
+void accent_box::debug_print()
+{
+  fprintf(stderr, "{ ");
+  p->debug_print();
+  fprintf(stderr, " } accent { ");
+  ab->debug_print();
+  fprintf(stderr, " }");
+}
+
+class overline_char_box : public simple_box {
+public:
+  overline_char_box();
+  void output();
+  void debug_print();
+};
+
+overline_char_box::overline_char_box()
+{
+}
+
+void overline_char_box::output()
+{
+  if (output_format == troff) {
+    printf("\\v'-%dM/2u-%dM'", 7*default_rule_thickness, x_height);
+    printf((draw_flag ? "\\D'l%dM 0'" : "\\l'%dM\\&\\(ru'"),
+	   accent_width);
+    printf("\\v'%dM/2u+%dM'", 7*default_rule_thickness, x_height);
+  }
+  else if (output_format == mathml)
+    printf("<mo>&macr;</mo>");
+}
+
+void overline_char_box::debug_print()
+{
+  fprintf(stderr, "<overline char>");
+}
+
+class overline_box : public pointer_box {
+public:
+  overline_box(box *);
+  int compute_metrics(int);
+  void output();
+  void debug_print();
+};
+
+box *make_overline_box(box *p)
+{
+  if (p->is_char())
+    return new accent_box(p, new overline_char_box);
+  else
+    return new overline_box(p);
+}
+
+overline_box::overline_box(box *pp) : pointer_box(pp)
+{
+}
+
+int overline_box::compute_metrics(int style)
+{
+  int r = p->compute_metrics(cramped_style(style));
+  // 9
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]+%dM\n",
+	 uid, p->uid, default_rule_thickness*5);
+  printf(".nr " WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]\n", uid, p->uid);
+  printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]\n", uid, p->uid);
+  return r;
+}
+
+void overline_box::output()
+{
+  if (output_format == troff) {
+    // 9
+    printf("\\Z" DELIMITER_CHAR);
+    printf("\\v'-\\n[" HEIGHT_FORMAT "]u-(%dM/2u)'",
+	   p->uid, 7*default_rule_thickness);
+    if (draw_flag)
+      printf("\\D'l\\n[" WIDTH_FORMAT "]u 0'", p->uid);
+    else
+      printf("\\l'\\n[" WIDTH_FORMAT "]u\\&\\(ru'", p->uid);
+    printf(DELIMITER_CHAR);
+    p->output();
+  }
+  else if (output_format == mathml) {
+    printf("<mover accent='false'>");
+    p->output();
+    printf("<mo>&macr;</mo></mover>");
+  }
+}
+
+void overline_box::debug_print()
+{
+  fprintf(stderr, "{ ");
+  p->debug_print();
+  fprintf(stderr, " } bar");
+}
+
+class uaccent_box : public pointer_box {
+  box *ab;
+public:
+  uaccent_box(box *, box *);
+  ~uaccent_box();
+  int compute_metrics(int);
+  void output();
+  void compute_subscript_kern();
+  void check_tabs(int);
+  void debug_print();
+};
+
+box *make_uaccent_box(box *p, box *q)
+{
+  return new uaccent_box(p, q);
+}
+
+uaccent_box::uaccent_box(box *pp, box *qq)
+: pointer_box(pp), ab(qq)
+{
+}
+
+uaccent_box::~uaccent_box()
+{
+  delete ab;
+}
+
+int uaccent_box::compute_metrics(int style)
+{
+  int r = p->compute_metrics(style);
+  ab->compute_metrics(style);
+  printf(".nr " LEFT_WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]/2"
+	 ">?(\\n[" WIDTH_FORMAT "]/2)\n",
+	 uid, p->uid, ab->uid);
+  printf(".nr " WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]/2"
+	 ">?(\\n[" WIDTH_FORMAT "]/2)"
+	 "+\\n[" LEFT_WIDTH_FORMAT "]\n",
+	 uid, p->uid, ab->uid, uid);
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]\n", uid, p->uid);
+  printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]"
+	 "+\\n[" DEPTH_FORMAT "]\n",
+	 uid, p->uid, ab->uid);
+  if (r)
+    printf(".nr " MARK_REG " +\\n[" LEFT_WIDTH_FORMAT "]"
+	   "-(\\n[" WIDTH_FORMAT "]/2)'\n",
+	   uid, p->uid);
+  return r;
+}
+
+void uaccent_box::output()
+{
+  if (output_format == troff) {
+    printf("\\Z" DELIMITER_CHAR);
+    printf("\\h'\\n[" LEFT_WIDTH_FORMAT "]u-(\\n[" WIDTH_FORMAT "]u/2u)'",
+	   uid, ab->uid);
+    printf("\\v'\\n[" DEPTH_FORMAT "]u'", p->uid); 
+    ab->output();
+    printf(DELIMITER_CHAR);
+    printf("\\Z" DELIMITER_CHAR);
+    printf("\\h'\\n[" LEFT_WIDTH_FORMAT "]u-(\\n[" WIDTH_FORMAT "]u/2u)'",
+	   uid, p->uid);
+    p->output();
+    printf(DELIMITER_CHAR);
+    printf("\\h'\\n[" WIDTH_FORMAT "]u'", uid);
+  }
+  else if (output_format == mathml) {
+    printf("<munder accent='true'>");
+    p->output();
+    ab->output();
+    printf("</munder>");
+  }
+}
+
+void uaccent_box::check_tabs(int level)
+{
+  ab->check_tabs(level + 1);
+  p->check_tabs(level + 1);
+}
+
+void uaccent_box::compute_subscript_kern()
+{
+  box::compute_subscript_kern(); // want 0 subscript kern
+}
+
+void uaccent_box::debug_print()
+{
+  fprintf(stderr, "{ ");
+  p->debug_print();
+  fprintf(stderr, " } uaccent { ");
+  ab->debug_print();
+  fprintf(stderr, " }");
+}
+
+class underline_char_box : public simple_box {
+public:
+  underline_char_box();
+  void output();
+  void debug_print();
+};
+
+underline_char_box::underline_char_box()
+{
+}
+
+void underline_char_box::output()
+{
+  if (output_format == troff) {
+    printf("\\v'%dM/2u'", 7*default_rule_thickness);
+    printf((draw_flag ? "\\D'l%dM 0'" : "\\l'%dM\\&\\(ru'"),
+	   accent_width);
+    printf("\\v'-%dM/2u'", 7*default_rule_thickness);
+  }
+  else if (output_format == mathml)
+    printf("<mo>&lowbar;</mo>");
+}
+
+void underline_char_box::debug_print()
+{
+  fprintf(stderr, "<underline char>");
+}
+
+
+class underline_box : public pointer_box {
+public:
+  underline_box(box *);
+  int compute_metrics(int);
+  void output();
+  void compute_subscript_kern();
+  void debug_print();
+};
+
+box *make_underline_box(box *p)
+{
+  if (p->is_char())
+    return new uaccent_box(p, new underline_char_box);
+  else
+    return new underline_box(p);
+}
+
+underline_box::underline_box(box *pp) : pointer_box(pp)
+{
+}
+
+int underline_box::compute_metrics(int style)
+{
+  int r = p->compute_metrics(style);
+  // 10
+  printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]+%dM\n",
+	 uid, p->uid, default_rule_thickness*5);
+  printf(".nr " WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]\n", uid, p->uid);
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]\n", uid, p->uid);
+  return r;
+}
+
+void underline_box::output()
+{
+  if (output_format == troff) {
+    // 10
+    printf("\\Z" DELIMITER_CHAR);
+    printf("\\v'\\n[" DEPTH_FORMAT "]u+(%dM/2u)'",
+	   p->uid, 7*default_rule_thickness);
+    if (draw_flag)
+      printf("\\D'l\\n[" WIDTH_FORMAT "]u 0'", p->uid);
+    else
+      printf("\\l'\\n[" WIDTH_FORMAT "]u\\&\\(ru'", p->uid);
+    printf(DELIMITER_CHAR);
+    p->output();
+  }
+  else if (output_format == mathml) {
+    printf("<munder accent='true'>");
+    p->output();
+    printf("<mo>&macr;</mo></munder>");
+  }
+}
+
+// we want an underline box to have 0 subscript kern
+
+void underline_box::compute_subscript_kern()
+{
+  box::compute_subscript_kern();
+}
+
+void underline_box::debug_print()
+{
+  fprintf(stderr, "{ ");
+  p->debug_print();
+  fprintf(stderr, " } under");
+}
+
+size_box::size_box(char *s, box *pp) : pointer_box(pp), size(s)
+{
+}
+
+int size_box::compute_metrics(int style)
+{
+  printf(".nr " SIZE_FORMAT " \\n[.ps]\n", uid);
+  printf(".ps %s\n", size);
+  printf(".nr " SMALL_SIZE_FORMAT " \\n[.ps]\n", uid);
+  int r = p->compute_metrics(style);
+  printf(".ps \\n[" SIZE_FORMAT "]u\n", uid);
+  printf(".nr " WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]\n", uid, p->uid);
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]\n", uid, p->uid);
+  printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]\n", uid, p->uid);
+  return r;
+}
+
+void size_box::output()
+{
+  if (output_format == troff) {
+    printf("\\s[\\n[" SMALL_SIZE_FORMAT "]u]", uid);
+    p->output();
+    printf("\\s[\\n[" SIZE_FORMAT "]u]", uid);
+  }
+  else if (output_format == mathml) {
+    printf("<mstyle mathsize='%s'>", size);
+    p->output();
+    printf("</mstyle>");
+  }
+}
+
+size_box::~size_box()
+{
+  free(size);
+}
+
+void size_box::debug_print()
+{
+  fprintf(stderr, "size %s { ", size);
+  p->debug_print();
+  fprintf(stderr, " }");
+}
+
+
+font_box::font_box(char *s, box *pp) : pointer_box(pp), f(s)
+{
+}
+
+font_box::~font_box()
+{
+  free(f);
+}
+
+int font_box::compute_metrics(int style)
+{
+  const char *old_roman_font = current_roman_font;
+  current_roman_font = f;
+  printf(".nr " FONT_FORMAT " \\n[.f]\n", uid);
+  printf(".ft %s\n", f);
+  int r = p->compute_metrics(style);
+  current_roman_font = old_roman_font;
+  printf(".ft \\n[" FONT_FORMAT "]\n", uid);
+  printf(".nr " WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]\n", uid, p->uid);
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]\n", uid, p->uid);
+  printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]\n", uid, p->uid);
+  return r;
+}
+
+void font_box::output()
+{
+  if (output_format == troff) {
+    printf("\\f[%s]", f);
+    const char *old_roman_font = current_roman_font;
+    current_roman_font = f;
+    p->output();
+    current_roman_font = old_roman_font;
+    printf("\\f[\\n[" FONT_FORMAT "]]", uid);
+  }
+  else if (output_format == mathml) {
+    const char *mlfont = f;
+    // bold and italic are already in MathML; translate eqn roman here
+    switch (f[0]) {
+    case 'I':
+    case 'i':
+      mlfont = "italic";
+      break;
+    case 'B':
+    case 'b':
+      mlfont = "bold";
+      break;
+    case 'R':
+    case 'r':
+    default:
+      mlfont = "normal";
+      break;
+    }
+    printf("<mstyle mathvariant='%s'>", mlfont);
+    p->output();
+    printf("</mstyle>");
+  }
+}
+
+void font_box::debug_print()
+{
+  fprintf(stderr, "font %s { ", f);
+  p->debug_print();
+  fprintf(stderr, " }");
+}
+
+fat_box::fat_box(box *pp) : pointer_box(pp)
+{
+}
+
+int fat_box::compute_metrics(int style)
+{
+  int r = p->compute_metrics(style);
+  printf(".nr " WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]+%dM\n",
+	 uid, p->uid, fat_offset);
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]\n", uid, p->uid);
+  printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]\n", uid, p->uid);
+  return r;
+}
+
+void fat_box::output()
+{
+  if (output_format == troff) {
+    p->output();
+    printf("\\h'-\\n[" WIDTH_FORMAT "]u'", p->uid);
+    printf("\\h'%dM'", fat_offset);
+    p->output();
+  }
+  else if (output_format == mathml) {
+    printf("<mstyle mathvariant='double-struck'>");
+    p->output();
+    printf("</mstyle>");
+  }
+}
+
+
+void fat_box::debug_print()
+{
+  fprintf(stderr, "fat { ");
+  p->debug_print();
+  fprintf(stderr, " }");
+}
+
+
+vmotion_box::vmotion_box(int i, box *pp) : pointer_box(pp), n(i)
+{
+}
+
+int vmotion_box::compute_metrics(int style)
+{
+  int r = p->compute_metrics(style);
+  printf(".nr " WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]\n", uid, p->uid);
+  if (n > 0) {
+    printf(".nr " HEIGHT_FORMAT " %dM+\\n[" HEIGHT_FORMAT "]\n",
+	   uid, n, p->uid);
+    printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]\n", uid, p->uid);
+  }
+  else {
+    printf(".nr " DEPTH_FORMAT " %dM+\\n[" DEPTH_FORMAT "]>?0\n",
+	   uid, -n, p->uid);
+    printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]\n",
+	   uid, p->uid);
+  }
+  return r;
+}
+
+void vmotion_box::output()
+{
+  if (output_format == troff) {
+    printf("\\v'%dM'", -n);
+    p->output();
+    printf("\\v'%dM'", n);
+  }
+  else if (output_format == mathml) {
+    printf("<merror>eqn vertical motion cannot be expressed "
+	   "in MathML</merror>");
+    p->output();
+  }
+}
+
+void vmotion_box::debug_print()
+{
+  if (n >= 0)
+    fprintf(stderr, "up %d { ", n);
+  else
+    fprintf(stderr, "down %d { ", -n);
+  p->debug_print();
+  fprintf(stderr, " }");
+}
+
+hmotion_box::hmotion_box(int i, box *pp) : pointer_box(pp), n(i)
+{
+}
+
+int hmotion_box::compute_metrics(int style)
+{
+  int r = p->compute_metrics(style);
+  printf(".nr " WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]+%dM\n",
+	 uid, p->uid, n);
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]\n", uid, p->uid);
+  printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]\n", uid, p->uid);
+  if (r)
+    printf(".nr " MARK_REG " +%dM\n", n);
+  return r;
+}
+
+void hmotion_box::output()
+{
+  if (output_format == troff) {
+    printf("\\h'%dM'", n);
+    p->output();
+  }
+  else if (output_format == mathml) {
+    printf("<merror>eqn horizontal motion cannot be expressed "
+	   "in MathML</merror>");
+    p->output();
+  }
+}
+
+void hmotion_box::debug_print()
+{
+  if (n >= 0)
+    fprintf(stderr, "fwd %d { ", n);
+  else
+    fprintf(stderr, "back %d { ", -n);
+  p->debug_print();
+  fprintf(stderr, " }");
+}
+
+vcenter_box::vcenter_box(box *pp) : pointer_box(pp)
+{
+}
+
+int vcenter_box::compute_metrics(int style)
+{
+  int r = p->compute_metrics(style);
+  printf(".nr " WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]\n", uid, p->uid);
+  printf(".nr " SUP_RAISE_FORMAT " \\n[" DEPTH_FORMAT "]-\\n["
+	 HEIGHT_FORMAT "]/2+%dM\n",
+	 uid, p->uid, p->uid, axis_height);
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]+\\n["
+	 SUP_RAISE_FORMAT "]>?0\n", uid, p->uid, uid);
+  printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]-\\n["
+	 SUP_RAISE_FORMAT "]>?0\n", uid, p->uid, uid);
+
+  return r;
+}
+
+void vcenter_box::output()
+{
+  if (output_format == troff)
+    printf("\\v'-\\n[" SUP_RAISE_FORMAT "]u'", uid);
+  p->output();
+  if (output_format == troff)
+    printf("\\v'\\n[" SUP_RAISE_FORMAT "]u'", uid);
+}
+
+void vcenter_box::debug_print()
+{
+  fprintf(stderr, "vcenter { ");
+  p->debug_print();
+  fprintf(stderr, " }");
+}
+
diff --git a/src/preproc/eqn/over.cpp b/src/preproc/eqn/over.cpp
new file mode 100644
index 0000000..6a9cd9b
--- /dev/null
+++ b/src/preproc/eqn/over.cpp
@@ -0,0 +1,204 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "eqn.h"
+#include "pbox.h"
+
+class over_box : public box {
+private:
+  int reduce_size;
+  box *num;
+  box *den;
+public:
+  over_box(int small, box *, box *);
+  ~over_box();
+  void debug_print();
+  int compute_metrics(int);
+  void output();
+  void check_tabs(int);
+};
+
+box *make_over_box(box *pp, box *qq)
+{
+  return new over_box(0, pp, qq);
+}
+
+box *make_small_over_box(box *pp, box *qq)
+{
+  return new over_box(1, pp, qq);
+}
+
+over_box::over_box(int is_small, box *pp, box *qq)
+: reduce_size(is_small), num(pp), den(qq)
+{
+  spacing_type = INNER_TYPE;
+}
+
+over_box::~over_box()
+{
+  delete num;
+  delete den;
+}
+
+int over_box::compute_metrics(int style)
+{
+  if (reduce_size) {
+    style = script_style(style);
+    printf(".nr " SIZE_FORMAT " \\n[.ps]\n", uid);
+    set_script_size();
+    printf(".nr " SMALL_SIZE_FORMAT " \\n[.ps]\n", uid);
+  }
+  int mark_uid = 0;
+  int res = num->compute_metrics(style);
+  if (res)
+    mark_uid = num->uid;
+  int r = den->compute_metrics(cramped_style(style));
+  if (r && res)
+    error("multiple marks and lineups");
+  else {
+    mark_uid = den->uid;
+    res = r;
+  }
+  if (reduce_size)
+    printf(".ps \\n[" SIZE_FORMAT "]u\n", uid);
+  printf(".nr " WIDTH_FORMAT " (\\n[" WIDTH_FORMAT "]>?\\n[" WIDTH_FORMAT "]", 
+	 uid, num->uid, den->uid);
+  // allow for \(ru being wider than both the numerator and denominator
+  if (!draw_flag)
+    fputs(">?\\w" DELIMITER_CHAR "\\(ru" DELIMITER_CHAR, stdout);
+  printf(")+%dM\n", null_delimiter_space*2 + over_hang*2);
+  // 15b
+  printf(".nr " SUP_RAISE_FORMAT " %dM\n",
+	 uid, (reduce_size ? num2 : num1));
+  printf(".nr " SUB_LOWER_FORMAT " %dM\n",
+	 uid, (reduce_size ? denom2 : denom1));
+
+  // 15d
+  printf(".nr " SUP_RAISE_FORMAT " +(\\n[" DEPTH_FORMAT
+	 "]-\\n[" SUP_RAISE_FORMAT "]+%dM+(%dM/2)+%dM)>?0\n",
+	 uid, num->uid, uid, axis_height, default_rule_thickness,
+	 default_rule_thickness*(reduce_size ? 1 : 3));
+  printf(".nr " SUB_LOWER_FORMAT " +(\\n[" HEIGHT_FORMAT
+	 "]-\\n[" SUB_LOWER_FORMAT "]-%dM+(%dM/2)+%dM)>?0\n",
+	 uid, den->uid, uid, axis_height, default_rule_thickness,
+	 default_rule_thickness*(reduce_size ? 1 : 3));
+
+
+  printf(".nr " HEIGHT_FORMAT " \\n[" SUP_RAISE_FORMAT "]+\\n["
+	 HEIGHT_FORMAT "]\n",
+	 uid, uid, num->uid);
+  printf(".nr " DEPTH_FORMAT " \\n[" SUB_LOWER_FORMAT "]+\\n["
+	 DEPTH_FORMAT "]\n",
+	 uid, uid, den->uid);
+  if (res)
+    printf(".nr " MARK_REG " +(\\n[" WIDTH_FORMAT "]-\\n["
+	   WIDTH_FORMAT "]/2)\n", uid, mark_uid);
+  return res;
+}
+
+#define USE_Z
+
+void over_box::output()
+{
+  if (output_format == troff) {
+    if (reduce_size)
+      printf("\\s[\\n[" SMALL_SIZE_FORMAT "]u]", uid);
+  #ifdef USE_Z
+    printf("\\Z" DELIMITER_CHAR);
+  #endif
+    // move up to the numerator baseline
+    printf("\\v'-\\n[" SUP_RAISE_FORMAT "]u'", uid);
+    // move across so that it's centered
+    printf("\\h'\\n[" WIDTH_FORMAT "]u-\\n[" WIDTH_FORMAT "]u/2u'",
+	   uid, num->uid);
+
+    // print the numerator
+    num->output();
+
+  #ifdef USE_Z
+    printf(DELIMITER_CHAR);
+  #else
+    // back again
+    printf("\\h'-\\n[" WIDTH_FORMAT "]u'", num->uid);
+    printf("\\h'-(\\n[" WIDTH_FORMAT "]u-\\n[" WIDTH_FORMAT "]u/2u)'",
+	   uid, num->uid);
+    // down again
+    printf("\\v'\\n[" SUP_RAISE_FORMAT "]u'", uid);
+  #endif
+  #ifdef USE_Z
+    printf("\\Z" DELIMITER_CHAR);
+  #endif
+    // move down to the denominator baseline
+    printf("\\v'\\n[" SUB_LOWER_FORMAT "]u'", uid);
+
+    // move across so that it's centered
+    printf("\\h'\\n[" WIDTH_FORMAT "]u-\\n[" WIDTH_FORMAT "]u/2u'",
+	   uid, den->uid);
+
+    // print the denominator
+    den->output();
+
+  #ifdef USE_Z
+    printf(DELIMITER_CHAR);
+  #else
+    // back again
+    printf("\\h'-\\n[" WIDTH_FORMAT "]u'", den->uid);
+    printf("\\h'-(\\n[" WIDTH_FORMAT "]u-\\n[" WIDTH_FORMAT "]u/2u)'",
+	   uid, den->uid);
+    // up again
+    printf("\\v'-\\n[" SUB_LOWER_FORMAT "]u'", uid);
+  #endif
+    if (reduce_size)
+      printf("\\s[\\n[" SIZE_FORMAT "]u]", uid);
+    // draw the line
+    printf("\\h'%dM'", null_delimiter_space);
+    printf("\\v'-%dM'", axis_height);
+    fputs(draw_flag ? "\\D'l" : "\\l'", stdout);
+    printf("\\n[" WIDTH_FORMAT "]u-%dM",
+	   uid, 2*null_delimiter_space);
+    fputs(draw_flag ? " 0'" : "\\&\\(ru'", stdout);
+    printf("\\v'%dM'", axis_height);
+    printf("\\h'%dM'", null_delimiter_space);
+  }
+  else if (output_format == mathml) {
+    // FIXME: passing a displaystyle attribute doesn't validate.
+    printf("<mfrac>");
+    num->output();
+    den->output();
+    printf("</mfrac>");
+  }
+}
+
+void over_box::debug_print()
+{
+  fprintf(stderr, "{ ");
+  num->debug_print();
+  if (reduce_size)
+    fprintf(stderr, " } smallover { ");
+  else
+    fprintf(stderr, " } over { ");
+  den->debug_print();
+  fprintf(stderr, " }");
+}
+
+void over_box::check_tabs(int level)
+{
+  num->check_tabs(level + 1);
+  den->check_tabs(level + 1);
+}
diff --git a/src/preproc/eqn/pbox.h b/src/preproc/eqn/pbox.h
new file mode 100644
index 0000000..b185419
--- /dev/null
+++ b/src/preproc/eqn/pbox.h
@@ -0,0 +1,140 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+extern int fat_offset;
+
+extern int over_hang;
+extern int accent_width;
+
+extern int delimiter_factor;
+extern int delimiter_shortfall;
+
+extern int null_delimiter_space;
+extern int script_space;
+extern int thin_space;
+extern int medium_space;
+extern int thick_space;
+
+extern int num1;
+extern int num2;
+// we don't use num3, because we don't have \atop
+extern int denom1;
+extern int denom2;
+extern int axis_height;
+extern int sup1;
+extern int sup2;
+extern int sup3;
+extern int default_rule_thickness;
+extern int sub1;
+extern int sub2;
+extern int sup_drop;
+extern int sub_drop;
+extern int x_height;
+extern int big_op_spacing1;
+extern int big_op_spacing2;
+extern int big_op_spacing3;
+extern int big_op_spacing4;
+extern int big_op_spacing5;
+
+extern int baseline_sep;
+extern int shift_down;
+extern int column_sep;
+extern int matrix_side_sep;
+
+// ms.eqn relies on this!
+
+#define LINE_STRING "10"
+#define MARK_OR_LINEUP_FLAG_REG "MK"
+
+#define WIDTH_FORMAT PREFIX "w%d"
+#define HEIGHT_FORMAT PREFIX "h%d"
+#define DEPTH_FORMAT PREFIX "d%d"
+#define TOTAL_FORMAT PREFIX "t%d"
+#define SIZE_FORMAT PREFIX "z%d"
+#define SMALL_SIZE_FORMAT PREFIX "Z%d"
+#define SUP_RAISE_FORMAT PREFIX "p%d"
+#define SUB_LOWER_FORMAT PREFIX "b%d"
+#define SUB_KERN_FORMAT PREFIX "k%d"
+#define FONT_FORMAT PREFIX "f%d"
+#define SKEW_FORMAT PREFIX "s%d"
+#define LEFT_WIDTH_FORMAT PREFIX "lw%d"
+#define LEFT_DELIM_STRING_FORMAT PREFIX "l%d"
+#define RIGHT_DELIM_STRING_FORMAT PREFIX "r%d"
+#define SQRT_STRING_FORMAT PREFIX "sqr%d"
+#define SQRT_WIDTH_FORMAT PREFIX "sq%d"
+#define BASELINE_SEP_FORMAT PREFIX "bs%d"
+// this needs two parameters, the uid and the column index
+#define COLUMN_WIDTH_FORMAT PREFIX "cw%d,%d"
+
+#define BAR_STRING PREFIX "sqb"
+#define TEMP_REG PREFIX "temp"
+#define MARK_REG PREFIX "mark"
+#define MARK_WIDTH_REG PREFIX "mwidth"
+#define SAVED_MARK_REG PREFIX "smark"
+#define MAX_SIZE_REG PREFIX "mxsz"
+#define REPEAT_APPEND_STRING_MACRO PREFIX "ras"
+#define TOP_HEIGHT_REG PREFIX "th"
+#define TOP_DEPTH_REG PREFIX "td"
+#define MID_HEIGHT_REG PREFIX "mh"
+#define MID_DEPTH_REG PREFIX "md"
+#define BOT_HEIGHT_REG PREFIX "bh"
+#define BOT_DEPTH_REG PREFIX "bd"
+#define EXT_HEIGHT_REG PREFIX "eh"
+#define EXT_DEPTH_REG PREFIX "ed"
+#define TOTAL_HEIGHT_REG PREFIX "tot"
+#define DELTA_REG PREFIX "delta"
+#define DELIM_STRING PREFIX "delim"
+#define DELIM_WIDTH_REG PREFIX "dwidth"
+#define SAVED_FONT_REG PREFIX "sfont"
+#define SAVED_PREV_FONT_REG PREFIX "spfont"
+#define SAVED_INLINE_FONT_REG PREFIX "sifont"
+#define SAVED_INLINE_PREV_FONT_REG PREFIX "sipfont"
+#define SAVED_SIZE_REG PREFIX "ssize"
+#define SAVED_INLINE_SIZE_REG PREFIX "sisize"
+#define SAVED_INLINE_PREV_SIZE_REG PREFIX "sipsize"
+#define SAVE_FONT_STRING PREFIX "sfont"
+#define RESTORE_FONT_STRING PREFIX "rfont"
+#define INDEX_REG PREFIX "i"
+#define TEMP_MACRO PREFIX "tempmac"
+
+#define DELIMITER_CHAR "\\(EQ"
+
+const int CRAMPED_SCRIPT_STYLE = 0;
+const int SCRIPT_STYLE = 1;
+const int CRAMPED_DISPLAY_STYLE = 2;
+const int DISPLAY_STYLE = 3;
+
+extern int script_style(int);
+extern int cramped_style(int);
+
+const int ORDINARY_TYPE = 0;
+const int OPERATOR_TYPE = 1;
+const int BINARY_TYPE = 2;
+const int RELATION_TYPE = 3;
+const int OPENING_TYPE = 4;
+const int CLOSING_TYPE = 5;
+const int PUNCTUATION_TYPE = 6;
+const int INNER_TYPE = 7;
+const int SUPPRESS_TYPE = 8;
+
+void set_script_size();
+
+enum { HINT_PREV_IS_ITALIC = 01, HINT_NEXT_IS_ITALIC = 02 };
+
+extern const char *current_roman_font;
diff --git a/src/preproc/eqn/pile.cpp b/src/preproc/eqn/pile.cpp
new file mode 100644
index 0000000..fcc2e92
--- /dev/null
+++ b/src/preproc/eqn/pile.cpp
@@ -0,0 +1,354 @@
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+// piles and matrices
+
+#include <assert.h>
+
+#include "eqn.h"
+#include "pbox.h"
+
+// SUP_RAISE_FORMAT gives the first baseline
+// BASELINE_SEP_FORMAT gives the separation between baselines
+
+int pile_box::compute_metrics(int style)
+{
+  int i;
+  for (i = 0; i < col.len; i++)
+    col.p[i]->compute_metrics(style);
+  printf(".nr " WIDTH_FORMAT " 0", uid);
+  for (i = 0; i < col.len; i++)
+    printf(">?\\n[" WIDTH_FORMAT "]", col.p[i]->uid);
+  printf("\n");
+  printf(".nr " BASELINE_SEP_FORMAT " %dM",
+	 uid, baseline_sep+col.space);
+  for (i = 1; i < col.len; i++)
+    printf(">?(\\n[" DEPTH_FORMAT "]+\\n[" HEIGHT_FORMAT "]+%dM)",
+	   col.p[i-1]->uid, col.p[i]->uid, default_rule_thickness*5);
+  // round it so that it's a multiple of the vertical motion quantum
+  printf("+(\\n(.V/2)/\\n(.V*\\n(.V\n");
+
+  printf(".nr " SUP_RAISE_FORMAT " \\n[" BASELINE_SEP_FORMAT "]*%d/2"
+	 "+%dM\n",
+	 uid, uid, col.len-1, axis_height - shift_down);
+  printf(".nr " HEIGHT_FORMAT " \\n[" SUP_RAISE_FORMAT "]+\\n["
+	 HEIGHT_FORMAT "]\n",
+	 uid, uid, col.p[0]->uid);
+  printf(".nr " DEPTH_FORMAT " \\n[" BASELINE_SEP_FORMAT "]*%d+\\n["
+	 DEPTH_FORMAT "]-\\n[" SUP_RAISE_FORMAT "]\n",
+	 uid, uid, col.len-1, col.p[col.len-1]->uid, uid);
+  return FOUND_NOTHING;
+}
+
+void pile_box::output()
+{
+  if (output_format == troff) {
+    int i;
+    printf("\\v'-\\n[" SUP_RAISE_FORMAT "]u'", uid);
+    for (i = 0; i < col.len; i++) {
+      switch (col.align) {
+      case LEFT_ALIGN:
+	break;
+      case CENTER_ALIGN:
+	printf("\\h'\\n[" WIDTH_FORMAT "]u-\\n[" WIDTH_FORMAT "]u/2u'",
+	       uid, col.p[i]->uid);
+	break;
+      case RIGHT_ALIGN:
+	printf("\\h'\\n[" WIDTH_FORMAT "]u-\\n[" WIDTH_FORMAT "]u'",
+	       uid, col.p[i]->uid);
+	break;
+      default:
+	assert(0);
+      }
+      col.p[i]->output();
+      printf("\\h'-\\n[" WIDTH_FORMAT "]u'", col.p[i]->uid);
+      switch (col.align) {
+      case LEFT_ALIGN:
+	break;
+      case CENTER_ALIGN:
+	printf("\\h'\\n[" WIDTH_FORMAT "]u-\\n[" WIDTH_FORMAT "]u/2u'",
+	       col.p[i]->uid, uid);
+	break;
+      case RIGHT_ALIGN:
+	printf("\\h'\\n[" WIDTH_FORMAT "]u-\\n[" WIDTH_FORMAT "]u'",
+	       col.p[i]->uid, uid);
+	break;
+      default:
+	assert(0);
+      }
+      if (i != col.len - 1)
+	printf("\\v'\\n[" BASELINE_SEP_FORMAT "]u'", uid);
+    }
+    printf("\\v'\\n[" SUP_RAISE_FORMAT "]u'", uid);
+    printf("\\v'-(%du*\\n[" BASELINE_SEP_FORMAT "]u)'", col.len - 1, uid);
+    printf("\\h'\\n[" WIDTH_FORMAT "]u'", uid);
+  }
+  else if (output_format == mathml) {
+    const char *av;
+    switch (col.align) {
+    case LEFT_ALIGN:
+      av = "left";
+      break;
+    case RIGHT_ALIGN:
+      av = "right";
+      break;
+    case CENTER_ALIGN:
+      av = "center";
+      break;
+    default:
+      assert(0);
+    }
+    printf("<mtable columnalign='%s'>", av);
+    for (int i = 0; i < col.len; i++) {
+      printf("<mtr><mtd>");
+      col.p[i]->output();
+      printf("</mtd></mtr>");
+    }
+    printf("</mtable>");
+  }
+}
+
+pile_box::pile_box(box *pp) : col(pp)
+{
+}
+
+void pile_box::check_tabs(int level)
+{
+  col.list_check_tabs(level);
+}
+
+void pile_box::debug_print()
+{
+  col.debug_print("pile");
+}
+
+int matrix_box::compute_metrics(int style)
+{
+  int i, j;
+  int max_len = 0;
+  int space = 0;
+  for (i = 0; i < len; i++) {
+    for (j = 0; j < p[i]->len; j++)
+      p[i]->p[j]->compute_metrics(style);
+    if (p[i]->len > max_len)
+      max_len = p[i]->len;
+    if (p[i]->space > space)
+      space = p[i]->space;
+  }
+  for (i = 0; i < len; i++) {
+    printf(".nr " COLUMN_WIDTH_FORMAT " 0", uid, i);
+    for (j = 0; j < p[i]->len; j++)
+      printf(">?\\n[" WIDTH_FORMAT "]", p[i]->p[j]->uid);
+    printf("\n");
+  }
+  printf(".nr " WIDTH_FORMAT " %dM",
+	 uid, column_sep*(len-1)+2*matrix_side_sep);
+  for (i = 0; i < len; i++)
+    printf("+\\n[" COLUMN_WIDTH_FORMAT "]", uid, i);
+  printf("\n");
+  printf(".nr " BASELINE_SEP_FORMAT " %dM",
+	 uid, baseline_sep+space);
+  for (i = 0; i < len; i++)
+    for (j = 1; j < p[i]->len; j++)
+      printf(">?(\\n[" DEPTH_FORMAT "]+\\n[" HEIGHT_FORMAT "]+%dM)",
+	   p[i]->p[j-1]->uid, p[i]->p[j]->uid, default_rule_thickness*5);
+  // round it so that it's a multiple of the vertical motion quantum
+  printf("+(\\n(.V/2)/\\n(.V*\\n(.V\n");
+  printf(".nr " SUP_RAISE_FORMAT " \\n[" BASELINE_SEP_FORMAT "]*%d/2"
+	 "+%dM\n",
+	 uid, uid, max_len-1, axis_height - shift_down);
+  printf(".nr " HEIGHT_FORMAT " 0\\n[" SUP_RAISE_FORMAT "]+(0",
+	 uid, uid);
+  for (i = 0; i < len; i++)
+    printf(">?\\n[" HEIGHT_FORMAT "]", p[i]->p[0]->uid);
+  printf(")>?0\n");
+  printf(".nr " DEPTH_FORMAT " \\n[" BASELINE_SEP_FORMAT "]*%d-\\n["
+	 SUP_RAISE_FORMAT "]+(0",
+	 uid, uid, max_len-1, uid);
+  for (i = 0; i < len; i++)
+    if (p[i]->len == max_len)
+      printf(">?\\n[" DEPTH_FORMAT "]", p[i]->p[max_len-1]->uid);
+  printf(")>?0\n");
+  return FOUND_NOTHING;
+}
+
+void matrix_box::output()
+{
+  if (output_format == troff) {
+    printf("\\h'%dM'", matrix_side_sep);
+    for (int i = 0; i < len; i++) {
+      int j;
+      printf("\\v'-\\n[" SUP_RAISE_FORMAT "]u'", uid);
+      for (j = 0; j < p[i]->len; j++) {
+	switch (p[i]->align) {
+	case LEFT_ALIGN:
+	  break;
+	case CENTER_ALIGN:
+	  printf("\\h'\\n[" COLUMN_WIDTH_FORMAT "]u-\\n[" WIDTH_FORMAT "]u/2u'",
+		 uid, i, p[i]->p[j]->uid);
+	  break;
+	case RIGHT_ALIGN:
+	  printf("\\h'\\n[" COLUMN_WIDTH_FORMAT "]u-\\n[" WIDTH_FORMAT "]u'",
+		 uid, i, p[i]->p[j]->uid);
+	  break;
+	default:
+	  assert(0);
+	}
+	p[i]->p[j]->output();
+	printf("\\h'-\\n[" WIDTH_FORMAT "]u'", p[i]->p[j]->uid);
+	switch (p[i]->align) {
+	case LEFT_ALIGN:
+	  break;
+	case CENTER_ALIGN:
+	  printf("\\h'\\n[" WIDTH_FORMAT "]u-\\n[" COLUMN_WIDTH_FORMAT "]u/2u'",
+		 p[i]->p[j]->uid, uid, i);
+	  break;
+	case RIGHT_ALIGN:
+	  printf("\\h'\\n[" WIDTH_FORMAT "]u-\\n[" COLUMN_WIDTH_FORMAT "]u'",
+		 p[i]->p[j]->uid, uid, i);
+	  break;
+	default:
+	  assert(0);
+	}
+	if (j != p[i]->len - 1)
+	  printf("\\v'\\n[" BASELINE_SEP_FORMAT "]u'", uid);
+      }
+      printf("\\v'\\n[" SUP_RAISE_FORMAT "]u'", uid);
+      printf("\\v'-(%du*\\n[" BASELINE_SEP_FORMAT "]u)'", p[i]->len - 1, uid);
+      printf("\\h'\\n[" COLUMN_WIDTH_FORMAT "]u'", uid, i);
+      if (i != len - 1)
+	printf("\\h'%dM'", column_sep);
+    }
+    printf("\\h'%dM'", matrix_side_sep);
+  }
+  else if (output_format == mathml) {
+    int n = p[0]->len;	// Each column must have the same number of rows in it
+    printf("<mtable>");
+    for (int i = 0; i < n; i++) {
+      printf("<mtr>");
+      for (int j = 0; j < len; j++) {
+	const char *av;
+	switch (p[j]->align) {
+	case LEFT_ALIGN:
+	  av = "left";
+	  break;
+	case RIGHT_ALIGN:
+	  av = "right";
+	  break;
+	case CENTER_ALIGN:
+	  av = "center";
+	  break;
+	default:
+	  assert(0);
+	}
+	printf("<mtd columnalign='%s'>", av);
+	p[j]->p[i]->output();
+	printf("</mtd>");
+      }
+      printf("</mtr>");
+    }
+    printf("</mtable>");
+  }
+}
+
+matrix_box::matrix_box(column *pp)
+{
+  p = new column*[10];
+  for (int i = 0; i < 10; i++)
+    p[i] = 0;
+  maxlen = 10;
+  len = 1;
+  p[0] = pp;
+}
+
+matrix_box::~matrix_box()
+{
+  for (int i = 0; i < len; i++)
+    delete p[i];
+  delete[] p;
+}
+
+void matrix_box::append(column *pp)
+{
+  if (len + 1 > maxlen) {
+    column **oldp = p;
+    maxlen *= 2;
+    p = new column*[maxlen];
+    memcpy(p, oldp, sizeof(column*)*len);
+    delete[] oldp;
+  }
+  p[len++] = pp;
+}
+
+void matrix_box::check_tabs(int level)
+{
+  for (int i = 0; i < len; i++)
+    p[i]->list_check_tabs(level);
+}
+
+void matrix_box::debug_print()
+{
+  fprintf(stderr, "matrix { ");
+  p[0]->debug_print("col");
+  for (int i = 1; i < len; i++) {
+    fprintf(stderr, " ");
+    p[i]->debug_print("col");
+  }
+  fprintf(stderr, " }");
+}
+
+column::column(box *pp) : box_list(pp), align(CENTER_ALIGN), space(0)
+{
+}
+
+void column::set_alignment(alignment a)
+{
+  align = a;
+}
+
+void column::set_space(int n)
+{
+  space = n;
+}
+
+void column::debug_print(const char *s)
+{
+  char c = '\0';		// shut up -Wall
+  switch (align) {
+  case LEFT_ALIGN:
+    c = 'l';
+    break;
+  case RIGHT_ALIGN:
+    c = 'r';
+    break;
+  case CENTER_ALIGN:
+    c = 'c';
+    break;
+  default:
+    assert(0);
+  }
+  fprintf(stderr, "%c%s %d { ", c, s, space);
+  list_debug_print(" above ");
+  fprintf(stderr, " }");
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/eqn/script.cpp b/src/preproc/eqn/script.cpp
new file mode 100644
index 0000000..f485eb9
--- /dev/null
+++ b/src/preproc/eqn/script.cpp
@@ -0,0 +1,250 @@
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <assert.h>
+
+#include "eqn.h"
+#include "pbox.h"
+
+class script_box : public pointer_box {
+private:
+  box *sub;
+  box *sup;
+public:
+  script_box(box *, box *, box *);
+  ~script_box();
+  int compute_metrics(int);
+  void output();
+  void debug_print();
+  int left_is_italic();
+  void hint(unsigned);
+  void check_tabs(int);
+};
+
+/* The idea is that the script should attach to the rightmost box
+of a list. For example, given '2x sup 3', the superscript should
+attach to 'x' rather than '2x'. */
+
+box *make_script_box(box *nuc, box *sub, box *sup)
+{
+  list_box *b = nuc->to_list_box();
+  if (b != 0) {
+    b->list.p[b->list.len-1] = make_script_box(b->list.p[b->list.len - 1],
+					       sub,
+					       sup);
+    return b;
+  }
+  else
+    return new script_box(nuc, sub, sup);
+}
+
+script_box::script_box(box *pp, box *qq, box *rr)
+: pointer_box(pp), sub(qq), sup(rr)
+{
+}
+
+script_box::~script_box()
+{
+  delete sub;
+  delete sup;
+}
+
+int script_box::left_is_italic()
+{
+  return p->left_is_italic();
+}
+
+int script_box::compute_metrics(int style)
+{
+  int res = p->compute_metrics(style);
+  p->compute_subscript_kern();
+  printf(".nr " SIZE_FORMAT " \\n[.ps]\n", uid);
+  if (!(style <= SCRIPT_STYLE && one_size_reduction_flag))
+    set_script_size();
+  printf(".nr " SMALL_SIZE_FORMAT " \\n[.ps]\n", uid);
+  if (sub != 0)
+    sub->compute_metrics(cramped_style(script_style(style)));
+  if (sup != 0)
+    sup->compute_metrics(script_style(style));
+  // 18a
+  if (p->is_char()) {
+    printf(".nr " SUP_RAISE_FORMAT " 0\n", uid);
+    printf(".nr " SUB_LOWER_FORMAT " 0\n", uid);
+  }
+  else {
+    printf(".nr " SUP_RAISE_FORMAT " \\n[" HEIGHT_FORMAT "]-%dM>?0\n",
+	   uid, p->uid, sup_drop);
+    printf(".nr " SUB_LOWER_FORMAT " \\n[" DEPTH_FORMAT "]+%dM\n",
+	   uid, p->uid, sub_drop);
+  }
+  printf(".ps \\n[" SIZE_FORMAT "]u\n", uid);
+  if (sup == 0) {
+    assert(sub != 0);
+    // 18b
+    printf(".nr " SUB_LOWER_FORMAT " \\n[" SUB_LOWER_FORMAT "]>?%dM>?(\\n["
+	   HEIGHT_FORMAT "]-(%dM*4/5))\n",
+	   uid, uid, sub1, sub->uid, x_height);
+  }
+  else {
+    // sup != 0
+    // 18c
+    int pos;
+    if (style == DISPLAY_STYLE)
+      pos = sup1;
+    else if (style & 1)		// not cramped
+      pos = sup2;
+    else
+      pos = sup3;
+    printf(".nr " SUP_RAISE_FORMAT " \\n[" SUP_RAISE_FORMAT
+	   "]>?%dM>?(\\n[" DEPTH_FORMAT "]+(%dM/4))\n",
+	   uid, uid, pos, sup->uid, x_height);
+    // 18d
+    if (sub != 0) {
+      printf(".nr " SUB_LOWER_FORMAT " \\n[" SUB_LOWER_FORMAT "]>?%dM\n",
+	     uid, uid, sub2);
+      // 18e
+      printf(".nr " TEMP_REG " \\n[" DEPTH_FORMAT "]-\\n["
+	     SUP_RAISE_FORMAT "]+\\n[" HEIGHT_FORMAT "]-\\n["
+	     SUB_LOWER_FORMAT "]+(4*%dM)\n",
+	     sup->uid, uid, sub->uid, uid, default_rule_thickness);
+      printf(".if \\n[" TEMP_REG "] \\{");
+      printf(".nr " SUB_LOWER_FORMAT " +\\n[" TEMP_REG "]\n", uid);
+      printf(".nr " TEMP_REG " (%dM*4/5)-\\n[" SUP_RAISE_FORMAT
+	     "]+\\n[" DEPTH_FORMAT "]>?0\n",
+	     x_height, uid, sup->uid);
+      printf(".nr " SUP_RAISE_FORMAT " +\\n[" TEMP_REG "]\n", uid);
+      printf(".nr " SUB_LOWER_FORMAT " -\\n[" TEMP_REG "]\n", uid);
+      printf(".\\}\n");
+    }
+  }
+  printf(".nr " WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]", uid, p->uid);
+  if (sub != 0 && sup != 0)
+    printf("+((\\n[" WIDTH_FORMAT "]-\\n[" SUB_KERN_FORMAT "]>?\\n["
+	   WIDTH_FORMAT "])+%dM)>?0\n",
+	   sub->uid, p->uid, sup->uid, script_space);
+  else if (sub != 0)
+    printf("+(\\n[" WIDTH_FORMAT "]-\\n[" SUB_KERN_FORMAT "]+%dM)>?0\n",
+	   sub->uid, p->uid, script_space);
+  else if (sup != 0)
+    printf("+(\\n[" WIDTH_FORMAT "]+%dM)>?0\n", sup->uid, script_space);
+  else
+    printf("\n");
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]",
+	 uid, p->uid);
+  if (sup != 0)
+    printf(">?(\\n[" SUP_RAISE_FORMAT "]+\\n[" HEIGHT_FORMAT "])",
+	   uid, sup->uid);
+  if (sub != 0)
+    printf(">?(-\\n[" SUB_LOWER_FORMAT "]+\\n[" HEIGHT_FORMAT "])",
+	   uid, sub->uid);
+  printf("\n");
+  printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]",
+	 uid, p->uid);
+  if (sub != 0)
+    printf(">?(\\n[" SUB_LOWER_FORMAT "]+\\n[" DEPTH_FORMAT "])",
+	   uid, sub->uid);
+  if (sup != 0)
+    printf(">?(-\\n[" SUP_RAISE_FORMAT "]+\\n[" DEPTH_FORMAT "])",
+	   uid, sup->uid);
+  printf("\n");
+  return res;
+}
+
+void script_box::output()
+{
+  if (output_format == troff) {
+    p->output();
+    if (sup != 0) {
+      printf("\\Z" DELIMITER_CHAR);
+      printf("\\v'-\\n[" SUP_RAISE_FORMAT "]u'", uid);
+      printf("\\s[\\n[" SMALL_SIZE_FORMAT "]u]", uid);
+      sup->output();
+      printf("\\s[\\n[" SIZE_FORMAT "]u]", uid);
+      printf(DELIMITER_CHAR);
+    }
+    if (sub != 0) {
+      printf("\\Z" DELIMITER_CHAR);
+      printf("\\v'\\n[" SUB_LOWER_FORMAT "]u'", uid);
+      printf("\\s[\\n[" SMALL_SIZE_FORMAT "]u]", uid);
+      printf("\\h'-\\n[" SUB_KERN_FORMAT "]u'", p->uid);
+      sub->output();
+      printf("\\s[\\n[" SIZE_FORMAT "]u]", uid);
+      printf(DELIMITER_CHAR);
+    }
+    printf("\\h'\\n[" WIDTH_FORMAT "]u-\\n[" WIDTH_FORMAT "]u'",
+	   uid, p->uid);
+  }
+  else if (output_format == mathml) {
+    if (sup != 0 && sub != 0) {
+      printf("<msubsup>");
+      p->output();
+      sub->output();
+      sup->output();
+      printf("</msubsup>");
+    }
+    else if (sup != 0) {
+      printf("<msup>");
+      p->output();
+      sup->output();
+      printf("</msup>");
+  }
+  else if (sub != 0) {
+      printf("<msub>");
+      p->output();
+      sub->output();
+      printf("</msub>");
+    }
+  }
+}
+
+void script_box::hint(unsigned flags)
+{
+  p->hint(flags & ~HINT_NEXT_IS_ITALIC);
+}
+
+void script_box::debug_print()
+{
+  fprintf(stderr, "{ ");
+  p->debug_print();
+  fprintf(stderr, " }");
+  if (sub) {
+    fprintf(stderr, " sub { ");
+    sub->debug_print();
+    fprintf(stderr, " }");
+  }
+  if (sup) {
+    fprintf(stderr, " sup { ");
+    sup->debug_print();
+    fprintf(stderr, " }");
+  }
+}
+
+void script_box::check_tabs(int level)
+{
+  if (sup)
+    sup->check_tabs(level + 1);
+  if (sub)
+    sub->check_tabs(level + 1);
+  p->check_tabs(level);
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/eqn/special.cpp b/src/preproc/eqn/special.cpp
new file mode 100644
index 0000000..8ad8238
--- /dev/null
+++ b/src/preproc/eqn/special.cpp
@@ -0,0 +1,117 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "eqn.h"
+#include "pbox.h"
+
+#define STRING_FORMAT PREFIX "str%d"
+
+#define SPECIAL_STRING "0s"
+#define SPECIAL_WIDTH_REG "0w"
+#define SPECIAL_HEIGHT_REG "0h"
+#define SPECIAL_DEPTH_REG "0d"
+#define SPECIAL_SUB_KERN_REG "0skern"
+#define SPECIAL_SKEW_REG "0skew"
+
+/*
+For example:
+
+.de Cl
+.ds 0s \Z'\\*[0s]'\v'\\n(0du'\D'l \\n(0wu -\\n(0hu-\\n(0du'\v'\\n(0hu'
+..
+.EQ
+define cancel 'special Cl'
+.EN
+*/
+
+
+class special_box : public pointer_box {
+  char *macro_name;
+public:
+  special_box(char *, box *);
+  ~special_box();
+  int compute_metrics(int);
+  void compute_subscript_kern();
+  void compute_skew();
+  void output();
+  void debug_print();
+};
+
+box *make_special_box(char *s, box *p)
+{
+  return new special_box(s, p);
+}
+
+special_box::special_box(char *s, box *pp) : pointer_box(pp), macro_name(s)
+{
+}
+
+special_box::~special_box()
+{
+  delete[] macro_name;
+}
+
+int special_box::compute_metrics(int style)
+{
+  int r = p->compute_metrics(style);
+  p->compute_subscript_kern();
+  p->compute_skew();
+  printf(".ds " SPECIAL_STRING " \"");
+  p->output();
+  printf("\n");
+  printf(".nr " SPECIAL_WIDTH_REG " 0\\n[" WIDTH_FORMAT "]\n", p->uid);
+  printf(".nr " SPECIAL_HEIGHT_REG " \\n[" HEIGHT_FORMAT "]\n", p->uid);
+  printf(".nr " SPECIAL_DEPTH_REG " \\n[" DEPTH_FORMAT "]\n", p->uid);
+  printf(".nr " SPECIAL_SUB_KERN_REG " \\n[" SUB_KERN_FORMAT "]\n", p->uid);
+  printf(".nr " SPECIAL_SKEW_REG " 0\\n[" SKEW_FORMAT "]\n", p->uid);
+  printf(".%s\n", macro_name);
+  printf(".rn " SPECIAL_STRING " " STRING_FORMAT "\n", uid);
+  printf(".nr " WIDTH_FORMAT " 0\\n[" SPECIAL_WIDTH_REG "]\n", uid);
+  printf(".nr " HEIGHT_FORMAT " 0>?\\n[" SPECIAL_HEIGHT_REG "]\n", uid);
+  printf(".nr " DEPTH_FORMAT " 0>?\\n[" SPECIAL_DEPTH_REG "]\n", uid);
+  printf(".nr " SUB_KERN_FORMAT " 0>?\\n[" SPECIAL_SUB_KERN_REG "]\n", uid);
+  printf(".nr " SKEW_FORMAT " 0\\n[" SPECIAL_SKEW_REG "]\n", uid);
+  // User will have to change MARK_REG if appropriate.
+  return r;
+}
+
+void special_box::compute_subscript_kern()
+{
+  // Already computed in compute_metrics(), so do nothing.
+}
+
+void special_box::compute_skew()
+{
+  // Already computed in compute_metrics(), so do nothing.
+}
+
+void special_box::output()
+{
+  if (output_format == troff)
+    printf("\\*[" STRING_FORMAT "]", uid);
+  else if (output_format == mathml)
+    printf("<merror>eqn specials cannot be expressed in MathML</merror>");
+}
+
+void special_box::debug_print()
+{
+  fprintf(stderr, "special %s { ", macro_name);
+  p->debug_print();
+  fprintf(stderr, " }");
+}
diff --git a/src/preproc/eqn/sqrt.cpp b/src/preproc/eqn/sqrt.cpp
new file mode 100644
index 0000000..e8d7c77
--- /dev/null
+++ b/src/preproc/eqn/sqrt.cpp
@@ -0,0 +1,186 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "eqn.h"
+#include "pbox.h"
+
+
+class sqrt_box : public pointer_box {
+public:
+  sqrt_box(box *);
+  int compute_metrics(int style);
+  void output();
+  void debug_print();
+  void check_tabs(int);
+};
+
+box *make_sqrt_box(box *pp)
+{
+  return new sqrt_box(pp);
+}
+
+sqrt_box::sqrt_box(box *pp) : pointer_box(pp)
+{
+}
+
+#define SQRT_CHAR "\\[sqrt]"
+#define RADICAL_EXTENSION_CHAR "\\[sqrtex]"
+
+#define SQRT_CHAIN "\\[sqrt\\\\n[" INDEX_REG "]]"
+#define BAR_CHAIN "\\[sqrtex\\\\n[" INDEX_REG "]]"
+
+int sqrt_box::compute_metrics(int style)
+{
+  // 11
+  int r = p->compute_metrics(cramped_style(style));
+  printf(".nr " TEMP_REG " \\n[" HEIGHT_FORMAT "]+\\n[" DEPTH_FORMAT
+	 "]+%dM+(%dM/4)\n",
+	 p->uid, p->uid, default_rule_thickness,
+	 (style > SCRIPT_STYLE ? x_height : default_rule_thickness));
+  printf(".nr " SIZE_FORMAT " \\n[.ps]\n", uid);
+  printf(".ds " SQRT_STRING_FORMAT " " SQRT_CHAR "\n", uid);
+  printf(".ds " BAR_STRING " " RADICAL_EXTENSION_CHAR "\n");
+  printf(".nr " SQRT_WIDTH_FORMAT
+	 " 0\\w" DELIMITER_CHAR SQRT_CHAR DELIMITER_CHAR "\n",
+	 uid);
+  printf(".if \\n[rst]-\\n[rsb]-%dM<\\n[" TEMP_REG "] \\{",
+	 default_rule_thickness);
+
+  printf(".nr " INDEX_REG " 0\n"
+	 ".de " TEMP_MACRO "\n"
+	 ".ie c" SQRT_CHAIN " \\{"
+	 ".ds " SQRT_STRING_FORMAT " " SQRT_CHAIN "\n"
+	 ".ie c" BAR_CHAIN " .ds " BAR_STRING " " BAR_CHAIN "\n"
+	 ".el .ds " BAR_STRING " " RADICAL_EXTENSION_CHAR "\n"
+	 ".nr " SQRT_WIDTH_FORMAT
+	 " 0\\w" DELIMITER_CHAR SQRT_CHAIN DELIMITER_CHAR "\n"
+	 ".if \\\\n[rst]-\\\\n[rsb]-%dM<\\n[" TEMP_REG "] \\{"
+	 ".nr " INDEX_REG " +1\n"
+	 "." TEMP_MACRO "\n"
+	 ".\\}\\}\n"
+	 ".el .nr " INDEX_REG " 0-1\n"
+	 "..\n"
+	 "." TEMP_MACRO "\n",
+	 uid, uid, default_rule_thickness);
+
+  printf(".if \\n[" INDEX_REG "]<0 \\{");
+
+  // Determine the maximum point size
+  printf(".ps 1000\n");
+  printf(".nr " MAX_SIZE_REG " \\n[.ps]\n");
+  printf(".ps \\n[" SIZE_FORMAT "]u\n", uid);
+  // We define a macro that will increase the current point size
+  // until we get a radical sign that's tall enough or we reach
+  // the maximum point size.
+  printf(".de " TEMP_MACRO "\n"
+	 ".nr " SQRT_WIDTH_FORMAT
+	 " 0\\w" DELIMITER_CHAR "\\*[" SQRT_STRING_FORMAT "]" DELIMITER_CHAR "\n"
+	 ".if \\\\n[rst]"
+	 "&(\\\\n[rst]-\\\\n[rsb]-%dM<\\n[" TEMP_REG "])"
+	 "&(\\\\n[.ps]<\\n[" MAX_SIZE_REG "]) \\{"
+	 ".ps +1\n"
+	 "." TEMP_MACRO "\n"
+	 ".\\}\n"
+	 "..\n"
+	 "." TEMP_MACRO "\n",
+	 uid, uid, default_rule_thickness);
+  
+  printf(".\\}\\}\n");
+
+  printf(".nr " SMALL_SIZE_FORMAT " \\n[.ps]\n", uid);
+  // set TEMP_REG to the amount by which the radical sign is too big
+  printf(".nr " TEMP_REG " \\n[rst]-\\n[rsb]-%dM-\\n[" TEMP_REG "]\n",
+	 default_rule_thickness);
+  // If TEMP_REG is negative, the bottom of the radical sign should
+  // be -TEMP_REG above the bottom of p. If it's positive, the bottom
+  // of the radical sign should be TEMP_REG/2 below the bottom of p.
+  // This calculates the amount by which the baseline of the radical
+  // should be raised.
+  printf(".nr " SUP_RAISE_FORMAT " (-\\n[" TEMP_REG "]>?(-\\n[" TEMP_REG "]/2))"
+	 "-\\n[rsb]-\\n[" DEPTH_FORMAT "]\n", uid, p->uid);
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]"
+	 ">?(\\n[" SUP_RAISE_FORMAT "]+\\n[rst])\n",
+	 uid, p->uid, uid);
+  printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]"
+	 ">?(-\\n[" SUP_RAISE_FORMAT "]-\\n[rsb])\n",
+	 uid, p->uid, uid);
+  // Do this last, so we don't lose height and depth information on
+  // the radical sign.
+  // Remember that the width of the bar might be greater than the width of p.
+
+  printf(".nr " TEMP_REG " "
+	 "\\n[" WIDTH_FORMAT "]"
+	 ">?\\w" DELIMITER_CHAR "\\*[" BAR_STRING "]" DELIMITER_CHAR "\n",
+	 p->uid);
+  printf(".as " SQRT_STRING_FORMAT " "
+	 "\\l'\\n[" TEMP_REG "]u\\&\\*[" BAR_STRING "]'\n",
+	 uid);
+  printf(".nr " WIDTH_FORMAT " \\n[" TEMP_REG "]"
+	 "+\\n[" SQRT_WIDTH_FORMAT "]\n",
+	 uid, uid);
+
+  if (r)
+    printf(".nr " MARK_REG " +\\n[" SQRT_WIDTH_FORMAT "]\n", uid);
+  // the top of the bar might be higher than the top of the radical sign
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]"
+	 ">?(\\n[" SUP_RAISE_FORMAT "]+\\n[rst])\n",
+	 uid, p->uid, uid);
+  // put a bit of extra space above the bar
+  printf(".nr " HEIGHT_FORMAT " +%dM\n", uid, default_rule_thickness);
+  printf(".ps \\n[" SIZE_FORMAT "]u\n", uid);
+  return r;
+}
+
+void sqrt_box::output()
+{
+  if (output_format == troff) {
+    printf("\\Z" DELIMITER_CHAR);
+    printf("\\s[\\n[" SMALL_SIZE_FORMAT "]u]", uid);
+    printf("\\v'-\\n[" SUP_RAISE_FORMAT "]u'", uid);
+    printf("\\*[" SQRT_STRING_FORMAT "]", uid);
+    printf("\\s[\\n[" SIZE_FORMAT "]u]", uid);
+    printf(DELIMITER_CHAR);
+
+    printf("\\Z" DELIMITER_CHAR);
+    printf("\\h'\\n[" WIDTH_FORMAT "]u-\\n[" WIDTH_FORMAT "]u"
+	   "+\\n[" SQRT_WIDTH_FORMAT "]u/2u'",
+	   uid, p->uid, uid);
+    p->output();
+    printf(DELIMITER_CHAR);
+
+    printf("\\h'\\n[" WIDTH_FORMAT "]u'", uid);
+  }
+  else if (output_format == mathml) {
+    printf("<msqrt>");
+    p->output();
+    printf("</msqrt>");
+  }
+}
+
+void sqrt_box::debug_print()
+{
+  fprintf(stderr, "sqrt { ");
+  p->debug_print();
+  fprintf(stderr, " }");
+}
+
+void sqrt_box::check_tabs(int level)
+{
+  p->check_tabs(level + 1);
+}
diff --git a/src/preproc/eqn/tests/diagnostics-report-correct-line-numbers.sh b/src/preproc/eqn/tests/diagnostics-report-correct-line-numbers.sh
new file mode 100755
index 0000000..feb78c1
--- /dev/null
+++ b/src/preproc/eqn/tests/diagnostics-report-correct-line-numbers.sh
@@ -0,0 +1,55 @@
+#!/bin/sh
+#
+# Copyright (C) 2022 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+eqn="${abs_top_builddir:-.}/eqn"
+fail=
+
+wail () {
+    echo "...FAILED" >&2
+    echo "$error"
+    fail=yes
+}
+
+# Verify that correct input file line numbers are reported.
+
+echo "checking for absent line number in early EOF diagnostic" >&2
+input='.EQ'
+error=$(printf "%s\n" "$input" | "$eqn" 2>&1 > /dev/null)
+echo "$error" | grep -Eq '^[^:]+:[^:]+: fatal' || wail
+
+echo "checking for correct line number in nested 'EQ' diagnostic" >&2
+input='.EQ
+.EQ'
+error=$(printf "%s\n" "$input" | "$eqn" 2>&1 > /dev/null)
+echo "$error" | grep -Eq '^[^:]+:[^:]+:2: fatal' || wail
+
+echo "checking for correct line number in invalid input character" \
+    "diagnostic" >&2
+error=$(printf ".EQ\nx\n.EN\n\200\n" | "$eqn" 2>&1 > /dev/null)
+echo "$error" | grep -Eq '^[^:]+:[^:]+:4: error' || wail
+
+echo "checking for correct line number in invalid input character" \
+    "diagnostic when 'lf' request used beforehand" >&2
+error=$(printf ".EQ\nx\n.EN\n.lf 99\n\200\n" | "$eqn" 2>&1 > /dev/null)
+echo "$error" | grep -Eq '^[^:]+:[^:]+:99: error' || wail
+
+test -z "$fail"
+
+# vim:set ai et sw=4 ts=4 tw=72:
diff --git a/src/preproc/eqn/text.cpp b/src/preproc/eqn/text.cpp
new file mode 100644
index 0000000..272f3fe
--- /dev/null
+++ b/src/preproc/eqn/text.cpp
@@ -0,0 +1,957 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <ctype.h>
+#include <stdlib.h>
+#include "eqn.h"
+#include "pbox.h"
+#include "ptable.h"
+
+struct map {
+  const char *from;
+  const char *to;
+};
+
+struct map entity_table[] = {
+  // Classic troff special characters
+  {"%", "&shy;"},	// ISOnum
+  {"'", "&acute;"},	// ISOdia
+  {"!=", "&ne;"},	// ISOtech
+  {"**", "&lowast;"},	// ISOtech
+  {"*a", "&alpha;"},	// ISOgrk3
+  {"*A", "A"},
+  {"*b", "&beta;"},	// ISOgrk3
+  {"*B", "B"},
+  {"*d", "&delta;"},	// ISOgrk3
+  {"*D", "&Delta;"},	// ISOgrk3
+  {"*e", "&epsilon;"},	// ISOgrk3
+  {"*E", "E"},
+  {"*f", "&phi;"},	// ISOgrk3
+  {"*F", "&Phi;"},	// ISOgrk3
+  {"*g", "&gamma;"},	// ISOgrk3
+  {"*G", "&Gamma;"},	// ISOgrk3
+  {"*h", "&theta;"},	// ISOgrk3
+  {"*H", "&Theta;"},	// ISOgrk3
+  {"*i", "&iota;"},	// ISOgrk3
+  {"*I", "I"},
+  {"*k", "&kappa;"},	// ISOgrk3
+  {"*K", "K;"},
+  {"*l", "&lambda;"},	// ISOgrk3
+  {"*L", "&Lambda;"},	// ISOgrk3
+  {"*m", "&mu;"},	// ISOgrk3
+  {"*M", "M"},
+  {"*n", "&nu;"},	// ISOgrk3
+  {"*N", "N"},
+  {"*o", "o"},
+  {"*O", "O"},
+  {"*p", "&pi;"},	// ISOgrk3
+  {"*P", "&Pi;"},	// ISOgrk3
+  {"*q", "&psi;"},	// ISOgrk3
+  {"*Q", "&PSI;"},	// ISOgrk3
+  {"*r", "&rho;"},	// ISOgrk3
+  {"*R", "R"},
+  {"*s", "&sigma;"},	// ISOgrk3
+  {"*S", "&Sigma;"},	// ISOgrk3
+  {"*t", "&tau;"},	// ISOgrk3
+  {"*T", "&Tau;"},	// ISOgrk3
+  {"*u", "&upsilon;"},	// ISOgrk3
+  {"*U", "&Upsilon;"},	// ISOgrk3
+  {"*w", "&omega;"},	// ISOgrk3
+  {"*W", "&Omega;"},	// ISOgrk3
+  {"*x", "&chi;"},	// ISOgrk3
+  {"*X", "&Chi;"},	// ISOgrk3
+  {"*y", "&eta;"},	// ISOgrk3
+  {"*Y", "&Eta;"},	// ISOgrk3
+  {"*z", "&zeta;"},	// ISOgrk3
+  {"*Z", "&Zeta;"},	// ISOgrk3
+  {"+-", "&plusmn;"},	// ISOnum
+  {"->", "&rarr;"},	// ISOnum
+  {"12", "&frac12;"},	// ISOnum
+  {"14", "&frac14;"},	// ISOnum
+  {"34", "&frac34;"},	// ISOnum
+  {"<-", "&larr;"},	// ISOnum
+  {"==", "&equiv;"},	// ISOtech
+  {"Fi", "&ffilig;"},	// ISOpub
+  {"Fl", "&ffllig;"},	// ISOpub
+  {"aa", "&acute;"},	// ISOdia
+  {"ap", "&sim;"},	// ISOtech
+  {"bl", "&phonexb;"},	// ISOpub
+  {"br", "&boxv;"},	// ISObox
+  {"bs", "&phone;"},	// ISOpub (for the Bell logo)
+  {"bu", "&bull;"},	// ISOpub
+  {"bv", "&verbar;"},	// ISOnum
+  {"ca", "&cap;"},	// ISOtech
+  {"ci", "&cir;"},	// ISOpub
+  {"co", "&copy;"},	// ISOnum
+  {"ct", "&cent;"},	// ISOnum
+  {"cu", "&cup;"},	// ISOtech
+  {"da", "&darr;"},	// ISOnum
+  {"de", "&deg;"},	// ISOnum
+  {"dg", "&dagger;"},	// ISOpub
+  {"dd", "&Dagger;"},	// ISOpub
+  {"di", "&divide;"},	// ISOnum
+  {"em", "&mdash;"},	// ISOpub
+  {"eq", "&equals;"},	// ISOnum
+  {"es", "&empty;"},	// ISOamso
+  {"ff", "&fflig;"},	// ISOpub
+  {"fi", "&filig;"},	// ISOpub
+  {"fl", "&fllig;"},	// ISOpub
+  {"fm", "&prime;"},	// ISOtech
+  {"ge", "&ge;"},	// ISOtech
+  {"gr", "&nabla;"},	// ISOtech
+  {"hy", "&hyphen;"},	// ISOnum
+  {"ib", "&sube;"},	// ISOtech
+  {"if", "&infin;"},	// ISOtech
+  {"ip", "&supe;"},	// ISOtech
+  {"is", "&int;"},	// ISOtech
+  {"le", "&le;"},	// ISOtech
+  // Some pile characters go here
+  {"mi", "&minus;"},	// ISOtech
+  {"mo", "&isin;"},	// ISOtech
+  {"mu", "&times;"},	// ISOnum
+  {"no", "&not;"},	// ISOnum
+  {"or", "&verbar;"},	// ISOnum
+  {"pl", "&plus;"},	// ISOnum
+  {"pt", "&prop;"},	// ISOtech
+  {"rg", "&trade;"},	// ISOnum
+  // More pile characters go here
+  {"rn", "&macr;"},	// ISOdia
+  {"ru", "&lowbar;"},	// ISOnum
+  {"sb", "&sub;"},	// ISOtech
+  {"sc", "&sect;"},	// ISOnum
+  {"sl", "/"},
+  {"sp", "&sup;"},	// ISOtech
+  {"sq", "&squf;"},	// ISOpub
+  {"sr", "&radic;"},	// ISOtech
+  {"ts", "&sigmav;"},	// ISOgrk3
+  {"ua", "&uarr;"},	// ISOnum
+  {"ul", "_"},
+  {"~=", "&cong;"},	// ISOtech
+  // Extended specials supported by groff; see groff_char(7).
+  // These are listed in the order they occur on that man page.
+  {"-D", "&ETH;"},	// ISOlat: Icelandic uppercase eth
+  {"Sd", "&eth;"},	// ISOlat1: Icelandic lowercase eth
+  {"TP", "&THORN;"},	// ISOlat1: Icelandic uppercase thorn
+  {"Tp", "&thorn;"},	// ISOlat1: Icelandic lowercase thorn
+  {"ss", "&szlig;"},	// ISOlat1
+  // Ligatures
+  // ff, fi, fl, ffi, ffl from old troff go here
+  {"AE", "&AElig;"},	// ISOlat1
+  {"ae", "&aelig;"},	// ISOlat1
+  {"OE", "&OElig;"},	// ISOlat2
+  {"oe", "&oelig;"},	// ISOlat2
+  {"IJ", "&ijlig;"}, 	// ISOlat2: Dutch IJ ligature
+  {"ij", "&IJlig;"}, 	// ISOlat2: Dutch ij ligature
+  {".i", "&inodot;"},	// ISOlat2,ISOamso
+  {".j", "&jnodot;"},	// ISOamso (undocumented but in 1.19)
+  // Accented characters
+  {"'A", "&Aacute;"},	// ISOlat1
+  {"'C", "&Cacute;"},	// ISOlat2
+  {"'E", "&Eacute;"},	// ISOlat1
+  {"'I", "&Iacute;"},	// ISOlat1
+  {"'O", "&Oacute;"},	// ISOlat1
+  {"'U", "&Uacute;"},	// ISOlat1
+  {"'Y", "&Yacute;"},	// ISOlat1
+  {"'a", "&aacute;"},	// ISOlat1
+  {"'c", "&cacute;"},	// ISOlat2
+  {"'e", "&eacute;"},	// ISOlat1
+  {"'i", "&iacute;"},	// ISOlat1
+  {"'o", "&oacute;"},	// ISOlat1
+  {"'u", "&uacute;"},	// ISOlat1
+  {"'y", "&yacute;"},	// ISOlat1
+  {":A", "&Auml;"},	// ISOlat1
+  {":E", "&Euml;"},	// ISOlat1
+  {":I", "&Iuml;"},	// ISOlat1
+  {":O", "&Ouml;"},	// ISOlat1
+  {":U", "&Uuml;"},	// ISOlat1
+  {":Y", "&Yuml;"},	// ISOlat2
+  {":a", "&auml;"},	// ISOlat1
+  {":e", "&euml;"},	// ISOlat1
+  {":i", "&iuml;"},	// ISOlat1
+  {":o", "&ouml;"},	// ISOlat1
+  {":u", "&uuml;"},	// ISOlat1
+  {":y", "&yuml;"},	// ISOlat1
+  {"^A", "&Acirc;"},	// ISOlat1
+  {"^E", "&Ecirc;"},	// ISOlat1
+  {"^I", "&Icirc;"},	// ISOlat1
+  {"^O", "&Ocirc;"},	// ISOlat1
+  {"^U", "&Ucirc;"},	// ISOlat1
+  {"^a", "&acirc;"},	// ISOlat1
+  {"^e", "&ecirc;"},	// ISOlat1
+  {"^i", "&icirc;"},	// ISOlat1
+  {"^o", "&ocirc;"},	// ISOlat1
+  {"^u", "&ucirc;"},	// ISOlat1
+  {"`A", "&Agrave;"},	// ISOlat1
+  {"`E", "&Egrave;"},	// ISOlat1
+  {"`I", "&Igrave;"},	// ISOlat1
+  {"`O", "&Ograve;"},	// ISOlat1
+  {"`U", "&Ugrave;"},	// ISOlat1
+  {"`a", "&agrave;"},	// ISOlat1
+  {"`e", "&egrave;"},	// ISOlat1
+  {"`i", "&igrave;"},	// ISOlat1
+  {"`o", "&ograve;"},	// ISOlat1
+  {"`u", "&ugrave;"},	// ISOlat1
+  {"~A", "&Atilde;"},	// ISOlat1
+  {"~N", "&Ntilde;"},	// ISOlat1
+  {"~O", "&Otilde;"},	// ISOlat1
+  {"~a", "&atilde;"},	// ISOlat1
+  {"~n", "&ntilde;"},	// ISOlat1
+  {"~o", "&otilde;"},	// ISOlat1
+  {"vS", "&Scaron;"},	// ISOlat2
+  {"vs", "&scaron;"},	// ISOlat2
+  {"vZ", "&Zcaron;"},	// ISOlat2
+  {"vz", "&zcaron;"},	// ISOlat2
+  {",C", "&Ccedil;"},	// ISOlat1
+  {",c", "&ccedil;"},	// ISOlat1
+  {"/L", "&Lstrok;"},	// ISOlat2: Polish L with a slash
+  {"/l", "&lstrok;"},	// ISOlat2: Polish l with a slash
+  {"/O", "&Oslash;"},	// ISOlat1
+  {"/o", "&oslash;"},	// ISOlat1
+  {"oA", "&Aring;"},	// ISOlat1
+  {"oa", "&aring;"},	// ISOlat1
+  // Accents
+  {"a\"","&dblac;"},	// ISOdia: double acute accent (Hungarian umlaut)
+  {"a-", "&macr;"},	// ISOdia: macron or bar accent
+  {"a.", "&dot;"},	// ISOdia: dot above
+  {"a^", "&circ;"},	// ISOdia: circumflex accent
+  {"aa", "&acute;"},	// ISOdia: acute accent
+  {"ga", "&grave;"},	// ISOdia: grave accent
+  {"ab", "&breve;"},	// ISOdia: breve accent
+  {"ac", "&cedil;"},	// ISOdia: cedilla accent
+  {"ad", "&uml;"},	// ISOdia: umlaut or dieresis
+  {"ah", "&caron;"},	// ISOdia: caron (aka hacek accent)
+  {"ao", "&ring;"},	// ISOdia: ring or circle accent
+  {"a~", "&tilde;"},	// ISOdia: tilde accent
+  {"ho", "&ogon;"},	// ISOdia: hook or ogonek accent
+  {"ha", "^"},		// ASCII circumflex, hat, caret
+  {"ti", "~"},		// ASCII tilde, large tilde
+  // Quotes
+  {"Bq", "&lsquor;"},	// ISOpub: low double comma quote
+  {"bq", "&ldquor;"},	// ISOpub: low single comma quote
+  {"lq", "&ldquo;"},	// ISOnum
+  {"rq", "&rdquo;"},	// ISOpub
+  {"oq", "&lsquo;"},	// ISOnum: single open quote
+  {"cq", "&rsquo;"},	// ISOnum: single closing quote (ASCII 39)
+  {"aq", "&zerosp;'"},	// apostrophe quote
+  {"dq", "\""},		// double quote (ASCII 34)
+  {"Fo", "&laquo;"},	// ISOnum
+  {"Fc", "&raquo;"},	// ISOnum
+  //{"fo", "&fo;"},
+  //{"fc", "&fc;"},
+  // Punctuation
+  {"r!", "&iexcl;"},	// ISOnum
+  {"r?", "&iquest;"},	// ISOnum
+  // Old troff \(em goes here
+  {"en", "&ndash;"},	// ISOpub: en dash
+  // Old troff \(hy goes here 
+  // Brackets
+  {"lB", "&lsqb;"},	// ISOnum: left (square) bracket
+  {"rB", "&rsqb;"},	// ISOnum: right (square) bracket
+  {"lC", "&lcub;"},	// ISOnum: left (curly) brace
+  {"rC", "&rcub;"},	// ISOnum: right (curly) brace
+  {"la", "&lang;"},	// ISOtech: left angle bracket
+  {"ra", "&rang;"},	// ISOtech: right angle bracket
+  // Old troff \(bv goes here
+  // Bracket-pile characters could go here.
+  // Arrows
+  // Old troff \(<- and \(-> go here
+  {"<>", "&harr;"},	// ISOamsa
+  {"da", "&darr;"},	// ISOnum
+  {"ua", "&uarr;"},	// ISOnum
+  {"lA", "&lArr;"},	// ISOtech
+  {"rA", "&rArr;"},	// ISOtech
+  {"hA", "&iff;"},	// ISOtech: horizontal double-headed arrow
+  {"dA", "&dArr;"},	// ISOamsa
+  {"uA", "&uArr;"},	// ISOamsa
+  {"vA", "&vArr;"}, 	// ISOamsa: vertical double-headed double arrow
+  //{"an", "&an;"},
+  // Lines
+  {"-h", "&planck;"},	// ISOamso: h-bar (Planck's constant)
+  // Old troff \(or goes here
+  {"ba", "&verbar;"},	// ISOnum
+  // Old troff \(br, \{u, \(ul, \(bv go here
+  {"bb", "&brvbar;"},	// ISOnum
+  {"sl", "/"},
+  {"rs", "&bsol;"},	// ISOnum
+  // Text markers
+  // Old troff \(ci, \(bu, \(dd, \(dg go here
+  {"lz", "&loz;"},	// ISOpub
+  // Old troff sq goes here
+  {"ps", "&para;"},	// ISOnum: paragraph or pilcrow sign
+  {"sc", "&sect;"},	// ISOnum (in old troff)
+  // Old troff \(lh, \{h go here
+  {"at", "&commat;"},	// ISOnum
+  {"sh", "&num;"},	// ISOnum
+  //{"CR", "&CR;"},
+  {"OK", "&check;"},	// ISOpub
+  // Legalize
+  // Old troff \(co, \{g go here
+  {"tm", "&trade;"},	// ISOnum
+  // Currency symbols
+  {"Do", "&dollar;"},	// ISOnum
+  {"ct", "&cent;"},	// ISOnum
+  {"eu", "&euro;"},
+  {"Eu", "&euro;"},
+  {"Ye", "&yen;"},	// ISOnum
+  {"Po", "&pound;"},	// ISOnum
+  {"Cs", "&curren;"},	// ISOnum: currency sign
+  {"Fn", "&fnof"},	// ISOtech
+  // Units
+  // Old troff de goes here
+  {"%0", "&permil;"},	// ISOtech: per thousand, per mille sign
+  // Old troff \(fm goes here
+  {"sd", "&Prime;"},	// ISOtech
+  {"mc", "&micro;"},	// ISOnum
+  {"Of", "&ordf;"},	// ISOnum
+  {"Om", "&ordm;"},	// ISOnum
+  // Logical symbols
+  {"AN", "&and;"},	// ISOtech
+  {"OR", "&or;"},	// ISOtech
+  // Old troff \(no goes here
+  {"te", "&exist;"}, 	// ISOtech: there exists, existential quantifier
+  {"fa", "&forall;"}, 	// ISOtech: for all, universal quantifier
+  {"st", "&bepsi"},	// ISOamsr: such that
+  {"3d", "&there4;"},	// ISOtech
+  {"tf", "&there4;"},	// ISOtech
+  // Mathematical symbols
+  // Old troff "12", "14", "34" goes here
+  {"S1", "&sup1;"},	// ISOnum
+  {"S2", "&sup2;"},	// ISOnum
+  {"S3", "&sup3;"},	// ISOnum
+  // Old troff \(pl", \-, \(+- go here
+  {"t+-", "&plusmn;"},	// ISOnum
+  {"-+", "&mnplus;"},	// ISOtech
+  {"pc", "&middot;"},	// ISOnum
+  {"md", "&middot;"},	// ISOnum
+  // Old troff \(mu goes here
+  {"tmu", "&times;"},	// ISOnum
+  {"c*", "&otimes;"},	// ISOamsb: multiply sign in a circle
+  {"c+", "&oplus;"},	// ISOamsb: plus sign in a circle
+  // Old troff \(di goes here
+  {"tdi", "&divide;"},	// ISOnum
+  {"f/", "&horbar;"},	// ISOnum: horizintal bar for fractions
+  // Old troff \(** goes here
+  {"<=", "&le;"},	// ISOtech
+  {">=", "&ge;"},	// ISOtech
+  {"<<", "&Lt;"},	// ISOamsr
+  {">>", "&Gt;"},	// ISOamsr
+  {"!=", "&ne;"},	// ISOtech
+  // Old troff \(eq and \(== go here
+  {"=~", "&cong;"},	// ISOamsr
+  // Old troff \(ap goes here
+  {"~~", "&ap;"},	// ISOtech
+  // This appears to be an error in the groff table.  
+  // It clashes with the Bell Labs use of ~= for a congruence sign
+  // {"~=", "&ap;"},	// ISOamsr
+  // Old troff \(pt, \(es, \(mo go here
+  {"nm", "&notin;"},	// ISOtech
+  {"nb", "&nsub;"},	// ISOamsr
+  {"nc", "&nsup;"},	// ISOamsn
+  {"ne", "&nequiv;"},	// ISOamsn
+  // Old troff \(sb, \(sp, \(ib, \(ip, \(ca, \(cu go here
+  {"/_", "&ang;"},	// ISOamso
+  {"pp", "&perp;"},	// ISOtech
+  // Old troff \(is goes here
+  {"sum", "&sum;"},	// ISOamsb
+  {"product", "&prod;"},	// ISOamsb
+  {"gr", "&nabla;"},	// ISOtech
+  // Old troff \(sr. \{n, \(if go here
+  {"Ah", "&aleph;"},	// ISOtech
+  {"Im", "&image;"},	// ISOamso: Fraktur I, imaginary
+  {"Re", "&real;"},	// ISOamso: Fraktur R, real
+  {"wp", "&weierp;"},	// ISOamso
+  {"pd", "&part;"},	// ISOtech: partial differentiation sign
+  // Their table duplicates the Greek letters here.
+  // We list only the variant forms here, mapping them into
+  // the ISO Greek 4 variants (which may or may not be correct :-() 
+  {"+f", "&b.phiv;"},	// ISOgrk4: variant phi
+  {"+h", "&b.thetas;"},	// ISOgrk4: variant theta
+  {"+p", "&b.omega;"},	// ISOgrk4: variant pi, looking like omega
+  // Card symbols
+  {"CL", "&clubs;"},	// ISOpub: club suit
+  {"SP", "&spades;"},	// ISOpub: spade suit
+  {"HE", "&hearts;"},	// ISOpub: heart suit
+  {"DI", "&diams;"},	// ISOpub: diamond suit
+};
+
+const char *special_to_entity(const char *sp)
+{
+  struct map *mp;
+  for (mp = entity_table; 
+       mp < entity_table + sizeof(entity_table)/sizeof(entity_table[0]); 
+       mp++) {
+    if (strcmp(mp->from, sp) == 0)
+      return mp->to;
+  }
+  return NULL;
+}
+
+class char_box : public simple_box {
+  unsigned char c;
+  char next_is_italic;
+  char prev_is_italic;
+public:
+  char_box(unsigned char);
+  void debug_print();
+  void output();
+  int is_char();
+  int left_is_italic();
+  int right_is_italic();
+  void hint(unsigned);
+  void handle_char_type(int, int);
+};
+
+class special_char_box : public simple_box {
+  char *s;
+public:
+  special_char_box(const char *);
+  ~special_char_box();
+  void output();
+  void debug_print();
+  int is_char();
+  void handle_char_type(int, int);
+};
+
+enum spacing_type {
+  s_ordinary,
+  s_operator,
+  s_binary,
+  s_relation,
+  s_opening,
+  s_closing,
+  s_punctuation,
+  s_inner,
+  s_suppress
+};
+
+const char *spacing_type_table[] = {
+  "ordinary",
+  "operator",
+  "binary",
+  "relation",
+  "opening",
+  "closing",
+  "punctuation",
+  "inner",
+  "suppress",
+  0,
+};
+
+const int DIGIT_TYPE = 0;
+const int LETTER_TYPE = 1;
+
+const char *font_type_table[] = {
+  "digit",
+  "letter",
+  0,
+};
+
+struct char_info {
+  int spacing_type;
+  int font_type;
+  char_info();
+};
+
+char_info::char_info()
+: spacing_type(ORDINARY_TYPE), font_type(DIGIT_TYPE)
+{
+}
+
+static char_info char_table[256];
+
+declare_ptable(char_info)
+implement_ptable(char_info)
+
+PTABLE(char_info) special_char_table;
+
+static int get_special_char_spacing_type(const char *ch)
+{
+  char_info *p = special_char_table.lookup(ch);
+  return p ? p->spacing_type : ORDINARY_TYPE;
+}
+
+static int get_special_char_font_type(const char *ch)
+{
+  char_info *p = special_char_table.lookup(ch);
+  return p ? p->font_type : DIGIT_TYPE;
+}
+
+static void set_special_char_type(const char *ch, int st, int ft)
+{
+  char_info *p = special_char_table.lookup(ch);
+  if (!p) {
+    p = new char_info[1];
+    special_char_table.define(ch, p);
+  }
+  if (st >= 0)
+    p->spacing_type = st;
+  if (ft >= 0)
+    p->font_type = ft;
+}
+
+void init_char_table()
+{
+  set_special_char_type("pl", s_binary, -1);
+  set_special_char_type("mi", s_binary, -1);
+  set_special_char_type("eq", s_relation, -1);
+  set_special_char_type("<=", s_relation, -1);
+  set_special_char_type(">=", s_relation, -1);
+  char_table['}'].spacing_type = s_closing;
+  char_table[')'].spacing_type = s_closing;
+  char_table[']'].spacing_type = s_closing;
+  char_table['{'].spacing_type = s_opening;
+  char_table['('].spacing_type = s_opening;
+  char_table['['].spacing_type = s_opening;
+  char_table[','].spacing_type = s_punctuation;
+  char_table[';'].spacing_type = s_punctuation;
+  char_table[':'].spacing_type = s_punctuation;
+  char_table['.'].spacing_type = s_punctuation;
+  char_table['>'].spacing_type = s_relation;
+  char_table['<'].spacing_type = s_relation;
+  char_table['*'].spacing_type = s_binary;
+  for (int i = 0; i < 256; i++)
+    if (csalpha(i))
+      char_table[i].font_type = LETTER_TYPE;
+}
+
+static int lookup_spacing_type(const char *type)
+{
+  for (int i = 0; spacing_type_table[i] != 0; i++)
+    if (strcmp(spacing_type_table[i], type) == 0)
+      return i;
+  return -1;
+}
+
+static int lookup_font_type(const char *type)
+{
+  for (int i = 0; font_type_table[i] != 0; i++)
+    if (strcmp(font_type_table[i], type) == 0)
+      return i;
+  return -1;
+}
+
+void box::set_spacing_type(char *type)
+{
+  int t = lookup_spacing_type(type);
+  if (t < 0)
+    error("unrecognised type '%1'", type);
+  else
+    spacing_type = t;
+  free(type);
+}
+
+char_box::char_box(unsigned char cc)
+: c(cc), next_is_italic(0), prev_is_italic(0)
+{
+  spacing_type = char_table[c].spacing_type;
+}
+
+void char_box::hint(unsigned flags)
+{
+  if (flags & HINT_PREV_IS_ITALIC)
+    prev_is_italic = 1;
+  if (flags & HINT_NEXT_IS_ITALIC)
+    next_is_italic = 1;
+}
+
+void char_box::output()
+{
+  if (output_format == troff) {
+    int font_type = char_table[c].font_type;
+    if (font_type != LETTER_TYPE)
+      printf("\\f[%s]", current_roman_font);
+    if (!prev_is_italic)
+      fputs("\\,", stdout);
+    if (c == '\\')
+      fputs("\\e", stdout);
+    else
+      putchar(c);
+    if (!next_is_italic)
+      fputs("\\/", stdout);
+    else
+      fputs("\\&", stdout);		// suppress ligaturing and kerning
+    if (font_type != LETTER_TYPE)
+      fputs("\\fP", stdout);
+  }
+  else if (output_format == mathml) {
+    if (isdigit(c))
+      printf("<mn>");
+    else if (char_table[c].spacing_type)
+      printf("<mo>");
+    else
+      printf("<mi>");
+    if (c == '<')
+      printf("&lt;");
+    else if (c == '>')
+      printf("&gt;");
+    else if (c == '&')
+      printf("&amp;");
+    else
+      putchar(c);
+    if (isdigit(c))
+      printf("</mn>");
+    else if (char_table[c].spacing_type)
+      printf("</mo>");
+    else
+      printf("</mi>");
+  }
+}
+
+int char_box::left_is_italic()
+{
+  int font_type = char_table[c].font_type;
+  return font_type == LETTER_TYPE;
+}
+
+int char_box::right_is_italic()
+{
+  int font_type = char_table[c].font_type;
+  return font_type == LETTER_TYPE;
+}
+
+int char_box::is_char()
+{
+  return 1;
+}
+
+void char_box::debug_print()
+{
+  if (c == '\\') {
+    putc('\\', stderr);
+    putc('\\', stderr);
+  }
+  else
+    putc(c, stderr);
+}
+
+special_char_box::special_char_box(const char *t)
+{
+  s = strsave(t);
+  spacing_type = get_special_char_spacing_type(s);
+}
+
+special_char_box::~special_char_box()
+{
+  free(s);
+}
+
+void special_char_box::output()
+{
+  if (output_format == troff) {
+    int font_type = get_special_char_font_type(s);
+    if (font_type != LETTER_TYPE)
+      printf("\\f[%s]", current_roman_font);
+    printf("\\,\\[%s]\\/", s);
+    if (font_type != LETTER_TYPE)
+      printf("\\fP");
+  }
+  else if (output_format == mathml) {
+    const char *entity = special_to_entity(s);
+    if (entity != NULL)
+      printf("<mo>%s</mo>", entity);
+    else
+      printf("<merror>unknown eqn/troff special char %s</merror>", s);
+  }
+}
+
+int special_char_box::is_char()
+{
+  return 1;
+}
+
+void special_char_box::debug_print()
+{
+  fprintf(stderr, "\\[%s]", s);
+}
+
+
+void char_box::handle_char_type(int st, int ft)
+{
+  if (st >= 0)
+    char_table[c].spacing_type = st;
+  if (ft >= 0)
+    char_table[c].font_type = ft;
+}
+
+void special_char_box::handle_char_type(int st, int ft)
+{
+  set_special_char_type(s, st, ft);
+}
+
+void set_char_type(const char *type, char *ch)
+{
+  assert(ch != 0);
+  int st = lookup_spacing_type(type);
+  int ft = lookup_font_type(type);
+  if (st < 0 && ft < 0) {
+    error("bad character type '%1'", type);
+    delete[] ch;
+    return;
+  }
+  box *b = split_text(ch);
+  b->handle_char_type(st, ft);
+  delete b;
+}
+
+/* We give primes special treatment so that in "x' sub 2", the "2"
+will be tucked under the prime */
+
+class prime_box : public pointer_box {
+  box *pb;
+public:
+  prime_box(box *);
+  ~prime_box();
+  int compute_metrics(int style);
+  void output();
+  void compute_subscript_kern();
+  void debug_print();
+  void handle_char_type(int, int);
+};
+
+box *make_prime_box(box *pp)
+{
+  return new prime_box(pp);
+}
+
+prime_box::prime_box(box *pp) : pointer_box(pp)
+{
+  pb = new special_char_box("fm");
+}
+
+prime_box::~prime_box()
+{
+  delete pb;
+}
+
+int prime_box::compute_metrics(int style)
+{
+  int res = p->compute_metrics(style);
+  pb->compute_metrics(style);
+  printf(".nr " WIDTH_FORMAT " 0\\n[" WIDTH_FORMAT "]"
+	 "+\\n[" WIDTH_FORMAT "]\n",
+	 uid, p->uid, pb->uid);
+  printf(".nr " HEIGHT_FORMAT " \\n[" HEIGHT_FORMAT "]"
+	 ">?\\n[" HEIGHT_FORMAT "]\n",
+	 uid, p->uid, pb->uid);
+  printf(".nr " DEPTH_FORMAT " \\n[" DEPTH_FORMAT "]"
+	 ">?\\n[" DEPTH_FORMAT "]\n",
+	 uid, p->uid, pb->uid);
+  return res;
+}
+
+void prime_box::compute_subscript_kern()
+{
+  p->compute_subscript_kern();
+  printf(".nr " SUB_KERN_FORMAT " 0\\n[" WIDTH_FORMAT "]"
+	 "+\\n[" SUB_KERN_FORMAT "]>?0\n",
+	 uid, pb->uid, p->uid);
+}
+
+void prime_box::output()
+{
+  p->output();
+  pb->output();
+}
+
+void prime_box::handle_char_type(int st, int ft)
+{
+  p->handle_char_type(st, ft);
+  pb->handle_char_type(st, ft);
+}
+
+void prime_box::debug_print()
+{
+  p->debug_print();
+  putc('\'', stderr);
+}
+
+box *split_text(char *text)
+{
+  list_box *lb = 0;
+  box *fb = 0;
+  char *s = text;
+  while (*s != '\0') {
+    char c = *s++;
+    box *b = 0;
+    switch (c) {
+    case '+':
+      b = new special_char_box("pl");
+      break;
+    case '-':
+      b = new special_char_box("mi");
+      break;
+    case '=':
+      b = new special_char_box("eq");
+      break;
+    case '\'':
+      b = new special_char_box("fm");
+      break;
+    case '<':
+      if (*s == '=') {
+	b = new special_char_box("<=");
+	s++;
+	break;
+      }
+      goto normal_char;
+    case '>':
+      if (*s == '=') {
+	b = new special_char_box(">=");
+	s++;
+	break;
+      }
+      goto normal_char;
+    case '\\':
+      if (*s == '\0') {
+	lex_error("bad escape");
+	break;
+      }
+      c = *s++;
+      switch (c) {
+      case '(':
+	{
+	  char buf[3];
+	  if (*s != '\0') {
+	    buf[0] = *s++;
+	    if (*s != '\0') {
+	      buf[1] = *s++;
+	      buf[2] = '\0';
+	      b = new special_char_box(buf);
+	    }
+	    else {
+	      lex_error("bad escape");
+	    }
+	  }
+	  else {
+	    lex_error("bad escape");
+	  }
+	}
+	break;
+      case '[':
+	{
+	  char *ch = s;
+	  while (*s != ']' && *s != '\0')
+	    s++;
+	  if (*s == '\0')
+	    lex_error("bad escape");
+	  else {
+	    *s++ = '\0';
+	    b = new special_char_box(ch);
+	  }
+	}
+	break;
+      case 'f':
+      case 'g':
+      case 'k':
+      case 'n':
+      case '*':
+	{
+	  char *escape_start = s - 2;
+	  switch (*s) {
+	  case '(':
+	    if (*++s != '\0')
+	      ++s;
+	    break;
+	  case '[':
+	    for (++s; *s != '\0' && *s != ']'; s++)
+	      ;
+	    break;
+	  }
+	  if (*s == '\0')
+	    lex_error("bad escape");
+	  else {
+	    ++s;
+	    char *buf = new char[s - escape_start + 1];
+	    memcpy(buf, escape_start, s - escape_start);
+	    buf[s - escape_start] = '\0';
+	    b = new quoted_text_box(buf);
+	  }
+	}
+	break;
+      case '-':
+      case '_':
+	{
+	  char buf[2];
+	  buf[0] = c;
+	  buf[1] = '\0';
+	  b = new special_char_box(buf);
+	}
+	break;
+      case '`':
+	b = new special_char_box("ga");
+	break;
+      case '\'':
+	b = new special_char_box("aa");
+	break;
+      case 'e':
+      case '\\':
+	b = new char_box('\\');
+	break;
+      case '^':
+      case '|':
+      case '0':
+	{
+	  char buf[3];
+	  buf[0] = '\\';
+	  buf[1] = c;
+	  buf[2] = '\0';
+	  b = new quoted_text_box(strsave(buf));
+	  break;
+	}
+      default:
+	lex_error("unquoted escape");
+	b = new quoted_text_box(strsave(s - 2));
+	s = strchr(s, '\0');
+	break;
+      }
+      break;
+    default:
+    normal_char:
+      b = new char_box(c);
+      break;
+    }
+    while (*s == '\'') {
+      if (b == 0)
+	b = new quoted_text_box(0);
+      b = new prime_box(b);
+      s++;
+    }
+    if (b != 0) {
+      if (lb != 0)
+	lb->append(b);
+      else if (fb != 0) {
+	lb = new list_box(fb);
+	lb->append(b);
+      }
+      else
+	fb = b;
+    }
+  }
+  free(text);
+  if (lb != 0)
+    return lb;
+  else if (fb != 0)
+    return fb;
+  else
+    return new quoted_text_box(0);
+}
+
diff --git a/src/preproc/grn/README b/src/preproc/grn/README
new file mode 100644
index 0000000..73273f7
--- /dev/null
+++ b/src/preproc/grn/README
@@ -0,0 +1,68 @@
+This is grn from the Berkeley ditroff distribution.  It has no
+AT&T code and is therefore freely distributable.
+
+Tim Theisen <tim@cs.wisc.edu>
+
+=====================================================================
+
+This is the modified code for the groff.  It uses the different
+devxxx format that is ascii rather than binary as in the
+Berkeley distribution.  Since groff does not have the \Ds option
+for line drawing (dotted, dashed, etc.), this version includes
+the routines for drawing curves and arcs, so it does not use the
+\D~, \Da nor \Dc.  Although also included in here is a routine
+for drawing the optional gremlin style curves, it is not used
+because the gremlin editor uses the conventional spline
+algorithm.  The Berkeley grn has the choice of different
+stipples.  Here, only different shades of gray will be painted
+depending on the gremlin file.  It is possible to upgrade this at
+a later time.  (Daniel Senderowicz <daniel@synchrods.com> 12/28/99)
+
+=====================================================================
+
+Gremlin produces three types of curves: B-Splines, interpolated
+curves and Bezier.  As the original Berkeley grn, now groff grn
+will honor B-Splines and interpolated curves.  Bezier curves will
+be printed as B-Splines.  (Daniel Senderowicz <daniel@synchrods.com>
+10/04/02)
+
+=====================================================================
+
+It has been further modified by Werner Lemberg <wl@gnu.org> to fit
+better into the groff package.
+
+  . Replaced Makefile with Makefile.sub.
+
+  . Removed dev.h since it is unused.
+
+  . Renamed grn.1 to grn.man; this man page has been extensively
+    revised.
+
+  . Used error() and fatal() from libgroff for all source files.
+
+  . Renamed *.c to *.cpp; updates as needed for C++ (prototypes, proper
+    casts, standard header files etc).  Heavy formatting.
+
+  . main.cpp:
+
+      Using groff's default values instead of DEVDIR, DEFAULTDEV,
+      PRINTER, TYPESETTER, and GREMLIB.
+
+      'res' is now an integer.
+
+      Added '-C' command flag (for compatibility mode) as with other
+      preprocessors.
+
+      Added '-F' and '-v' option (similar to troff).
+
+      Renamed '-L' option to '-M' for consistence.
+
+      Removed '-P' option.
+
+      Using font::load_desc() for scanning DESC files.
+
+      Removed SYSV-specific code.
+
+      Using macro_path.open_file() for getting gremlin graphic files.
+
+      Added usage().
diff --git a/src/preproc/grn/gprint.h b/src/preproc/grn/gprint.h
new file mode 100644
index 0000000..772d79a
--- /dev/null
+++ b/src/preproc/grn/gprint.h
@@ -0,0 +1,90 @@
+/* Last non-groff version: gprint.h  1.1  84/10/08
+ *
+ * This file contains standard definitions used by the gprint program.
+ */
+
+#include <stdio.h>
+#include <math.h>
+
+
+#define xorn(x,y)	(x)
+			/* was 512 */
+#define yorn(x,y)	(511 - (y))	/* switch direction for */
+					/* y-coordinates        */
+
+#define STYLES 6
+#define SIZES 4
+#define FONTS 4
+#define SOLID -1
+#define DOTTED 004		/* 014 */
+#define DASHED 020		/* 034 */
+#define DOTDASHED 024		/* 054 */
+#define LONGDASHED 074
+
+#define DEFTHICK	-1	/* default thickness */
+#define DEFSTYLE	SOLID	/* default line style */
+
+#define TRUE	1
+#define FALSE	0
+
+#define nullelt	-1
+#define nullpt	-1
+#define nullun	NULL
+
+#define BOTLEFT	0
+#define BOTRIGHT 1
+#define CENTCENT 2
+#define VECTOR 3
+#define ARC 4
+#define CURVE 5
+#define POLYGON 6
+#define BSPLINE 7
+#define BEZIER 8
+#define TOPLEFT 10
+#define TOPCENT 11
+#define TOPRIGHT 12
+#define CENTLEFT 13
+#define CENTRIGHT 14
+#define BOTCENT 15
+#define TEXT(t) ( (t <= CENTCENT) || (t >= TOPLEFT) )
+
+/* WARNING * WARNING * WARNING * WARNING * WARNING * WARNING * WARNING
+ *    The above (TEXT) test is dependent on the relative values of the
+ *    constants and will have to change if these values change or if new
+ *    commands are added with value greater than BOTCENT
+ */
+
+#define NUSER 4
+#define NFONTS 4
+#define NBRUSHES 6
+#define NSIZES 4
+#define NJUSTS 9
+#define NSTIPPLES 16
+
+#define ADD 1
+#define DELETE 2
+#define MOD 3
+
+typedef struct point {
+  double x, y;
+  struct point *nextpt;
+} POINT;
+
+typedef struct elmt {
+  int type, brushf, size, textlength;
+  char *textpt;
+  POINT *ptlist;
+  struct elmt *nextelt, *setnext;
+} ELT;
+
+#define DBNextElt(elt) (elt->nextelt)
+#define DBNextofSet(elt) (elt->setnext)
+#define DBNullelt(elt) (elt == NULL)
+#define Nullpoint(pt)  ((pt) == (POINT *) NULL)
+#define PTNextPoint(pt) (pt->nextpt)
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/grn/grn.1.man b/src/preproc/grn/grn.1.man
new file mode 100644
index 0000000..cbc15ae
--- /dev/null
+++ b/src/preproc/grn/grn.1.man
@@ -0,0 +1,978 @@
+'\" t
+.TH @g@grn @MAN1EXT@ "@MDATE@" "groff @VERSION@"
+.SH Name
+@g@grn \- embed Gremlin images in
+.I groff
+documents
+.
+.
+.\" ====================================================================
+.\" Legal Terms
+.\" ====================================================================
+.\"
+.\" Copyright (C) 2000-2020 Free Software Foundation, Inc.
+.\"
+.\" Permission is granted to make and distribute verbatim copies of this
+.\" manual provided the copyright notice and this permission notice are
+.\" preserved on all copies.
+.\"
+.\" Permission is granted to copy and distribute modified versions of
+.\" this manual under the conditions for verbatim copying, provided that
+.\" the entire resulting derived work is distributed under the terms of
+.\" a permission notice identical to this one.
+.\"
+.\" Permission is granted to copy and distribute translations of this
+.\" manual into another language, under the above conditions for
+.\" modified versions, except that this permission notice may be
+.\" included in translations approved by the Free Software Foundation
+.\" instead of in the original English.
+.
+.
+.\" Save and disable compatibility mode (for, e.g., Solaris 10/11).
+.do nr *groff_grn_1_man_C \n[.cp]
+.cp 0
+.
+.\" Define fallback for groff 1.23's MR macro if the system lacks it.
+.nr do-fallback 0
+.if !\n(.f           .nr do-fallback 1 \" mandoc
+.if  \n(.g .if !d MR .nr do-fallback 1 \" older groff
+.if !\n(.g           .nr do-fallback 1 \" non-groff *roff
+.if \n[do-fallback]  \{\
+.  de MR
+.    ie \\n(.$=1 \
+.      I \%\\$1
+.    el \
+.      IR \%\\$1 (\\$2)\\$3
+.  .
+.\}
+.rr do-fallback
+.
+.
+.\" ====================================================================
+.SH Synopsis
+.\" ====================================================================
+.
+.SY @g@grn
+.RB [ \-C ]
+.RB [ \-T\~\c
+.IR dev ]
+.RB [ \-M\~\c
+.IR dir ]
+.RB [ \-F\~\c
+.IR dir ]
+.RI [ file\~ .\|.\|.]
+.YS
+.
+.
+.SY @g@grn
+.B \-?
+.
+.SY @g@grn
+.B \-\-help
+.YS
+.
+.
+.SY @g@grn
+.B \-v
+.
+.SY @g@grn
+.B \-\-version
+.YS
+.
+.
+.\" ====================================================================
+.SH Description
+.\" ====================================================================
+.
+.I @g@grn
+is a preprocessor for including
+.I gremlin
+pictures in
+.MR @g@troff @MAN1EXT@
+input.
+.
+.I @g@grn
+writes to standard output,
+processing only input lines between two that start with
+.B .GS
+and
+.BR .GE .
+.
+Those lines must contain
+.I @g@grn
+commands
+(see below).
+.
+These macros request a
+.I gremlin
+file;
+the picture in that file is converted and placed in the
+.I @g@troff
+input stream.
+.
+.B .GS
+may be called with a
+.BR C ,
+.BR L ,
+or
+.B R
+argument to center,
+left-,
+or right-justify the whole
+.I gremlin
+picture
+(the default is to center).
+.
+If no
+.I file
+is mentioned,
+the standard input is read.
+.
+At the end of the picture,
+the position on the page is the bottom of the
+.I gremlin
+picture.
+.
+If the
+.I @g@grn
+entry is ended with
+.B .GF
+instead of
+.BR .GE ,
+the position is left at the top of the picture.
+.
+.
+.PP
+Currently only the
+.I me
+macro package has support for
+.BR .GS ,
+.BR .GE ,
+and
+.BR .GF .
+.
+.
+.PP
+.I @g@grn
+produces drawing escape sequences that use
+.IR groff 's
+color scheme extension
+.RB ( \[rs]D\[aq]F \~.\|.\|.\& \[aq] ),
+and thus may not work with other
+.IR troff s.
+.
+.
+.\" ====================================================================
+.SS "\f[I]grn\f[] commands"
+.\" ====================================================================
+.
+Each input line between
+.B .GS
+and
+.B .GE
+may have one
+.I @g@grn
+command.
+.
+Commands consist of one or two strings separated by white space,
+the first string being the command and the second its operand.
+.
+Commands may be upper- or lowercase and abbreviated down to one
+character.
+.
+.
+.PP
+Commands that affect a picture's environment
+(those listed before
+.RB \%\[lq] default \[rq],
+see below)
+are only in effect for the current picture:
+the environment is reinitialized to the defaults at the start of the
+next picture.
+.
+The commands are as follows.
+.
+.
+.TP
+.BI 1\~ N
+.TQ
+.BI 2\~ N
+.TQ
+.BI 3\~ N
+.TQ
+.BI 4\~ N
+.
+Set
+.IR gremlin 's
+text size number 1
+(2,
+3,
+or 4)
+to
+.I N
+points.
+.
+The default is 12
+(16,
+24,
+and 36,
+respectively).
+.
+.
+.TP
+.BI roman\~ f
+.TQ
+.BI italics\~ f
+.TQ
+.BI bold\~ f
+.TQ
+.BI special\~ f
+Set the roman
+(italics,
+bold,
+or special)
+font to
+.IR @g@troff 's
+font
+.I f
+(either a name or number).
+.
+The default is R
+(I,
+B,
+and S,
+respectively).
+.
+.
+.TP
+.BI l\~ f
+.TQ
+.BI stipple\~ f
+Set the stipple font to
+.IR @g@troff 's
+stipple font
+.I f
+(name or number).
+.
+The command
+.B \%stipple
+may be abbreviated down as far as
+.RB \[lq] st \[rq]
+(to avoid confusion with
+.RB \%\[lq] special \[rq]).
+.
+There is
+.I no
+default for stipples
+(unless one is set by the
+.RB \%\[lq] default \[rq]
+command),
+and it is invalid to include a
+.I gremlin
+picture with polygons without specifying a stipple font.
+.
+.
+.TP
+.BI x\~ N
+.TQ
+.BI scale\~ N
+Magnify the picture
+(in addition to any default magnification)
+by
+.IR N ,
+a floating-point number larger than zero.
+.
+The command
+.B scale
+may be abbreviated down to
+.RB \[lq] sc \[rq].
+.
+.
+.TP
+.BI narrow\~ N
+.TQ
+.BI medium\~ N
+.TQ
+.BI thick\~ N
+.
+Set the thickness of
+.IR gremlin 's
+narrow
+(medium and thick,
+respectively)
+lines to
+.I N
+times 0.15pt
+(this value can be changed at compile time).
+.
+The default is 1.0
+(3.0 and 5.0,
+respectively),
+which corresponds to 0.15pt
+(0.45pt and 0.75pt,
+respectively).
+.
+A thickness value of zero selects the smallest available line thickness.
+.
+Negative values cause the line thickness to be proportional to the
+current point size.
+.
+.
+.TP
+.BR pointscale\~ [ off | on ]
+Scale text to match the picture.
+.
+Gremlin text is usually printed in the point size specified with the
+commands
+.BR 1 ,
+.BR 2 ,
+.BR 3 ,
+.RB or\~ 4 ,
+regardless of any scaling factors in the picture.
+.
+Setting
+.B pointscale
+will cause the point sizes to scale with the picture
+(within
+.IR @g@troff 's
+limitations,
+of course).
+.
+An operand of anything but
+.B off
+will turn text scaling on.
+.
+.
+.TP
+.B default
+Reset the picture environment defaults to the settings in the current
+picture.
+.
+This is meant to be used as a global parameter setting mechanism at
+the beginning of the
+.I @g@troff
+input file,
+but can be used at any time to reset the default settings.
+.
+.
+.TP
+.BI width\~ N
+Force the picture to be
+.I N
+inches wide.
+.
+This overrides any scaling factors present in the same picture.
+.
+.RB \[lq] "width 0" \[rq]
+is ignored.
+.
+.
+.TP
+.BI height\~ N
+Force the picture to be
+.I N
+inches high,
+overriding other scaling factors.
+.
+If both
+.B width
+and
+.B height
+are specified,
+the tighter constraint will determine the scale of the picture.
+.
+.B height
+and
+.B width
+commands are not saved with a
+.RB \%\[lq] default \[rq]
+command.
+.
+They will,
+however,
+affect point size scaling if that option is set.
+.
+.
+.TP
+.BI file\~ name
+Get picture from
+.I gremlin
+file
+.I name
+located the current directory
+(or in the library directory;
+see the
+.B \-M
+option above).
+.
+If multiple
+.B file
+commands are given,
+the last one controls.
+.
+If
+.I name
+doesn't exist,
+an error message is reported and processing continues from the
+.B .GE
+line.
+.
+.
+.\" ====================================================================
+.SS "Usage with \f[I]groff\f[]"
+.\" ====================================================================
+.
+Since
+.I @g@grn
+is a preprocessor,
+it has no access to elements of formatter state,
+such as
+indentation,
+line length,
+type size,
+or
+register values.
+.
+Consequently,
+no
+.I @g@troff
+input can be placed between the
+.B .GS
+and
+.B .GE
+macros.
+.
+However,
+.I gremlin
+text elements are subsequently processed by
+.IR @g@troff ,
+so anything valid in a single line of
+.I @g@troff
+input is valid in a line of
+.I gremlin
+text
+(barring the dot control character \[lq].\[rq] at the beginning of a
+line).
+.
+Thus,
+it is possible to have equations within a
+.I gremlin
+figure by including in the
+.I gremlin
+file
+.I eqn \" language
+expressions enclosed by previously defined delimiters
+(e.g.,
+\[lq]$$\[rq]).
+.
+.
+.PP
+When using
+.I @g@grn
+along with other preprocessors,
+it is best to run
+.MR @g@tbl @MAN1EXT@
+before
+.IR @g@grn ,
+.MR @g@pic @MAN1EXT@ ,
+and/or
+.I ideal \" no GNU version yet
+to avoid overworking
+.IR @g@tbl .
+.
+.MR @g@eqn @MAN1EXT@
+should always be run last.
+.
+.MR groff @MAN1EXT@
+will automatically run preprocessors in the correct order.
+.
+.
+.PP
+A picture is considered an entity,
+but that doesn't stop
+.I @g@troff
+from trying to break it up if it falls off the end of a page.
+.
+Placing the picture between \[lq]keeps\[rq] in the
+.I me
+macros will ensure proper placement.
+.
+.
+.PP
+.I @g@grn
+uses
+.IR @g@troff 's
+registers
+.B g1
+through
+.B g9
+and sets registers
+.B g1
+and
+.B g2
+to the width and height of the
+.I gremlin
+figure
+(in device units)
+before entering the
+.B .GS
+macro
+(this is for those who want to rewrite these macros).
+.
+.
+.\" ====================================================================
+.SS "Gremlin file format"
+.\" ====================================================================
+.
+There exist two distinct
+.I gremlin
+file formats:
+the original format for AED graphic terminals,
+and the Sun or X11 version.
+.
+An extension used by the Sun/X11 version allowing reference points with
+negative coordinates is
+.I not
+compatible with the AED version.
+.
+As long as a
+.I gremlin
+file does not contain negative coordinates,
+either format will be read correctly by either version of
+.I gremlin
+or
+.IR @g@grn .
+.
+The other difference in
+Sun/X11 format is the use of names for picture objects
+(e.g.,
+.BR POLYGON ,
+.BR CURVE )
+instead of numbers.
+.
+Files representing the same picture are shown below.
+.
+.
+.PP
+.ie t .ne 18v
+.el   .ne 19v
+.TS
+center, tab(@);
+l lw(0.1i) l.
+sungremlinfile@@gremlinfile
+0 240.00 128.00@@0 240.00 128.00
+CENTCENT@@2
+240.00 128.00@@240.00 128.00
+185.00 120.00@@185.00 120.00
+240.00 120.00@@240.00 120.00
+296.00 120.00@@296.00 120.00
+*@@\-1.00 \-1.00
+2 3@@2 3
+10 A Triangle@@10 A Triangle
+POLYGON@@6
+224.00 416.00@@224.00 416.00
+96.00 160.00@@96.00 160.00
+384.00 160.00@@384.00 160.00
+*@@\-1.00 \-1.00
+5 1@@5 1
+0@@0
+\-1@@\-1
+.TE
+.
+.
+.IP \[bu] 2n
+The first line of each
+.I gremlin
+file contains either the string
+.RB \[lq] gremlinfile \[rq]
+(AED)
+or
+.RB \[lq] sungremlinfile \[rq]
+(Sun/X11).
+.
+.
+.IP \[bu]
+The second line of the file contains an orientation and
+.I x
+and
+.I y
+values for a positioning point,
+separated by spaces.
+.
+The orientation,
+either
+.B 0
+or
+.BR 1 ,
+is ignored by the Sun/X11 version.
+.
+.B 0
+means that
+.I gremlin
+will display things in horizontal format
+(a drawing area wider than it is tall,
+with a menu across the top).
+.
+.B 1
+means that
+.I gremlin
+will display things in vertical format
+(a drawing area taller than it is wide,
+with a menu on the left side).
+.
+.I x
+and
+.I y
+are floating-point values giving a positioning point to be used when
+this file is read into another file.
+.
+The stuff on this line really isn't all that important;
+a value of
+.RB \[lq] "1 0.00 0.00" \[rq]
+is suggested.
+.
+.
+.IP \[bu]
+The rest of the file consists of zero or more element specifications.
+.
+After the last element specification is a line containing the string
+.RB \[lq] \-1 \[rq].
+.
+.
+.IP \[bu]
+Lines longer than 127 characters are truncated to that length.
+.
+.
+.\" ====================================================================
+.SS "Element specifications"
+.\" ====================================================================
+.
+.IP \[bu] 2n
+The first line of each element contains a single decimal number giving
+the type of the element (AED) or its name (Sun/X11).
+.
+.
+.IP
+.ie t .ne 18v
+.el   .ne 19v
+.TS
+center, tab(@);
+css
+ccc
+nBlBl.
+\f[I]gremlin\f[] File Format: Object Type Specification
+_
+AED Number@Sun/X11 Name@Description
+0@BOTLEFT@bottom-left-justified text
+1@BOTRIGHT@bottom-right-justified text
+2@CENTCENT@center-justified text
+3@VECTOR@vector
+4@ARC@arc
+5@CURVE@curve
+6@POLYGON@polygon
+7@BSPLINE@b-spline
+8@BEZIER@B\['e]zier
+10@TOPLEFT@top-left-justified text
+11@TOPCENT@top-center-justified text
+12@TOPRIGHT@top-right-justified text
+13@CENTLEFT@left-center-justified text
+14@CENTRIGHT@right-center-justified text
+15@BOTCENT@bottom-center-justified text
+.TE
+.
+.
+.IP \[bu]
+After the object type comes a variable number of lines,
+each specifying a point used to display the element.
+.
+Each line contains an x-coordinate and a y-coordinate in floating-point
+format,
+separated by spaces.
+.
+The list of points is terminated by a line containing the string
+.RB \[lq] "\-1.0 \-1.0" \[rq]
+(AED) or a single asterisk,
+.RB \[lq] * \[rq]
+(Sun/X11).
+.
+.
+.IP \[bu]
+After the points comes a line containing two decimal values,
+giving the brush and size for the element.
+.
+The brush determines the style in which things are drawn.
+.
+For vectors,
+arcs,
+and curves there are six valid brush values.
+.
+.
+.IP
+.TS
+center, tab(@);
+nB l.
+1@thin dotted lines
+2@thin dot-dashed lines
+3@thick solid lines
+4@thin dashed lines
+5@thin solid lines
+6@medium solid lines
+.TE
+.
+.
+.IP
+For polygons,
+one more value,
+0,
+is valid.
+.
+It specifies a polygon with an invisible border.
+.
+For text,
+the brush selects a font as follows.
+.
+.
+.IP
+.TS
+center, tab(@);
+nB l.
+1@roman (R font in \f[I]@g@troff\f[])
+2@italics (I font in \f[I]@g@troff\f[])
+3@bold (B font in \f[I]@g@troff\f[])
+4@special (S font in \f[I]@g@troff\f[])
+.TE
+.
+.
+.IP
+If you're using
+.I @g@grn
+to run your pictures through
+.IR groff ,
+the font is really just a starting font.
+.
+The text string can contain formatting sequences like
+\[lq]\[rs]fI\[rq]
+or
+\[lq]\[rs]d\[rq]
+which may change the font
+(as well as do many other things).
+.
+For text,
+the size field is a decimal value between 1 and 4.
+.
+It selects the size of the font in which the text will be drawn.
+.
+For polygons,
+this size field is interpreted as a stipple number to fill the polygon
+with.
+.
+The number is used to index into a stipple font at print time.
+.
+.
+.IP \[bu]
+The last line of each element contains a decimal number and a string of
+characters,
+separated by a single space.
+.
+The number is a count of the number of characters in the string.
+.
+This information is used only for text elements,
+and contains the text string.
+.
+There can be spaces inside the text.
+.
+For arcs,
+curves,
+and vectors,
+the character count is zero
+.RB ( 0 ),
+followed by exactly one space before the newline.
+.
+.
+.\" ====================================================================
+.SS Coordinates
+.\" ====================================================================
+.
+.I gremlin
+was designed for AED terminals,
+and its coordinates reflect the AED coordinate space.
+.
+For vertical pictures,
+.IR x \~values
+range 116 to 511,
+and
+.IR y \~values
+from 0 to 483.
+.
+For horizontal pictures,
+.IR x \~values
+range from 0 to 511,
+and
+.IR y \~values
+from 0 to 367.
+.
+Although you needn't absolutely stick to this range,
+you'll get better results if you at least stay in this vicinity.
+.
+Also,
+point lists are terminated by a point of
+(\-1,
+\-1),
+so you shouldn't ever use negative coordinates.
+.
+.I gremlin
+writes out coordinates using the
+.MR printf 3
+format \[lq]%f1.2\[rq];
+it's probably a good idea to use the same format if you want to modify
+the
+.I @g@grn
+code.
+.
+.
+.\" ====================================================================
+.SS "Sun/X11 coordinates"
+.\" ====================================================================
+.
+There is no restriction on the range of coordinates used to create
+objects in the Sun/X11 version of
+.IR gremlin .
+.
+However,
+files with negative coordinates
+.I will
+cause problems if displayed on the AED.
+.
+.
+.\" ====================================================================
+.SH Options
+.\" ====================================================================
+.
+.B \-?\&
+and
+.B \-\-help
+display a usage message,
+while
+.B \-v
+and
+.B \-\-version
+show version information;
+all exit afterward.
+.
+.
+.TP
+.B \-C
+Recognize
+.B .GS
+and
+.B .GE
+(and
+.BR .GF )
+even when followed by a character other than space or newline.
+.
+.
+.TP
+.BI \-F\~ dir
+Search
+.I dir
+for subdirectories
+.IR dev name
+.RI ( name
+is the name of the output driver)
+for the
+.I DESC
+file before the default font directories
+.IR @LOCALFONTDIR@ ,
+.IR @FONTDIR@ ,
+and
+.IR @LEGACYFONTDIR@ .
+.
+.
+.TP
+.BI \-M\~ dir
+Prepend
+.I dir
+to the search path for
+.I gremlin
+files.
+.
+The default search path is the current directory,
+the home directory,
+.if !'@COMPATIBILITY_WRAPPERS@'no' .IR @SYSTEMMACRODIR@ ,
+.IR @LOCALMACRODIR@ ,
+and
+.IR @MACRODIR@ ,
+in that order.
+.\".
+.\".
+.\".TP
+.\".B \-s
+.\"This switch causes the picture to be traversed twice:
+.\"The first time,
+.\"only the interiors of filled polygons
+.\"(as borderless polygons)
+.\"are printed.
+.\".
+.\"The second time,
+.\"the outline is printed as a series of line segments.
+.\".
+.\"This way,
+.\"postprocessors that overwrite rather than merge picture elements
+.\"(such as PostScript)
+.\"can still have text and graphics on a shaded background.
+.
+.
+.TP
+.BI \-T\~ dev
+Prepare device output using output driver
+.IR dev .
+.
+The default is
+.BR @DEVICE@ .
+.
+See
+.MR groff @MAN1EXT@
+for a list of valid devices.
+.
+.
+.\" ====================================================================
+.SH Files
+.\" ====================================================================
+.
+.TP
+.IR @FONTDIR@/\:\%dev name /\:DESC
+describes the output device
+.IR name .
+.
+.
+.\" ====================================================================
+.SH Authors
+.\" ====================================================================
+.
+David Slattengren and Barry Roitblat wrote the original Berkeley
+.IR grn .
+.
+Daniel Senderowicz and Werner Lemberg modified it for
+.IR groff .
+.
+.
+.\" ====================================================================
+.SH "See also"
+.\" ====================================================================
+.
+.MR gremlin 1 ,
+.MR groff @MAN1EXT@ ,
+.MR @g@pic @MAN1EXT@ ,
+.MR ideal 1
+.
+.
+.\" Restore compatibility mode (for, e.g., Solaris 10/11).
+.cp \n[*groff_grn_1_man_C]
+.do rr *groff_grn_1_man_C
+.
+.
+.\" Local Variables:
+.\" fill-column: 72
+.\" mode: nroff
+.\" End:
+.\" vim: set filetype=groff textwidth=72:
diff --git a/src/preproc/grn/grn.am b/src/preproc/grn/grn.am
new file mode 100644
index 0000000..f45fa24
--- /dev/null
+++ b/src/preproc/grn/grn.am
@@ -0,0 +1,35 @@
+# Copyright (C) 2014-2020 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+prefixexecbin_PROGRAMS += grn
+grn_SOURCES = \
+  src/preproc/grn/hdb.cpp \
+  src/preproc/grn/hpoint.cpp \
+  src/preproc/grn/hgraph.cpp \
+  src/preproc/grn/main.cpp \
+  src/preproc/grn/gprint.h
+src/preproc/grn/main.$(OBJEXT): defs.h
+grn_LDADD = libgroff.a lib/libgnu.a $(LIBM)
+PREFIXMAN1 += src/preproc/grn/grn.1
+EXTRA_DIST += src/preproc/grn/README src/preproc/grn/grn.1.man
+
+
+# Local Variables:
+# fill-column: 72
+# mode: makefile-automake
+# End:
+# vim: set autoindent filetype=automake textwidth=72:
diff --git a/src/preproc/grn/hdb.cpp b/src/preproc/grn/hdb.cpp
new file mode 100644
index 0000000..9ba3eaa
--- /dev/null
+++ b/src/preproc/grn/hdb.cpp
@@ -0,0 +1,441 @@
+ /* Last non-groff version: hdb.c  1.8 (Berkeley) 84/10/20
+ *
+ * Copyright -C- 1982 Barry S. Roitblat
+ *
+ * This file contains database routines for the hard copy programs of
+ * the gremlin picture editor.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdlib.h>
+#include "gprint.h"
+#include <string.h>
+#include <ctype.h>
+
+#include "errarg.h"
+#include "error.h"
+
+#define MAXSTRING 128
+#define MAXSTRING_S "127"
+
+/* imports from main.cpp */
+
+extern char gremlinfile[];	/* name of file currently reading */
+extern int SUNFILE;		/* TRUE if SUN gremlin file */
+extern int compatibility_flag;	/* TRUE if in compatibility mode */
+extern void *grnmalloc(size_t size, const char *what);
+extern void savebounds(double x, double y);
+
+/* imports from hpoint.cpp */
+
+extern POINT *PTInit();
+extern POINT *PTMakePoint(double x, double y, POINT ** pplist);
+
+
+int DBGetType(char *s);
+
+static long lineno = 0;		/* line number of gremlin file */
+
+/*
+ * This routine returns a pointer to an initialized database element
+ * which would be the only element in an empty list.
+ */
+ELT *
+DBInit()
+{
+  return ((ELT *) NULL);
+}				/* end DBInit */
+
+
+/*
+ * This routine creates a new element with the specified attributes and
+ * links it into database.
+ */
+ELT *
+DBCreateElt(int type,
+	    POINT * pointlist,
+	    int brush,
+	    int size,
+	    char *text,
+	    ELT **db)
+{
+  ELT *temp = 0;
+
+  temp = (ELT *) grnmalloc(sizeof(ELT), "picture element");
+  temp->nextelt = *db;
+  temp->type = type;
+  temp->ptlist = pointlist;
+  temp->brushf = brush;
+  temp->size = size;
+  temp->textpt = text;
+  *db = temp;
+  return (temp);
+}				/* end CreateElt */
+
+
+/*
+ * This routine reads the specified file into a database and returns a
+ * pointer to that database.
+ */
+ELT *
+DBRead(FILE *file)
+{
+  int i;
+  int done;		/* flag for input exhausted */
+  double nx;		/* x holder so x is not set before orienting */
+  int type;			/* element type */
+  ELT *elist;			/* pointer to the file's elements */
+  POINT *plist;			/* pointer for reading in points */
+  char string[MAXSTRING], *txt;
+  double x, y;			/* x and y are read in point coords */
+  int len, brush, size;
+  int lastpoint;
+
+  SUNFILE = FALSE;
+  elist = DBInit();
+  int nitems = fscanf(file, "%" MAXSTRING_S "s%*[^\n]\n", string);
+  if (nitems != 1) {
+    error_with_file_and_line(gremlinfile, lineno,
+			     "malformed input; giving up on this"
+			     " picture");
+    return (elist);
+  }
+  lineno++;
+  if (strcmp(string, "gremlinfile")) {
+    if (strcmp(string, "sungremlinfile")) {
+      error_with_file_and_line(gremlinfile, lineno,
+			       "not a gremlin file; giving up on this"
+			       " picture");
+      return (elist);
+    }
+    SUNFILE = TRUE;
+  }
+
+  nitems = fscanf(file, "%d%lf%lf\n", &size, &x, &y);
+  if (nitems != 3) {
+    error_with_file_and_line(gremlinfile, lineno,
+			     "malformed input; giving up on this"
+			     " picture");
+    return (elist);
+  }
+  lineno++;
+  /* ignore orientation and file positioning point */
+
+  done = FALSE;
+  while (!done) {
+    /* if (fscanf(file,"%" MAXSTRING_S "s\n", string) == EOF) */
+    /* I changed the scanf format because the element */
+    /* can have two words (e.g. CURVE SPLINE)         */
+    if (fscanf(file, "\n%"
+		      MAXSTRING_S
+		     "[^\n]%*[^\n]\n", string) == EOF) {
+      lineno++;
+      error_with_file_and_line(gremlinfile, lineno, "error in format;"
+			       " giving up on this picture");
+      return (elist);
+    }
+    lineno++;
+
+    type = DBGetType(string);	/* interpret element type */
+    if (type < 0) {		/* no more data */
+      done = TRUE;
+    } else {
+      /* always one point */
+#ifdef UW_FASTSCAN
+      (void) xscanf(file, &x, &y);
+#else
+      nitems = fscanf(file, "%lf%lf\n", &x, &y);
+      if (nitems != 2) {
+	error_with_file_and_line(gremlinfile, lineno,
+				 "malformed input; giving up on this"
+				 " picture");
+	return (elist);
+      }
+      lineno++;
+#endif	/* UW_FASTSCAN */
+      plist = PTInit();		/* NULL point list */
+
+      /*
+       * Files created on the SUN have point lists terminated by a line
+       * containing only an asterisk ('*').  Files created on the AED
+       * have point lists terminated by the coordinate pair (-1.00
+       * -1.00).
+       */
+      if (TEXT(type)) {	/* read only first point for TEXT elements */
+	nx = xorn(x, y);
+	y = yorn(x, y);
+	(void) PTMakePoint(nx, y, &plist);
+	savebounds(nx, y);
+
+#ifdef UW_FASTSCAN
+	while (xscanf(file, &x, &y));
+#else
+	lastpoint = FALSE;
+	do {
+	  char *cp = fgets(string, MAXSTRING, file);
+	  if (0 /* nullptr */ == cp) {
+	    error_with_file_and_line(gremlinfile, lineno,
+				     "premature end-of-file or error"
+				     " reading input; giving up on this"
+				     " picture");
+	    return(elist);
+	  }
+	  lineno++;
+	  if (string[0] == '*') {	/* SUN gremlin file */
+	    lastpoint = TRUE;
+	  } else {
+	    if (!sscanf(string, "%lf%lf", &x, &y)) {
+	      error_with_file_and_line(gremlinfile, lineno,
+				       "expected coordinate pair, got"
+				       " '%1'; giving up on this"
+				       " picture", string);
+	      return(elist);
+	    }
+	    if ((x == -1.00 && y == -1.00) && (!SUNFILE))
+	      lastpoint = TRUE;
+	    else {
+	      if (compatibility_flag)
+		savebounds(xorn(x, y), yorn(x, y));
+	    }
+	  }
+	} while (!lastpoint);
+#endif	/* UW_FASTSCAN */
+      } else {			/* not TEXT element */
+#ifdef UW_FASTSCAN
+	do {
+	  nx = xorn(x, y);
+	  y = yorn(x, y);
+	  (void) PTMakePoint(nx, y, &plist);
+	  savebounds(nx, y);
+	} while (xscanf(file, &x, &y));
+#else
+	lastpoint = FALSE;
+	while (!lastpoint) {
+	  nx = xorn(x, y);
+	  y = yorn(x, y);
+	  (void) PTMakePoint(nx, y, &plist);
+	  savebounds(nx, y);
+
+	  char *cp = fgets(string, MAXSTRING, file);
+	  if (0 /* nullptr */ == cp) {
+	    error_with_file_and_line(gremlinfile, lineno,
+				     "premature end-of-file or error"
+				     " reading input; giving up on this"
+				     " picture");
+	    return(elist);
+	  }
+	  lineno++;
+	  if (string[0] == '*') {	/* SUN gremlin file */
+	    lastpoint = TRUE;
+	  } else {
+	    (void) sscanf(string, "%lf%lf", &x, &y);
+	    if ((x == -1.00 && y == -1.00) && (!SUNFILE))
+	      lastpoint = TRUE;
+	  }
+	}
+#endif	/* UW_FASTSCAN */
+      }
+      nitems = fscanf(file, "%d%d\n", &brush, &size);
+      if (nitems != 2) {
+	error_with_file_and_line(gremlinfile, lineno,
+				 "malformed input; giving up on this"
+				 " picture");
+	return (elist);
+      }
+      lineno++;
+      nitems = fscanf(file, "%d", &len);	/* text length */
+      if (nitems != 1) {
+	error_with_file_and_line(gremlinfile, lineno,
+				 "malformed input; giving up on this"
+				 " picture");
+	return (elist);
+      }
+      (void) getc(file);		/* eat blank */
+      lineno++;				/* advance line counter early */
+      if (len < 0) {
+	error_with_file_and_line(gremlinfile, lineno,
+				 "length claimed for text is nonsense:"
+				 " '%1'; giving up on this picture",
+				 len);
+	return (elist);
+      }
+      txt = (char *) grnmalloc((unsigned) len + 1, "element text");
+      for (i = 0; i < len; ++i) {	/* read text */
+        int c = getc(file);
+        if (c == EOF)
+          break;
+	txt[i] = c;
+      }
+      if (feof(file)) {
+	error_with_file_and_line(gremlinfile, lineno,
+				 "end of file while reading text of"
+				 " length %1; giving up on this"
+				 " picture", len);
+	return (elist);
+      }
+      txt[len] = '\0';
+      (void) DBCreateElt(type, plist, brush, size, txt, &elist);
+    }				/* end else */
+  } /* end while not done */ ;
+  return (elist);
+}				/* end DBRead */
+
+
+/*
+ * Interpret element type in string s.
+ * Old file format consisted of integer element types.
+ * New file format has literal names for element types.
+ */
+int
+DBGetType(char *s)
+{
+  if (isdigit(s[0]) || (s[0] == '-'))	/* old element format or EOF */
+    return (atoi(s));
+
+  switch (s[0]) {
+  case 'P':
+    return (POLYGON);
+  case 'V':
+    return (VECTOR);
+  case 'A':
+    return (ARC);
+  case 'C':
+    if (s[1] == 'U') {
+      if (s[5] == '\n')
+	return (CURVE);
+      switch (s[7]) {
+      case 'S':
+	return(BSPLINE);
+      case 'E':
+	warning_with_file_and_line(gremlinfile, lineno,
+				   "using B-spline for Bezier curve");
+	return(BSPLINE);
+      default:
+	return(CURVE);
+      }
+    }
+    switch (s[4]) {
+    case 'L':
+      return (CENTLEFT);
+    case 'C':
+      return (CENTCENT);
+    case 'R':
+      return (CENTRIGHT);
+    default:
+      error_with_file_and_line(gremlinfile, lineno,
+			       "unknown element type '%1'", s);
+      return -1;
+    }
+  case 'B':
+    switch (s[3]) {
+    case 'L':
+      return (BOTLEFT);
+    case 'C':
+      return (BOTCENT);
+    case 'R':
+      return (BOTRIGHT);
+    default:
+      error_with_file_and_line(gremlinfile, lineno,
+			       "unknown element type '%1'", s);
+      return -1;
+    }
+  case 'T':
+    switch (s[3]) {
+    case 'L':
+      return (TOPLEFT);
+    case 'C':
+      return (TOPCENT);
+    case 'R':
+      return (TOPRIGHT);
+    default:
+      error_with_file_and_line(gremlinfile, lineno,
+			       "unknown element type '%1'", s);
+      return -1;
+    }
+  default:
+    error_with_file_and_line(gremlinfile, lineno,
+			     "unknown element type '%1'", s);
+    return -1;
+  }
+}
+
+#ifdef UW_FASTSCAN
+/*
+ * Optimization hack added by solomon@crys.wisc.edu, 12/2/86.
+ * A huge fraction of the time was spent reading floating point numbers
+ * from the input file, but the numbers always have the format 'ddd.dd'.
+ * Thus the following special-purpose version of fscanf.
+ *
+ * xscanf(f,xp,yp) does roughly what fscanf(f,"%f%f",xp,yp) does except:
+ *   -the next piece of input must be of the form
+ *      <space>* <digit>*'.'<digit>* <space>* <digit>*'.'<digit>*
+ *   -xscanf eats the character following the second number
+ *   -xscanf returns 0 for "end-of-data" indication, 1 otherwise, where
+ *    end-of-data is signalled by a '*' [in which case the rest of the
+ *    line is gobbled], or by '-1.00 -1.00' [but only if !SUNFILE].
+ */
+int
+xscanf(FILE *f,
+       double *xp,
+       double *yp)
+{
+  int c, i, j, m, frac;
+  int iscale = 1, jscale = 1;	/* x = i/scale, y=j/jscale */
+
+  while ((c = getc(f)) == ' ');
+  if (c == '*') {
+    while ((c = getc(f)) != '\n');
+    return 0;
+  }
+  i = m = frac = 0;
+  while (isdigit(c) || c == '.' || c == '-') {
+    if (c == '-') {
+      m++;
+      c = getc(f);
+      continue;
+    }
+    if (c == '.')
+      frac = 1;
+    else {
+      if (frac)
+	iscale *= 10;
+      i = 10 * i + c - '0';
+    }
+    c = getc(f);
+  }
+  if (m)
+    i = -i;
+  *xp = (double) i / (double) iscale;
+
+  while ((c = getc(f)) == ' ');
+  j = m = frac = 0;
+  while (isdigit(c) || c == '.' || c == '-') {
+    if (c == '-') {
+      m++;
+      c = getc(f);
+      continue;
+    }
+    if (c == '.')
+      frac = 1;
+    else {
+      if (frac)
+	jscale *= 10;
+      j = 10 * j + c - '0';
+    }
+    c = getc(f);
+  }
+  if (m)
+    j = -j;
+  *yp = (double) j / (double) jscale;
+  return (SUNFILE || i != -iscale || j != -jscale);
+}
+#endif	/* UW_FASTSCAN */
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/grn/hgraph.cpp b/src/preproc/grn/hgraph.cpp
new file mode 100644
index 0000000..9ed81a4
--- /dev/null
+++ b/src/preproc/grn/hgraph.cpp
@@ -0,0 +1,1060 @@
+/* Last non-groff version: hgraph.c  1.14 (Berkeley) 84/11/27
+ *
+ * This file contains the graphics routines for converting gremlin
+ * pictures to troff input.
+ */
+
+#include "lib.h"
+
+#include "gprint.h"
+
+#define MAXVECT	40
+#define MAXPOINTS	200
+#define LINELENGTH	1
+#define PointsPerInterval 64
+#define pi		3.14159265358979324
+#define twopi		(2.0 * pi)
+#define len(a, b)	groff_hypot((double)(b.x-a.x), \
+			            (double)(b.y-a.y))
+
+
+extern int dotshifter;		/* for the length of dotted curves */
+
+extern int style[];		/* line and character styles */
+extern double thick[];
+extern char *tfont[];
+extern int tsize[];
+extern int stipple_index[];	/* stipple font idx for stipples 0-16 */
+extern char *stipple;		/* stipple type (cf or ug) */
+
+
+extern double troffscale;	/* imports from main.c */
+extern double linethickness;
+extern int linmod;
+extern int lastx;
+extern int lasty;
+extern int lastyline;
+extern int ytop;
+extern int ybottom;
+extern int xleft;
+extern int xright;
+extern enum E {
+  OUTLINE, FILL, BOTH
+} polyfill;
+
+extern double adj1;
+extern double adj2;
+extern double adj3;
+extern double adj4;
+extern int res;
+
+void HGSetFont(int font, int size);
+void HGPutText(int justify, POINT pnt, char *string);
+void HGSetBrush(int mode);
+void tmove2(int px, int py);
+void doarc(POINT cp, POINT sp, int angle);
+void tmove(POINT * ptr);
+void cr();
+void drawwig(POINT * ptr, int type);
+void HGtline(int x1, int y1);
+void deltax(double x);
+void deltay(double y);
+void HGArc(int cx, int cy, int px, int py, int angle);
+void picurve(int *x, int *y, int npts);
+void HGCurve(int *x, int *y, int numpoints);
+void Parameterize(int x[], int y[], double h[], int n);
+void PeriodicSpline(double h[], int z[],
+		    double dz[], double d2z[], double d3z[],
+		    int npoints);
+void NaturalEndSpline(double h[], int z[],
+		      double dz[], double d2z[], double d3z[],
+		      int npoints);
+
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	HGPrintElt (element_pointer, baseline)
+ |
+ | Results:	Examines a picture element and calls the appropriate
+ |		routine(s) to print them according to their type.  After
+ |		the picture is drawn, current position is (lastx,lasty).
+ *--------------------------------------------------------------------*/
+
+void
+HGPrintElt(ELT *element,
+	   int /* baseline */)
+{
+  POINT *p1;
+  POINT *p2;
+  int length;
+  int graylevel;
+
+  if (!DBNullelt(element) && !Nullpoint((p1 = element->ptlist))) {
+    /* p1 always has first point */
+    if (TEXT(element->type)) {
+      HGSetFont(element->brushf, element->size);
+      switch (element->size) {
+      case 1:
+	p1->y += adj1;
+	break;
+      case 2:
+	p1->y += adj2;
+	break;
+      case 3:
+	p1->y += adj3;
+	break;
+      case 4:
+	p1->y += adj4;
+	break;
+      default:
+	break;
+      }
+      HGPutText(element->type, *p1, element->textpt);
+    } else {
+      if (element->brushf)		/* if there is a brush, the */
+	HGSetBrush(element->brushf);	/* graphics need it set     */
+
+      switch (element->type) {
+
+      case ARC:
+	p2 = PTNextPoint(p1);
+	tmove(p2);
+	doarc(*p1, *p2, element->size);
+	cr();
+	break;
+
+      case CURVE:
+	length = 0;	/* keep track of line length */
+	drawwig(p1, CURVE);
+	cr();
+	break;
+
+      case BSPLINE:
+	length = 0;	/* keep track of line length */
+	drawwig(p1, BSPLINE);
+	cr();
+	break;
+
+      case VECTOR:
+	length = 0;		/* keep track of line length so */
+	tmove(p1);		/* single lines don't get long  */
+	while (!Nullpoint((p1 = PTNextPoint(p1)))) {
+	  HGtline((int) (p1->x * troffscale),
+		  (int) (p1->y * troffscale));
+	  if (length++ > LINELENGTH) {
+	    length = 0;
+	    printf("\\\n");
+	  }
+	}			/* end while */
+	cr();
+	break;
+
+      case POLYGON:
+	{
+	  /* brushf = style of outline; size = color of fill:
+	   * on first pass (polyfill=FILL), do the interior using 'P'
+	   *    unless size=0
+	   * on second pass (polyfill=OUTLINE), do the outline using a
+	   *    series of vectors. It might make more sense to use \D'p
+	   *    ...', but there is no uniform way to specify a 'fill
+	   *    character' that prints as 'no fill' on all output
+	   *    devices (and stipple fonts).
+	   * If polyfill=BOTH, just use the \D'p ...' command.
+	   */
+	  double firstx = p1->x;
+	  double firsty = p1->y;
+
+	  length = 0;		/* keep track of line length so */
+				/* single lines don't get long  */
+
+	  if (polyfill == FILL || polyfill == BOTH) {
+	    /* do the interior */
+	    char command = (polyfill == BOTH && element->brushf)
+			   ? 'p' : 'P';
+
+	    /* include outline, if there is one and */
+	    /* the -p flag was set                  */
+
+	    /* switch based on what gremlin gives */
+	    switch (element->size) {
+	    case 1:
+	      graylevel = 1;
+	      break;
+	    case 3:
+	      graylevel = 2;
+	      break;
+	    case 12:
+	      graylevel = 3;
+	      break;
+	    case 14:
+	      graylevel = 4;
+	      break;
+	    case 16:
+	      graylevel = 5;
+	      break;
+	    case 19:
+	      graylevel = 6;
+	      break;
+	    case 21:
+	      graylevel = 7;
+	      break;
+	    case 23:
+	      graylevel = 8;
+	      break;
+	    default:		/* who's giving something else? */
+	      graylevel = NSTIPPLES;
+	      break;
+	    }
+	    /* int graylevel = element->size; */
+
+	    if (graylevel < 0)
+	      break;
+	    if (graylevel > NSTIPPLES)
+	      graylevel = NSTIPPLES;
+	    printf("\\D'Fg %.3f'",
+		   double(1000 - stipple_index[graylevel]) / 1000.0);
+	    cr();
+	    tmove(p1);
+	    printf("\\D'%c", command);
+
+	    while (!Nullpoint((PTNextPoint(p1)))) {
+	      p1 = PTNextPoint(p1);
+	      deltax((double) p1->x);
+	      deltay((double) p1->y);
+	      if (length++ > LINELENGTH) {
+		length = 0;
+		printf("\\\n");
+	      }
+	    } /* end while */
+
+	    /* close polygon if not done so by user */
+	    if ((firstx != p1->x) || (firsty != p1->y)) {
+	      deltax((double) firstx);
+	      deltay((double) firsty);
+	    }
+	    putchar('\'');
+	    cr();
+	    break;
+	  }
+	  /* else polyfill == OUTLINE; only draw the outline */
+	  if (!(element->brushf))
+	    break;
+	  length = 0;		/* keep track of line length */
+	  tmove(p1);
+
+	  while (!Nullpoint((PTNextPoint(p1)))) {
+	    p1 = PTNextPoint(p1);
+	    HGtline((int) (p1->x * troffscale),
+		    (int) (p1->y * troffscale));
+	    if (length++ > LINELENGTH) {
+	      length = 0;
+	      printf("\\\n");
+	    }
+	  }			/* end while */
+
+	  /* close polygon if not done so by user */
+	  if ((firstx != p1->x) || (firsty != p1->y)) {
+	    HGtline((int) (firstx * troffscale),
+		    (int) (firsty * troffscale));
+	  }
+	  cr();
+	  break;
+	}			/* end case POLYGON */
+      }				/* end switch */
+    }				/* end else Text */
+  }				/* end if */
+}				/* end PrintElt */
+
+
+/*---------------------------------------------------------------------*
+ | Routine:	HGPutText (justification, position_point, string)
+ |
+ | Results:	Given the justification, a point to position with, and a
+ |		string to put, HGPutText first sends the string into a
+ |		diversion, moves to the positioning point, then outputs
+ |		local vertical and horizontal motions as needed to
+ |		justify the text.  After all motions are done, the
+ |		diversion is printed out.
+ *--------------------------------------------------------------------*/
+
+void
+HGPutText(int justify,
+	  POINT pnt,
+	  char *string)
+{
+  int savelasty = lasty;	/* vertical motion for text is to be */
+				/* ignored.  Save current y here     */
+
+  printf(".nr g8 \\n(.d\n");	/* save current vertical position. */
+  printf(".ds g9 \"");		/* define string containing the text. */
+  while (*string) {		/* put out the string */
+    if (*string == '\\' &&
+	*(string + 1) == '\\') {	/* one character at a */
+      printf("\\\\\\");			/* time replacing //  */
+      string++;				/* by //// to prevent */
+    }					/* interpretation at  */
+    printf("%c", *(string++));		/* printout time      */
+  }
+  printf("\n");
+
+  tmove(&pnt);			/* move to positioning point */
+
+  switch (justify) {
+    /* local vertical motions--the numbers here are used to be
+       somewhat compatible with gprint */
+  case CENTLEFT:
+  case CENTCENT:
+  case CENTRIGHT:
+    printf("\\v'0.85n'");	/* down half */
+    break;
+
+  case TOPLEFT:
+  case TOPCENT:
+  case TOPRIGHT:
+    printf("\\v'1.7n'");	/* down whole */
+  }
+
+  switch (justify) {
+    /* local horizontal motions */
+  case BOTCENT:
+  case CENTCENT:
+  case TOPCENT:
+    printf("\\h'-\\w'\\*(g9'u/2u'");	/* back half */
+    break;
+
+  case BOTRIGHT:
+  case CENTRIGHT:
+  case TOPRIGHT:
+    printf("\\h'-\\w'\\*(g9'u'");	/* back whole */
+  }
+
+  printf("\\&\\*(g9\n");	/* now print the text. */
+  printf(".sp |\\n(g8u\n");	/* restore vertical position */
+  lasty = savelasty;		/* vertical position restored to */
+  lastx = xleft;		/* where it was before text, also */
+				/* horizontal is at left */
+}				/* end HGPutText */
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	doarc (center_point, start_point, angle)
+ |
+ | Results:	Produces either drawarc command or a drawcircle command
+ |		depending on the angle needed to draw through.
+ *--------------------------------------------------------------------*/
+
+void
+doarc(POINT cp,
+      POINT sp,
+      int angle)
+{
+  if (angle)			/* arc with angle */
+    HGArc((int) (cp.x * troffscale), (int) (cp.y * troffscale),
+	  (int) (sp.x * troffscale), (int) (sp.y * troffscale), angle);
+  else				/* a full circle (angle == 0) */
+    HGArc((int) (cp.x * troffscale), (int) (cp.y * troffscale),
+	  (int) (sp.x * troffscale), (int) (sp.y * troffscale), 0);
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	HGSetFont (font_number, Point_size)
+ |
+ | Results:	ALWAYS outputs a .ft and .ps directive to troff.  This
+ |		is done because someone may change stuff inside a text
+ |		string.  Changes thickness back to default thickness.
+ |		Default thickness depends on font and point size.
+ *--------------------------------------------------------------------*/
+
+void
+HGSetFont(int font,
+	  int size)
+{
+  printf(".ft %s\n"
+	 ".ps %d\n", tfont[font - 1], tsize[size - 1]);
+  linethickness = DEFTHICK;
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	HGSetBrush (line_mode)
+ |
+ | Results:	Generates the troff commands to set up the line width
+ |		and style of subsequent lines.  Does nothing if no
+ |		change is needed.
+ |
+ | Side Efct:	Sets 'linmode' and 'linethickness'.
+ *--------------------------------------------------------------------*/
+
+void
+HGSetBrush(int mode)
+{
+  int printed = 0;
+
+  if (linmod != style[--mode]) {
+    /* Groff doesn't understand \Ds, so we take it out */
+    /* printf ("\\D's %du'", linmod = style[mode]); */
+    linmod = style[mode];
+    printed = 1;
+  }
+  if (linethickness != thick[mode]) {
+    linethickness = thick[mode];
+    printf("\\h'-%.2fp'\\D't %.2fp'", linethickness, linethickness);
+    printed = 1;
+  }
+  if (printed)
+    cr();
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	deltax (x_destination)
+ |
+ | Results:	Scales and outputs a number for delta x (with a leading
+ |		space) given 'lastx' and x_destination.
+ |
+ | Side Efct:	Resets 'lastx' to x_destination.
+ *--------------------------------------------------------------------*/
+
+void
+deltax(double x)
+{
+  int ix = (int) (x * troffscale);
+
+  printf(" %du", ix - lastx);
+  lastx = ix;
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	deltay (y_destination)
+ |
+ | Results:	Scales and outputs a number for delta y (with a leading
+ |		space) given 'lastyline' and y_destination.
+ |
+ | Side Efct:	Resets 'lastyline' to y_destination.  Since 'line'
+ |		vertical motions don't affect 'page' ones, 'lasty' isn't
+ |		updated.
+ *--------------------------------------------------------------------*/
+
+void
+deltay(double y)
+{
+  int iy = (int) (y * troffscale);
+
+  printf(" %du", iy - lastyline);
+  lastyline = iy;
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	tmove2 (px, py)
+ |
+ | Results:	Produces horizontal and vertical moves for troff given
+ |		the pair of points to move to and knowing the current
+ |		position.  Also puts out a horizontal move to start the
+ |		line.  This is a variation without the .sp command.
+ *--------------------------------------------------------------------*/
+
+void
+tmove2(int px,
+       int py)
+{
+  int dx;
+  int dy;
+
+  if ((dy = py - lasty)) {
+    printf("\\v'%du'", dy);
+  }
+  lastyline = lasty = py;	/* lasty is always set to current */
+  if ((dx = px - lastx)) {
+    printf("\\h'%du'", dx);
+    lastx = px;
+  }
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	tmove (point_pointer)
+ |
+ | Results:	Produces horizontal and vertical moves for troff given
+ |		the pointer of a point to move to and knowing the
+ |		current position.  Also puts out a horizontal move to
+ |		start the line.
+ *--------------------------------------------------------------------*/
+
+void
+tmove(POINT * ptr)
+{
+  int ix = (int) (ptr->x * troffscale);
+  int iy = (int) (ptr->y * troffscale);
+  int dx;
+  int dy;
+
+  if ((dy = iy - lasty)) {
+    printf(".sp %du\n", dy);
+  }
+  lastyline = lasty = iy;	/* lasty is always set to current */
+  if ((dx = ix - lastx)) {
+    printf("\\h'%du'", dx);
+    lastx = ix;
+  }
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	cr ( )
+ |
+ | Results:	Ends off an input line.  '.sp -1' is also added to
+ |		counteract the vertical move done at the end of text
+ |		lines.
+ |
+ | Side Efct:	Sets 'lastx' to 'xleft' for troff's return to left
+ |		margin.
+ *--------------------------------------------------------------------*/
+
+void
+cr()
+{
+  printf("\n.sp -1\n");
+  lastx = xleft;
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	line ( )
+ |
+ | Results:	Draws a single solid line to (x,y).
+ *--------------------------------------------------------------------*/
+
+void
+line(int px,
+     int py)
+{
+  printf("\\D'l");
+  printf(" %du", px - lastx);
+  printf(" %du'", py - lastyline);
+  lastx = px;
+  lastyline = lasty = py;
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	drawwig (ptr, type)
+ |
+ | Results:	The point sequence found in the structure pointed by ptr
+ |		is placed in integer arrays for further manipulation by
+ |		the existing routing.  With the corresponding type
+ |		parameter, either picurve or HGCurve are called.
+ *--------------------------------------------------------------------*/
+
+void
+drawwig(POINT * ptr,
+	int type)
+{
+  int npts;			/* point list index */
+  int x[MAXPOINTS], y[MAXPOINTS];	/* point list */
+
+  for (npts = 1; !Nullpoint(ptr); ptr = PTNextPoint(ptr), npts++) {
+    x[npts] = (int) (ptr->x * troffscale);
+    y[npts] = (int) (ptr->y * troffscale);
+  }
+  if (--npts) {
+    if (type == CURVE) /* Use the 2 different types of curves */
+      HGCurve(&x[0], &y[0], npts);
+    else
+      picurve(&x[0], &y[0], npts);
+  }
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	HGArc (xcenter, ycenter, xstart, ystart, angle)
+ |
+ | Results:	This routine plots an arc centered about (cx, cy)
+ |		counter-clockwise starting from the point (px, py)
+ |		through 'angle' degrees.  If angle is 0, a full circle
+ |		is drawn.  It does so by creating a draw-path around the
+ |		arc whose density of points depends on the size of the
+ |		arc.
+ *--------------------------------------------------------------------*/
+
+void
+HGArc(int cx,
+      int cy,
+      int px,
+      int py,
+      int angle)
+{
+  double xs, ys, resolution, fullcircle;
+  int m;
+  int mask;
+  int extent;
+  int nx;
+  int ny;
+  int length;
+  double epsilon;
+
+  xs = px - cx;
+  ys = py - cy;
+
+  length = 0;
+
+  resolution = (1.0 + groff_hypot(xs, ys) / res) * PointsPerInterval;
+  /* mask = (1 << (int) log10(resolution + 1.0)) - 1; */
+  (void) frexp(resolution, &m);		/* more elegant than log10 */
+  for (mask = 1; mask < m; mask = mask << 1);
+  mask -= 1;
+
+  epsilon = 1.0 / resolution;
+  fullcircle = (2.0 * pi) * resolution;
+  if (angle == 0)
+    extent = (int) fullcircle;
+  else
+    extent = (int) (angle * fullcircle / 360.0);
+
+  HGtline(px, py);
+  while (--extent >= 0) {
+    xs += epsilon * ys;
+    nx = cx + (int) (xs + 0.5);
+    ys -= epsilon * xs;
+    ny = cy + (int) (ys + 0.5);
+    if (!(extent & mask)) {
+      HGtline(nx, ny);		/* put out a point on circle */
+      if (length++ > LINELENGTH) {
+	length = 0;
+	printf("\\\n");
+      }
+    }
+  }				/* end for */
+}				/* end HGArc */
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	picurve (xpoints, ypoints, num_of_points)
+ |
+ | Results:	Draws a curve delimited by (not through) the line
+ |		segments traced by (xpoints, ypoints) point list.  This
+ |		is the 'Pic'-style curve.
+ *--------------------------------------------------------------------*/
+
+void
+picurve(int *x,
+	int *y,
+	int npts)
+{
+  int nseg;		/* effective resolution for each curve */
+  int xp;		/* current point (and temporary) */
+  int yp;
+  int pxp, pyp;		/* previous point (to make lines from) */
+  int i;		/* inner curve segment traverser */
+  int length = 0;
+  double w;			/* position factor */
+  double t1, t2, t3;		/* calculation temps */
+
+  if (x[1] == x[npts] && y[1] == y[npts]) {
+    x[0] = x[npts - 1];		/* if the lines' ends meet, make */
+    y[0] = y[npts - 1];		/* sure the curve meets          */
+    x[npts + 1] = x[2];
+    y[npts + 1] = y[2];
+  } else {			/* otherwise, make the ends of the  */
+    x[0] = x[1];		/* curve touch the ending points of */
+    y[0] = y[1];		/* the line segments                */
+    x[npts + 1] = x[npts];
+    y[npts + 1] = y[npts];
+  }
+
+  pxp = (x[0] + x[1]) / 2;	/* make the last point pointers       */
+  pyp = (y[0] + y[1]) / 2;	/* point to the start of the 1st line */
+  tmove2(pxp, pyp);
+
+  for (; npts--; x++, y++) {	/* traverse the line segments */
+    xp = x[0] - x[1];
+    yp = y[0] - y[1];
+    nseg = (int) groff_hypot((double) xp, (double) yp);
+    xp = x[1] - x[2];
+    yp = y[1] - y[2];
+				/* 'nseg' is the number of line    */
+				/* segments that will be drawn for */
+				/* each curve segment.             */
+    nseg = (int) ((double) (nseg + (int) groff_hypot((double) xp,
+						     (double) yp)) /
+		  res * PointsPerInterval);
+
+    for (i = 1; i < nseg; i++) {
+      w = (double) i / (double) nseg;
+      t1 = w * w;
+      t3 = t1 + 1.0 - (w + w);
+      t2 = 2.0 - (t3 + t1);
+      xp = (((int) (t1 * x[2] + t2 * x[1] + t3 * x[0])) + 1) / 2;
+      yp = (((int) (t1 * y[2] + t2 * y[1] + t3 * y[0])) + 1) / 2;
+
+      HGtline(xp, yp);
+      if (length++ > LINELENGTH) {
+	length = 0;
+	printf("\\\n");
+      }
+    }
+  }
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	HGCurve(xpoints, ypoints, num_points)
+ |
+ | Results:	This routine generates a smooth curve through a set of
+ |		points.  The method used is the parametric spline curve
+ |		on unit knot mesh described in 'Spline Curve Techniques'
+ |		by Patrick Baudelaire, Robert Flegal, and Robert Sproull
+ |		-- Xerox Parc.
+ *--------------------------------------------------------------------*/
+
+void
+HGCurve(int *x,
+	int *y,
+	int numpoints)
+{
+  double h[MAXPOINTS], dx[MAXPOINTS], dy[MAXPOINTS];
+  double d2x[MAXPOINTS], d2y[MAXPOINTS], d3x[MAXPOINTS], d3y[MAXPOINTS];
+  double t, t2, t3;
+  int j;
+  int k;
+  int nx;
+  int ny;
+  int lx, ly;
+  int length = 0;
+
+  lx = x[1];
+  ly = y[1];
+  tmove2(lx, ly);
+
+  /*
+   * Solve for derivatives of the curve at each point separately for x
+   * and y (parametric).
+   */
+  Parameterize(x, y, h, numpoints);
+
+  /* closed curve */
+  if ((x[1] == x[numpoints]) && (y[1] == y[numpoints])) {
+    PeriodicSpline(h, x, dx, d2x, d3x, numpoints);
+    PeriodicSpline(h, y, dy, d2y, d3y, numpoints);
+  } else {
+    NaturalEndSpline(h, x, dx, d2x, d3x, numpoints);
+    NaturalEndSpline(h, y, dy, d2y, d3y, numpoints);
+  }
+
+  /*
+   * Generate the curve using the above information and
+   * PointsPerInterval vectors between each specified knot.
+   */
+
+  for (j = 1; j < numpoints; ++j) {
+    if ((x[j] == x[j + 1]) && (y[j] == y[j + 1]))
+      continue;
+    for (k = 0; k <= PointsPerInterval; ++k) {
+      t = (double) k *h[j] / (double) PointsPerInterval;
+      t2 = t * t;
+      t3 = t * t * t;
+      nx = x[j] + (int) (t * dx[j] + t2 * d2x[j] / 2 + t3 * d3x[j] / 6);
+      ny = y[j] + (int) (t * dy[j] + t2 * d2y[j] / 2 + t3 * d3y[j] / 6);
+      HGtline(nx, ny);
+      if (length++ > LINELENGTH) {
+	length = 0;
+	printf("\\\n");
+      }
+    }				/* end for k */
+  }				/* end for j */
+}				/* end HGCurve */
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	Parameterize (xpoints, ypoints, hparams, num_points)
+ |
+ | Results:	This routine calculates parametric values for use in
+ |		calculating curves.  The parametric values are returned
+ |		in the array h.  The values are an approximation of
+ |		cumulative arc lengths of the curve (uses cord length).
+ |		For additional information, see paper cited below.
+ *--------------------------------------------------------------------*/
+
+void
+Parameterize(int x[],
+	     int y[],
+	     double h[],
+	     int n)
+{
+  int dx;
+  int dy;
+  int i;
+  int j;
+  double u[MAXPOINTS];
+
+  for (i = 1; i <= n; ++i) {
+    u[i] = 0;
+    for (j = 1; j < i; j++) {
+      dx = x[j + 1] - x[j];
+      dy = y[j + 1] - y[j];
+      /* Here was overflowing, so I changed it.       */
+      /* u[i] += sqrt ((double) (dx * dx + dy * dy)); */
+      u[i] += groff_hypot((double) dx, (double) dy);
+    }
+  }
+  for (i = 1; i < n; ++i)
+    h[i] = u[i + 1] - u[i];
+}				/* end Parameterize */
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	PeriodicSpline (h, z, dz, d2z, d3z, npoints)
+ |
+ | Results:	This routine solves for the cubic polynomial to fit a
+ |		spline curve to the points specified by the list of
+ |		values.  The curve generated is periodic.  The
+ |		algorithms for this curve are from the 'Spline Curve
+ |		Techniques' paper cited above.
+ *--------------------------------------------------------------------*/
+
+void
+PeriodicSpline(double h[],	/* parameterization  */
+	       int z[],		/* point list */
+	       double dz[],	/* to return the 1st derivative */
+	       double d2z[],	/* 2nd derivative */
+	       double d3z[],	/* 3rd derivative */
+	       int npoints)	/* number of valid points */
+{
+  double d[MAXPOINTS];
+  double deltaz[MAXPOINTS], a[MAXPOINTS], b[MAXPOINTS];
+  double c[MAXPOINTS], r[MAXPOINTS], s[MAXPOINTS];
+  int i;
+
+  /* step 1 */
+  for (i = 1; i < npoints; ++i) {
+    deltaz[i] = h[i] ? ((double) (z[i + 1] - z[i])) / h[i] : 0;
+  }
+  h[0] = h[npoints - 1];
+  deltaz[0] = deltaz[npoints - 1];
+
+  /* step 2 */
+  for (i = 1; i < npoints - 1; ++i) {
+    d[i] = deltaz[i + 1] - deltaz[i];
+  }
+  d[0] = deltaz[1] - deltaz[0];
+
+  /* step 3a */
+  a[1] = 2 * (h[0] + h[1]);
+  b[1] = d[0];
+  c[1] = h[0];
+  for (i = 2; i < npoints - 1; ++i) {
+    a[i] = 2 * (h[i - 1] + h[i]) -
+	   pow((double) h[i - 1], (double) 2.0) / a[i - 1];
+    b[i] = d[i - 1] - h[i - 1] * b[i - 1] / a[i - 1];
+    c[i] = -h[i - 1] * c[i - 1] / a[i - 1];
+  }
+
+  /* step 3b */
+  r[npoints - 1] = 1;
+  s[npoints - 1] = 0;
+  for (i = npoints - 2; i > 0; --i) {
+    r[i] = -(h[i] * r[i + 1] + c[i]) / a[i];
+    s[i] = (6 * b[i] - h[i] * s[i + 1]) / a[i];
+  }
+
+  /* step 4 */
+  d2z[npoints - 1] = (6 * d[npoints - 2] - h[0] * s[1]
+		      - h[npoints - 1] * s[npoints - 2])
+		     / (h[0] * r[1] + h[npoints - 1] * r[npoints - 2]
+		      + 2 * (h[npoints - 2] + h[0]));
+  for (i = 1; i < npoints - 1; ++i) {
+    d2z[i] = r[i] * d2z[npoints - 1] + s[i];
+  }
+  d2z[npoints] = d2z[1];
+
+  /* step 5 */
+  for (i = 1; i < npoints; ++i) {
+    dz[i] = deltaz[i] - h[i] * (2 * d2z[i] + d2z[i + 1]) / 6;
+    d3z[i] = h[i] ? (d2z[i + 1] - d2z[i]) / h[i] : 0;
+  }
+}				/* end PeriodicSpline */
+
+
+/*--------------------------------------------------------------------
+ | Routine:	NaturalEndSpline (h, z, dz, d2z, d3z, npoints)
+ |
+ | Results:	This routine solves for the cubic polynomial to fit a
+ |		spline curve the points specified by the list of values.
+ |		The algorithms for this curve are from the 'Spline Curve
+ |		Techniques' paper cited above.
+ *--------------------------------------------------------------------*/
+
+void
+NaturalEndSpline(double h[],	/* parameterization */
+		 int z[],	/* Point list */
+		 double dz[],	/* to return the 1st derivative */
+		 double d2z[],	/* 2nd derivative */
+		 double d3z[],	/* 3rd derivative */
+		 int npoints)	/* number of valid points */
+{
+  double d[MAXPOINTS];
+  double deltaz[MAXPOINTS], a[MAXPOINTS], b[MAXPOINTS];
+  int i;
+
+  /* step 1 */
+  for (i = 1; i < npoints; ++i) {
+    deltaz[i] = h[i] ? ((double) (z[i + 1] - z[i])) / h[i] : 0;
+  }
+  deltaz[0] = deltaz[npoints - 1];
+
+  /* step 2 */
+  for (i = 1; i < npoints - 1; ++i) {
+    d[i] = deltaz[i + 1] - deltaz[i];
+  }
+  d[0] = deltaz[1] - deltaz[0];
+
+  /* step 3 */
+  a[0] = 2 * (h[2] + h[1]);
+  b[0] = d[1];
+  for (i = 1; i < npoints - 2; ++i) {
+    a[i] = 2 * (h[i + 1] + h[i + 2]) -
+	    pow((double) h[i + 1], (double) 2.0) / a[i - 1];
+    b[i] = d[i + 1] - h[i + 1] * b[i - 1] / a[i - 1];
+  }
+
+  /* step 4 */
+  d2z[npoints] = d2z[1] = 0;
+  for (i = npoints - 1; i > 1; --i) {
+    d2z[i] = (6 * b[i - 2] - h[i] * d2z[i + 1]) / a[i - 2];
+  }
+
+  /* step 5 */
+  for (i = 1; i < npoints; ++i) {
+    dz[i] = deltaz[i] - h[i] * (2 * d2z[i] + d2z[i + 1]) / 6;
+    d3z[i] = h[i] ? (d2z[i + 1] - d2z[i]) / h[i] : 0;
+  }
+}				/* end NaturalEndSpline */
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	change (x_position, y_position, visible_flag)
+ |
+ | Results:	As HGtline passes from the invisible to visible (or vice
+ |		versa) portion of a line, change is called to either
+ |		draw the line, or initialize the beginning of the next
+ |		one.  Change calls line to draw segments if visible_flag
+ |		is set (which means we're leaving a visible area).
+ *--------------------------------------------------------------------*/
+
+void
+change(int x,
+       int y,
+       int vis)
+{
+  static int length = 0;
+
+  if (vis) {			/* leaving a visible area, draw it. */
+    line(x, y);
+    if (length++ > LINELENGTH) {
+      length = 0;
+      printf("\\\n");
+    }
+  } else {			/* otherwise entering one; remember */
+				/* beginning                        */
+    tmove2(x, y);
+  }
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	HGtline (xstart, ystart, xend, yend)
+ |
+ | Results:	Draws a line from current position to (x1,y1) using
+ |		line(x1, y1) to place individual segments of dotted or
+ |		dashed lines.
+ *--------------------------------------------------------------------*/
+
+void
+HGtline(int x_1,
+	int y_1)
+{
+  int x_0 = lastx;
+  int y_0 = lasty;
+  int dx;
+  int dy;
+  int oldcoord;
+  int res1;
+  int visible;
+  int res2;
+  int xinc;
+  int yinc;
+  int dotcounter;
+
+  if (linmod == SOLID) {
+    line(x_1, y_1);
+    return;
+  }
+
+  /* for handling different resolutions */
+  dotcounter = linmod << dotshifter;
+
+  xinc = 1;
+  yinc = 1;
+  if ((dx = x_1 - x_0) < 0) {
+    xinc = -xinc;
+    dx = -dx;
+  }
+  if ((dy = y_1 - y_0) < 0) {
+    yinc = -yinc;
+    dy = -dy;
+  }
+  res1 = 0;
+  res2 = 0;
+  visible = 0;
+  if (dx >= dy) {
+    oldcoord = y_0;
+    while (x_0 != x_1) {
+      if ((x_0 & dotcounter) && !visible) {
+	change(x_0, y_0, 0);
+	visible = 1;
+      } else if (visible && !(x_0 & dotcounter)) {
+	change(x_0 - xinc, oldcoord, 1);
+	visible = 0;
+      }
+      if (res1 > res2) {
+	oldcoord = y_0;
+	res2 += dx - res1;
+	res1 = 0;
+	y_0 += yinc;
+      }
+      res1 += dy;
+      x_0 += xinc;
+    }
+  } else {
+    oldcoord = x_0;
+    while (y_0 != y_1) {
+      if ((y_0 & dotcounter) && !visible) {
+	change(x_0, y_0, 0);
+	visible = 1;
+      } else if (visible && !(y_0 & dotcounter)) {
+	change(oldcoord, y_0 - yinc, 1);
+	visible = 0;
+      }
+      if (res1 > res2) {
+	oldcoord = x_0;
+	res2 += dy - res1;
+	res1 = 0;
+	x_0 += xinc;
+      }
+      res1 += dx;
+      y_0 += yinc;
+    }
+  }
+  if (visible)
+    change(x_1, y_1, 1);
+  else
+    change(x_1, y_1, 0);
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/grn/hpoint.cpp b/src/preproc/grn/hpoint.cpp
new file mode 100644
index 0000000..5ef0c0a
--- /dev/null
+++ b/src/preproc/grn/hpoint.cpp
@@ -0,0 +1,59 @@
+/* Last non-groff version: hpoint.c  1.1  84/10/08 */
+
+/*
+ * This file contains routines for manipulating the point data
+ * structures for the gremlin picture editor.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdlib.h>
+#include "gprint.h"
+
+/* imports from main.cpp */
+extern void *grnmalloc(size_t size, const char *what);
+
+/*
+ * Return pointer to empty point list.
+ */
+POINT *
+PTInit()
+{
+  return ((POINT *) NULL);
+}
+
+
+/*
+ * This routine creates a new point with coordinates x and y and links
+ * it into the point list.
+ */
+POINT *
+PTMakePoint(double x,
+	    double y,
+	    POINT **pplist)
+{
+  POINT *pt;
+
+  if (Nullpoint(pt = *pplist)) {	/* empty list */
+    *pplist = (POINT *) grnmalloc(sizeof(POINT), "initial point");
+    pt = *pplist;
+  } else {
+    while (!Nullpoint(pt->nextpt))
+      pt = pt->nextpt;
+    pt->nextpt = (POINT *) grnmalloc(sizeof(POINT), "subsequent point");
+    pt = pt->nextpt;
+  }
+
+  pt->x = x;
+  pt->y = y;
+  pt->nextpt = PTInit();
+  return (pt);
+}				/* end PTMakePoint */
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/grn/main.cpp b/src/preproc/grn/main.cpp
new file mode 100644
index 0000000..6d6d586
--- /dev/null
+++ b/src/preproc/grn/main.cpp
@@ -0,0 +1,977 @@
+/* Last non-groff version: main.c 1.23  (Berkeley)  85/08/05
+ *
+ * Adapted to GNU troff by Daniel Senderowicz 99/12/29.
+ *
+ * Further refinements by Werner Lemberg 00/02/20.
+ *
+ *
+ * This file contains the main and file system dependent routines for
+ * processing gremlin files into troff input.  The program watches input
+ * go by to standard output, only interpreting things between .GS and
+ * .GE lines.  Default values (font, size, scale, thickness) may be
+ * overridden with a 'default' command and are further overridden by
+ * commands in the input.
+ *
+ * Inside the GS and GE, commands are accepted to reconfigure the
+ * picture.  At most one command may reside on each line, and each
+ * command is followed by a parameter separated by white space.  The
+ * commands are as follows, and may be abbreviated down to one character
+ * (with exception of 'scale' and 'stipple' down to "sc" and "st") and
+ * may be upper or lower case.
+ *
+ *                        default  -  Make all settings in the current
+ *                                    .GS/.GE the global defaults.
+ *                                    Height, width and file are NOT
+ *                                    saved.
+ *                     1, 2, 3, 4  -  Set size 1, 2, 3, or 4 (followed
+ *                                    by an integer point size).
+ *  roman, italics, bold, special  -  Set gremlin's fonts to any other
+ *                                    troff font (1 or 2 characters).
+ *                     stipple, l  -  Use a stipple font for polygons.
+ *                                    Arg is troff font name.  No
+ *                                    default.  Can use only one stipple
+ *                                    font per picture.  (See below for
+ *                                    stipple font index.)
+ *                       scale, x  -  Scale is IN ADDITION to the global
+ *                                    scale factor from the default.
+ *                     pointscale  -  Turn on scaling point sizes to
+ *                                    match 'scale' commands.  (Optional
+ *                                    operand 'off' to turn it off.)
+ *          narrow, medium, thick  -  Set widths of lines.
+ *                           file  -  Set the file name to read the
+ *                                    gremlin picture from.  If the file
+ *                                    isn't in the current directory,
+ *                                    the gremlin library is tried.
+ *                  width, height  -  These two commands override any
+ *                                    scaling factor that is in effect,
+ *                                    and forces the picture to fit into
+ *                                    either the height or width
+ *                                    specified, whichever makes the
+ *                                    picture smaller.  The operand for
+ *                                    these two commands is a
+ *                                    floating-point number in units of
+ *                                    inches.
+ *            l<nn> (integer <nn>) -  Set association between stipple
+ *                                    <nn> and a stipple 'character'.
+ *                                    <nn> must be in the range 0 to
+ *                                    NSTIPPLES (16) inclusive.  The
+ *                                    integer operand is an index in the
+ *                                    stipple font selected.  Valid cf
+ *                                    (cifplot) indices are 1-32
+ *                                    (although 24 is not defined),
+ *                                    valid ug (unigrafix) indices are
+ *                                    1-14, and valid gs (gray scale)
+ *                                    indices are 0-16.  Nonetheless,
+ *                                    any number between 0 and 255 is
+ *                                    accepted since new stipple fonts
+ *                                    may be added.  An integer operand
+ *                                    is required.
+ *
+ * Troff number registers used: g1 through g9.  g1 is the width of the
+ * picture, and g2 is the height.  g3, and g4, save information, g8 and
+ * g9 are used for text processing and g5-g7 are reserved.
+ */
+
+
+#include "lib.h"
+
+#include <ctype.h>
+#include <stdlib.h>
+#include <errno.h> // errno
+#include "gprint.h"
+
+#include "device.h"
+#include "font.h"
+#include "searchpath.h"
+#include "macropath.h"
+
+#include "errarg.h"
+#include "error.h"
+#include "defs.h"
+
+extern "C" const char *Version_string;
+
+/* database imports */
+
+extern void HGPrintElt(ELT *element, int baseline);
+extern ELT *DBInit();
+extern ELT *DBRead(FILE *file);
+extern POINT *PTInit();
+extern POINT *PTMakePoint(double x, double y, POINT **pplist);
+
+#define INIT_FILE_SIZE 50  /* Initial sz of file array from cmd line. */
+#define FILE_SIZE_INCR 50  /* Amount to increase array of files by. */
+
+#define SUN_SCALEFACTOR 0.70
+
+/* #define DEFSTIPPLE    "gs" */
+#define DEFSTIPPLE	"cf"
+/*
+ * This grn implementation emits '.st' requests to control stipple
+ * effects, but groff does not (currently) support any such request.
+ *
+ * This hack disables the emission of such requests, without destroying
+ * the infrastructure necessary to support the feature in the future; to
+ * enable the emission of '.st' requests, at a future date when groff
+ * can support them, simply rewrite the following #define as:
+ *
+ *   #define USE_ST_REQUEST  stipple
+ *
+ * with accompanying comment: "emit '.st' requests as required".
+ */
+#define USE_ST_REQUEST  0	/* never emit '.st' requests */
+
+#define MAXINLINE	100	/* input line length */
+
+#define SCREENtoINCH	0.02	/* scaling factor, screen to inches */
+
+#define BIG	999999999999.0	/* unwieldy large floating number */
+
+
+/* static char sccsid[] = "@(#) (Berkeley) 8/5/85, 12/28/99"; */
+
+int res;			/* the printer's resolution goes here */
+
+int dotshifter;			/* for the length of dotted curves */
+
+double linethickness;		/* brush styles */
+int linmod;
+int lastx;			/* point registers for printing */
+int lasty;			/* elements                     */
+int lastyline;			/* A line's vertical position is NOT  */
+				/* the same after that line is over,  */
+				/* so for a line of drawing commands, */
+				/* vertical spacing is kept in        */
+				/* lastyline.                         */
+
+/* These are the default fonts, sizes, line styles, */
+/* and thicknesses.  They can be modified from a    */
+/* 'default' command and are reset each time the    */
+/* start of a picture (.GS) is found.               */
+
+const char *deffont[] =
+{"R", "I", "B", "S"};
+int defsize[] =
+{10, 16, 24, 36};
+/* #define BASE_THICKNESS 1.0 */
+#define BASE_THICKNESS 0.15
+double defthick[STYLES] =
+{1 * BASE_THICKNESS,
+ 1 * BASE_THICKNESS,
+ 5 * BASE_THICKNESS,
+ 1 * BASE_THICKNESS,
+ 1 * BASE_THICKNESS,
+ 3 * BASE_THICKNESS};
+
+/* int cf_stipple_index[NSTIPPLES + 1] =                              */
+/* {0, 1, 3, 12, 14, 16, 19, 21, 23};                                 */
+/* a logarithmic scale looks better than a linear one for gray shades */
+/*                                                                    */
+/* int other_stipple_index[NSTIPPLES + 1] =                           */
+/* {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16};        */
+
+int cf_stipple_index[NSTIPPLES + 1] =
+{0, 18, 32, 56, 100, 178, 316, 562, 1000};	/* only 1-8 used */
+int other_stipple_index[NSTIPPLES + 1] =
+{0, 62, 125, 187, 250, 312, 375, 437, 500,
+ 562, 625, 687, 750, 812, 875, 937, 1000};
+
+/* int *defstipple_index = other_stipple_index; */
+int *defstipple_index = cf_stipple_index;
+
+int style[STYLES] =
+{DOTTED, DOTDASHED, SOLID, DASHED, SOLID, SOLID};
+double scale = 1.0;		/* no scaling, default */
+int defpoint = 0;		/* flag for point size scaling */
+char *defstipple = (char *) 0;
+enum E {
+  OUTLINE, FILL, BOTH
+} polyfill;
+
+/* flag to control filling of polygons */
+
+double adj1 = 0.0;
+double adj2 = 0.0;
+double adj3 = 0.0;
+double adj4 = 0.0;
+
+double thick[STYLES];		/* thicknesses set by defaults, then  */
+				/* by commands                        */
+char *tfont[FONTS];		/* fonts originally set to deffont    */
+				/* values, then optionally changed by */
+int tsize[SIZES];		/* commands inside grn                */
+int stipple_index[NSTIPPLES + 1];	/* stipple font file indices  */
+char *stipple;
+
+double xscale;		/* scaling factor from individual pictures */
+double troffscale;	/* scaling factor at output time */
+
+double width;		/* user-request maximum width for picture */
+			/* (in inches)                            */
+double height;		/* user-request height */
+int pointscale;		/* flag for point size scaling */
+int setdefault;		/* flag for a .GS/.GE to remember all */
+			/* settings                           */
+int sflag;		/* -s flag: sort order (do polyfill first) */
+
+double toppoint;	/* remember the picture */
+double bottompoint;	/* bounds in these variables */
+double leftpoint;
+double rightpoint;
+
+int ytop;		/* these are integer versions of the above */
+int ybottom;		/* so not to convert each time they're used */
+int xleft;
+int xright;
+
+static int linenum = 0;		/* line number of troff input file */
+char inputline[MAXINLINE];	/* spot to filter through the file */
+char *c1 = inputline;		/* c1, c2, and c3 will be used to */
+char *c2 = inputline + 1;	/* hunt for lines that begin with */
+char *c3 = inputline + 2;	/* '.GS' by looking individually */
+char *c4 = inputline + 3;	/* needed for compatibility mode */
+char GScommand[MAXINLINE];	/* put user's '.GS' command line here */
+char gremlinfile[MAXINLINE];	/* filename to use for a picture */
+int SUNFILE = FALSE;		/* TRUE if SUN gremlin file */
+int compatibility_flag = FALSE;	/* TRUE if in compatibility mode */
+
+
+void getres();
+int doinput(FILE *fp);
+void conv(FILE *fp, int baseline);
+void savestate();
+int has_polygon(ELT *elist);
+void interpret(char *line);
+
+void *
+grnmalloc(size_t size,
+	  const char *what)
+{
+  void *ptr = 0;
+  ptr = malloc(size);
+  if (!ptr) {
+    fatal("memory allocation failed for %1: %2", what, strerror(errno));
+  }
+  return ptr;
+}
+
+void
+usage(FILE *stream)
+{
+  fprintf(stream,
+	  "usage: %s [-Cs] [-M dir] [-F dir] [-T dev] [file ...]\n"
+	  "usage: %s {-v | --version}\n"
+	  "usage: %s --help\n",
+	  program_name, program_name, program_name);
+}
+
+
+/* Add a new file entry in the array, expanding array if needs be. */
+
+char **
+add_file(char **file,
+	 char *new_file,
+	 int *count,
+	 int *cur_size)
+{
+  if (*count >= *cur_size) {
+    *cur_size += FILE_SIZE_INCR;
+    file = (char **) realloc(file, *cur_size * sizeof(char *));
+    if (file == NULL) {
+      fatal("unable to extend file array");
+    }
+  }
+  file[*count] = new_file;
+  *count += 1;
+
+  return file;
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	main (argument_count, argument_pointer)
+ |
+ | Results:	Parses the command line, accumulating input file names,
+ |		then reads the inputs, passing it directly to output
+ |		until a '.GS' line is read.  Main then passes control to
+ |		'conv' to do the gremlin file conversions.
+ *--------------------------------------------------------------------*/
+
+int
+main(int argc,
+     char **argv)
+{
+  setlocale(LC_NUMERIC, "C");
+  program_name = argv[0];
+  FILE *fp;
+  int k;
+  char c;
+  int gfil = 0;
+  char **file = NULL;
+  int file_cur_size = INIT_FILE_SIZE;
+  char *operand(int *argcp, char ***argvp);
+
+  file = (char **) grnmalloc(file_cur_size * sizeof(char *),
+			     "file array");
+  while (--argc) {
+    if (**++argv != '-')
+      file = add_file(file, *argv, &gfil, &file_cur_size);
+    else
+      switch (c = (*argv)[1]) {
+
+      case 0:
+	file = add_file(file, NULL, &gfil, &file_cur_size);
+	break;
+
+      case 'C':		/* compatibility mode */
+	compatibility_flag = TRUE;
+	break;
+
+      case 'F':		/* font path to find DESC */
+	font::command_line_font_dir(operand(&argc, &argv));
+	break;
+
+      case 'T':		/* final output typesetter name */
+	device = operand(&argc, &argv);
+	break;
+
+      case 'M':		/* set library directory */
+	macro_path.command_line_dir(operand(&argc, &argv));
+	break;
+
+      case 's':		/* preserve order of elements */
+	sflag = 1;
+	break;
+
+      case '-':
+	if (strcmp(*argv,"--version")==0) {
+      case 'v':
+	  printf("GNU grn (groff) version %s\n", Version_string);
+	  exit(0);
+	  break;
+	}
+	if (strcmp(*argv,"--help")==0) {
+      case '?':
+	  usage(stdout);
+	  exit(0);
+	  break;
+	}
+	// fallthrough
+      default:
+	error("unknown switch: %1", c);
+	usage(stderr);
+	exit(1);
+      }
+  }
+
+  getres();		/* set the resolution for an output device */
+
+  if (gfil == 0) {		/* no filename, use standard input */
+    file[0] = NULL;
+    gfil++;
+  }
+
+  for (k = 0; k < gfil; k++) {
+    if (file[k] != NULL) {
+      if ((fp = fopen(file[k], "r")) == NULL)
+	fatal("can't open %1", file[k]);
+    } else
+      fp = stdin;
+
+    while (doinput(fp)) {
+      if (*c1 == '.' && *c2 == 'G' && *c3 == 'S') {
+	if (compatibility_flag ||
+	    *c4 == '\n' || *c4 == ' ' || *c4 == '\0')
+	  conv(fp, linenum);
+	else
+	  fputs(inputline, stdout);
+      } else
+	fputs(inputline, stdout);
+    }
+  }
+
+  return 0;
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	char  * operand (& argc, & argv)
+ |
+ | Results:	Returns address of the operand given with a command-line
+ |		option.  It uses either '-Xoperand' or '-X operand',
+ |		whichever is present.  The program is terminated if no
+ |		option is present.
+ |
+ | Side Efct:	argc and argv are updated as necessary.
+ *--------------------------------------------------------------------*/
+
+char *
+operand(int *argcp,
+	char ***argvp)
+{
+  if ((**argvp)[2])
+    return (**argvp + 2);	/* operand immediately follows */
+  if ((--*argcp) <= 0) {	/* no operand */
+    error("command-line option operand missing.");
+    exit(8);
+  }
+  return (*(++(*argvp)));	/* operand is next word */
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	getres ()
+ |
+ | Results:	Sets 'res' to the resolution of the output device.
+ *--------------------------------------------------------------------*/
+
+void
+getres()
+{
+  int linepiece;
+
+  if (0 /* nullptr */ == font::load_desc())
+    fatal("cannot load 'DESC' description file for device '%1'",
+	  device);
+
+  res = font::res;
+
+  /* Correct the brush thicknesses based on res */
+  /* if (res >= 256) {
+      defthick[0] = res >> 8;
+      defthick[1] = res >> 8;
+      defthick[2] = res >> 4;
+      defthick[3] = res >> 8;
+      defthick[4] = res >> 8;
+      defthick[5] = res >> 6;
+      } */
+
+  linepiece = res >> 9;
+  for (dotshifter = 0; linepiece; dotshifter++)
+    linepiece = linepiece >> 1;
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	int  doinput (file_pointer)
+ |
+ | Results:	A line of input is read into 'inputline'.
+ |
+ | Side Efct:	"linenum" is incremented.
+ |
+ | Bugs:	Lines longer than MAXINLINE are NOT checked, except for
+ |		updating 'linenum'.
+ *--------------------------------------------------------------------*/
+
+int
+doinput(FILE *fp)
+{
+  if (fgets(inputline, MAXINLINE, fp) == NULL)
+    return 0;
+  if (strchr(inputline, '\n'))	/* ++ only if it's a complete line */
+    linenum++;
+  return 1;
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	initpic ( )
+ |
+ | Results:	Sets all parameters to the normal defaults, possibly
+ |		overridden by a setdefault command.  Initialize the
+ |		picture variables, and output the startup commands to
+ |		troff to begin the picture.
+ *--------------------------------------------------------------------*/
+
+void
+initpic()
+{
+  int i;
+
+  for (i = 0; i < STYLES; i++) {	/* line thickness defaults */
+    thick[i] = defthick[i];
+  }
+  for (i = 0; i < FONTS; i++) {		/* font name defaults */
+    tfont[i] = (char *)deffont[i];
+  }
+  for (i = 0; i < SIZES; i++) {		/* font size defaults */
+    tsize[i] = defsize[i];
+  }
+  for (i = 0; i <= NSTIPPLES; i++) {	/* stipple font file default */
+					/* indices                   */
+    stipple_index[i] = defstipple_index[i];
+  }
+  stipple = defstipple;
+
+  gremlinfile[0] = 0;		/* filename is 'null' */
+  setdefault = 0;		/* not the default settings (yet) */
+
+  toppoint = BIG;		/* set the picture bounds out */
+  bottompoint = -BIG;		/* of range so they'll be set */
+  leftpoint = BIG;		/* by 'savebounds' on input */
+  rightpoint = -BIG;
+
+  pointscale = defpoint;/* flag for scaling point sizes default */
+  xscale = scale;	/* default scale of individual pictures */
+  width = 0.0;		/* size specifications input by user */
+  height = 0.0;
+
+  linethickness = DEFTHICK;	/* brush styles */
+  linmod = DEFSTYLE;
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	conv (file_pointer, starting_line)
+ |
+ | Results:	At this point, we just passed a '.GS' line in the input
+ |		file.  conv reads the input and calls 'interpret' to
+ |		process commands, gathering up information until a '.GE'
+ |		line is found.  It then calls 'HGPrint' to do the
+ |		translation of the gremlin file to troff commands.
+ *--------------------------------------------------------------------*/
+
+void
+conv(FILE *fp,
+     int baseline)
+{
+  FILE *gfp = NULL;	/* input file pointer */
+  int done = 0;	/* flag to remember if finished */
+  ELT *e;		/* current element pointer */
+  ELT *PICTURE;		/* whole picture data base pointer */
+  double temp;		/* temporary calculating area */
+  /* POINT ptr; */	/* coordinates of a point to pass to 'mov' */
+			/* routine                                 */
+  int flyback;		/* flag 'want to end up at the top of the */
+			/* picture?'                              */
+  int compat;		/* test character after .GE or .GF */
+
+
+  initpic();			/* set defaults, ranges, etc. */
+  strcpy(GScommand, inputline);	/* save '.GS' line for later */
+
+  do {
+    done = !doinput(fp);		/* test for EOF */
+    flyback = (*c3 == 'F');		/* and .GE or .GF */
+    compat = (compatibility_flag ||
+	      *c4 == '\n' || *c4 == ' ' || *c4 == '\0');
+    done |= (*c1 == '.' && *c2 == 'G' && (*c3 == 'E' || flyback) &&
+	     compat);
+
+    if (done) {
+      if (setdefault)
+	savestate();
+
+      if (!gremlinfile[0]) {
+	if (!setdefault)
+	  error("no picture file name at line %1", baseline);
+	return;
+      }
+      char *path;
+      gfp = macro_path.open_file(gremlinfile, &path);
+      if (0 /* nullptr */ == gfp) {
+	error("cannot open picture file '%1'", gremlinfile);
+	return;
+      }
+      PICTURE = DBRead(gfp);	/* read picture file */
+      fclose(gfp);
+      free(path);
+      if (DBNullelt(PICTURE))
+	return;			/* If a request is made to make the  */
+				/* picture fit into a specific area, */
+				/* set the scale to do that.         */
+
+      if (stipple == (char *) NULL)	/* if user forgot stipple    */
+	if (has_polygon(PICTURE))	/* and picture has a polygon */
+	  stipple = (char *)DEFSTIPPLE;	/* then set the default      */
+
+      if ((temp = bottompoint - toppoint) < 0.1)
+	temp = 0.1;
+      temp = (height != 0.0) ? height / (temp * SCREENtoINCH) : BIG;
+      if ((troffscale = rightpoint - leftpoint) < 0.1)
+	troffscale = 0.1;
+      troffscale = (width != 0.0) ?
+	  width / (troffscale * SCREENtoINCH) : BIG;
+      if (temp == BIG && troffscale == BIG)
+	troffscale = xscale;
+      else {
+	if (temp < troffscale)
+	  troffscale = temp;
+      }				/* here, troffscale is the  */
+				/* picture's scaling factor */
+      if (pointscale) {
+	int i;			/* do point scaling here, when   */
+				/* scale is known, before output */
+	for (i = 0; i < SIZES; i++)
+	  tsize[i] = (int) (troffscale * (double) tsize[i] + 0.5);
+      }
+
+					/* change to device units */
+      troffscale *= SCREENtoINCH * res;	/* from screen units      */
+
+      /* Calculate integer versions of the picture limits. */
+      ytop = (int) (toppoint * troffscale);
+      ybottom = (int) (bottompoint * troffscale);
+      xleft = (int) (leftpoint * troffscale);
+      xright = (int) (rightpoint * troffscale);
+
+      /* save stuff in number registers,    */
+      /*   register g1 = picture width and  */
+      /*   register g2 = picture height,    */
+      /*   set vertical spacing, no fill,   */
+      /*   and break (to make sure picture  */
+      /*   starts on left), and put out the */
+      /*   user's '.GS' line.               */
+      printf(".br\n"
+	     ".nr g1 %du\n"
+	     ".nr g2 %du\n"
+	     "%s"
+	     ".nr g3 \\n(.f\n"
+	     ".nr g4 \\n(.s\n"
+	     "\\0\n"
+	     ".sp -1\n",
+	     xright - xleft, ybottom - ytop, GScommand);
+
+      if (USE_ST_REQUEST)	/* stipple requested for this picture */
+	printf(".st %s\n", stipple);
+      lastx = xleft;		/* note where we are (upper left */
+      lastyline = lasty = ytop;	/* corner of the picture)        */
+
+      /* Just dump everything in the order it appears.
+       *
+       * If -s command-line option, traverse picture twice: First time,
+       * print only the interiors of filled polygons (as borderless
+       * polygons).  Second time, print the outline as series of line
+       * segments.  This way, postprocessors that overwrite rather than
+       * merge picture elements (such as Postscript) can still have text
+       * and graphics on a shaded background.
+       */
+      /* if (sflag) */
+      if (!sflag) {	/* changing the default for filled polygons */
+	e = PICTURE;
+	polyfill = FILL;
+	while (!DBNullelt(e)) {
+	  printf(".mk\n");
+	  if (e->type == POLYGON)
+	    HGPrintElt(e, baseline);
+	  printf(".rt\n");
+	  lastx = xleft;
+	  lastyline = lasty = ytop;
+	  e = DBNextElt(e);
+	}
+      }
+      e = PICTURE;
+
+      /* polyfill = !sflag ? BOTH : OUTLINE; */
+      polyfill = sflag ? BOTH : OUTLINE;	/* changing default */
+      while (!DBNullelt(e)) {
+	printf(".mk\n");
+	HGPrintElt(e, baseline);
+	printf(".rt\n");
+	lastx = xleft;
+	lastyline = lasty = ytop;
+	e = DBNextElt(e);
+      }
+
+      /* decide where to end picture */
+
+      /* I [Senderowicz?] changed everything here.  I always use the */
+      /* combination .mk and .rt, so once finished I just space down */
+      /* height of the picture that is \n(g2u.                       */
+      if (flyback) {		/* end picture at upper left */
+	/* ptr.x = leftpoint;
+	   ptr.y = toppoint; */
+      } else {			/* end picture at lower left */
+	/* ptr.x = leftpoint;
+	   ptr.y = bottompoint; */
+	printf(".sp \\n(g2u\n");
+      }
+
+      /* tmove(&ptr); */	/* restore default line parameters */
+
+      /* Restore everything to the way it was before the .GS, then */
+      /* put out the '.GE' line from user                          */
+
+      /* printf("\\D't %du'\\D's %du'\n", DEFTHICK, DEFSTYLE); */
+      /* groff doesn't understand the \Ds command */
+
+      printf("\\D't %du'\n", DEFTHICK);
+      if (flyback)		/* make sure we end up at top of */
+	printf(".sp -1\n");	/* picture if 'flying back'      */
+      if (USE_ST_REQUEST)	/* restore stipple to previous */
+	printf(".st\n");
+      printf(".br\n"
+	     ".ft \\n(g3\n"
+	     ".ps \\n(g4\n"
+	     "%s", inputline);
+    } else
+      interpret(inputline);	/* take commands from the input file */
+  } while (!done);
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	savestate  ( )
+ |
+ | Results:	All the current scaling/font size/font name/thickness/
+ |		pointscale settings are made the defaults.  Scaled
+ |		point sizes are NOT saved.  The scaling is done each
+ |		time a new picture is started.
+ |
+ | Side Efct:	scale, and def* are modified.
+ *--------------------------------------------------------------------*/
+
+void
+savestate()
+{
+  int i;
+
+  for (i = 0; i < STYLES; i++)	/* line thickness defaults */
+    defthick[i] = thick[i];
+  for (i = 0; i < FONTS; i++)	/* font name defaults */
+    deffont[i] = tfont[i];
+  for (i = 0; i < SIZES; i++)	/* font size defaults */
+    defsize[i] = tsize[i];
+  /* stipple font file default indices */
+  for (i = 0; i <= NSTIPPLES; i++)
+    defstipple_index[i] = stipple_index[i];
+
+  defstipple = stipple;	/* if stipple has been set, it's remembered */
+  scale *= xscale;	/* default scale of individual pictures */
+  defpoint = pointscale;/* flag to scale point sizes from x factors */
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	savebounds (x_coordinate, y_coordinate)
+ |
+ | Results:	Keeps track of the maximum and minimum extent of a
+ |		picture in the global variables: left-, right-, top- and
+ |		bottompoint.  'savebounds' assumes that the points have
+ |		been oriented to the correct direction.  No scaling has
+ |		taken place, though.
+ *--------------------------------------------------------------------*/
+
+void
+savebounds(double x,
+	   double y)
+{
+  if (x < leftpoint)
+    leftpoint = x;
+  if (x > rightpoint)
+    rightpoint = x;
+  if (y < toppoint)
+    toppoint = y;
+  if (y > bottompoint)
+    bottompoint = y;
+}
+
+
+/*--------------------------------------------------------------------*
+ | Routine:	interpret (character_string)
+ |
+ | Results:	Commands are taken from the input string and performed.
+ |		Commands are separated by newlines, and are of the
+ |		format:
+ |			string1 string2
+ |		where string1 is the command, string2 the argument.
+ |
+ | Side Efct:	Font and size strings, plus the gremlin file name and
+ |		the width and height variables are set by this routine.
+ *--------------------------------------------------------------------*/
+
+void
+interpret(char *line)
+{
+  char str1[MAXINLINE];
+  char str2[MAXINLINE];
+  char *chr;
+  int i;
+  double par;
+
+  str2[0] = '\0';
+  sscanf(line, "%80s%80s", &str1[0], &str2[0]);
+  for (chr = &str1[0]; *chr; chr++)	/* convert command to */
+    if (isupper(*chr))
+      *chr = tolower(*chr);	/* lower case */
+
+  switch (str1[0]) {
+
+  case '1':
+  case '2':			/* font sizes */
+  case '3':
+  case '4':
+    i = atoi(str2);
+    if (i > 0 && i < 1000)
+      tsize[str1[0] - '1'] = i;
+    else
+      error("bad font size value at line %1", linenum);
+    break;
+
+  case 'r':			/* roman */
+    if (str2[0] < '0')
+      goto nofont;
+    tfont[0] = (char *) grnmalloc(strlen(str2) + 1, "roman command");
+    strcpy(tfont[0], str2);
+    break;
+
+  case 'i':			/* italics */
+    if (str2[0] < '0')
+      goto nofont;
+    tfont[1] = (char *) grnmalloc(strlen(str2) + 1, "italics command");
+    strcpy(tfont[1], str2);
+    break;
+
+  case 'b':			/* bold */
+    if (str2[0] < '0')
+      goto nofont;
+    tfont[2] = (char *) grnmalloc(strlen(str2) + 1, "bold command");
+    strcpy(tfont[2], str2);
+    break;
+
+  case 's':			/* special */
+    if (str1[1] == 'c')
+      goto scalecommand;	/* or scale */
+
+    if (str2[0] < '0') {
+  nofont:
+      error("no font name specified in line %1", linenum);
+      break;
+    }
+    if (str1[1] == 't')
+      goto stipplecommand;	/* or stipple */
+
+    tfont[3] = (char *) grnmalloc(strlen(str2) + 1, "special command");
+    strcpy(tfont[3], str2);
+    break;
+
+  case 'l':			/* l */
+    if (isdigit(str1[1])) {	/* set stipple index */
+      int idx = atoi(str1 + 1), val;
+
+      if (idx < 0 || idx > NSTIPPLES) {
+	error("bad stipple number %1 at line %2", idx, linenum);
+	break;
+      }
+      if (!defstipple_index)
+	defstipple_index = other_stipple_index;
+      val = atoi(str2);
+      if (val >= 0 && val < 256)
+	stipple_index[idx] = val;
+      else
+	error("bad stipple index value at line %1", linenum);
+      break;
+    }
+
+  stipplecommand:		/* set stipple name */
+    stipple = (char *) grnmalloc(strlen(str2) + 1, "stipple command");
+    strcpy(stipple, str2);
+    /* if it's a 'known' font (currently only 'cf'), set indices    */
+    if (strcmp(stipple, "cf") == 0)
+      defstipple_index = cf_stipple_index;
+    else
+      defstipple_index = other_stipple_index;
+    for (i = 0; i <= NSTIPPLES; i++)
+      stipple_index[i] = defstipple_index[i];
+    break;
+
+  case 'a':			/* text adjust */
+    par = atof(str2);
+    switch (str1[1]) {
+    case '1':
+      adj1 = par;
+      break;
+    case '2':
+      adj2 = par;
+      break;
+    case '3':
+      adj3 = par;
+      break;
+    case '4':
+      adj4 = par;
+      break;
+    default:
+      error("bad adjust command at line %1", linenum);
+      break;
+    }
+    break;
+
+  case 't':			/* thick */
+    thick[2] = defthick[0] * atof(str2);
+    break;
+
+  case 'm':			/* medium */
+    thick[5] = defthick[0] * atof(str2);
+    break;
+
+  case 'n':			/* narrow */
+    thick[0] = thick[1] = thick[3] = thick[4] =
+	defthick[0] * atof(str2);
+    break;
+
+  case 'x':			/* x */
+  scalecommand:			/* scale */
+    par = atof(str2);
+    if (par > 0.0)
+      xscale *= par;
+    else
+      error("invalid scale value on line %1", linenum);
+    break;
+
+  case 'f':			/* file */
+    strcpy(gremlinfile, str2);
+    break;
+
+  case 'w':			/* width */
+    width = atof(str2);
+    if (width < 0.0)
+      width = -width;
+    break;
+
+  case 'h':			/* height */
+    height = atof(str2);
+    if (height < 0.0)
+      height = -height;
+    break;
+
+  case 'd':			/* defaults */
+    setdefault = 1;
+    break;
+
+  case 'p':			/* pointscale */
+    if (strcmp("off", str2))
+      pointscale = 1;
+    else
+      pointscale = 0;
+    break;
+
+  default:
+    error("unknown command '%1' on line %2", str1, linenum);
+    exit(8);
+    break;
+  };
+}
+
+
+/*
+ * return TRUE if picture contains a polygon
+ * otherwise FALSE
+ */
+
+int
+has_polygon(ELT *elist)
+{
+  while (!DBNullelt(elist)) {
+    if (elist->type == POLYGON)
+      return (1);
+    elist = DBNextElt(elist);
+  }
+
+  return (0);
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/html/html.am b/src/preproc/html/html.am
new file mode 100644
index 0000000..ac5ca9d
--- /dev/null
+++ b/src/preproc/html/html.am
@@ -0,0 +1,32 @@
+# Copyright (C) 2014-2020 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+bin_PROGRAMS += pre-grohtml
+pre_grohtml_LDADD = libgroff.a lib/libgnu.a $(LIBM)
+pre_grohtml_SOURCES = \
+  src/preproc/html/pre-html.cpp \
+  src/preproc/html/pushback.cpp \
+  src/preproc/html/pre-html.h \
+  src/preproc/html/pushback.h
+src/preproc/html/pre-html.$(OBJEXT): defs.h
+
+
+# Local Variables:
+# fill-column: 72
+# mode: makefile-automake
+# End:
+# vim: set autoindent filetype=automake textwidth=72:
diff --git a/src/preproc/html/pre-html.cpp b/src/preproc/html/pre-html.cpp
new file mode 100644
index 0000000..fecfb05
--- /dev/null
+++ b/src/preproc/html/pre-html.cpp
@@ -0,0 +1,1819 @@
+/* Copyright (C) 2000-2021 Free Software Foundation, Inc.
+ * Written by Gaius Mulley (gaius@glam.ac.uk).
+ *
+ * This file is part of groff.
+ *
+ * groff is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * groff is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with groff; see the file COPYING.  If not, write to the Free
+ * Software Foundation, 51 Franklin St - Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#define PREHTMLC
+
+#include "lib.h"
+
+#include <assert.h>
+#include <ctype.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdlib.h>
+
+#include "errarg.h"
+#include "error.h"
+#include "stringclass.h"
+#include "posix.h"
+#include "defs.h"
+#include "searchpath.h"
+#include "paper.h"
+#include "device.h"
+#include "font.h"
+
+#include <errno.h>
+#include <sys/types.h>
+#ifdef HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+
+#ifdef _POSIX_VERSION
+# include <sys/wait.h>
+# define PID_T pid_t
+#else /* not _POSIX_VERSION */
+# define PID_T int
+#endif /* not _POSIX_VERSION */
+
+#include <stdarg.h>
+
+#include "nonposix.h"
+
+#if 0
+# define DEBUGGING
+#endif
+
+/* Establish some definitions to facilitate discrimination between
+   differing runtime environments. */
+
+#undef MAY_FORK_CHILD_PROCESS
+#undef MAY_SPAWN_ASYNCHRONOUS_CHILD
+
+#if defined(__MSDOS__) || defined(_WIN32)
+
+// Most MS-DOS and Win32 environments will be missing the 'fork'
+// capability (some, like Cygwin, have it, but it is better avoided).
+
+# define MAY_FORK_CHILD_PROCESS 0
+
+// On these systems, we use 'spawn...', instead of 'fork' ... 'exec...'.
+# include <process.h>	// for 'spawn...'
+# include <fcntl.h>	// for attributes of pipes
+
+# if defined(__CYGWIN__) || defined(_UWIN) || defined(_WIN32)
+
+// These Win32 implementations allow parent and 'spawn...'ed child to
+// multitask asynchronously.
+
+#  define MAY_SPAWN_ASYNCHRONOUS_CHILD 1
+
+# else
+
+// Others may adopt MS-DOS behaviour where parent must sleep,
+// from 'spawn...' until child terminates.
+
+#  define MAY_SPAWN_ASYNCHRONOUS_CHILD 0
+
+# endif /* not defined __CYGWIN__, _UWIN, or _WIN32 */
+
+# if defined(DEBUGGING) && !defined(DEBUG_FILE_DIR)
+/* When we are building a DEBUGGING version we need to tell pre-grohtml
+   where to put intermediate files (the DEBUGGING version will preserve
+   these on exit).
+
+   On a Unix host, we might simply use '/tmp', but MS-DOS and Win32 will
+   probably not have this on all disk drives, so default to using
+   'c:/temp' instead.  (Note that user may choose to override this by
+   supplying a definition such as
+
+     -DDEBUG_FILE_DIR=d:/path/to/debug/files
+
+   in the CPPFLAGS to 'make'.) */
+
+#  define DEBUG_FILE_DIR c:/temp
+# endif
+
+#else /* not __MSDOS__ or _WIN32 */
+
+// For non-Microsoft environments assume Unix conventions,
+// so 'fork' is required and child processes are asynchronous.
+# define MAY_FORK_CHILD_PROCESS 1
+# define MAY_SPAWN_ASYNCHRONOUS_CHILD 1
+
+# if defined(DEBUGGING) && !defined(DEBUG_FILE_DIR)
+/* For a DEBUGGING version, on the Unix host, we can also usually rely
+   on being able to use '/tmp' for temporary file storage.  (Note that,
+   as in the __MSDOS__ or _WIN32 case above, the user may override this
+   by defining
+
+     -DDEBUG_FILE_DIR=/path/to/debug/files
+
+   in the CPPFLAGS.) */
+
+#  define DEBUG_FILE_DIR /tmp
+# endif
+
+#endif /* not __MSDOS__ or _WIN32 */
+
+#ifdef DEBUGGING
+// For a DEBUGGING version, we need some additional macros,
+// to direct the captured debugging mode output to appropriately named
+// files in the specified DEBUG_FILE_DIR.
+
+# define DEBUG_TEXT(text) #text
+# define DEBUG_NAME(text) DEBUG_TEXT(text)
+# define DEBUG_FILE(name) DEBUG_NAME(DEBUG_FILE_DIR) "/" name
+#endif
+
+extern "C" const char *Version_string;
+
+#include "pre-html.h"
+#include "pushback.h"
+#include "html-strings.h"
+
+#define DEFAULT_LINE_LENGTH 7	// inches wide
+#define DEFAULT_IMAGE_RES 100	// number of pixels per inch resolution
+#define IMAGE_BORDER_PIXELS 0
+#define INLINE_LEADER_CHAR '\\'
+
+// Don't use colour names here!  Otherwise there is a dependency on
+// a file called 'rgb.txt' which maps names to colours.
+#define TRANSPARENT "-background rgb:f/f/f -transparent rgb:f/f/f"
+#define MIN_ALPHA_BITS 0
+#define MAX_ALPHA_BITS 4
+
+#define PAGE_TEMPLATE_SHORT "pg"
+#define PAGE_TEMPLATE_LONG "-page-"
+#define PS_TEMPLATE_SHORT "ps"
+#define PS_TEMPLATE_LONG "-ps-"
+#define REGION_TEMPLATE_SHORT "rg"
+#define REGION_TEMPLATE_LONG "-regions-"
+
+typedef enum {
+  CENTERED, LEFT, RIGHT, INLINE
+} IMAGE_ALIGNMENT;
+
+typedef enum {xhtml, html4} html_dialect;
+
+static int postscriptRes = -1;		// PostScript resolution,
+					// dots per inch
+static int stdoutfd = 1;		// output file descriptor -
+					// normally 1 but might move
+					// -1 means closed
+static char *psFileName = 0 /* nullptr */;	// PostScript file name
+static char *psPageName = 0 /* nullptr */;	// name of file
+						// containing current
+						// PostScript page
+static char *regionFileName = 0 /* nullptr */;	// name of file
+						// containing all image
+						// regions
+static char *imagePageName = 0 /* nullptr */;	// name of bitmap image
+						// file containing
+						// current page
+static const char *image_device = "pnmraw";
+static int image_res = DEFAULT_IMAGE_RES;
+static int vertical_offset = 0;
+static char *image_template = 0 /* nullptr */;	// image file name
+						// template
+static char *macroset_template= 0 /* nullptr */;	// image file
+							// name template
+							// passed to
+							// troff by -D
+static int troff_arg = 0;		// troff arg index
+static char *image_dir = 0 /* nullptr */;	// user-specified image
+						// directory
+static int textAlphaBits = MAX_ALPHA_BITS;
+static int graphicAlphaBits = MAX_ALPHA_BITS;
+static char *antiAlias = 0 /* nullptr */;	// anti-alias arguments
+						// to be passed to gs
+static bool want_progress_report = false;	// display page numbers
+						// as they are processed
+static int currentPageNo = -1;		// current image page number
+#if defined(DEBUGGING)
+static bool debugging = false;
+static char *troffFileName = 0 /* nullptr */;	// pre-html output sent
+						// to troff -Tps
+static char *htmlFileName = 0 /* nullptr */;	// pre-html output sent
+						// to troff -Thtml
+#endif
+static bool need_eqn = false;		// must we preprocess via eqn?
+
+static char *linebuf = 0 /* nullptr */;	// for scanning devps/DESC
+static int linebufsize = 0;
+static const char *image_gen = 0 /* nullptr */;	// the 'gs' program
+
+static const char devhtml_desc[] = "devhtml/DESC";
+static const char devps_desc[] = "devps/DESC";
+
+const char *const FONT_ENV_VAR = "GROFF_FONT_PATH";
+static search_path font_path(FONT_ENV_VAR, FONTPATH, 0, 0);
+static html_dialect dialect = html4;
+
+
+/*
+ *  Images are generated via PostScript, gs, and the pnm utilities.
+ */
+#define IMAGE_DEVICE "-Tps"
+
+
+/*
+ *  sys_fatal - Write a fatal error message.
+ *              Taken from src/roff/groff/pipeline.c.
+ */
+
+void sys_fatal(const char *s)
+{
+  fatal("%1: %2", s, strerror(errno));
+}
+
+/*
+ *  get_line - Copy a line (w/o newline) from a file to the
+ *             global line buffer.
+ */
+
+int get_line(FILE *f)
+{
+  if (f == 0)
+    return 0;
+  if (linebuf == 0) {
+    linebuf = new char[128];
+    linebufsize = 128;
+  }
+  int i = 0;
+  // skip leading whitespace
+  for (;;) {
+    int c = getc(f);
+    if (c == EOF)
+      return 0;
+    if (c != ' ' && c != '\t') {
+      ungetc(c, f);
+      break;
+    }
+  }
+  for (;;) {
+    int c = getc(f);
+    if (c == EOF)
+      break;
+    if (i + 1 >= linebufsize) {
+      char *old_linebuf = linebuf;
+      linebuf = new char[linebufsize * 2];
+      memcpy(linebuf, old_linebuf, linebufsize);
+      delete[] old_linebuf;
+      linebufsize *= 2;
+    }
+    linebuf[i++] = c;
+    if (c == '\n') {
+      i--;
+      break;
+    }
+  }
+  linebuf[i] = '\0';
+  return 1;
+}
+
+/*
+ *  get_resolution - Return the PostScript device resolution.
+ */
+
+static unsigned int get_resolution(void)
+{
+  char *pathp;
+  FILE *f;
+  unsigned int res = 0;
+  f = font_path.open_file(devps_desc, &pathp);
+  if (0 == f)
+    fatal("cannot open file '%1'", devps_desc);
+  free(pathp);
+  // XXX: We should break out of this loop if we hit a "charset" line.
+  // "This line and everything following it in the file are ignored."
+  // (groff_font(5))
+  while (get_line(f))
+    (void) sscanf(linebuf, "res %u", &res);
+  fclose(f);
+  return res;
+}
+
+
+/*
+ *  get_image_generator - Return the declared program from the HTML
+ *                        device description.
+ */
+
+static char *get_image_generator(void)
+{
+  char *pathp;
+  FILE *f;
+  char *generator = 0;
+  const char keyword[] = "image_generator";
+  const size_t keyword_len = strlen(keyword);
+  f = font_path.open_file(devhtml_desc, &pathp);
+  if (0 == f)
+    fatal("cannot open file '%1'", devhtml_desc);
+  free(pathp);
+  // XXX: We should break out of this loop if we hit a "charset" line.
+  // "This line and everything following it in the file are ignored."
+  // (groff_font(5))
+  while (get_line(f)) {
+    char *cursor = linebuf;
+    size_t limit = strlen(linebuf);
+    char *end = linebuf + limit;
+    if (0 == (strncmp(linebuf, keyword, keyword_len))) {
+      cursor += keyword_len;
+      // At least one space or tab is required.
+      if(!(' ' == *cursor) || ('\t' == *cursor))
+	continue;
+      cursor++;
+      while((cursor < end) && ((' ' == *cursor) || ('\t' == *cursor)))
+	cursor++;
+      if (cursor == end)
+	continue;
+      generator = cursor;
+    }
+  }
+  fclose(f);
+  return generator;
+}
+
+/*
+ *  html_system - A wrapper for system().
+ */
+
+void html_system(const char *s, int redirect_stdout)
+{
+#if defined(DEBUGGING)
+  if (debugging) {
+    fprintf(stderr, "executing: ");
+    fwrite(s, sizeof(char), strlen(s), stderr);
+    fflush(stderr);
+  }
+#endif
+  {
+    int saved_stdout = dup(1);
+    int fdnull = open(NULL_DEV, O_WRONLY|O_BINARY, 0666);
+    if (redirect_stdout && saved_stdout > 1 && fdnull > 1)
+      dup2(fdnull, 1);
+    if (fdnull >= 0)
+      close(fdnull);
+    int status = system(s);
+    if (redirect_stdout)
+      dup2(saved_stdout, 1);
+    if (status == -1)
+      fprintf(stderr, "Calling '%s' failed\n", s);
+    else if (status)
+      fprintf(stderr, "Calling '%s' returned status %d\n", s, status);
+    close(saved_stdout);
+  }
+}
+
+/*
+ *  make_string - Create a string via `malloc()`, place the variadic
+ *                arguments as formatted by `fmt` into it, and return
+ *                it.  Adapted from Linux man-pages' printf(3) example.
+ *                We never return a null pointer, instead treating
+ *                failure as invariably fatal.
+ */
+
+char *make_string(const char *fmt, ...)
+{
+  size_t size = 0;
+  char *p = 0 /* nullptr */;
+  va_list ap;
+  va_start(ap, fmt);
+  int n = vsnprintf(p, size, fmt, ap);
+  va_end(ap);
+  if (n < 0)
+    sys_fatal("vsnprintf");
+  size = static_cast<size_t>(n) + 1 /* '\0' */;
+  p = static_cast<char *>(malloc(size));
+  if (0 /* nullptr */ == p)
+    sys_fatal("vsnprintf");
+  va_start(ap, fmt);
+  n = vsnprintf(p, size, fmt, ap);
+  va_end(ap);
+  if (n < 0)
+    sys_fatal("vsnprintf");
+  assert(p != 0 /* nullptr */);
+  return p;
+}
+
+/*
+ *  classes and methods for retaining ascii text
+ */
+
+struct char_block {
+  enum { SIZE = 256 };
+  char buffer[SIZE];
+  int used;
+  char_block *next;
+
+  char_block();
+};
+
+char_block::char_block()
+: used(0), next(0)
+{
+  for (int i = 0; i < SIZE; i++)
+    buffer[i] = 0;
+}
+
+class char_buffer {
+public:
+  char_buffer();
+  ~char_buffer();
+  void read_file(FILE *fp);
+  int do_html(int argc, char *argv[]);
+  int do_image(int argc, char *argv[]);
+  void emit_troff_output(int device_format_selector);
+  void write_upto_newline(char_block **t, int *i, int is_html);
+  bool can_see(char_block **t, int *i, const char *string);
+  void skip_until_newline(char_block **t, int *i);
+private:
+  char_block *head;
+  char_block *tail;
+  int run_output_filter(int device_format_selector, int argc,
+			char *argv[]);
+};
+
+char_buffer::char_buffer()
+: head(0), tail(0)
+{
+}
+
+char_buffer::~char_buffer()
+{
+  while (head != 0 /* nullptr */) {
+    char_block *temp = head;
+    head = head->next;
+    delete temp;
+  }
+}
+
+/*
+ *  read_file - Read file `fp` into char_blocks.
+ */
+
+void char_buffer::read_file(FILE *fp)
+{
+  int n;
+  while (!feof(fp)) {
+    if (0 /* nullptr */ == tail) {
+      tail = new char_block;
+      head = tail;
+    }
+    else {
+      if (tail->used == char_block::SIZE) {
+	tail->next = new char_block;
+	tail = tail->next;
+      }
+    }
+    // We now have a tail ready for the next `SIZE` bytes of the file.
+    n = fread(tail->buffer, sizeof(char), char_block::SIZE-tail->used,
+	      fp);
+    if ((n < 0) || ((0 == n) && !feof(fp)))
+      sys_fatal("fread");
+    tail->used += n * sizeof(char);
+  }
+}
+
+/*
+ *  writeNbytes - Write n bytes to stdout.
+ */
+
+static void writeNbytes(const char *s, int l)
+{
+  int n = 0;
+  int r;
+
+  while (n < l) {
+    r = write(stdoutfd, s, l - n);
+    if (r < 0)
+      sys_fatal("write");
+    n += r;
+    s += r;
+  }
+}
+
+/*
+ *  writeString - Write a string to stdout.
+ */
+
+static void writeString(const char *s)
+{
+  writeNbytes(s, strlen(s));
+}
+
+/*
+ *  makeFileName - Create the image filename template
+ *                 and the macroset image template.
+ */
+
+static void makeFileName(void)
+{
+  if ((image_dir != 0 /* nullptr */)
+      && (strchr(image_dir, '%') != 0 /* nullptr */))
+    fatal("'%%' is prohibited within the image directory name");
+  if ((image_template != 0 /* nullptr */)
+      && (strchr(image_template, '%') != 0 /* nullptr */))
+    fatal("'%%' is prohibited within the image template");
+  if (0 /* nullptr */ == image_dir)
+    image_dir = (char *)"";
+  else if (strlen(image_dir) > 0
+	   && image_dir[strlen(image_dir) - 1] != '/')
+    image_dir = make_string("%s/", image_dir);
+  if (0 /* nullptr */ == image_template)
+    macroset_template = make_string("%sgrohtml-%d-", image_dir,
+				     int(getpid()));
+  else
+    macroset_template = make_string("%s%s-", image_dir,
+				     image_template);
+  size_t mtlen = strlen(macroset_template);
+  image_template = (char *)malloc(strlen("%d") + mtlen + 1);
+  if (0 /* nullptr */ == image_template)
+    sys_fatal("malloc");
+  char *s = strcpy(image_template, macroset_template);
+  s += mtlen;
+  // Keep this format string synced with troff:suppress_node::tprint().
+  strcpy(s, "%d");
+}
+
+/*
+ *  setupAntiAlias - Set up the antialias string, used when we call gs.
+ */
+
+static void setupAntiAlias(void)
+{
+  if (textAlphaBits == 0 && graphicAlphaBits == 0)
+    antiAlias = make_string(" ");
+  else if (textAlphaBits == 0)
+    antiAlias = make_string("-dGraphicsAlphaBits=%d ",
+			    graphicAlphaBits);
+  else if (graphicAlphaBits == 0)
+    antiAlias = make_string("-dTextAlphaBits=%d ", textAlphaBits);
+  else
+    antiAlias = make_string("-dTextAlphaBits=%d"
+			    " -dGraphicsAlphaBits=%d ", textAlphaBits,
+			    graphicAlphaBits);
+}
+
+/*
+ *  checkImageDir - Check whether the image directory is available.
+ */
+
+static void checkImageDir(void)
+{
+  if (image_dir != 0 /* nullptr */ && strcmp(image_dir, "") != 0)
+    if (!(mkdir(image_dir, 0777) == 0 || errno == EEXIST))
+      fatal("cannot create directory '%1': %2", image_dir,
+	    strerror(errno));
+}
+
+/*
+ *  write_end_image - End the image.  Write out the image extents if we
+ *                    are using -Tps.
+ */
+
+static void write_end_image(int is_html)
+{
+  /*
+   *  if we are producing html then these
+   *    emit image name and enable output
+   *  else
+   *    we are producing images
+   *    in which case these generate image
+   *    boundaries
+   */
+  writeString("\\O[4]\\O[2]");
+  if (is_html)
+    writeString("\\O[1]");
+  else
+    writeString("\\O[0]");
+}
+
+/*
+ *  write_start_image - Write troff code which will:
+ *
+ *                      (i)  disable html output for the following image
+ *                      (ii) reset the max/min x/y registers during
+ *                           Postscript Rendering.
+ */
+
+static void write_start_image(IMAGE_ALIGNMENT pos, int is_html)
+{
+  writeString("\\O[5");
+  switch (pos) {
+  case INLINE:
+    writeString("i");
+    break;
+  case LEFT:
+    writeString("l");
+    break;
+  case RIGHT:
+    writeString("r");
+    break;
+  case CENTERED:
+  default:
+    writeString("c");
+    break;
+  }
+  writeString(image_template);
+  writeString(".png]");
+  if (is_html)
+    writeString("\\O[0]\\O[3]");
+  else
+    // reset min/max registers
+    writeString("\\O[1]\\O[3]");
+}
+
+/*
+ *  write_upto_newline - Write the contents of the buffer until a
+ *                       newline is seen.  Check for
+ *                       HTML_IMAGE_INLINE_BEGIN and
+ *                       HTML_IMAGE_INLINE_END; process them if they are
+ *                       present.
+ */
+
+void char_buffer::write_upto_newline(char_block **t, int *i,
+				     int is_html)
+{
+  int j = *i;
+
+  if (*t) {
+    while (j < (*t)->used
+	   && (*t)->buffer[j] != '\n'
+	   && (*t)->buffer[j] != INLINE_LEADER_CHAR)
+      j++;
+    if (j < (*t)->used
+	&& (*t)->buffer[j] == '\n')
+      j++;
+    writeNbytes((*t)->buffer + (*i), j - (*i));
+    if (j < char_block::SIZE && (*t)->buffer[j] == INLINE_LEADER_CHAR) {
+      if (can_see(t, &j, HTML_IMAGE_INLINE_BEGIN))
+	write_start_image(INLINE, is_html);
+      else if (can_see(t, &j, HTML_IMAGE_INLINE_END))
+	write_end_image(is_html);
+      else {
+	if (j < (*t)->used) {
+	  *i = j;
+	  j++;
+	  writeNbytes((*t)->buffer + (*i), j - (*i));
+	}
+      }
+    }
+    if (j == (*t)->used) {
+      *i = 0;
+      *t = (*t)->next;
+      if (*t && (*t)->buffer[j - 1] != '\n')
+	write_upto_newline(t, i, is_html);
+    }
+    else
+      // newline was seen
+      *i = j;
+  }
+}
+
+/*
+ *  can_see - Return true if we can see string in t->buffer[i] onwards.
+ */
+
+bool char_buffer::can_see(char_block **t, int *i, const char *str)
+{
+  int j = 0;
+  int l = strlen(str);
+  int k = *i;
+  char_block *s = *t;
+
+  while (s) {
+    while (k < s->used && j < l && s->buffer[k] == str[j]) {
+      j++;
+      k++;
+    }
+    if (j == l) {
+      *i = k;
+      *t = s;
+      return true;
+    }
+    else if (k < s->used && s->buffer[k] != str[j])
+      return false;
+    s = s->next;
+    k = 0;
+  }
+  return false;
+}
+
+/*
+ *  skip_until_newline - Skip all characters until a newline is seen.
+ *                       The newline is not consumed.
+ */
+
+void char_buffer::skip_until_newline(char_block **t, int *i)
+{
+  int j = *i;
+
+  if (*t) {
+    while (j < (*t)->used && (*t)->buffer[j] != '\n')
+      j++;
+    if (j == (*t)->used) {
+      *i = 0;
+      *t = (*t)->next;
+      skip_until_newline(t, i);
+    }
+    else
+      // newline was seen
+      *i = j;
+  }
+}
+
+#define DEVICE_FORMAT(filter) (filter == HTML_OUTPUT_FILTER)
+#define HTML_OUTPUT_FILTER     0
+#define IMAGE_OUTPUT_FILTER    1
+#define OUTPUT_STREAM(name)   creat((name), S_IWUSR | S_IRUSR)
+#define PS_OUTPUT_STREAM      OUTPUT_STREAM(psFileName)
+#define REGION_OUTPUT_STREAM  OUTPUT_STREAM(regionFileName)
+
+/*
+ *  emit_troff_output - Write formatted buffer content to the troff
+ *                      post-processor data pipeline.
+ */
+
+void char_buffer::emit_troff_output(int device_format_selector)
+{
+  // Handle output for BOTH html and image device formats
+  // if 'device_format_selector' is passed as
+  //
+  //   HTML_FORMAT(HTML_OUTPUT_FILTER)
+  //     Buffer data is written to the output stream
+  //     with template image names translated to actual image names.
+  //
+  //   HTML_FORMAT(IMAGE_OUTPUT_FILTER)
+  //     Buffer data is written to the output stream
+  //     with no translation, for image file creation in the
+  //     post-processor.
+
+  int idx = 0;
+  char_block *element = head;
+
+  while (element != 0 /* nullptr */)
+    write_upto_newline(&element, &idx, device_format_selector);
+
+#if 0
+  if (close(stdoutfd) < 0)
+    sys_fatal ("close");
+
+  // now we grab fd=1 so that the next pipe cannot use fd=1
+  if (stdoutfd == 1) {
+    if (dup(2) != stdoutfd)
+      sys_fatal ("dup failed to use fd=1");
+  }
+#endif /* 0 */
+}
+
+/*
+ *  The image class remembers the position of all images in the
+ *  PostScript file and assigns names for each image.
+ */
+
+struct imageItem {
+  imageItem *next;
+  int X1;
+  int Y1;
+  int X2;
+  int Y2;
+  char *imageName;
+  int resolution;
+  int maxx;
+  int pageNo;
+
+  imageItem(int x1, int y1, int x2, int y2,
+	    int page, int res, int max_width, char *name);
+  ~imageItem();
+};
+
+/*
+ *  imageItem - Constructor.
+ */
+
+imageItem::imageItem(int x1, int y1, int x2, int y2,
+		     int page, int res, int max_width, char *name)
+{
+  X1 = x1;
+  Y1 = y1;
+  X2 = x2;
+  Y2 = y2;
+  pageNo = page;
+  resolution = res;
+  maxx = max_width;
+  imageName = name;
+  next = 0 /* nullptr */;
+}
+
+/*
+ *  imageItem - Destructor.
+ */
+
+imageItem::~imageItem()
+{
+  if (imageName)
+    free(imageName);
+}
+
+/*
+ *  imageList - A class containing a list of imageItems.
+ */
+
+class imageList {
+private:
+  imageItem *head;
+  imageItem *tail;
+  int count;
+public:
+  imageList();
+  ~imageList();
+  void add(int x1, int y1, int x2, int y2,
+	   int page, int res, int maxx, char *name);
+  void createImages(void);
+  int createPage(int pageno);
+  void createImage(imageItem *i);
+  int getMaxX(int pageno);
+};
+
+/*
+ *  imageList - Constructor.
+ */
+
+imageList::imageList()
+: head(0), tail(0), count(0)
+{
+}
+
+/*
+ *  imageList - Destructor.
+ */
+
+imageList::~imageList()
+{
+  while (head != 0 /* nullptr */) {
+    imageItem *i = head;
+    head = head->next;
+    delete i;
+  }
+}
+
+/*
+ *  createPage - Create image of page `pageno` from PostScript file.
+ */
+
+int imageList::createPage(int pageno)
+{
+  char *s;
+
+  if (currentPageNo == pageno)
+    return 0;
+
+  if (currentPageNo >= 1) {
+    /*
+     *  We need to unlink the files which change each time a new page is
+     *  processed.  The final unlink is done by xtmpfile when
+     *  pre-grohtml exits.
+     */
+    unlink(imagePageName);
+    unlink(psPageName);
+  }
+
+  if (want_progress_report) {
+    fprintf(stderr, "[%d] ", pageno);
+    fflush(stderr);
+  }
+
+#if defined(DEBUGGING)
+  if (debugging)
+    fprintf(stderr, "creating page %d\n", pageno);
+#endif
+
+  s = make_string("psselect -q -p%d %s %s\n",
+		   pageno, psFileName, psPageName);
+  html_system(s, 1);
+  assert(strlen(image_gen) > 0);
+  s = make_string("echo showpage | "
+		  "%s%s -q -dBATCH -dSAFER "
+		  "-dDEVICEHEIGHTPOINTS=792 "
+		  "-dDEVICEWIDTHPOINTS=%d -dFIXEDMEDIA=true "
+		  "-sDEVICE=%s -r%d %s "
+		  "-sOutputFile=%s %s -\n",
+		  image_gen,
+		  EXE_EXT,
+		  (getMaxX(pageno) * image_res) / postscriptRes,
+		  image_device,
+		  image_res,
+		  antiAlias,
+		  imagePageName,
+		  psPageName);
+  html_system(s, 1);
+  free(s);
+  currentPageNo = pageno;
+  return 0;
+}
+
+/*
+ *  min - Return the minimum of two numbers.
+ */
+
+int min(int x, int y)
+{
+  if (x < y)
+    return x;
+  else
+    return y;
+}
+
+/*
+ *  max - Return the maximum of two numbers.
+ */
+
+int max(int x, int y)
+{
+  if (x > y)
+    return x;
+  else
+    return y;
+}
+
+/*
+ *  getMaxX - Return the largest right-hand position for any image
+ *            on `pageno`.
+ */
+
+int imageList::getMaxX(int pageno)
+{
+  imageItem *h = head;
+  int x = postscriptRes * DEFAULT_LINE_LENGTH;
+
+  while (h != 0 /* nullptr */) {
+    if (h->pageNo == pageno)
+      x = max(h->X2, x);
+    h = h->next;
+  }
+  return x;
+}
+
+/*
+ *  createImage - Generate a minimal PNG file from the set of page
+ *                images.
+ */
+
+void imageList::createImage(imageItem *i)
+{
+  if (i->X1 != -1) {
+    char *s;
+    int x1 = max(min(i->X1, i->X2) * image_res / postscriptRes
+		   - IMAGE_BORDER_PIXELS,
+		 0);
+    int y1 = max(image_res * vertical_offset / 72
+		   + min(i->Y1, i->Y2) * image_res / postscriptRes
+		   - IMAGE_BORDER_PIXELS,
+		 0);
+    int x2 = max(i->X1, i->X2) * image_res / postscriptRes
+	     + IMAGE_BORDER_PIXELS;
+    int y2 = image_res * vertical_offset / 72
+	     + max(i->Y1, i->Y2) * image_res / postscriptRes
+	     + 1 + IMAGE_BORDER_PIXELS;
+    if (createPage(i->pageNo) == 0) {
+      s = make_string("pnmcut%s %d %d %d %d < %s "
+		      "| pnmcrop%s -quiet | pnmtopng%s -quiet %s"
+		      "> %s\n",
+		      EXE_EXT,
+		      x1, y1, x2 - x1 + 1, y2 - y1 + 1,
+		      imagePageName,
+		      EXE_EXT,
+		      EXE_EXT,
+		      TRANSPARENT,
+		      i->imageName);
+      html_system(s, 0);
+      free(s);
+    }
+    else {
+      fprintf(stderr, "failed to generate image of page %d\n",
+	      i->pageNo);
+      fflush(stderr);
+    }
+#if defined(DEBUGGING)
+  }
+  else {
+    if (debugging) {
+      fprintf(stderr, "ignoring image as x1 coord is -1\n");
+      fflush(stderr);
+    }
+#endif
+  }
+}
+
+/*
+ *  add - Add an image description to the imageList.
+ */
+
+void imageList::add(int x1, int y1, int x2, int y2,
+		    int page, int res, int maxx, char *name)
+{
+  imageItem *i = new imageItem(x1, y1, x2, y2, page, res, maxx, name);
+
+  if (0 /* nullptr */ == head) {
+    head = i;
+    tail = i;
+  }
+  else {
+    tail->next = i;
+    tail = i;
+  }
+}
+
+/*
+ *  createImages - For each image descriptor on the imageList,
+ *                 create the actual image.
+ */
+
+void imageList::createImages(void)
+{
+  imageItem *h = head;
+
+  while (h != 0 /* nullptr */) {
+    createImage(h);
+    h = h->next;
+  }
+}
+
+static imageList listOfImages;	// list of images defined by region file
+
+/*
+ *  generateImages - Parse the region file and generate images from the
+ *                   PostScript file.  The region file contains the
+ *                   x1,y1--x2,y2 extents of each image.
+ */
+
+static void generateImages(char *region_file_name)
+{
+  pushBackBuffer *f=new pushBackBuffer(region_file_name);
+
+  while (f->putPB(f->getPB()) != eof) {
+    if (f->isString("grohtml-info:page")) {
+      int page = f->readInt();
+      int x1 = f->readInt();
+      int y1 = f->readInt();
+      int x2 = f->readInt();
+      int y2 = f->readInt();
+      int maxx = f->readInt();
+      char *name = f->readString();
+      int res = postscriptRes;
+      listOfImages.add(x1, y1, x2, y2, page, res, maxx, name);
+      while (f->putPB(f->getPB()) != '\n'
+	     && f->putPB(f->getPB()) != eof)
+	(void)f->getPB();
+      if (f->putPB(f->getPB()) == '\n')
+	(void)f->getPB();
+    }
+    else {
+      /* Write any error messages out to the user. */
+      fputc(f->getPB(), stderr);
+    }
+  }
+  fflush(stderr);
+
+  listOfImages.createImages();
+  if (want_progress_report) {
+    fprintf(stderr, "done\n");
+    fflush(stderr);
+  }
+  delete f;
+}
+
+/*
+ *  set_redirection - Redirect file descriptor `was` to file descriptor
+ *                    `willbe`.
+ */
+
+static void set_redirection(int was, int willbe)
+{
+  // Nothing to do if 'was' and 'willbe' already have same handle.
+  if (was != willbe) {
+    // Otherwise attempt the specified redirection.
+    if (dup2(willbe, was) < 0) {
+      // Redirection failed, so issue diagnostic and bail out.
+      fprintf(stderr, "failed to replace fd=%d with %d\n", was, willbe);
+      if (willbe == STDOUT_FILENO)
+	fprintf(stderr,
+		"likely that stdout should be opened before %d\n", was);
+      sys_fatal("dup2");
+    }
+
+    // When redirection has been successfully completed assume redundant
+    // handle 'willbe' is no longer required, so close it.
+    if (close(willbe) < 0)
+      // Issue diagnostic if 'close' fails.
+      sys_fatal("close");
+  }
+}
+
+/*
+ *  save_and_redirect - Duplicate file descriptor for `was` on file
+ *                      descriptor `willbe`.
+ */
+
+static int save_and_redirect(int was, int willbe)
+{
+  if (was == willbe)
+    // No redirection specified; silently bail out.
+    return (was);
+
+  // Proceeding with redirection so first save and verify our duplicate
+  // handle for 'was'.
+  int saved = dup(was);
+  if (saved < 0) {
+    fprintf(stderr, "unable to get duplicate handle for %d\n", was);
+    sys_fatal("dup");
+  }
+
+  // Duplicate handle safely established so complete redirection.
+  set_redirection(was, willbe);
+
+  // Finally return the saved duplicate descriptor for the original
+  // 'was' descriptor.
+  return saved;
+}
+
+/*
+ *  alterDeviceTo - If toImage is set
+ *                     the argument list is altered to include
+ *                     IMAGE_DEVICE; we invoke groff rather than troff.
+ *                  Else
+ *                     set -Thtml and groff.
+ */
+
+static void alterDeviceTo(int argc, char *argv[], int toImage)
+{
+  int i = 0;
+
+  if (toImage) {
+    while (i < argc) {
+      if ((strcmp(argv[i], "-Thtml") == 0) ||
+	  (strcmp(argv[i], "-Txhtml") == 0))
+	argv[i] = (char *)IMAGE_DEVICE;
+      i++;
+    }
+    argv[troff_arg] = (char *)"groff";	/* rather than troff */
+  }
+  else {
+    while (i < argc) {
+      if (strcmp(argv[i], IMAGE_DEVICE) == 0) {
+	if (dialect == xhtml)
+	  argv[i] = (char *)"-Txhtml";
+	else
+	  argv[i] = (char *)"-Thtml";
+      }
+      i++;
+    }
+    argv[troff_arg] = (char *)"groff";	/* use groff -Z */
+  }
+}
+
+/*
+ *  addArg - Append newarg onto the command list for groff.
+ */
+
+char **addArg(int argc, char *argv[], char *newarg)
+{
+  char **new_argv = (char **)malloc((argc + 2) * sizeof(char *));
+  int i = 0;
+
+  if (0 /* nullptr */ == new_argv)
+    sys_fatal("malloc");
+
+  if (argc > 0) {
+    new_argv[i] = argv[i];
+    i++;
+  }
+  new_argv[i] = newarg;
+  while (i < argc) {
+    new_argv[i + 1] = argv[i];
+    i++;
+  }
+  argc++;
+  new_argv[argc] = 0 /* nullptr */;
+  return new_argv;
+}
+
+/*
+ *  addRegDef - Append a defined register or string onto the command
+ *              list for troff.
+ */
+
+char **addRegDef(int argc, char *argv[], const char *numReg)
+{
+  char **new_argv = (char **)malloc((argc + 2) * sizeof(char *));
+  int i = 0;
+
+  if (0 /* nullptr */ == new_argv)
+    sys_fatal("malloc");
+
+  while (i < argc) {
+    new_argv[i] = argv[i];
+    i++;
+  }
+  new_argv[argc] = strsave(numReg);
+  argc++;
+  new_argv[argc] = 0 /* nullptr */;
+  return new_argv;
+}
+
+/*
+ *  dump_args - Display the argument list.
+ */
+
+void dump_args(int argc, char *argv[])
+{
+  fprintf(stderr, "  %d arguments:", argc);
+  for (int i = 0; i < argc; i++)
+    fprintf(stderr, " %s", argv[i]);
+  fprintf(stderr, "\n");
+}
+
+/*
+ *  print_args - Print arguments as if issued on the command line.
+ */
+
+#if defined(DEBUGGING)
+
+void print_args(int argc, char *argv[])
+{
+  if (debugging) {
+    fprintf(stderr, "executing: ");
+    for (int i = 0; i < argc; i++)
+      fprintf(stderr, "%s ", argv[i]);
+    fprintf(stderr, "\n");
+  }
+}
+
+#else
+
+void print_args(int, char **)
+{
+}
+
+#endif
+
+int char_buffer::run_output_filter(int filter, int argc, char **argv)
+{
+  int pipedes[2];
+  PID_T child_pid;
+  int wstatus;
+
+  print_args(argc, argv);
+  if (pipe(pipedes) < 0)
+    sys_fatal("pipe");
+
+#if MAY_FORK_CHILD_PROCESS
+  // This is the Unix process model.  To invoke our post-processor,
+  // we must 'fork' the current process.
+
+  if ((child_pid = fork()) < 0)
+    sys_fatal("fork");
+
+  else if (child_pid == 0) {
+    // This is the child process.  We redirect its input file descriptor
+    // to read data emerging from our pipe.  There is no point in
+    // saving, since we won't be able to restore later!
+
+    set_redirection(STDIN_FILENO, pipedes[0]);
+
+    // The parent process will be writing this data; release the child's
+    // writeable handle on the pipe since we have no use for it.
+
+    if (close(pipedes[1]) < 0)
+      sys_fatal("close");
+
+    // The IMAGE_OUTPUT_FILTER needs special output redirection...
+
+    if (filter == IMAGE_OUTPUT_FILTER) {
+      // ...with BOTH 'stdout' AND 'stderr' diverted to files, the
+      // latter so that `generateImages()` can scrape "grohtml-info"
+      // from it.
+
+      set_redirection(STDOUT_FILENO, PS_OUTPUT_STREAM);
+      set_redirection(STDERR_FILENO, REGION_OUTPUT_STREAM);
+    }
+
+    // Now we are ready to launch the output filter.
+
+    execvp(argv[0], argv); // does not return unless it fails
+    fatal("cannot execute '%1': %2", argv[0], strerror(errno));
+  }
+
+  else {
+    // This is the parent process.  We write data to the filter pipeline
+    // where the child will read it.  We have no need to read from the
+    // input side ourselves, so close it.
+
+    if (close(pipedes[0]) < 0)
+      sys_fatal("close");
+
+    // Now redirect the standard output file descriptor to the inlet end
+    // of the pipe, and push the formatted data to the filter.
+
+    pipedes[1] = save_and_redirect(STDOUT_FILENO, pipedes[1]);
+    emit_troff_output(DEVICE_FORMAT(filter));
+
+    // After emitting all the data we close our connection to the inlet
+    // end of the pipe so the child process will detect end of data.
+
+    set_redirection(STDOUT_FILENO, pipedes[1]);
+
+    // Finally, we must wait for the child process to complete.
+
+    if (WAIT(&wstatus, child_pid, _WAIT_CHILD) != child_pid)
+      sys_fatal("wait");
+  }
+
+#elif MAY_SPAWN_ASYNCHRONOUS_CHILD
+
+  // We do not have `fork` (or we prefer not to use it), but
+  // asynchronous processes are allowed, passing data through pipes.
+  // This should be okay for most Win32 systems and is preferred to
+  // `fork` for starting child processes under Cygwin.
+
+  // Before we start the post-processor we bind its inherited standard
+  // input file descriptor to the readable end of our pipe, saving our
+  // own standard input file descriptor in `pipedes[0]`.
+
+  pipedes[0] = save_and_redirect(STDIN_FILENO, pipedes[0]);
+
+  // For the Win32 model,
+  // we need special provision for saving BOTH 'stdout' and 'stderr'.
+
+  int saved_stdout = dup(STDOUT_FILENO);
+  int saved_stderr = STDERR_FILENO;
+
+  // The IMAGE_OUTPUT_FILTER needs special output redirection...
+
+  if (filter == IMAGE_OUTPUT_FILTER) {
+    // with BOTH 'stdout' AND 'stderr' diverted to files while saving a
+    // duplicate handle for 'stderr'.
+
+    set_redirection(STDOUT_FILENO, PS_OUTPUT_STREAM);
+    saved_stderr = save_and_redirect(STDERR_FILENO,
+				     REGION_OUTPUT_STREAM);
+  }
+
+  // Use an asynchronous spawn request to start the post-processor.
+
+  if ((child_pid = spawnvp(_P_NOWAIT, argv[0], argv)) < 0) {
+    fatal("cannot spawn %1: %2", argv[0], strerror(errno));
+  }
+
+  // Once the post-processor has been started we revert our 'stdin'
+  // to its original saved source, which also closes the readable handle
+  // for the pipe.
+
+  set_redirection(STDIN_FILENO, pipedes[0]);
+
+  // if we redirected 'stderr', for use by the image post-processor,
+  // then we also need to reinstate its original assignment.
+
+  if (filter == IMAGE_OUTPUT_FILTER)
+    set_redirection(STDERR_FILENO, saved_stderr);
+
+  // Now we redirect the standard output to the inlet end of the pipe,
+  // and push out the appropriately formatted data to the filter.
+
+  set_redirection(STDOUT_FILENO, pipedes[1]);
+  emit_troff_output(DEVICE_FORMAT(filter));
+
+  // After emitting all the data we close our connection to the inlet
+  // end of the pipe so the child process will detect end of data.
+
+  set_redirection(STDOUT_FILENO, saved_stdout);
+
+  // And finally, we must wait for the child process to complete.
+
+  if (WAIT(&wstatus, child_pid, _WAIT_CHILD) != child_pid)
+    sys_fatal("wait");
+
+#else /* can't do asynchronous pipes! */
+
+  // TODO: code to support an MS-DOS style process model should go here
+  fatal("output filtering not supported on this platform");
+
+#endif /* MAY_FORK_CHILD_PROCESS or MAY_SPAWN_ASYNCHRONOUS_CHILD */
+
+  return wstatus;
+}
+
+/*
+ *  do_html - Set the troff number htmlflip and
+ *            write out the buffer to troff -Thtml.
+ */
+
+int char_buffer::do_html(int argc, char *argv[])
+{
+  string s;
+
+  alterDeviceTo(argc, argv, 0);
+  argv += troff_arg;		// skip all arguments up to groff
+  argc -= troff_arg;
+  argv = addArg(argc, argv, (char *)"-Z");
+  argc++;
+
+  s = (char *)"-dwww-image-template=";
+  s += macroset_template;	// Do not combine these statements,
+				// otherwise they will not work.
+  s += '\0';			// The trailing '\0' is ignored.
+  argv = addRegDef(argc, argv, s.contents());
+  argc++;
+
+  if (dialect == xhtml) {
+    argv = addRegDef(argc, argv, "-rxhtml=1");
+    argc++;
+    if (need_eqn) {
+      argv = addRegDef(argc, argv, "-e");
+      argc++;
+    }
+  }
+
+#if defined(DEBUGGING)
+# define HTML_DEBUG_STREAM  OUTPUT_STREAM(htmlFileName)
+  // slight security risk: only enabled if defined(DEBUGGING)
+  if (debugging) {
+    int saved_stdout = save_and_redirect(STDOUT_FILENO,
+					 HTML_DEBUG_STREAM);
+    emit_troff_output(DEVICE_FORMAT(HTML_OUTPUT_FILTER));
+    set_redirection(STDOUT_FILENO, saved_stdout);
+  }
+#endif
+
+  return run_output_filter(HTML_OUTPUT_FILTER, argc, argv);
+}
+
+/*
+ *  do_image - Write out the buffer to troff -Tps.
+ */
+
+int char_buffer::do_image(int argc, char *argv[])
+{
+  string s;
+
+  alterDeviceTo(argc, argv, 1);
+  argv += troff_arg;		// skip all arguments up to troff/groff
+  argc -= troff_arg;
+  argv = addRegDef(argc, argv, "-rps4html=1");
+  argc++;
+
+  s = "-dwww-image-template=";
+  s += macroset_template;
+  s += '\0';
+  argv = addRegDef(argc, argv, s.contents());
+  argc++;
+
+  // Override local settings and produce a letter-size PostScript page
+  // file.
+  argv = addRegDef(argc, argv, "-P-pletter");
+  argc++;
+
+  if (dialect == xhtml) {
+    if (need_eqn) {
+      argv = addRegDef(argc, argv, "-rxhtml=1");
+      argc++;
+    }
+    argv = addRegDef(argc, argv, "-e");
+    argc++;
+  }
+
+#if defined(DEBUGGING)
+# define IMAGE_DEBUG_STREAM  OUTPUT_STREAM(troffFileName)
+  // slight security risk: only enabled if defined(DEBUGGING)
+  if (debugging) {
+    int saved_stdout = save_and_redirect(STDOUT_FILENO,
+					 IMAGE_DEBUG_STREAM);
+    emit_troff_output(DEVICE_FORMAT(IMAGE_OUTPUT_FILTER));
+    set_redirection(STDOUT_FILENO, saved_stdout);
+  }
+#endif
+
+  return run_output_filter(IMAGE_OUTPUT_FILTER, argc, argv);
+}
+
+static char_buffer inputFile;
+
+/*
+ *  usage - Emit usage message.
+ */
+
+static void usage(FILE *stream)
+{
+  fprintf(stream,
+"usage: %s [-epV] [-a anti-aliasing-text-bits] [-D image-directory]"
+" [-F font-directory] [-g anti-aliasing-graphics-bits] [-i resolution]"
+" [-I image-stem] [-o image-vertical-offset] [-x html-dialect]"
+" troff-command troff-argument ...\n"
+"usage: %s {-v | --version}\n"
+"usage: %s --help\n",
+	 program_name, program_name, program_name);
+  if (stdout == stream) {
+    fputs(
+"\n"
+"Prepare a troff(1) document for HTML formatting.\n"
+"\n"
+"This program is not intended to be executed standalone; it is\n"
+"normally part of a groff pipeline.  If your need to run it manually\n"
+"(e.g., for debugging purposes), give the 'groff' program the\n"
+"command-line option '-V' to inspect the arguments with which\n",
+	  stream);
+    fprintf(stream,
+"'%s' is called.  See the grohtml(1) manual page.\n",
+	  program_name);
+    exit(EXIT_SUCCESS);
+  }
+}
+
+/*
+ *  scanArguments - Scan for all arguments including -P-i, -P-o, -P-D,
+ *                  and -P-I.  Return the argument index of the first
+ *                  non-option.
+ */
+
+static int scanArguments(int argc, char **argv)
+{
+  const char *cmdprefix = getenv("GROFF_COMMAND_PREFIX");
+  if (!cmdprefix)
+    cmdprefix = PROG_PREFIX;
+  size_t pfxlen = strlen(cmdprefix);
+  char *troff_name = new char[pfxlen + strlen("troff") + 1];
+  char *s = strcpy(troff_name, cmdprefix);
+  s += pfxlen;
+  strcpy(s, "troff");
+  int c, i;
+  static const struct option long_options[] = {
+    { "help", no_argument, 0, CHAR_MAX + 1 },
+    { "version", no_argument, 0, 'v' },
+    { 0 /* nullptr */, 0, 0, 0 }
+  };
+  while ((c = getopt_long(argc, argv,
+	  "+a:bCdD:eF:g:Ghi:I:j:lno:prs:S:vVx:y", long_options,
+	  0 /* nullptr */))
+	 != EOF)
+    switch(c) {
+    case 'a':
+      textAlphaBits = min(max(MIN_ALPHA_BITS, atoi(optarg)),
+			  MAX_ALPHA_BITS);
+      if (textAlphaBits == 3)
+	fatal("cannot use 3 bits of antialiasing information");
+      break;
+    case 'b':
+      // handled by post-grohtml (set background color to white)
+      break;
+    case 'C':
+      // handled by post-grohtml (don't write Creator HTML comment)
+      break;
+    case 'd':
+#if defined(DEBUGGING)
+      debugging = true;
+#endif
+      break;
+    case 'D':
+      image_dir = optarg;
+      break;
+    case 'e':
+      need_eqn = true;
+      break;
+    case 'F':
+      font_path.command_line_dir(optarg);
+      break;
+    case 'g':
+      graphicAlphaBits = min(max(MIN_ALPHA_BITS, atoi(optarg)),
+			     MAX_ALPHA_BITS);
+      if (graphicAlphaBits == 3)
+	fatal("cannot use 3 bits of antialiasing information");
+      break;
+    case 'G':
+      // handled by post-grohtml (don't write CreationDate HTML comment)
+      break;
+    case 'h':
+      // handled by post-grohtml (write headings with font size changes)
+      break;
+    case 'i':
+      image_res = atoi(optarg);
+      break;
+    case 'I':
+      image_template = optarg;
+      break;
+    case 'j':
+      // handled by post-grohtml (set job name for multiple file output)
+      break;
+    case 'l':
+      // handled by post-grohtml (no automatic section links)
+      break;
+    case 'n':
+      // handled by post-grohtml (generate simple heading anchors)
+      break;
+    case 'o':
+      vertical_offset = atoi(optarg);
+      break;
+    case 'p':
+      want_progress_report = true;
+      break;
+    case 'r':
+      // handled by post-grohtml (no header and footer lines)
+      break;
+    case 's':
+      // handled by post-grohtml (use font size n as the HTML base size)
+      break;
+    case 'S':
+      // handled by post-grohtml (set file split level)
+      break;
+    case 'v':
+      printf("GNU pre-grohtml (groff) version %s\n", Version_string);
+      exit(EXIT_SUCCESS);
+    case 'V':
+      // handled by post-grohtml (create validator button)
+      break;
+    case 'x':
+      // html dialect
+      if (strcmp(optarg, "x") == 0)
+	dialect = xhtml;
+      else if (strcmp(optarg, "4") == 0)
+	dialect = html4;
+      else
+	warning("unsupported HTML dialect: '%1'", optarg);
+      break;
+    case 'y':
+      // handled by post-grohtml (create groff signature)
+      break;
+    case CHAR_MAX + 1: // --help
+      usage(stdout);
+      break;
+    case '?':
+      usage(stderr);
+      exit(EXIT_FAILURE);
+      break;
+    default:
+      break;
+    }
+
+  i = optind;
+  while (i < argc) {
+    if (strcmp(argv[i], troff_name) == 0)
+      troff_arg = i;
+    else if (argv[i][0] != '-')
+      return i;
+    i++;
+  }
+  delete[] troff_name;
+
+  return argc;
+}
+
+/*
+ *  makeTempFiles - Name the temporary files.
+ */
+
+static void makeTempFiles(void)
+{
+#if defined(DEBUGGING)
+  psFileName = DEBUG_FILE("prehtml-ps");
+  regionFileName = DEBUG_FILE("prehtml-region");
+  imagePageName = DEBUG_FILE("prehtml-page");
+  psPageName = DEBUG_FILE("prehtml-psn");
+  troffFileName = DEBUG_FILE("prehtml-troff");
+  htmlFileName = DEBUG_FILE("prehtml-html");
+#else /* not DEBUGGING */
+  FILE *f;
+
+  // psPageName contains a single page of PostScript.
+  f = xtmpfile(&psPageName, PS_TEMPLATE_LONG, PS_TEMPLATE_SHORT, true);
+  if (0 /* nullptr */ == f)
+    sys_fatal("xtmpfile");
+  fclose(f);
+
+  // imagePageName contains a bitmap image of a single PostScript page.
+  f = xtmpfile(&imagePageName, PAGE_TEMPLATE_LONG, PAGE_TEMPLATE_SHORT,
+	       true);
+  if (0 /* nullptr */ == f)
+    sys_fatal("xtmpfile");
+  fclose(f);
+
+  // psFileName contains a PostScript file of the complete document.
+  f = xtmpfile(&psFileName, PS_TEMPLATE_LONG, PS_TEMPLATE_SHORT, true);
+  if (0 /* nullptr */ == f)
+    sys_fatal("xtmpfile");
+  fclose(f);
+
+  // regionFileName contains a list of the images and their boxed
+  // coordinates.
+  f = xtmpfile(&regionFileName,
+	       REGION_TEMPLATE_LONG, REGION_TEMPLATE_SHORT, true);
+  if (0 /* nullptr */ == f)
+    sys_fatal("xtmpfile");
+  fclose(f);
+#endif /* not DEBUGGING */
+}
+
+static bool do_file(const char *filename)
+{
+  FILE *fp;
+
+  current_filename = filename;
+  if (strcmp(filename, "-") == 0)
+    fp = stdin;
+  else {
+    fp = fopen(filename, "r");
+    if (0 /* nullptr*/ == fp) {
+      error("unable to open '%1': %2", filename, strerror(errno));
+      return false;
+    }
+  }
+  inputFile.read_file(fp);
+  if (fp != stdin)
+    if (fclose(fp) != 0)
+      sys_fatal("fclose");
+  current_filename = 0 /* nullptr */;
+  return true;
+}
+
+static void cleanup(void)
+{
+  free(const_cast<char *>(image_gen));
+}
+
+int main(int argc, char **argv)
+{
+#ifdef CAPTURE_MODE
+  fprintf(stderr, "%s: invoked with %d arguments ...\n", argv[0], argc);
+  for (int i = 0; i < argc; i++)
+    fprintf(stderr, "%2d: %s\n", i, argv[i]);
+  FILE *dump = fopen(DEBUG_FILE("pre-html-data"), "wb");
+  if (dump != 0 /* nullptr */) {
+    while((int ch = fgetc(stdin)) >= 0)
+      fputc(ch, dump);
+    fclose(dump);
+  }
+  exit(EXIT_FAILURE);
+#endif /* CAPTURE_MODE */
+  program_name = argv[0];
+  if (atexit(&cleanup) != 0)
+    sys_fatal("atexit");
+  int operand_index = scanArguments(argc, argv);
+  image_gen = strsave(get_image_generator());
+  if (0 == image_gen)
+    fatal("'image_generator' directive not found in file '%1'",
+	  devhtml_desc);
+  postscriptRes = get_resolution();
+  if (postscriptRes < 1) // TODO: what's a more sane minimum value?
+    fatal("'res' directive missing or invalid in file '%1'",
+	  devps_desc);
+  setupAntiAlias();
+  checkImageDir();
+  makeFileName();
+  bool have_file_operand = false;
+  while (operand_index < argc) {
+    if (argv[operand_index][0] != '-') {
+      if(!do_file(argv[operand_index]))
+	exit(EXIT_FAILURE);
+      have_file_operand = true;
+    }
+    operand_index++;
+  }
+
+  if (!have_file_operand)
+    do_file("-");
+  makeTempFiles();
+  int wstatus = inputFile.do_image(argc, argv);
+  if (wstatus == 0) {
+    generateImages(regionFileName);
+    wstatus = inputFile.do_html(argc, argv);
+  }
+  else
+    if (WEXITSTATUS(wstatus) != 0)
+      // XXX: This is a crappy suggestion.  See Savannah #62673.
+      fatal("'%1' exited with status %2; re-run with a different output"
+	    " driver to see diagnostic messages", argv[0],
+	    WEXITSTATUS(wstatus));
+  exit(EXIT_SUCCESS);
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/html/pre-html.h b/src/preproc/html/pre-html.h
new file mode 100644
index 0000000..f257854
--- /dev/null
+++ b/src/preproc/html/pre-html.h
@@ -0,0 +1,38 @@
+// -*- C++ -*-
+/* Copyright (C) 2000-2020 Free Software Foundation, Inc.
+ * Written by Gaius Mulley (gaius@glam.ac.uk).
+ *
+ * This file is part of groff.
+ *
+ * groff is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * groff is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with groff; see the file COPYING.  If not, write to the Free Software
+ * Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA. 
+ */
+
+/*
+ *  defines functions implemented within pre-html.cpp
+ */
+
+#if !defined(PREHTMLH)
+#  define PREHTMLH
+#  if defined(PREHTMLC)
+#     define EXTERN
+#  else
+#     define EXTERN extern
+#  endif
+
+
+extern void sys_fatal (const char *s);
+
+#undef EXTERN
+#endif
diff --git a/src/preproc/html/pushback.cpp b/src/preproc/html/pushback.cpp
new file mode 100644
index 0000000..100ac0b
--- /dev/null
+++ b/src/preproc/html/pushback.cpp
@@ -0,0 +1,336 @@
+/* Copyright (C) 2000-2020 Free Software Foundation, Inc.
+     Written by Gaius Mulley (gaius@glam.ac.uk).
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "lib.h"
+
+#include <signal.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <errno.h>
+#include "errarg.h"
+#include "error.h"
+#include "stringclass.h"
+#include "posix.h"
+#include "nonposix.h"
+
+#include <errno.h>
+#include <sys/types.h>
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#include "pushback.h"
+#include "pre-html.h"
+
+#if !defined(TRUE)
+#   define TRUE  (1==1)
+#endif
+
+#if !defined(FALSE)
+#   define FALSE (1==0)
+#endif
+
+#   define ERROR(X)   (void)(fprintf(stderr, "%s:%d error %s\n", __FILE__, __LINE__, X) && \
+                            (fflush(stderr)) && localexit(1))
+
+
+#define MAXPUSHBACKSTACK 4096                  /* maximum number of character that can be pushed back */
+
+
+/*
+ *  constructor for pushBackBuffer
+ */
+
+pushBackBuffer::pushBackBuffer (char *filename)
+{
+  charStack = (char *)malloc(MAXPUSHBACKSTACK);
+  if (charStack == 0) {
+    sys_fatal("malloc");
+  }
+  stackPtr = 0;   /* index to push back stack        */
+  verbose  = 0;
+  eofFound = FALSE;
+  lineNo   = 1;
+  if (strcmp(filename, "") != 0) {
+    stdIn = dup(0);
+    if (stdIn < 0) {
+      sys_fatal("dup stdin");
+    }
+    close(0);
+    if (open(filename, O_RDONLY) != 0) {
+      sys_fatal("when trying to open file");
+    } else {
+      fileName = filename;
+    }
+  }
+}
+
+pushBackBuffer::~pushBackBuffer ()
+{
+  if (charStack != 0) {
+    free(charStack);
+  }
+  close(0);
+  /* restore stdin in file descriptor 0 */
+  if (dup(stdIn) < 0) {
+    sys_fatal("restore stdin");
+  }
+  close(stdIn);
+}
+
+/*
+ *  localexit - wraps exit with a return code to aid the ERROR macro.
+ */
+
+int localexit (int i)
+{
+  exit(i);
+  return( 1 );
+}
+
+/*
+ *  getPB - returns a character, possibly a pushed back character.
+ */
+
+char pushBackBuffer::getPB (void)
+{
+  if (stackPtr>0) {
+    stackPtr--;
+    return( charStack[stackPtr] );
+  } else {
+    char ch;
+
+    if (read(0, &ch, 1) == 1) {
+      if (verbose) {
+	printf("%c", ch);
+      }
+      if (ch == '\n') {
+	lineNo++;
+      }
+      return( ch );
+    } else {
+      eofFound = TRUE;
+      return( eof );
+    }
+  }
+}
+
+/*
+ *  putPB - pushes a character onto the push back stack.
+ *          The same character is returned.
+ */
+
+char pushBackBuffer::putPB (char ch)
+{
+  if (stackPtr<MAXPUSHBACKSTACK) {
+    charStack[stackPtr] = ch ;
+    stackPtr++;
+  } else {
+    ERROR("max push back stack exceeded, increase MAXPUSHBACKSTACK constant");
+  }
+  return( ch );
+}
+
+/*
+ *  isWhite - returns TRUE if a white character is found. This character is NOT consumed.
+ */
+
+static int isWhite (char ch)
+{
+  return( (ch==' ') || (ch == '\t') || (ch == '\n') );
+}
+
+/*
+ *  skipToNewline - skips characters until a newline is seen.
+ */
+
+void pushBackBuffer::skipToNewline (void)
+{
+  while ((putPB(getPB()) != '\n') && (! eofFound)) {
+    getPB();
+  }
+}
+
+/*
+ *  skipUntilToken - skips until a token is seen
+ */
+
+void pushBackBuffer::skipUntilToken (void)
+{
+  char ch;
+
+  while ((isWhite(putPB(getPB())) || (putPB(getPB()) == '#')) && (! eofFound)) {
+    ch = getPB();
+    if (ch == '#') {
+      skipToNewline();
+    }
+  }
+}
+
+/*
+ *  isString - returns TRUE if the string, s, matches the pushed back string.
+ *             if TRUE is returned then this string is consumed, otherwise it is
+ *             left alone.
+ */
+
+int pushBackBuffer::isString (const char *s)
+{
+  int length=strlen(s);
+  int i=0;
+
+  while ((i<length) && (putPB(getPB())==s[i])) {
+    if (getPB() != s[i]) {
+      ERROR("assert failed");
+    }
+    i++;
+  }
+  if (i==length) {
+    return( TRUE );
+  } else {
+    i--;
+    while (i>=0) {
+      if (putPB(s[i]) != s[i]) {
+	ERROR("assert failed");
+      }
+      i--;
+    }
+  }
+  return( FALSE );
+}
+
+/*
+ *  isDigit - returns TRUE if the character, ch, is a digit.
+ */
+
+static int isDigit (char ch)
+{
+  return( ((ch>='0') && (ch<='9')) );
+}
+
+/*
+ *  isHexDigit - returns TRUE if the character, ch, is a hex digit.
+ */
+
+#if 0
+static int isHexDigit (char ch)
+{
+  return( (isDigit(ch)) || ((ch>='a') && (ch<='f')) );
+}
+#endif
+
+/*
+ *  readInt - returns an integer from the input stream.
+ */
+
+int pushBackBuffer::readInt (void)
+{
+  int  c =0;
+  int  i =0;
+  int  s =1;
+  char ch=getPB();
+
+  while (isWhite(ch)) {
+    ch=getPB();
+  }
+  // now read integer
+
+  if (ch == '-') {
+    s = -1;
+    ch = getPB();
+  }
+  while (isDigit(ch)) {
+    i *= 10;
+    if ((ch>='0') && (ch<='9')) {
+      i += (int)(ch-'0');
+    }
+    ch = getPB();
+    c++;
+  }
+  if (ch != putPB(ch)) {
+    ERROR("assert failed");
+  }
+  return( i*s );
+}
+
+/*
+ *  convertToFloat - converts integers, a and b into a.b
+ */
+
+static double convertToFloat (int a, int b)
+{
+  int c=10;
+  double f;
+
+  while (b>c) {
+    c *= 10;
+  }
+  f = ((double)a) + (((double)b)/((double)c));
+  return( f );
+}
+
+/*
+ *  readNumber - returns a float representing the word just read.
+ */
+
+double pushBackBuffer::readNumber (void)
+{
+  int i;
+  char ch;
+
+  i = readInt();
+  if ((ch = getPB()) == '.') {
+    return convertToFloat(i, readInt());
+  }
+  putPB(ch);
+  return (double)i;
+}
+
+/*
+ *  readString - reads a string terminated by white space
+ *               and returns a malloced area of memory containing
+ *               a copy of the characters.
+ */
+
+char *pushBackBuffer::readString (void)
+{
+  char  buffer[MAXPUSHBACKSTACK];
+  char *str = 0;
+  int   i=0;
+  char ch=getPB();
+
+  while (isWhite(ch)) {
+    ch=getPB();
+  }
+  while ((i < MAXPUSHBACKSTACK) && (! isWhite(ch)) && (! eofFound)) {
+    buffer[i] = ch;
+    i++;
+    ch = getPB();
+  }
+  if (i < MAXPUSHBACKSTACK) {
+    buffer[i] = (char)0;
+    str = (char *)malloc(strlen(buffer)+1);
+    strcpy(str, buffer);
+  }
+  return( str );
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/html/pushback.h b/src/preproc/html/pushback.h
new file mode 100644
index 0000000..263a6c5
--- /dev/null
+++ b/src/preproc/html/pushback.h
@@ -0,0 +1,52 @@
+// -*- C -*-
+/* Copyright (C) 2000-2020 Free Software Foundation, Inc.
+     Written by Gaius Mulley (gaius@glam.ac.uk).
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+
+#define eof              (char)-1
+
+
+/*
+ *  defines the class and methods implemented within pushback.cpp
+ */
+
+class pushBackBuffer
+{
+ private:
+  char       *charStack;
+  int         stackPtr;   /* index to push back stack        */
+  int         verbose;
+  int         eofFound;
+  char       *fileName;
+  int         lineNo;
+  int         stdIn;
+
+ public:
+         pushBackBuffer (char *);
+  ~      pushBackBuffer ();
+  char   getPB          (void);
+  char   putPB          (char ch);
+  void   skipUntilToken (void);
+  void   skipToNewline  (void);
+  double readNumber     (void);
+  int    readInt        (void);
+  char  *readString     (void);
+  int    isString       (const char *string);
+};
+
+
diff --git a/src/preproc/pic/TODO b/src/preproc/pic/TODO
new file mode 100644
index 0000000..53ca282
--- /dev/null
+++ b/src/preproc/pic/TODO
@@ -0,0 +1,35 @@
+In troff mode, dotted and dashed splines.
+
+Make DELIMITED have type lstr; this would allow us to give better
+error messages for problems within the body of for and if constructs.
+
+In troff mode without -x, fake \D't' with .ps commands.
+
+Perhaps an option to set command char.
+
+Add an output class for dumb line printers. It wouldn't be pretty but
+it would be better than nothing. Integrate it with texinfo.  Useful
+for groff -Tascii as well.
+
+Option to allow better positioning of arrowheads on arcs.
+
+Perhaps add PostScript output mode.
+
+Change the interface to the output class so that output devices have
+the opportunity to handle arrowheads themselves.
+
+Consider whether the line thickness should scale.
+
+Consider whether the test in a for loop should be fuzzy (as it
+apparently is in grap).
+
+Possibly change fillval so that zero is black.
+
+Provide a way of getting text blocks (positioned with '.in' rather
+than \h), into pic.  Should be possible to use block of diverted text
+in pic.  Possibly something similar to T{ and T} in tbl.
+
+Option to provide macro backtraces.
+
+Have a path that is searched by 'copy' statement.  Set by environment
+variable or command-line option.
diff --git a/src/preproc/pic/common.cpp b/src/preproc/pic/common.cpp
new file mode 100644
index 0000000..6a4a93e
--- /dev/null
+++ b/src/preproc/pic/common.cpp
@@ -0,0 +1,647 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "pic.h"
+#include "common.h"
+
+// output a dashed circle as a series of arcs
+
+void common_output::dashed_circle(const position &cent, double rad,
+				  const line_type &lt)
+{
+  assert(lt.type == line_type::dashed);
+  line_type slt = lt;
+  slt.type = line_type::solid;
+  double dash_angle = lt.dash_width/rad;
+  int ndashes;
+  double gap_angle;
+  if (dash_angle >= M_PI/4.0) {
+    if (dash_angle < M_PI/2.0) {
+      gap_angle = M_PI/2.0 - dash_angle;
+      ndashes = 4;
+    }
+    else if (dash_angle < M_PI) {
+      gap_angle = M_PI - dash_angle;
+      ndashes = 2;
+    }
+    else {
+      circle(cent, rad, slt, -1.0);
+      return;
+    }
+  }
+  else {
+    ndashes = 4*int(ceil(M_PI/(4.0*dash_angle)));
+    gap_angle = (M_PI*2.0)/ndashes - dash_angle;
+  }
+  for (int i = 0; i < ndashes; i++) {
+    double start_angle = i*(dash_angle+gap_angle) - dash_angle/2.0;
+    solid_arc(cent, rad, start_angle, start_angle + dash_angle, lt);
+  }
+}
+
+// output a dotted circle as a series of dots
+
+void common_output::dotted_circle(const position &cent, double rad,
+				  const line_type &lt)
+{
+  assert(lt.type == line_type::dotted);
+  double gap_angle = lt.dash_width/rad;
+  int ndots;
+  if (gap_angle >= M_PI/2.0) {
+    // always have at least 2 dots
+    gap_angle = M_PI;
+    ndots = 2;
+  }
+  else {
+    ndots = 4*int(M_PI/(2.0*gap_angle));
+    gap_angle = (M_PI*2.0)/ndots;
+  }
+  double ang = 0.0;
+  for (int i = 0; i < ndots; i++, ang += gap_angle)
+    dot(cent + position(cos(ang), sin(ang))*rad, lt);
+}
+
+// recursive function for dash drawing, used by dashed_ellipse
+
+void common_output::ellipse_arc(const position &cent,
+				const position &z0, const position &z1,
+				const distance &dim, const line_type &lt)
+{
+  assert(lt.type == line_type::solid);
+  assert(dim.x != 0 && dim.y != 0);
+  double eps = 0.0001;
+  position zml = (z0 + z1) / 2;
+  // apply affine transformation (from ellipse to circle) to compute angle
+  // of new position, then invert transformation to get exact position
+  double psi = atan2(zml.y / dim.y, zml.x / dim.x);
+  position zm = position(dim.x * cos(psi), dim.y * sin(psi));
+  // to approximate the ellipse arc with one or more circle arcs, we
+  // first compute the radius of curvature in zm
+  double a_2 = dim.x * dim.x;
+  double a_4 = a_2 * a_2;
+  double b_2 = dim.y * dim.y;
+  double b_4 = b_2 * b_2;
+  double e_2 = a_2 - b_2;
+  double temp = a_4 * zm.y * zm.y + b_4 * zm.x * zm.x;
+  double rho = sqrt(temp / a_4 / b_4 * temp / a_4 / b_4 * temp);
+  // compute center of curvature circle
+  position M = position(e_2 * zm.x / a_2 * zm.x / a_2 * zm.x,
+			-e_2 * zm.y / b_2 * zm.y / b_2 * zm.y);
+  // compute distance between circle and ellipse arc at start and end
+  double phi0 = atan2(z0.y - M.y, z0.x - M.x);
+  double phi1 = atan2(z1.y - M.y, z1.x - M.x);
+  position M0 = position(rho * cos(phi0), rho * sin(phi0)) + M;
+  position M1 = position(rho * cos(phi1), rho * sin(phi1)) + M;
+  double dist0 = hypot(z0 - M0) / sqrt(z0 * z0);
+  double dist1 = hypot(z1 - M1) / sqrt(z1 * z1);
+  if (dist0 < eps && dist1 < eps)
+    solid_arc(M + cent, rho, phi0, phi1, lt);
+  else {
+    ellipse_arc(cent, z0, zm, dim, lt);
+    ellipse_arc(cent, zm, z1, dim, lt);
+  }
+}
+
+// output a dashed ellipse as a series of arcs
+
+void common_output::dashed_ellipse(const position &cent, const distance &dim,
+				   const line_type &lt)
+{
+  assert(lt.type == line_type::dashed);
+  double dim_x = dim.x / 2;
+  double dim_y = dim.y / 2;
+  line_type slt = lt;
+  slt.type = line_type::solid;
+  double dw = lt.dash_width;
+  // we use an approximation to compute the ellipse length (found in:
+  // Bronstein, Semendjajew, Taschenbuch der Mathematik)
+  double lambda = (dim.x - dim.y) / (dim.x + dim.y);
+  double le = M_PI / 2 * (dim.x + dim.y)
+	      * ((64 - 3 * lambda * lambda * lambda * lambda )
+		 / (64 - 16 * lambda * lambda));
+  // for symmetry we make nmax a multiple of 8
+  int nmax = 8 * int(le / dw / 8 + 0.5);
+  if (nmax < 8) {
+    nmax = 8;
+    dw = le / 8;
+  }
+  int ndash = nmax / 2;
+  double gapwidth = (le - dw * ndash) / ndash;
+  double l = 0;
+  position z = position(dim_x, 0);
+  position zdot = z;
+  int j = 0;
+  int jmax = int(10 / lt.dash_width);
+  for (int i = 0; i <= nmax; i++) {
+    position zold = z;
+    position zpre = zdot;
+    double ld = (int(i / 2) + 0.5) * dw + int((i + 1) / 2) * gapwidth;
+    double lold = 0;
+    double dl = 1;
+    // find next position for fixed arc length
+    while (l < ld) {
+      j++;
+      lold = l;
+      zold = z;
+      double phi = j * 2 * M_PI / jmax;
+      z = position(dim_x * cos(phi), dim_y * sin(phi));
+      dl = hypot(z - zold);
+      l += dl;
+    }
+    // interpolate linearly between the last two points,
+    // using the length difference as the scaling factor
+    double delta = (ld - lold) / dl;
+    zdot = zold + (z - zold) * delta;
+    // compute angle of new position on the affine circle
+    // and use it to get the exact value on the ellipse
+    double psi = atan2(zdot.y / dim_y, zdot.x / dim_x);
+    zdot = position(dim_x * cos(psi), dim_y * sin(psi));
+    if ((i % 2 == 0) && (i > 1))
+      ellipse_arc(cent, zpre, zdot, dim / 2, slt);
+  }
+}
+
+// output a dotted ellipse as a series of dots
+
+void common_output::dotted_ellipse(const position &cent, const distance &dim,
+				   const line_type &lt)
+{
+  assert(lt.type == line_type::dotted);
+  double dim_x = dim.x / 2;
+  double dim_y = dim.y / 2;
+  line_type slt = lt;
+  slt.type = line_type::solid;
+  // we use an approximation to compute the ellipse length (found in:
+  // Bronstein, Semendjajew, Taschenbuch der Mathematik)
+  double lambda = (dim.x - dim.y) / (dim.x + dim.y);
+  double le = M_PI / 2 * (dim.x + dim.y)
+	      * ((64 - 3 * lambda * lambda * lambda * lambda )
+		 / (64 - 16 * lambda * lambda));
+  // for symmetry we make nmax a multiple of 4
+  int ndots = 4 * int(le / lt.dash_width / 4 + 0.5);
+  if (ndots < 4)
+    ndots = 4;
+  double l = 0;
+  position z = position(dim_x, 0);
+  int j = 0;
+  int jmax = int(10 / lt.dash_width);
+  for (int i = 1; i <= ndots; i++) {
+    position zold = z;
+    double lold = l;
+    double ld = i * le / ndots;
+    double dl = 1;
+    // find next position for fixed arc length
+    while (l < ld) {
+      j++;
+      lold = l;
+      zold = z;
+      double phi = j * 2 * M_PI / jmax;
+      z = position(dim_x * cos(phi), dim_y * sin(phi));
+      dl = hypot(z - zold);
+      l += dl;
+    }
+    // interpolate linearly between the last two points,
+    // using the length difference as the scaling factor
+    double delta = (ld - lold) / dl;
+    position zdot = zold + (z - zold) * delta;
+    // compute angle of new position on the affine circle
+    // and use it to get the exact value on the ellipse
+    double psi = atan2(zdot.y / dim_y, zdot.x / dim_x);
+    zdot = position(dim_x * cos(psi), dim_y * sin(psi));
+    dot(cent + zdot, slt);
+  }
+}
+
+// return non-zero iff we can compute a center
+
+int compute_arc_center(const position &start, const position &cent,
+		       const position &end, position *result)
+{
+  // This finds the point along the vector from start to cent that
+  // is equidistant between start and end.
+  distance c = cent - start;
+  distance e = end - start;
+  double n = c*e;
+  if (n == 0.0)
+    return 0;
+  *result = start + c*((e*e)/(2.0*n));
+  return 1;
+}
+
+// output a dashed arc as a series of arcs
+
+void common_output::dashed_arc(const position &start, const position &cent,
+			       const position &end, const line_type &lt)
+{
+  assert(lt.type == line_type::dashed);
+  position c;
+  if (!compute_arc_center(start, cent, end, &c)) {
+    line(start, &end, 1, lt);
+    return;
+  }
+  distance start_offset = start - c;
+  distance end_offset = end - c;
+  double start_angle = atan2(start_offset.y, start_offset.x);
+  double end_angle = atan2(end_offset.y, end_offset.x);
+  double rad = hypot(c - start);
+  double dash_angle = lt.dash_width/rad;
+  double total_angle = end_angle - start_angle;
+  while (total_angle < 0)
+    total_angle += M_PI + M_PI;
+  if (total_angle <= dash_angle*2.0) {
+    solid_arc(cent, rad, start_angle, end_angle, lt);
+    return;
+  }
+  int ndashes = int((total_angle - dash_angle)/(dash_angle*2.0) + .5);
+  double dash_and_gap_angle = (total_angle - dash_angle)/ndashes;
+  for (int i = 0; i <= ndashes; i++)
+    solid_arc(cent, rad, start_angle + i*dash_and_gap_angle,
+	      start_angle + i*dash_and_gap_angle + dash_angle, lt);
+}
+
+// output a dotted arc as a series of dots
+
+void common_output::dotted_arc(const position &start, const position &cent,
+			       const position &end, const line_type &lt)
+{
+  assert(lt.type == line_type::dotted);
+  position c;
+  if (!compute_arc_center(start, cent, end, &c)) {
+    line(start, &end, 1, lt);
+    return;
+  }
+  distance start_offset = start - c;
+  distance end_offset = end - c;
+  double start_angle = atan2(start_offset.y, start_offset.x);
+  double total_angle = atan2(end_offset.y, end_offset.x) - start_angle;
+  while (total_angle < 0)
+    total_angle += M_PI + M_PI;
+  double rad = hypot(c - start);
+  int ndots = int(total_angle/(lt.dash_width/rad) + .5);
+  if (ndots == 0)
+    dot(start, lt);
+  else {
+    for (int i = 0; i <= ndots; i++) {
+      double a = start_angle + (total_angle*i)/ndots;
+      dot(cent + position(cos(a), sin(a))*rad, lt);
+    }
+  }
+}
+
+void common_output::solid_arc(const position &cent, double rad,
+			      double start_angle, double end_angle,
+			      const line_type &lt)
+{
+  line_type slt = lt;
+  slt.type = line_type::solid;
+  arc(cent + position(cos(start_angle), sin(start_angle))*rad,
+      cent,
+      cent + position(cos(end_angle), sin(end_angle))*rad,
+      slt);
+}
+
+
+void common_output::rounded_box(const position &cent, const distance &dim,
+				double rad, const line_type &lt,
+			        double fill, char *color_fill)
+{
+  if (fill >= 0.0 || color_fill)
+    filled_rounded_box(cent, dim, rad, fill);
+  switch (lt.type) {
+  case line_type::invisible:
+    break;
+  case line_type::dashed:
+    dashed_rounded_box(cent, dim, rad, lt);
+    break;
+  case line_type::dotted:
+    dotted_rounded_box(cent, dim, rad, lt);
+    break;
+  case line_type::solid:
+    solid_rounded_box(cent, dim, rad, lt);
+    break;
+  default:
+    assert(0);
+  }
+}
+
+
+void common_output::dashed_rounded_box(const position &cent,
+				       const distance &dim, double rad,
+				       const line_type &lt)
+{
+  line_type slt = lt;
+  slt.type = line_type::solid;
+
+  double hor_length = dim.x + (M_PI/2.0 - 2.0)*rad;
+  int n_hor_dashes = int(hor_length/(lt.dash_width*2.0) + .5);
+  double hor_gap_width = (n_hor_dashes != 0
+			  ? hor_length/n_hor_dashes - lt.dash_width
+			  : 0.0);
+
+  double vert_length = dim.y + (M_PI/2.0 - 2.0)*rad;
+  int n_vert_dashes = int(vert_length/(lt.dash_width*2.0) + .5);
+  double vert_gap_width = (n_vert_dashes != 0
+			   ? vert_length/n_vert_dashes - lt.dash_width
+			   : 0.0);
+  // Note that each corner arc has to be split into two for dashing,
+  // because one part is dashed using vert_gap_width, and the other
+  // using hor_gap_width.
+  double offset = lt.dash_width/2.0;
+  dash_arc(cent + position(dim.x/2.0 - rad, -dim.y/2.0 + rad), rad,
+	   -M_PI/4.0, 0, slt, lt.dash_width, vert_gap_width, &offset);
+  dash_line(cent + position(dim.x/2.0, -dim.y/2.0 + rad),
+	    cent + position(dim.x/2.0, dim.y/2.0 - rad),
+	    slt, lt.dash_width, vert_gap_width, &offset);
+  dash_arc(cent + position(dim.x/2.0 - rad, dim.y/2.0 - rad), rad,
+	   0, M_PI/4.0, slt, lt.dash_width, vert_gap_width, &offset);
+
+  offset = lt.dash_width/2.0;
+  dash_arc(cent + position(dim.x/2.0 - rad, dim.y/2.0 - rad), rad,
+	   M_PI/4.0, M_PI/2, slt, lt.dash_width, hor_gap_width, &offset);
+  dash_line(cent + position(dim.x/2.0 - rad, dim.y/2.0),
+	    cent + position(-dim.x/2.0 + rad, dim.y/2.0),
+	    slt, lt.dash_width, hor_gap_width, &offset);
+  dash_arc(cent + position(-dim.x/2.0 + rad, dim.y/2.0 - rad), rad,
+	   M_PI/2, 3*M_PI/4.0, slt, lt.dash_width, hor_gap_width, &offset);
+
+  offset = lt.dash_width/2.0;
+  dash_arc(cent + position(-dim.x/2.0 + rad, dim.y/2.0 - rad), rad,
+	   3.0*M_PI/4.0, M_PI, slt, lt.dash_width, vert_gap_width, &offset);
+  dash_line(cent + position(-dim.x/2.0, dim.y/2.0 - rad),
+	    cent + position(-dim.x/2.0, -dim.y/2.0 + rad),
+	    slt, lt.dash_width, vert_gap_width, &offset);
+  dash_arc(cent + position(-dim.x/2.0 + rad, -dim.y/2.0 + rad), rad,
+	   M_PI, 5.0*M_PI/4.0, slt, lt.dash_width, vert_gap_width, &offset);
+
+  offset = lt.dash_width/2.0;
+  dash_arc(cent + position(-dim.x/2.0 + rad, -dim.y/2.0 + rad), rad,
+	   5*M_PI/4.0, 3*M_PI/2.0, slt, lt.dash_width, hor_gap_width, &offset);
+  dash_line(cent + position(-dim.x/2.0 + rad, -dim.y/2.0),
+	    cent + position(dim.x/2.0 - rad, -dim.y/2.0),
+	    slt, lt.dash_width, hor_gap_width, &offset);
+  dash_arc(cent + position(dim.x/2.0 - rad, -dim.y/2.0 + rad), rad,
+	   3*M_PI/2, 7*M_PI/4, slt, lt.dash_width, hor_gap_width, &offset);
+}
+
+// Used by dashed_rounded_box.
+
+void common_output::dash_arc(const position &cent, double rad,
+			     double start_angle, double end_angle,
+			     const line_type &lt,
+			     double dash_width, double gap_width,
+			     double *offsetp)
+{
+  double length = (end_angle - start_angle)*rad;
+  double pos = 0.0;
+  for (;;) {
+    if (*offsetp >= dash_width) {
+      double rem = dash_width + gap_width - *offsetp;
+      if (pos + rem > length) {
+	*offsetp += length - pos;
+	break;
+      }
+      else {
+	pos += rem;
+	*offsetp = 0.0;
+      }
+    }
+    else {
+      double rem = dash_width  - *offsetp;
+      if (pos + rem > length) {
+	solid_arc(cent, rad, start_angle + pos/rad, end_angle, lt);
+	*offsetp += length - pos;
+	break;
+      }
+      else {
+	solid_arc(cent, rad, start_angle + pos/rad,
+		  start_angle + (pos + rem)/rad, lt);
+	pos += rem;
+	*offsetp = dash_width;
+      }
+    }
+  }
+}
+
+// Used by dashed_rounded_box.
+
+void common_output::dash_line(const position &start, const position &end,
+			      const line_type &lt,
+			      double dash_width, double gap_width,
+			      double *offsetp)
+{
+  distance dist = end - start;
+  double length = hypot(dist);
+  if (length == 0.0)
+    return;
+  double pos = 0.0;
+  for (;;) {
+    if (*offsetp >= dash_width) {
+      double rem = dash_width + gap_width - *offsetp;
+      if (pos + rem > length) {
+	*offsetp += length - pos;
+	break;
+      }
+      else {
+	pos += rem;
+	*offsetp = 0.0;
+      }
+    }
+    else {
+      double rem = dash_width  - *offsetp;
+      if (pos + rem > length) {
+	line(start + dist*(pos/length), &end, 1, lt);
+	*offsetp += length - pos;
+	break;
+      }
+      else {
+	position p(start + dist*((pos + rem)/length));
+	line(start + dist*(pos/length), &p, 1, lt);
+	pos += rem;
+	*offsetp = dash_width;
+      }
+    }
+  }
+}
+
+void common_output::dotted_rounded_box(const position &cent,
+				       const distance &dim, double rad,
+				       const line_type &lt)
+{
+  line_type slt = lt;
+  slt.type = line_type::solid;
+
+  double hor_length = dim.x + (M_PI/2.0 - 2.0)*rad;
+  int n_hor_dots = int(hor_length/lt.dash_width + .5);
+  double hor_gap_width = (n_hor_dots != 0
+			  ? hor_length/n_hor_dots
+			  : lt.dash_width);
+
+  double vert_length = dim.y + (M_PI/2.0 - 2.0)*rad;
+  int n_vert_dots = int(vert_length/lt.dash_width + .5);
+  double vert_gap_width = (n_vert_dots != 0
+			   ? vert_length/n_vert_dots
+			   : lt.dash_width);
+  double epsilon = lt.dash_width/(rad*100.0);
+
+  double offset = 0.0;
+  dot_arc(cent + position(dim.x/2.0 - rad, -dim.y/2.0 + rad), rad,
+	   -M_PI/4.0, 0, slt, vert_gap_width, &offset);
+  dot_line(cent + position(dim.x/2.0, -dim.y/2.0 + rad),
+	    cent + position(dim.x/2.0, dim.y/2.0 - rad),
+	    slt, vert_gap_width, &offset);
+  dot_arc(cent + position(dim.x/2.0 - rad, dim.y/2.0 - rad), rad,
+	   0, M_PI/4.0 - epsilon, slt, vert_gap_width, &offset);
+
+  offset = 0.0;
+  dot_arc(cent + position(dim.x/2.0 - rad, dim.y/2.0 - rad), rad,
+	   M_PI/4.0, M_PI/2, slt, hor_gap_width, &offset);
+  dot_line(cent + position(dim.x/2.0 - rad, dim.y/2.0),
+	    cent + position(-dim.x/2.0 + rad, dim.y/2.0),
+	    slt, hor_gap_width, &offset);
+  dot_arc(cent + position(-dim.x/2.0 + rad, dim.y/2.0 - rad), rad,
+	   M_PI/2, 3*M_PI/4.0 - epsilon, slt, hor_gap_width, &offset);
+
+  offset = 0.0;
+  dot_arc(cent + position(-dim.x/2.0 + rad, dim.y/2.0 - rad), rad,
+	   3.0*M_PI/4.0, M_PI, slt, vert_gap_width, &offset);
+  dot_line(cent + position(-dim.x/2.0, dim.y/2.0 - rad),
+	    cent + position(-dim.x/2.0, -dim.y/2.0 + rad),
+	    slt, vert_gap_width, &offset);
+  dot_arc(cent + position(-dim.x/2.0 + rad, -dim.y/2.0 + rad), rad,
+	   M_PI, 5.0*M_PI/4.0 - epsilon, slt, vert_gap_width, &offset);
+
+  offset = 0.0;
+  dot_arc(cent + position(-dim.x/2.0 + rad, -dim.y/2.0 + rad), rad,
+	   5*M_PI/4.0, 3*M_PI/2.0, slt, hor_gap_width, &offset);
+  dot_line(cent + position(-dim.x/2.0 + rad, -dim.y/2.0),
+	    cent + position(dim.x/2.0 - rad, -dim.y/2.0),
+	    slt, hor_gap_width, &offset);
+  dot_arc(cent + position(dim.x/2.0 - rad, -dim.y/2.0 + rad), rad,
+	   3*M_PI/2, 7*M_PI/4 - epsilon, slt, hor_gap_width, &offset);
+}
+
+// Used by dotted_rounded_box.
+
+void common_output::dot_arc(const position &cent, double rad,
+			    double start_angle, double end_angle,
+			    const line_type &lt, double gap_width,
+			    double *offsetp)
+{
+  double length = (end_angle - start_angle)*rad;
+  double pos = 0.0;
+  for (;;) {
+    if (*offsetp == 0.0) {
+      double ang = start_angle + pos/rad;
+      dot(cent + position(cos(ang), sin(ang))*rad, lt);
+    }
+    double rem = gap_width - *offsetp;
+    if (pos + rem > length) {
+      *offsetp += length - pos;
+      break;
+    }
+    else {
+      pos += rem;
+      *offsetp = 0.0;
+    }
+  }
+}
+
+// Used by dotted_rounded_box.
+
+void common_output::dot_line(const position &start, const position &end,
+			     const line_type &lt, double gap_width,
+			     double *offsetp)
+{
+  distance dist = end - start;
+  double length = hypot(dist);
+  if (length == 0.0)
+    return;
+  double pos = 0.0;
+  for (;;) {
+    if (*offsetp == 0.0)
+      dot(start + dist*(pos/length), lt);
+    double rem = gap_width - *offsetp;
+    if (pos + rem > length) {
+      *offsetp += length - pos;
+      break;
+    }
+    else {
+      pos += rem;
+      *offsetp = 0.0;
+    }
+  }
+}
+
+void common_output::solid_rounded_box(const position &cent,
+				      const distance &dim, double rad,
+				      const line_type &lt)
+{
+  position tem = cent - dim/2.0;
+  arc(tem + position(0.0, rad),
+      tem + position(rad, rad),
+      tem + position(rad, 0.0),
+      lt);
+  tem = cent + position(-dim.x/2.0, dim.y/2.0);
+  arc(tem + position(rad, 0.0),
+      tem + position(rad, -rad),
+      tem + position(0.0, -rad),
+      lt);
+  tem = cent + dim/2.0;
+  arc(tem + position(0.0, -rad),
+      tem + position(-rad, -rad),
+      tem + position(-rad, 0.0),
+      lt);
+  tem = cent + position(dim.x/2.0, -dim.y/2.0);
+  arc(tem + position(-rad, 0.0),
+      tem + position(-rad, rad),
+      tem + position(0.0, rad),
+      lt);
+  position end;
+  end = cent + position(-dim.x/2.0, dim.y/2.0 - rad);
+  line(cent - dim/2.0 + position(0.0, rad), &end, 1, lt);
+  end = cent + position(dim.x/2.0 - rad, dim.y/2.0);
+  line(cent + position(-dim.x/2.0 + rad, dim.y/2.0), &end, 1, lt);
+  end = cent + position(dim.x/2.0, -dim.y/2.0 + rad);
+  line(cent + position(dim.x/2.0, dim.y/2.0 - rad), &end, 1, lt);
+  end = cent + position(-dim.x/2.0 + rad, -dim.y/2.0);
+  line(cent + position(dim.x/2.0 - rad, -dim.y/2.0), &end, 1, lt);
+}
+
+void common_output::filled_rounded_box(const position &cent,
+				       const distance &dim, double rad,
+				       double fill)
+{
+  line_type ilt;
+  ilt.type = line_type::invisible;
+  circle(cent + position(dim.x/2.0 - rad, dim.y/2.0 - rad), rad, ilt, fill);
+  circle(cent + position(-dim.x/2.0 + rad, dim.y/2.0 - rad), rad, ilt, fill);
+  circle(cent + position(-dim.x/2.0 + rad, -dim.y/2.0 + rad), rad, ilt, fill);
+  circle(cent + position(dim.x/2.0 - rad, -dim.y/2.0 + rad), rad, ilt, fill);
+  position vec[4];
+  vec[0] = cent + position(dim.x/2.0, dim.y/2.0 - rad);
+  vec[1] = cent + position(-dim.x/2.0, dim.y/2.0 - rad);
+  vec[2] = cent + position(-dim.x/2.0, -dim.y/2.0 + rad);
+  vec[3] = cent + position(dim.x/2.0, -dim.y/2.0 + rad);
+  polygon(vec, 4, ilt, fill);
+  vec[0] = cent + position(dim.x/2.0 - rad, dim.y/2.0);
+  vec[1] = cent + position(-dim.x/2.0 + rad, dim.y/2.0);
+  vec[2] = cent + position(-dim.x/2.0 + rad, -dim.y/2.0);
+  vec[3] = cent + position(dim.x/2.0 - rad, -dim.y/2.0);
+  polygon(vec, 4, ilt, fill);
+}
diff --git a/src/preproc/pic/common.h b/src/preproc/pic/common.h
new file mode 100644
index 0000000..a2d5f70
--- /dev/null
+++ b/src/preproc/pic/common.h
@@ -0,0 +1,79 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+class common_output : public output {
+private:
+  void dash_line(const position &start, const position &end,
+		 const line_type &lt, double dash_width, double gap_width,
+		 double *offsetp);
+  void dash_arc(const position &cent, double rad,
+		double start_angle, double end_angle, const line_type &lt,
+		double dash_width, double gap_width, double *offsetp);
+  void dot_line(const position &start, const position &end,
+		const line_type &lt, double gap_width, double *offsetp);
+  void dot_arc(const position &cent, double rad,
+	       double start_angle, double end_angle, const line_type &lt,
+	       double gap_width, double *offsetp);
+protected:
+  virtual void dot(const position &, const line_type &) = 0;
+  void ellipse_arc(const position &, const position &,
+		   const position &, const distance &,
+		   const line_type &);
+  void dashed_circle(const position &, double rad, const line_type &);
+  void dotted_circle(const position &, double rad, const line_type &);
+  void dashed_ellipse(const position &, const distance &, const line_type &);
+  void dotted_ellipse(const position &, const distance &, const line_type &);
+  void dashed_arc(const position &, const position &, const position &,
+		  const line_type &);
+  void dotted_arc(const position &, const position &, const position &,
+		  const line_type &);
+  virtual void solid_arc(const position &cent, double rad, double start_angle,
+			 double end_angle, const line_type &lt);
+  void dashed_rounded_box(const position &, const distance &, double,
+			  const line_type &);
+  void dotted_rounded_box(const position &, const distance &, double,
+			  const line_type &);
+  void solid_rounded_box(const position &, const distance &, double,
+			 const line_type &);
+  void filled_rounded_box(const position &, const distance &, double,
+			  double);
+public:
+  void start_picture(double sc, const position &ll, const position &ur) = 0;
+  void finish_picture() = 0;
+  void circle(const position &, double rad, const line_type &, double) = 0;
+  void text(const position &, text_piece *, int, double) = 0;
+  void line(const position &, const position *, int n, const line_type &) = 0;
+  void polygon(const position *, int n, const line_type &, double) = 0;
+  void spline(const position &, const position *, int n,
+	      const line_type &) = 0;
+  void arc(const position &, const position &, const position &,
+	   const line_type &) = 0;
+  void ellipse(const position &, const distance &,
+	       const line_type &, double) = 0;
+  void rounded_box(const position &, const distance &, double,
+		   const line_type &, double, char *);
+  void set_color(char *, char *) = 0;
+  void reset_color() = 0;
+  char *get_last_filled() = 0;
+  char *get_outline_color() = 0;
+};
+
+int compute_arc_center(const position &start, const position &cent,
+		       const position &end, position *result);
+
diff --git a/src/preproc/pic/lex.cpp b/src/preproc/pic/lex.cpp
new file mode 100644
index 0000000..e59801b
--- /dev/null
+++ b/src/preproc/pic/lex.cpp
@@ -0,0 +1,2039 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "pic.h"
+#include "ptable.h"
+#include "object.h"
+#include "pic.hpp"
+
+declare_ptable(char)
+implement_ptable(char)
+
+PTABLE(char) macro_table;
+
+// First character of the range representing $1-$<MAX_ARG>.
+// All of them must be invalid input characters.
+#ifndef IS_EBCDIC_HOST
+#define ARG1 0x80
+#define MAX_ARG 32
+#else
+#define ARG1 0x30
+#define MAX_ARG 16
+#endif
+
+class macro_input : public input {
+  char *s;
+  char *p;
+public:
+  macro_input(const char *);
+  ~macro_input();
+  int get();
+  int peek();
+};
+
+class argument_macro_input : public input {
+  char *s;
+  char *p;
+  char *ap;
+  int argc;
+  char *argv[MAX_ARG];
+public:
+  argument_macro_input(const char *, int, char **);
+  ~argument_macro_input();
+  int get();
+  int peek();
+};
+
+input::input() : next(0)
+{
+}
+
+input::~input()
+{
+}
+
+int input::get_location(const char **, int *)
+{
+  return 0;
+}
+
+file_input::file_input(FILE *f, const char *fn)
+: fp(f), filename(fn), lineno(0), ptr("")
+{
+}
+
+file_input::~file_input()
+{
+  fclose(fp);
+}
+
+int file_input::read_line()
+{
+  for (;;) {
+    line.clear();
+    lineno++;
+    for (;;) {
+      int c = getc(fp);
+      if (c == '\r') {
+	c = getc(fp);
+	if (c != '\n')
+	  lex_error("invalid input character code %1", '\r');
+      }
+      if (c == EOF)
+	break;
+      else if (is_invalid_input_char(c))
+	lex_error("invalid input character code %1", c);
+      else {
+	line += char(c);
+	if (c == '\n') 
+	  break;
+      }
+    }
+    if (line.length() == 0)
+      return 0;
+    if (!(line.length() >= 3 && line[0] == '.' && line[1] == 'P'
+	  && (line[2] == 'S' || line[2] == 'E' || line[2] == 'F')
+	  && (line.length() == 3 || line[3] == ' ' || line[3] == '\n'
+	      || compatible_flag))) {
+      line += '\0';
+      ptr = line.contents();
+      return 1;
+    }
+  }
+}
+
+int file_input::get()
+{
+  if (*ptr != '\0' || read_line())
+    return (unsigned char)*ptr++;
+  else
+    return EOF;
+}
+
+int file_input::peek()
+{
+  if (*ptr != '\0' || read_line())
+    return (unsigned char)*ptr;
+  else
+    return EOF;
+}
+
+int file_input::get_location(const char **fnp, int *lnp)
+{
+  *fnp = filename;
+  *lnp = lineno;
+  return 1;
+}
+
+macro_input::macro_input(const char *str)
+{
+  p = s = strsave(str);
+}
+
+macro_input::~macro_input()
+{
+  free(s);
+}
+
+int macro_input::get()
+{
+  if (p == 0 || *p == '\0')
+    return EOF;
+  else
+    return (unsigned char)*p++;
+}
+
+int macro_input::peek()
+{
+  if (p == 0 || *p == '\0')
+    return EOF;
+  else
+    return (unsigned char)*p;
+}
+
+char *process_body(const char *body)
+{
+  char *s = strsave(body);
+  int j = 0;
+  for (int i = 0; s[i] != '\0'; i++)
+    if (s[i] == '$' && csdigit(s[i + 1])) {
+      int n = 0;
+      int start = i;
+      i++;
+      while (csdigit(s[i]))
+	if (n > MAX_ARG)
+	  i++;
+	else
+	  n = 10 * n + s[i++] - '0';
+      if (n > MAX_ARG) {
+	string arg;
+	for (int k = start; k < i; k++)
+	  arg += s[k];
+	lex_error("invalid macro argument number %1", arg.contents());
+      }
+      else if (n > 0)
+	s[j++] = ARG1 + n - 1;
+      i--;
+    }
+    else
+      s[j++] = s[i];
+  s[j] = '\0';
+  return s;
+}
+
+argument_macro_input::argument_macro_input(const char *body, int ac, char **av)
+: ap(0), argc(ac)
+{
+  for (int i = 0; i < argc; i++)
+    argv[i] = av[i];
+  p = s = process_body(body);
+}
+
+argument_macro_input::~argument_macro_input()
+{
+  for (int i = 0; i < argc; i++)
+    free(argv[i]);
+  free(s);
+}
+
+int argument_macro_input::get()
+{
+  if (ap) {
+    if (*ap != '\0')
+      return (unsigned char)*ap++;
+    ap = 0;
+  }
+  if (p == 0)
+    return EOF;
+  while ((unsigned char)*p >= ARG1 
+	 && (unsigned char)*p <= ARG1 + MAX_ARG - 1) {
+    int i = (unsigned char)*p++ - ARG1;
+    if (i < argc && argv[i] != 0 && argv[i][0] != '\0') {
+      ap = argv[i];
+      return (unsigned char)*ap++;
+    }
+  }
+  if (*p == '\0')
+    return EOF;
+  return (unsigned char)*p++;
+}
+
+int argument_macro_input::peek()
+{
+  if (ap) {
+    if (*ap != '\0')
+      return (unsigned char)*ap;
+    ap = 0;
+  }
+  if (p == 0)
+    return EOF;
+  while ((unsigned char)*p >= ARG1
+	 && (unsigned char)*p <= ARG1 + MAX_ARG - 1) {
+    int i = (unsigned char)*p++ - ARG1;
+    if (i < argc && argv[i] != 0 && argv[i][0] != '\0') {
+      ap = argv[i];
+      return (unsigned char)*ap;
+    }
+  }
+  if (*p == '\0')
+    return EOF;
+  return (unsigned char)*p;
+}
+
+class input_stack {
+  static input *current_input;
+  static int bol_flag;
+public:
+  static void push(input *);
+  static void clear();
+  static int get_char();
+  static int peek_char();
+  static int get_location(const char **fnp, int *lnp);
+  static void push_back(unsigned char c, int was_bol = 0);
+  static int bol();
+};
+
+input *input_stack::current_input = 0;
+int input_stack::bol_flag = 0;
+
+inline int input_stack::bol()
+{
+  return bol_flag;
+}
+
+void input_stack::clear()
+{
+  while (current_input != 0) {
+    input *tem = current_input;
+    current_input = current_input->next;
+    delete tem;
+  }
+  bol_flag = 1;
+}
+
+void input_stack::push(input *in)
+{
+  in->next = current_input;
+  current_input = in;
+}
+
+void lex_init(input *top)
+{
+  input_stack::clear();
+  input_stack::push(top);
+}
+
+void lex_cleanup()
+{
+  while (input_stack::get_char() != EOF)
+    ;
+}
+
+int input_stack::get_char()
+{
+  while (current_input != 0) {
+    int c = current_input->get();
+    if (c != EOF) {
+      bol_flag = c == '\n';
+      return c;
+    }
+    // don't pop the top-level input off the stack
+    if (current_input->next == 0)
+      return EOF;
+    input *tem = current_input;
+    current_input = current_input->next;
+    delete tem;
+  }
+  return EOF;
+}
+
+int input_stack::peek_char()
+{
+  while (current_input != 0) {
+    int c = current_input->peek();
+    if (c != EOF)
+      return c;
+    if (current_input->next == 0)
+      return EOF;
+    input *tem = current_input;
+    current_input = current_input->next;
+    delete tem;
+  }
+  return EOF;
+}
+
+class char_input : public input {
+  int c;
+public:
+  char_input(int);
+  int get();
+  int peek();
+};
+
+char_input::char_input(int n) : c((unsigned char)n)
+{
+}
+
+int char_input::get()
+{
+  int n = c;
+  c = EOF;
+  return n;
+}
+
+int char_input::peek()
+{
+  return c;
+}
+
+void input_stack::push_back(unsigned char c, int was_bol)
+{
+  push(new char_input(c));
+  bol_flag = was_bol;
+}
+
+int input_stack::get_location(const char **fnp, int *lnp)
+{
+  for (input *p = current_input; p; p = p->next)
+    if (p->get_location(fnp, lnp))
+      return 1;
+  return 0;
+}
+
+string context_buffer;
+
+string token_buffer;
+double token_double;
+int token_int;
+
+void interpolate_macro_with_args(const char *body)
+{
+  char *argv[MAX_ARG];
+  int argc = 0;
+  int ignore = 0;
+  int i;
+  for (i = 0; i < MAX_ARG; i++)
+    argv[i] = 0;
+  int level = 0;
+  int c;
+  enum { NORMAL, IN_STRING, IN_STRING_QUOTED } state = NORMAL;
+  do {
+    token_buffer.clear();
+    for (;;) {
+      c = input_stack::get_char();
+      if (c == EOF) {
+	lex_error("end of input while scanning macro arguments");
+	break;
+      }
+      if (state == NORMAL && level == 0 && (c == ',' || c == ')')) {
+	if (token_buffer.length() > 0) {
+	  token_buffer +=  '\0';
+	  if (!ignore) {
+	    if (argc == MAX_ARG) {
+	      lex_warning("only %1 macro arguments supported", MAX_ARG);
+	      ignore = 1;
+	    }
+	    else
+	      argv[argc] = strsave(token_buffer.contents());
+	  }
+	}
+	// for 'foo()', argc = 0
+	if (argc > 0 || c != ')' || i > 0)
+	  if (!ignore)
+	    argc++;
+	break;
+      }
+      token_buffer += char(c);
+      switch (state) {
+      case NORMAL:
+	if (c == '"')
+	  state = IN_STRING;
+	else if (c == '(')
+	  level++;
+	else if (c == ')')
+	  level--;
+	break;
+      case IN_STRING:
+	if (c == '"')
+	  state = NORMAL;
+	else if (c == '\\')
+	  state = IN_STRING_QUOTED;
+	break;
+      case IN_STRING_QUOTED:
+	state = IN_STRING;
+	break;
+      }
+    }
+  } while (c != ')' && c != EOF);
+  input_stack::push(new argument_macro_input(body, argc, argv));
+}
+
+static int docmp(const char *s1, int n1, const char *s2, int n2)
+{
+  if (n1 < n2) {
+    int r = memcmp(s1, s2, n1);
+    return r ? r : -1;
+  }
+  else if (n1 > n2) {
+    int r = memcmp(s1, s2, n2);
+    return r ? r : 1;
+  }
+  else
+    return memcmp(s1, s2, n1);
+}
+
+int lookup_keyword(const char *str, int len)
+{
+  static struct keyword {
+    const char *name;
+    int token;
+  } table[] = {
+    { "Here", HERE },
+    { "above", ABOVE },
+    { "aligned", ALIGNED },
+    { "and", AND },
+    { "arc", ARC },
+    { "arrow", ARROW },
+    { "at", AT },
+    { "atan2", ATAN2 },
+    { "below", BELOW },
+    { "between", BETWEEN },
+    { "bottom", BOTTOM },
+    { "box", BOX },
+    { "by", BY },
+    { "ccw", CCW },
+    { "center", CENTER },
+    { "chop", CHOP },
+    { "circle", CIRCLE },
+    { "color", COLORED },
+    { "colored", COLORED },
+    { "colour", COLORED },
+    { "coloured", COLORED },
+    { "command", COMMAND },
+    { "copy", COPY },
+    { "cos", COS },
+    { "cw", CW },
+    { "dashed", DASHED },
+    { "define", DEFINE },
+    { "diam", DIAMETER },
+    { "diameter", DIAMETER },
+    { "do", DO },
+    { "dotted", DOTTED },
+    { "down", DOWN },
+    { "east", EAST },
+    { "ellipse", ELLIPSE },
+    { "else", ELSE },
+    { "end", END },
+    { "exp", EXP },
+    { "figname", FIGNAME },
+    { "fill", FILL },
+    { "filled", FILL },
+    { "for", FOR },
+    { "from", FROM },
+    { "height", HEIGHT },
+    { "ht", HEIGHT },
+    { "if", IF },
+    { "int", INT },
+    { "invis", INVISIBLE },
+    { "invisible", INVISIBLE },
+    { "last", LAST },
+    { "left", LEFT },
+    { "line", LINE },
+    { "ljust", LJUST },
+    { "log", LOG },
+    { "lower", LOWER },
+    { "max", K_MAX },
+    { "min", K_MIN },
+    { "move", MOVE },
+    { "north", NORTH },
+    { "of", OF },
+    { "outline", OUTLINED },
+    { "outlined", OUTLINED },
+    { "plot", PLOT },
+    { "print", PRINT },
+    { "rad", RADIUS },
+    { "radius", RADIUS },
+    { "rand", RAND },
+    { "reset", RESET },
+    { "right", RIGHT },
+    { "rjust", RJUST },
+    { "same", SAME },
+    { "sh", SH },
+    { "shaded", SHADED },
+    { "sin", SIN },
+    { "solid", SOLID },
+    { "south", SOUTH },
+    { "spline", SPLINE },
+    { "sprintf", SPRINTF },
+    { "sqrt", SQRT },
+    { "srand", SRAND },
+    { "start", START },
+    { "the", THE },
+    { "then", THEN },
+    { "thick", THICKNESS },
+    { "thickness", THICKNESS },
+    { "thru", THRU },
+    { "to", TO },
+    { "top", TOP },
+    { "undef", UNDEF },
+    { "until", UNTIL },
+    { "up", UP },
+    { "upper", UPPER },
+    { "way", WAY },
+    { "west", WEST },
+    { "wid", WIDTH },
+    { "width", WIDTH },
+    { "with", WITH },
+    { "xslanted", XSLANTED },
+    { "yslanted", YSLANTED },
+  };
+  
+  const keyword *start = table;
+  const keyword *end = table + sizeof(table)/sizeof(table[0]);
+  while (start < end) {
+    // start <= target < end
+    const keyword *mid = start + (end - start)/2;
+    
+    int cmp = docmp(str, len, mid->name, strlen(mid->name));
+    if (cmp == 0)
+      return mid->token;
+    if (cmp < 0)
+      end = mid;
+    else
+      start = mid + 1;
+  }
+  return 0;
+}
+
+int get_token_after_dot(int c)
+{
+  // get_token deals with the case where c is a digit
+  switch (c) {
+  case 'h':
+    input_stack::get_char();
+    c = input_stack::peek_char();
+    if (c == 't') {
+      input_stack::get_char();
+      context_buffer = ".ht";
+      return DOT_HT;
+    }
+    else if (c == 'e') {
+      input_stack::get_char();
+      c = input_stack::peek_char();
+      if (c == 'i') {
+	input_stack::get_char();
+	c = input_stack::peek_char();
+	if (c == 'g') {
+	  input_stack::get_char();
+	  c = input_stack::peek_char();
+	  if (c == 'h') {
+	    input_stack::get_char();
+	    c = input_stack::peek_char();
+	    if (c == 't') {
+	      input_stack::get_char();
+	      context_buffer = ".height";
+	      return DOT_HT;
+	    }
+	    input_stack::push_back('h');
+	  }
+	  input_stack::push_back('g');
+	}
+	input_stack::push_back('i');
+      }
+      input_stack::push_back('e');
+    }
+    input_stack::push_back('h');
+    return '.';
+  case 'x':
+    input_stack::get_char();
+    context_buffer = ".x";
+    return DOT_X;
+  case 'y':
+    input_stack::get_char();
+    context_buffer = ".y";
+    return DOT_Y;
+  case 'c':
+    input_stack::get_char();
+    c = input_stack::peek_char();
+    if (c == 'e') {
+      input_stack::get_char();
+      c = input_stack::peek_char();
+      if (c == 'n') {
+	input_stack::get_char();
+	c = input_stack::peek_char();
+	if (c == 't') {
+	  input_stack::get_char();
+	  c = input_stack::peek_char();
+	  if (c == 'e') {
+	    input_stack::get_char();
+	    c = input_stack::peek_char();
+	    if (c == 'r') {
+	      input_stack::get_char();
+	      context_buffer = ".center";
+	      return DOT_C;
+	    }
+	    input_stack::push_back('e');
+	  }
+	  input_stack::push_back('t');
+	}
+	input_stack::push_back('n');
+      }
+      input_stack::push_back('e');
+    }
+    context_buffer = ".c";
+    return DOT_C;
+  case 'n':
+    input_stack::get_char();
+    c = input_stack::peek_char();
+    if (c == 'e') {
+      input_stack::get_char();
+      context_buffer = ".ne";
+      return DOT_NE;
+    }
+    else if (c == 'w') {
+      input_stack::get_char();
+      context_buffer = ".nw";
+      return DOT_NW;
+    }
+    else {
+      context_buffer = ".n";
+      return DOT_N;
+    }
+    break;
+  case 'e':
+    input_stack::get_char();
+    c = input_stack::peek_char();
+    if (c == 'n') {
+      input_stack::get_char();
+      c = input_stack::peek_char();
+      if (c == 'd') {
+	input_stack::get_char();
+	context_buffer = ".end";
+	return DOT_END;
+      }
+      input_stack::push_back('n');
+      context_buffer = ".e";
+      return DOT_E;
+    }
+    context_buffer = ".e";
+    return DOT_E;
+  case 'w':
+    input_stack::get_char();
+    c = input_stack::peek_char();
+    if (c == 'i') {
+      input_stack::get_char();
+      c = input_stack::peek_char();
+      if (c == 'd') {
+	input_stack::get_char();
+	c = input_stack::peek_char();
+	if (c == 't') {
+	  input_stack::get_char();
+	  c = input_stack::peek_char();
+	  if (c == 'h') {
+	    input_stack::get_char();
+	    context_buffer = ".width";
+	    return DOT_WID;
+	  }
+	  input_stack::push_back('t');
+	}
+	context_buffer = ".wid";
+	return DOT_WID;
+      }
+      input_stack::push_back('i');
+    }
+    context_buffer = ".w";
+    return DOT_W;
+  case 's':
+    input_stack::get_char();
+    c = input_stack::peek_char();
+    if (c == 'e') {
+      input_stack::get_char();
+      context_buffer = ".se";
+      return DOT_SE;
+    }
+    else if (c == 'w') {
+      input_stack::get_char();
+      context_buffer = ".sw";
+      return DOT_SW;
+    }
+    else {
+      if (c == 't') {
+	input_stack::get_char();
+	c = input_stack::peek_char();
+	if (c == 'a') {
+	  input_stack::get_char();
+	  c = input_stack::peek_char();
+	  if (c == 'r') {
+	    input_stack::get_char();
+	    c = input_stack::peek_char();
+	    if (c == 't') {
+	      input_stack::get_char();
+	      context_buffer = ".start";
+	      return DOT_START;
+	    }
+	    input_stack::push_back('r');
+	  }
+	  input_stack::push_back('a');
+	}
+	input_stack::push_back('t');
+      }
+      context_buffer = ".s";
+      return DOT_S;
+    }
+    break;
+  case 't':
+    input_stack::get_char();
+    c = input_stack::peek_char();
+    if (c == 'o') {
+      input_stack::get_char();
+      c = input_stack::peek_char();
+      if (c == 'p') {
+	input_stack::get_char();
+	context_buffer = ".top";
+	return DOT_N;
+      }
+      input_stack::push_back('o');
+    }
+    context_buffer = ".t";
+    return DOT_N;
+  case 'l':
+    input_stack::get_char();
+    c = input_stack::peek_char();
+    if (c == 'e') {
+      input_stack::get_char();
+      c = input_stack::peek_char();
+      if (c == 'f') {
+	input_stack::get_char();
+	c = input_stack::peek_char();
+	if (c == 't') {
+	  input_stack::get_char();
+	  context_buffer = ".left";
+	  return DOT_W;
+	}
+	input_stack::push_back('f');
+      }
+      input_stack::push_back('e');
+    }
+    context_buffer = ".l";
+    return DOT_W;
+  case 'r':
+    input_stack::get_char();
+    c = input_stack::peek_char();
+    if (c == 'a') {
+      input_stack::get_char();
+      c = input_stack::peek_char();
+      if (c == 'd') {
+	input_stack::get_char();
+	context_buffer = ".rad";
+	return DOT_RAD;
+      }
+      input_stack::push_back('a');
+    }
+    else if (c == 'i') {
+      input_stack::get_char();
+      c = input_stack::peek_char();
+      if (c == 'g') {
+	input_stack::get_char();
+	c = input_stack::peek_char();
+	if (c == 'h') {
+	  input_stack::get_char();
+	  c = input_stack::peek_char();
+	  if (c == 't') {
+	    input_stack::get_char();
+	    context_buffer = ".right";
+	    return DOT_E;
+	  }
+	  input_stack::push_back('h');
+	}
+	input_stack::push_back('g');
+      }
+      input_stack::push_back('i');
+    }
+    context_buffer = ".r";
+    return DOT_E;
+  case 'b':
+    input_stack::get_char();
+    c = input_stack::peek_char();
+    if (c == 'o') {
+      input_stack::get_char();
+      c = input_stack::peek_char();
+      if (c == 't') {
+	input_stack::get_char();
+	c = input_stack::peek_char();
+	if (c == 't') {
+	  input_stack::get_char();
+	  c = input_stack::peek_char();
+	  if (c == 'o') {
+	    input_stack::get_char();
+	    c = input_stack::peek_char();
+	    if (c == 'm') {
+	      input_stack::get_char();
+	      context_buffer = ".bottom";
+	      return DOT_S;
+	    }
+	    input_stack::push_back('o');
+	  }
+	  input_stack::push_back('t');
+	}
+	context_buffer = ".bot";
+	return DOT_S;
+      }
+      input_stack::push_back('o');
+    }
+    context_buffer = ".b";
+    return DOT_S;
+  default:
+    context_buffer = '.';
+    return '.';
+  }
+}
+
+int get_token(int lookup_flag)
+{
+  context_buffer.clear();
+  for (;;) {
+    int n = 0;
+    int bol = input_stack::bol();
+    int c = input_stack::get_char();
+    if (bol && c == command_char) {
+      token_buffer.clear();
+      token_buffer += c;
+      // the newline is not part of the token
+      for (;;) {
+	c = input_stack::peek_char();
+	if (c == EOF || c == '\n')
+	  break;
+	input_stack::get_char();
+	token_buffer += char(c);
+      }
+      context_buffer = token_buffer;
+      return COMMAND_LINE;
+    }
+    switch (c) {
+    case EOF:
+      return EOF;
+    case ' ':
+    case '\t':
+      break;
+    case '\\':
+      {
+	int d = input_stack::peek_char();
+	if (d != '\n') {
+	  context_buffer = '\\';
+	  return '\\';
+	}
+	input_stack::get_char();
+	break;
+      }
+    case '#':
+      do {
+	c = input_stack::get_char();
+      } while (c != '\n' && c != EOF);
+      if (c == '\n')
+	context_buffer = '\n';
+      return c;
+    case '"':
+      context_buffer = '"';
+      token_buffer.clear();
+      for (;;) {
+	c = input_stack::get_char();
+	if (c == '\\') {
+	  context_buffer += '\\';
+	  c = input_stack::peek_char();
+	  if (c == '"') {
+	    input_stack::get_char();
+	    token_buffer += '"';
+	    context_buffer += '"';
+	  }
+	  else
+	    token_buffer += '\\';
+	}
+	else if (c == '\n') {
+	  error("newline in string");
+	  break;
+	}
+	else if (c == EOF) {
+	  error("missing '\"'");
+	  break;
+	}
+	else if (c == '"') {
+	  context_buffer += '"';
+	  break;
+	}
+	else {
+	  context_buffer += char(c);
+	  token_buffer += char(c);
+	}
+      }
+      return TEXT;
+    case '0':
+    case '1':
+    case '2':
+    case '3':
+    case '4':
+    case '5':
+    case '6':
+    case '7':
+    case '8':
+    case '9':
+      {   
+	int overflow = 0;
+	n = 0;
+	for (;;) {
+	  if (n > (INT_MAX - 9)/10) {
+	    overflow = 1;
+	    break;
+	  }
+	  n *= 10;
+	  n += c - '0';
+	  context_buffer += char(c);
+	  c = input_stack::peek_char();
+	  if (c == EOF || !csdigit(c))
+	    break;
+	  c = input_stack::get_char();
+	}
+	token_double = n;
+	if (overflow) {
+	  for (;;) {
+	    token_double *= 10.0;
+	    token_double += c - '0';
+	    context_buffer += char(c);
+	    c = input_stack::peek_char();
+	    if (c == EOF || !csdigit(c))
+	      break;
+	    c = input_stack::get_char();
+	  }
+	  // if somebody asks for 1000000000000th, we will silently
+	  // give them INT_MAXth
+	  double temp = token_double; // work around gas 1.34/sparc bug
+	  if (token_double > INT_MAX)
+	    n = INT_MAX;
+	  else
+	    n = int(temp);
+	}
+      }
+      switch (c) {
+      case 'i':
+      case 'I':
+	context_buffer += char(c);
+	input_stack::get_char();
+	return NUMBER;
+      case '.':
+	{
+	  context_buffer += '.';
+	  input_stack::get_char();
+	got_dot:
+	  double factor = 1.0;
+	  for (;;) {
+	    c = input_stack::peek_char();
+	    if (c == EOF || !csdigit(c))
+	      break;
+	    input_stack::get_char();
+	    context_buffer += char(c);
+	    factor /= 10.0;
+	    if (c != '0')
+	      token_double += factor*(c - '0');
+	  }
+	  if (c != 'e' && c != 'E') {
+	    if (c == 'i' || c == 'I') {
+	      context_buffer += char(c);
+	      input_stack::get_char();
+	    }
+	    return NUMBER;
+	  }
+	}
+	// fall through
+      case 'e':
+      case 'E':
+	{
+	  int echar = c;
+	  input_stack::get_char();
+	  c = input_stack::peek_char();
+	  int sign = '+';
+	  if (c == '+' || c == '-') {
+	    sign = c;
+	    input_stack::get_char();
+	    c = input_stack::peek_char();
+	    if (c == EOF || !csdigit(c)) {
+	      input_stack::push_back(sign);
+	      input_stack::push_back(echar);
+	      return NUMBER;
+	    }
+	    context_buffer += char(echar);
+	    context_buffer += char(sign);
+	  }
+	  else {
+	    if (c == EOF || !csdigit(c)) {
+	      input_stack::push_back(echar);
+	      return NUMBER;
+	    }
+	    context_buffer += char(echar);
+	  }
+	  input_stack::get_char();
+	  context_buffer += char(c);
+	  n = c - '0';
+	  for (;;) {
+	    c = input_stack::peek_char();
+	    if (c == EOF || !csdigit(c))
+	      break;
+	    input_stack::get_char();
+	    context_buffer += char(c);
+	    n = n*10 + (c - '0');
+	  }
+	  if (sign == '-')
+	    n = -n;
+	  if (c == 'i' || c == 'I') {
+	    context_buffer += char(c);
+	    input_stack::get_char();
+	  }
+	  token_double *= pow(10.0, n);
+	  return NUMBER;
+	}
+      case 'n':
+	input_stack::get_char();
+	c = input_stack::peek_char();
+	if (c == 'd') {
+	  input_stack::get_char();
+	  token_int = n;
+	  context_buffer += "nd";
+	  return ORDINAL;
+	}
+	input_stack::push_back('n');
+	return NUMBER;
+      case 'r':
+	input_stack::get_char();
+	c = input_stack::peek_char();
+	if (c == 'd') {
+	  input_stack::get_char();
+	  token_int = n;
+	  context_buffer += "rd";
+	  return ORDINAL;
+	}
+	input_stack::push_back('r');
+	return NUMBER;
+      case 't':
+	input_stack::get_char();
+	c = input_stack::peek_char();
+	if (c == 'h') {
+	  input_stack::get_char();
+	  token_int = n;
+	  context_buffer += "th";
+	  return ORDINAL;
+	}
+	input_stack::push_back('t');
+	return NUMBER;
+      case 's':
+	input_stack::get_char();
+	c = input_stack::peek_char();
+	if (c == 't') {
+	  input_stack::get_char();
+	  token_int = n;
+	  context_buffer += "st";
+	  return ORDINAL;
+	}
+	input_stack::push_back('s');
+	return NUMBER;
+      default:
+	return NUMBER;
+      }
+      break;
+    case '\'':
+      {
+	c = input_stack::peek_char();
+	if (c == 't') {
+	  input_stack::get_char();
+	  c = input_stack::peek_char();
+	  if (c == 'h') {
+	    input_stack::get_char();
+	    context_buffer = "'th";
+	    return TH;
+	  }
+	  else
+	    input_stack::push_back('t');
+	}
+	context_buffer = "'";
+	return '\'';
+      }
+    case '.':
+      {
+	c = input_stack::peek_char();
+	if (c != EOF && csdigit(c)) {
+	  n = 0;
+	  token_double = 0.0;
+	  context_buffer = '.';
+	  goto got_dot;
+	}
+	return get_token_after_dot(c);
+      }
+    case '<':
+      c = input_stack::peek_char();
+      if (c == '-') {
+	input_stack::get_char();
+	c = input_stack::peek_char();
+	if (c == '>') {
+	  input_stack::get_char();
+	  context_buffer = "<->";
+	  return DOUBLE_ARROW_HEAD;
+	}
+	context_buffer = "<-";
+	return LEFT_ARROW_HEAD;
+      }
+      else if (c == '=') {
+	input_stack::get_char();
+	context_buffer = "<=";
+	return LESSEQUAL;
+      }
+      context_buffer = "<";
+      return '<';
+    case '-':
+      c = input_stack::peek_char();
+      if (c == '>') {
+	input_stack::get_char();
+	context_buffer = "->";
+	return RIGHT_ARROW_HEAD;
+      }
+      context_buffer = "-";
+      return '-';
+    case '!':
+      c = input_stack::peek_char();
+      if (c == '=') {
+	input_stack::get_char();
+	context_buffer = "!=";
+	return NOTEQUAL;
+      }
+      context_buffer = "!";
+      return '!';
+    case '>':
+      c = input_stack::peek_char();
+      if (c == '=') {
+	input_stack::get_char();
+	context_buffer = ">=";
+	return GREATEREQUAL;
+      }
+      context_buffer = ">";
+      return '>';
+    case '=':
+      c = input_stack::peek_char();
+      if (c == '=') {
+	input_stack::get_char();
+	context_buffer = "==";
+	return EQUALEQUAL;
+      }
+      context_buffer = "=";
+      return '=';
+    case '&':
+      c = input_stack::peek_char();
+      if (c == '&') {
+	input_stack::get_char();
+	context_buffer = "&&";
+	return ANDAND;
+      }
+      context_buffer = "&";
+      return '&';
+    case '|':
+      c = input_stack::peek_char();
+      if (c == '|') {
+	input_stack::get_char();
+	context_buffer = "||";
+	return OROR;
+      }
+      context_buffer = "|";
+      return '|';
+    default:
+      if (c != EOF && csalpha(c)) {
+	token_buffer.clear();
+	token_buffer = c;
+	for (;;) {
+	  c = input_stack::peek_char();
+	  if (c == EOF || (!csalnum(c) && c != '_'))
+	    break;
+	  input_stack::get_char();
+	  token_buffer += char(c);
+	}
+	int tok = lookup_keyword(token_buffer.contents(),
+				 token_buffer.length());
+	if (tok != 0) {
+	  context_buffer = token_buffer;
+	  return tok;
+	}
+	char *def = 0;
+	if (lookup_flag) {
+	  token_buffer += '\0';
+	  def = macro_table.lookup(token_buffer.contents());
+	  token_buffer.set_length(token_buffer.length() - 1);
+	  if (def) {
+	    if (c == '(') {
+	      input_stack::get_char();
+	      interpolate_macro_with_args(def);
+	    }
+	    else
+	      input_stack::push(new macro_input(def));
+	  }
+	}
+	if (!def) {
+	  context_buffer = token_buffer;
+	  if (csupper(token_buffer[0]))
+	    return LABEL;
+	  else
+	    return VARIABLE;
+	}
+      }
+      else {
+	context_buffer = char(c);
+	return (unsigned char)c;
+      }
+      break;
+    }
+  }
+}
+
+int get_delimited()
+{
+  token_buffer.clear();
+  int c = input_stack::get_char();
+  while (c == ' ' || c == '\t' || c == '\n')
+    c = input_stack::get_char();
+  if (c == EOF) {
+    lex_error("missing delimiter");
+    return 0;
+  }
+  context_buffer = char(c);
+  int had_newline = 0;
+  int start = c;
+  int level = 0;
+  enum { NORMAL, IN_STRING, IN_STRING_QUOTED, DELIM_END } state = NORMAL;
+  for (;;) {
+    c = input_stack::get_char();
+    if (c == EOF) {
+      lex_error("missing closing delimiter");
+      return 0;
+    }
+    if (c == '\n')
+      had_newline = 1;
+    else if (!had_newline)
+      context_buffer += char(c);
+    switch (state) {
+    case NORMAL:
+      if (start == '{') {
+	if (c == '{') {
+	  level++;
+	  break;
+	}
+	if (c == '}') {
+	  if (--level < 0)
+	    state = DELIM_END;
+	  break;
+	}
+      }
+      else {
+	if (c == start) {
+	  state = DELIM_END;
+	  break;
+	}
+      }
+      if (c == '"')
+	state = IN_STRING;
+      break;
+    case IN_STRING_QUOTED:
+      if (c == '\n')
+	state = NORMAL;
+      else
+	state = IN_STRING;
+      break;
+    case IN_STRING:
+      if (c == '"' || c == '\n')
+	state = NORMAL;
+      else if (c == '\\')
+	state = IN_STRING_QUOTED;
+      break;
+    case DELIM_END:
+      // This case it just to shut cfront 2.0 up.
+    default:
+      assert(0);
+    }
+    if (state == DELIM_END)
+      break;
+    token_buffer += c;
+  }
+  return 1;
+}
+
+void do_define()
+{
+  int t = get_token(0);		// do not expand what we are defining
+  if (t != VARIABLE && t != LABEL) {
+    lex_error("can only define variable or placename");
+    return;
+  }
+  token_buffer += '\0';
+  string nm = token_buffer;
+  const char *name = nm.contents();
+  if (!get_delimited())
+    return;
+  token_buffer += '\0';
+  macro_table.define(name, strsave(token_buffer.contents()));
+}
+
+void do_undef()
+{
+  int t = get_token(0);		// do not expand what we are undefining
+  if (t != VARIABLE && t != LABEL) {
+    lex_error("can only define variable or placename");
+    return;
+  }
+  token_buffer += '\0';
+  macro_table.define(token_buffer.contents(), 0);
+}
+
+
+class for_input : public input {
+  char *var;
+  char *body;
+  double from;
+  double to;
+  int by_is_multiplicative;
+  double by;
+  const char *p;
+  int done_newline;
+public:
+  for_input(char *, double, double, int, double, char *);
+  ~for_input();
+  int get();
+  int peek();
+};
+
+for_input::for_input(char *vr, double f, double t,
+		     int bim, double b, char *bd)
+: var(vr), body(bd), from(f), to(t), by_is_multiplicative(bim), by(b),
+  p(body), done_newline(0)
+{
+}
+
+for_input::~for_input()
+{
+  free(var);
+  free(body);
+}
+
+int for_input::get()
+{
+  if (p == 0)
+    return EOF;
+  for (;;) {
+    if (*p != '\0')
+      return (unsigned char)*p++;
+    if (!done_newline) {
+      done_newline = 1;
+      return '\n';
+    }
+    double val;
+    if (!lookup_variable(var, &val)) {
+      lex_error("body of 'for' terminated enclosing block");
+      return EOF;
+    }
+    if (by_is_multiplicative)
+      val *= by;
+    else
+      val += by;
+    define_variable(var, val);
+    if ((from <= to && val > to)
+	|| (from >= to && val < to)) {
+      p = 0;
+      return EOF;
+    }
+    p = body;
+    done_newline = 0;
+  }
+}
+
+int for_input::peek()
+{
+  if (p == 0)
+    return EOF;
+  if (*p != '\0')
+    return (unsigned char)*p;
+  if (!done_newline)
+    return '\n';
+  double val;
+  if (!lookup_variable(var, &val))
+    return EOF;
+  if (by_is_multiplicative) {
+    if (val * by > to)
+      return EOF;
+  }
+  else {
+    if ((from <= to && val + by > to)
+	|| (from >= to && val + by < to))
+      return EOF;
+  }
+  if (*body == '\0')
+    return EOF;
+  return (unsigned char)*body;
+}
+
+void do_for(char *var, double from, double to, int by_is_multiplicative,
+	    double by, char *body)
+{
+  define_variable(var, from);
+  if ((by_is_multiplicative && by <= 0)
+      || (by > 0 && from > to)
+      || (by < 0 && from < to))
+    return;
+  input_stack::push(new for_input(var, from, to,
+				  by_is_multiplicative, by, body));
+}
+
+
+void do_copy(const char *filename)
+{
+  errno = 0;
+  FILE *fp = fopen(filename, "r");
+  if (fp == 0) {
+    lex_error("can't open '%1': %2", filename, strerror(errno));
+    return;
+  }
+  input_stack::push(new file_input(fp, filename));
+}
+
+class copy_thru_input : public input {
+  int done;
+  char *body;
+  char *until;
+  const char *p;
+  const char *ap;
+  int argv[MAX_ARG];
+  int argc;
+  string line;
+  int get_line();
+  virtual int inget() = 0;
+public:
+  copy_thru_input(const char *b, const char *u);
+  ~copy_thru_input();
+  int get();
+  int peek();
+};
+
+class copy_file_thru_input : public copy_thru_input {
+  input *in;
+public:
+  copy_file_thru_input(input *, const char *b, const char *u);
+  ~copy_file_thru_input();
+  int inget();
+};
+
+copy_file_thru_input::copy_file_thru_input(input *i, const char *b,
+					   const char *u)
+: copy_thru_input(b, u), in(i)
+{
+}
+
+copy_file_thru_input::~copy_file_thru_input()
+{
+  delete in;
+}
+
+int copy_file_thru_input::inget()
+{
+  if (!in)
+    return EOF;
+  else
+    return in->get();
+}
+
+class copy_rest_thru_input : public copy_thru_input {
+public:
+  copy_rest_thru_input(const char *, const char *u);
+  int inget();
+};
+
+copy_rest_thru_input::copy_rest_thru_input(const char *b, const char *u)
+: copy_thru_input(b, u)
+{
+}
+
+int copy_rest_thru_input::inget()
+{
+  while (next != 0) {
+    int c = next->get();
+    if (c != EOF)
+      return c;
+    if (next->next == 0)
+      return EOF;
+    input *tem = next;
+    next = next->next;
+    delete tem;
+  }
+  return EOF;
+
+}
+
+copy_thru_input::copy_thru_input(const char *b, const char *u)
+: done(0)
+{
+  ap = 0;
+  body = process_body(b);
+  p = 0;
+  until = strsave(u);
+}
+
+
+copy_thru_input::~copy_thru_input()
+{
+  delete[] body;
+  delete[] until;
+}
+
+int copy_thru_input::get()
+{
+  if (ap) {
+    if (*ap != '\0')
+      return (unsigned char)*ap++;
+    ap = 0;
+  }
+  for (;;) {
+    if (p == 0) {
+      if (!get_line())
+	break;
+      p = body;
+    }
+    if (*p == '\0') {
+      p = 0;
+      return '\n';
+    }
+    while ((unsigned char)*p >= ARG1
+	   && (unsigned char)*p <= ARG1 + MAX_ARG - 1) {
+      int i = (unsigned char)*p++ - ARG1;
+      if (i < argc && line[argv[i]] != '\0') {
+	ap = line.contents() + argv[i];
+	return (unsigned char)*ap++;
+      }
+    }
+    if (*p != '\0')
+      return (unsigned char)*p++;
+  }
+  return EOF;
+}
+
+int copy_thru_input::peek()
+{
+  if (ap) {
+    if (*ap != '\0')
+      return (unsigned char)*ap;
+    ap = 0;
+  }
+  for (;;) {
+    if (p == 0) {
+      if (!get_line())
+	break;
+      p = body;
+    }
+    if (*p == '\0')
+      return '\n';
+    while ((unsigned char)*p >= ARG1
+	   && (unsigned char)*p <= ARG1 + MAX_ARG - 1) {
+      int i = (unsigned char)*p++ - ARG1;
+      if (i < argc && line[argv[i]] != '\0') {
+	ap = line.contents() + argv[i];
+	return (unsigned char)*ap;
+      }
+    }
+    if (*p != '\0')
+      return (unsigned char)*p;
+  }
+  return EOF;
+}
+
+int copy_thru_input::get_line()
+{
+  if (done)
+    return 0;
+  line.clear();
+  argc = 0;
+  int c = inget();
+  for (;;) {
+    while (c == ' ')
+      c = inget();
+    if (c == EOF || c == '\n')
+      break;
+    if (argc == MAX_ARG) {
+      do {
+	c = inget();
+      } while (c != '\n' && c != EOF);
+      break;
+    }
+    argv[argc++] = line.length();
+    do {
+      line += char(c);
+      c = inget();
+    } while (c != ' ' && c != '\n');
+    line += '\0';
+  }
+  if (until != 0 && argc > 0 && strcmp(&line[argv[0]], until) == 0) {
+    done = 1;
+    return 0;
+  }
+  return argc > 0 || c == '\n';
+}
+
+class simple_file_input : public input {
+  const char *filename;
+  int lineno;
+  FILE *fp;
+public:
+  simple_file_input(FILE *, const char *);
+  ~simple_file_input();
+  int get();
+  int peek();
+  int get_location(const char **, int *);
+};
+
+simple_file_input::simple_file_input(FILE *p, const char *s)
+: filename(s), lineno(1), fp(p)
+{
+}
+
+simple_file_input::~simple_file_input()
+{
+  // don't delete the filename
+  fclose(fp);
+}
+
+int simple_file_input::get()
+{
+  int c = getc(fp);
+  while (is_invalid_input_char(c)) {
+    error("invalid input character code %1", c);
+    c = getc(fp);
+  }
+  if (c == '\n')
+    lineno++;
+  return c;
+}
+
+int simple_file_input::peek()
+{
+  int c = getc(fp);
+  while (is_invalid_input_char(c)) {
+    error("invalid input character code %1", c);
+    c = getc(fp);
+  }
+  if (c != EOF)
+    ungetc(c, fp);
+  return c;
+}
+
+int simple_file_input::get_location(const char **fnp, int *lnp)
+{
+  *fnp = filename;
+  *lnp = lineno;
+  return 1;
+}
+
+
+void copy_file_thru(const char *filename, const char *body, const char *until)
+{
+  errno = 0;
+  FILE *fp = fopen(filename, "r");
+  if (fp == 0) {
+    lex_error("can't open '%1': %2", filename, strerror(errno));
+    return;
+  }
+  input *in = new copy_file_thru_input(new simple_file_input(fp, filename),
+				       body, until);
+  input_stack::push(in);
+}
+
+void copy_rest_thru(const char *body, const char *until)
+{
+  input_stack::push(new copy_rest_thru_input(body, until));
+}
+
+void push_body(const char *s)
+{
+  input_stack::push(new char_input('\n'));
+  input_stack::push(new macro_input(s));
+}
+
+int delim_flag = 0;
+
+char *get_thru_arg()
+{
+  int c = input_stack::peek_char();
+  while (c == ' ') {
+    input_stack::get_char();
+    c = input_stack::peek_char();
+  }
+  if (c != EOF && csalpha(c)) {
+    // looks like a macro
+    input_stack::get_char();
+    token_buffer = c;
+    for (;;) {
+      c = input_stack::peek_char();
+      if (c == EOF || (!csalnum(c) && c != '_'))
+	break;
+      input_stack::get_char();
+      token_buffer += char(c);
+    }
+    context_buffer = token_buffer;
+    token_buffer += '\0';
+    char *def = macro_table.lookup(token_buffer.contents());
+    if (def)
+      return strsave(def);
+    // I guess it wasn't a macro after all; so push the macro name back.
+    // -2 because we added a '\0'
+    for (int i = token_buffer.length() - 2; i >= 0; i--)
+      input_stack::push_back(token_buffer[i]);
+  }
+  if (get_delimited()) {
+    token_buffer += '\0';
+    return strsave(token_buffer.contents());
+  }
+  else
+    return 0;
+}
+
+int lookahead_token = -1;
+string old_context_buffer;
+
+void do_lookahead()
+{
+  if (lookahead_token == -1) {
+    old_context_buffer = context_buffer;
+    lookahead_token = get_token(1);
+  }
+}
+
+int yylex()
+{
+  if (delim_flag) {
+    assert(lookahead_token == -1);
+    if (delim_flag == 2) {
+      if ((yylval.str = get_thru_arg()) != 0)
+	return DELIMITED;
+      else
+	return 0;
+    }
+    else {
+      if (get_delimited()) {
+	token_buffer += '\0';
+	yylval.str = strsave(token_buffer.contents());
+	return DELIMITED;
+      }
+      else
+	return 0;
+    }
+  }
+  for (;;) {
+    int t;
+    if (lookahead_token >= 0) {
+      t = lookahead_token;
+      lookahead_token = -1;
+    }
+    else
+      t = get_token(1);
+    switch (t) {
+    case '\n':
+      return ';';
+    case EOF:
+      return 0;
+    case DEFINE:
+      do_define();
+      break;
+    case UNDEF:
+      do_undef();
+      break;
+    case ORDINAL:
+      yylval.n = token_int;
+      return t;
+    case NUMBER:
+      yylval.x = token_double;
+      return t;
+    case COMMAND_LINE:
+    case TEXT:
+      token_buffer += '\0';
+      if (!input_stack::get_location(&yylval.lstr.filename,
+				     &yylval.lstr.lineno)) {
+	yylval.lstr.filename = 0;
+	yylval.lstr.lineno = -1;
+      }
+      yylval.lstr.str = strsave(token_buffer.contents());
+      return t;
+    case LABEL:
+    case VARIABLE:
+      token_buffer += '\0';
+      yylval.str = strsave(token_buffer.contents());
+      return t;
+    case LEFT:
+      // change LEFT to LEFT_CORNER when followed by OF
+      old_context_buffer = context_buffer;
+      lookahead_token = get_token(1);
+      if (lookahead_token == OF)
+	return LEFT_CORNER;
+      else
+	return t;
+    case RIGHT:
+      // change RIGHT to RIGHT_CORNER when followed by OF
+      old_context_buffer = context_buffer;
+      lookahead_token = get_token(1);
+      if (lookahead_token == OF)
+	return RIGHT_CORNER;
+      else
+	return t;
+    case UPPER:
+      // recognise UPPER only before LEFT or RIGHT
+      old_context_buffer = context_buffer;
+      lookahead_token = get_token(1);
+      if (lookahead_token != LEFT && lookahead_token != RIGHT) {
+	yylval.str = strsave("upper");
+	return VARIABLE;
+      }
+      else
+	return t;
+    case LOWER:
+      // recognise LOWER only before LEFT or RIGHT
+      old_context_buffer = context_buffer;
+      lookahead_token = get_token(1);
+      if (lookahead_token != LEFT && lookahead_token != RIGHT) {
+	yylval.str = strsave("lower");
+	return VARIABLE;
+      }
+      else
+	return t;
+    case NORTH:
+      // recognise NORTH only before OF
+      old_context_buffer = context_buffer;
+      lookahead_token = get_token(1);
+      if (lookahead_token != OF) {
+	yylval.str = strsave("north");
+	return VARIABLE;
+      }
+      else
+	return t;
+    case SOUTH:
+      // recognise SOUTH only before OF
+      old_context_buffer = context_buffer;
+      lookahead_token = get_token(1);
+      if (lookahead_token != OF) {
+	yylval.str = strsave("south");
+	return VARIABLE;
+      }
+      else
+	return t;
+    case EAST:
+      // recognise EAST only before OF
+      old_context_buffer = context_buffer;
+      lookahead_token = get_token(1);
+      if (lookahead_token != OF) {
+	yylval.str = strsave("east");
+	return VARIABLE;
+      }
+      else
+	return t;
+    case WEST:
+      // recognise WEST only before OF
+      old_context_buffer = context_buffer;
+      lookahead_token = get_token(1);
+      if (lookahead_token != OF) {
+	yylval.str = strsave("west");
+	return VARIABLE;
+      }
+      else
+	return t;
+    case TOP:
+      // recognise TOP only before OF
+      old_context_buffer = context_buffer;
+      lookahead_token = get_token(1);
+      if (lookahead_token != OF) {
+	yylval.str = strsave("top");
+	return VARIABLE;
+      }
+      else
+	return t;
+    case BOTTOM:
+      // recognise BOTTOM only before OF
+      old_context_buffer = context_buffer;
+      lookahead_token = get_token(1);
+      if (lookahead_token != OF) {
+	yylval.str = strsave("bottom");
+	return VARIABLE;
+      }
+      else
+	return t;
+    case CENTER:
+      // recognise CENTER only before OF
+      old_context_buffer = context_buffer;
+      lookahead_token = get_token(1);
+      if (lookahead_token != OF) {
+	yylval.str = strsave("center");
+	return VARIABLE;
+      }
+      else
+	return t;
+    case START:
+      // recognise START only before OF
+      old_context_buffer = context_buffer;
+      lookahead_token = get_token(1);
+      if (lookahead_token != OF) {
+	yylval.str = strsave("start");
+	return VARIABLE;
+      }
+      else
+	return t;
+    case END:
+      // recognise END only before OF
+      old_context_buffer = context_buffer;
+      lookahead_token = get_token(1);
+      if (lookahead_token != OF) {
+	yylval.str = strsave("end");
+	return VARIABLE;
+      }
+      else
+	return t;
+    default:
+      return t;
+    }
+  }
+}
+
+void lex_error(const char *message,
+	       const errarg &arg1,
+	       const errarg &arg2,
+	       const errarg &arg3)
+{
+  const char *filename;
+  int lineno;
+  if (!input_stack::get_location(&filename, &lineno))
+    error(message, arg1, arg2, arg3);
+  else
+    error_with_file_and_line(filename, lineno, message, arg1, arg2, arg3);
+}
+
+void lex_warning(const char *message,
+		 const errarg &arg1,
+		 const errarg &arg2,
+		 const errarg &arg3)
+{
+  const char *filename;
+  int lineno;
+  if (!input_stack::get_location(&filename, &lineno))
+    warning(message, arg1, arg2, arg3);
+  else
+    warning_with_file_and_line(filename, lineno, message, arg1, arg2, arg3);
+}
+
+void yyerror(const char *s)
+{
+  const char *filename;
+  int lineno;
+  const char *context = 0;
+  if (lookahead_token == -1) {
+    if (context_buffer.length() > 0) {
+      context_buffer += '\0';
+      context = context_buffer.contents();
+    }
+  }
+  else {
+    if (old_context_buffer.length() > 0) {
+      old_context_buffer += '\0';
+      context = old_context_buffer.contents();
+    }
+  }
+  if (!input_stack::get_location(&filename, &lineno)) {
+    if (context) {
+      if (context[0] == '\n' && context[1] == '\0')
+	error("%1 before newline", s);
+      else
+	error("%1 before '%2'", s, context);
+    }
+    else
+      error("%1 at end of picture", s);
+  }
+  else {
+    if (context) {
+      if (context[0] == '\n' && context[1] == '\0')
+	error_with_file_and_line(filename, lineno, "%1 before newline", s);
+      else
+	error_with_file_and_line(filename, lineno, "%1 before '%2'",
+				 s, context);
+    }
+    else
+      error_with_file_and_line(filename, lineno, "%1 at end of picture", s);
+  }
+}
+
diff --git a/src/preproc/pic/main.cpp b/src/preproc/pic/main.cpp
new file mode 100644
index 0000000..f7e194f
--- /dev/null
+++ b/src/preproc/pic/main.cpp
@@ -0,0 +1,664 @@
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "pic.h"
+
+extern int yyparse();
+extern "C" const char *Version_string;
+
+output *out;
+char *graphname;		// the picture box name in TeX mode
+
+bool want_flyback = false;
+// groff pic supports '.PY' to work around mm package stepping on 'PF'.
+bool want_alternate_flyback = false;
+int zero_length_line_flag = 0;
+// Non-zero means we're using a groff driver.
+int driver_extension_flag = 1;
+int compatible_flag = 0;
+int safer_flag = 1;
+int command_char = '.';		// the character that introduces lines
+				// that should be passed through transparently
+static int lf_flag = 1;		// non-zero if we should attempt to understand
+				// lines beginning with '.lf'
+
+// Non-zero means a parse error was encountered.
+static int had_parse_error = 0;
+
+void do_file(const char *filename);
+
+class top_input : public input {
+  FILE *fp;
+  int bol;
+  int eof;
+  int push_back[3];
+  int start_lineno;
+public:
+  top_input(FILE *);
+  int get();
+  int peek();
+  int get_location(const char **, int *);
+};
+
+top_input::top_input(FILE *p) : fp(p), bol(1), eof(0)
+{
+  push_back[0] = push_back[1] = push_back[2] = EOF;
+  start_lineno = current_lineno;
+}
+
+int top_input::get()
+{
+  if (eof)
+    return EOF;
+  if (push_back[2] != EOF) {
+    int c = push_back[2];
+    push_back[2] = EOF;
+    return c;
+  }
+  else if (push_back[1] != EOF) {
+    int c = push_back[1];
+    push_back[1] = EOF;
+    return c;
+  }
+  else if (push_back[0] != EOF) {
+    int c = push_back[0];
+    push_back[0] = EOF;
+    return c;
+  }
+  int c = getc(fp);
+  while (is_invalid_input_char(c)) {
+    error("invalid input character code %1", int(c));
+    c = getc(fp);
+    bol = 0;
+  }
+  if (bol && c == '.') {
+    c = getc(fp);
+    if (c == 'P') {
+      c = getc(fp);
+      if (c == 'E' || c == 'F' || c == 'Y') {
+	int d = getc(fp);
+	if (d != EOF)
+	  ungetc(d, fp);
+	if (d == EOF || d == ' ' || d == '\n' || compatible_flag) {
+	  eof = 1;
+	  want_flyback = (c == 'F');
+	  want_alternate_flyback = (c == 'Y');
+	  return EOF;
+	}
+	push_back[0] = c;
+	push_back[1] = 'P';
+	return '.';
+      }
+      if (c == 'S') {
+	c = getc(fp);
+	if (c != EOF)
+	  ungetc(c, fp);
+	if (c == EOF || c == ' ' || c == '\n' || compatible_flag) {
+	  error("nested .PS");
+	  eof = 1;
+	  return EOF;
+	}
+	push_back[0] = 'S';
+	push_back[1] = 'P';
+	return '.';
+      }
+      if (c != EOF)
+	ungetc(c, fp);
+      push_back[0] = 'P';
+      return '.';
+    }
+    else {
+      if (c != EOF)
+	ungetc(c, fp);
+      return '.';
+    }
+  }
+  if (c == '\n') {
+    bol = 1;
+    current_lineno++;
+    return '\n';
+  }
+  bol = 0;
+  if (c == EOF) {
+    eof = 1;
+    error("end of file before .PE, .PF, or .PY");
+    error_with_file_and_line(current_filename, start_lineno - 1,
+			     ".PS was here");
+  }
+  return c;
+}
+
+int top_input::peek()
+{
+  if (eof)
+    return EOF;
+  if (push_back[2] != EOF)
+    return push_back[2];
+  if (push_back[1] != EOF)
+    return push_back[1];
+  if (push_back[0] != EOF)
+    return push_back[0];
+  int c = getc(fp);
+  while (is_invalid_input_char(c)) {
+    error("invalid input character code %1", int(c));
+    c = getc(fp);
+    bol = 0;
+  }
+  if (bol && c == '.') {
+    c = getc(fp);
+    if (c == 'P') {
+      c = getc(fp);
+      if (c == 'E' || c == 'F' || c == 'Y') {
+	int d = getc(fp);
+	if (d != EOF)
+	  ungetc(d, fp);
+	if (d == EOF || d == ' ' || d == '\n' || compatible_flag) {
+	  eof = 1;
+	  want_flyback = (c == 'F');
+	  want_alternate_flyback = (c == 'Y');
+	  return EOF;
+	}
+	push_back[0] = c;
+	push_back[1] = 'P';
+	push_back[2] = '.';
+	return '.';
+      }
+      if (c == 'S') {
+	c = getc(fp);
+	if (c != EOF)
+	  ungetc(c, fp);
+	if (c == EOF || c == ' ' || c == '\n' || compatible_flag) {
+	  error("nested .PS");
+	  eof = 1;
+	  return EOF;
+	}
+	push_back[0] = 'S';
+	push_back[1] = 'P';
+	push_back[2] = '.';
+	return '.';
+      }
+      if (c != EOF)
+	ungetc(c, fp);
+      push_back[0] = 'P';
+      push_back[1] = '.';
+      return '.';
+    }
+    else {
+      if (c != EOF)
+	ungetc(c, fp);
+      push_back[0] = '.';
+      return '.';
+    }
+  }
+  if (c != EOF)
+    ungetc(c, fp);
+  if (c == '\n')
+    return '\n';
+  return c;
+}
+
+int top_input::get_location(const char **filenamep, int *linenop)
+{
+  *filenamep = current_filename;
+  *linenop = current_lineno;
+  return 1;
+}
+
+void do_picture(FILE *fp)
+{
+  want_flyback = false;
+  int c;
+  if (!graphname)
+    free(graphname);
+  graphname = strsave("graph");		// default picture name in TeX mode
+  while ((c = getc(fp)) == ' ')
+    ;
+  if (c == '<') {
+    string filename;
+    while ((c = getc(fp)) == ' ')
+      ;
+    while (c != EOF && c != ' ' && c != '\n') {
+      filename += char(c);
+      c = getc(fp);
+    }
+    if (c == ' ') {
+      do {
+	c = getc(fp);
+      } while (c != EOF && c != '\n');
+    }
+    if (c == '\n') 
+      current_lineno++;
+    if (filename.length() == 0)
+      error("missing filename after '<'");
+    else {
+      filename += '\0';
+      const char *old_filename = current_filename;
+      int old_lineno = current_lineno;
+      // filenames must be permanent
+      do_file(strsave(filename.contents()));
+      current_filename = old_filename;
+      current_lineno = old_lineno;
+    }
+    out->set_location(current_filename, current_lineno);
+  }
+  else {
+    out->set_location(current_filename, current_lineno);
+    string start_line;
+    while (c != EOF) {
+      if (c == '\n') {
+	current_lineno++;
+	break;
+      }
+      start_line += c;
+      c = getc(fp);
+    }
+    if (c == EOF)
+      return;
+    start_line += '\0';
+    double wid, ht;
+    switch (sscanf(&start_line[0], "%lf %lf", &wid, &ht)) {
+    case 1:
+      ht = 0.0;
+      break;
+    case 2:
+      break;
+    default:
+      ht = wid = 0.0;
+      break;
+    }
+    out->set_desired_width_height(wid, ht);
+    out->set_args(start_line.contents());
+    lex_init(new top_input(fp));
+    if (yyparse()) {
+      had_parse_error = 1;
+      lex_error("giving up on this picture");
+    }
+    parse_cleanup();
+    lex_cleanup();
+
+    // skip the rest of the .PE/.PF/.PY line
+    while ((c = getc(fp)) != EOF && c != '\n')
+      ;
+    if (c == '\n')
+      current_lineno++;
+    out->set_location(current_filename, current_lineno);
+  }
+}
+
+void do_file(const char *filename)
+{
+  FILE *fp;
+  if (strcmp(filename, "-") == 0)
+    fp = stdin;
+  else {
+    errno = 0;
+    fp = fopen(filename, "r");
+    if (fp == 0) {
+      delete out;
+      fatal("can't open '%1': %2", filename, strerror(errno));
+    }
+  }
+  string fn(filename);
+  fn += '\0';
+  normalize_for_lf(fn);
+  current_filename = fn.contents();
+  out->set_location(current_filename, 1);
+  current_lineno = 1;
+  enum { START, MIDDLE, HAD_DOT, HAD_P, HAD_PS, HAD_l, HAD_lf } state = START;
+  for (;;) {
+    int c = getc(fp);
+    while (is_invalid_input_char(c)) {
+      error("invalid input character code %1", int(c));
+      c = getc(fp);
+    }
+    if (c == EOF)
+      break;
+    switch (state) {
+    case START:
+      if (c == '.')
+	state = HAD_DOT;
+      else {
+	putchar(c);
+	if (c == '\n') {
+	  current_lineno++;
+	  state = START;
+	}
+	else
+	  state = MIDDLE;
+      }
+      break;
+    case MIDDLE:
+      putchar(c);
+      if (c == '\n') {
+	current_lineno++;
+	state = START;
+      }
+      break;
+    case HAD_DOT:
+      if (c == 'P')
+	state = HAD_P;
+      else if (lf_flag && c == 'l')
+	state = HAD_l;
+      else {
+	putchar('.');
+	putchar(c);
+	if (c == '\n') {
+	  current_lineno++;
+	  state = START;
+	}
+	else
+	  state = MIDDLE;
+      }
+      break;
+    case HAD_P:
+      if (c == 'S')
+	state = HAD_PS;
+      else  {
+	putchar('.');
+	putchar('P');
+	putchar(c);
+	if (c == '\n') {
+	  current_lineno++;
+	  state = START;
+	}
+	else
+	  state = MIDDLE;
+      }
+      break;
+    case HAD_PS:
+      if (c == ' ' || c == '\n' || compatible_flag) {
+	ungetc(c, fp);
+	do_picture(fp);
+	state = START;
+      }
+      else {
+	fputs(".PS", stdout);
+	putchar(c);
+	state = MIDDLE;
+      }
+      break;
+    case HAD_l:
+      if (c == 'f')
+	state = HAD_lf;
+      else {
+	putchar('.');
+	putchar('l');
+	putchar(c);
+	if (c == '\n') {
+	  current_lineno++;
+	  state = START;
+	}
+	else
+	  state = MIDDLE;
+      }
+      break;
+    case HAD_lf:
+      if (c == ' ' || c == '\n' || compatible_flag) {
+	string line;
+	while (c != EOF) {
+	  line += c;
+	  if (c == '\n') {
+	    current_lineno++;
+	    break;
+	  }
+	  c = getc(fp);
+	}
+	line += '\0';
+	interpret_lf_args(line.contents());
+	printf(".lf%s", line.contents());
+	state = START;
+      }
+      else {
+	fputs(".lf", stdout);
+	putchar(c);
+	state = MIDDLE;
+      }
+      break;
+    default:
+      assert(0);
+    }
+  }
+  switch (state) {
+  case START:
+    break;
+  case MIDDLE:
+    putchar('\n');
+    break;
+  case HAD_DOT:
+    fputs(".\n", stdout);
+    break;
+  case HAD_P:
+    fputs(".P\n", stdout);
+    break;
+  case HAD_PS:
+    fputs(".PS\n", stdout);
+    break;
+  case HAD_l:
+    fputs(".l\n", stdout);
+    break;
+  case HAD_lf:
+    fputs(".lf\n", stdout);
+    break;
+  }
+  if (fp != stdin)
+    fclose(fp);
+}
+
+#ifdef FIG_SUPPORT
+void do_whole_file(const char *filename)
+{
+  // Do not set current_filename.
+  FILE *fp;
+  if (strcmp(filename, "-") == 0)
+    fp = stdin;
+  else {
+    errno = 0;
+    fp = fopen(filename, "r");
+    if (fp == 0)
+      fatal("can't open '%1': %2", filename, strerror(errno));
+  }
+  lex_init(new file_input(fp, filename));
+  if (yyparse())
+    had_parse_error = 1;
+  parse_cleanup();
+  lex_cleanup();
+}
+#endif
+
+void usage(FILE *stream)
+{
+  fprintf(stream, "usage: %s [-CnSU] [file ...]\n", program_name);
+#ifdef TEX_SUPPORT
+  fprintf(stream, "usage: %s -t [-cCSUz] [file ...]\n", program_name);
+#endif
+#ifdef FIG_SUPPORT
+  fprintf(stream, "usage: %s -f [-v] [file]\n", program_name);
+#endif
+  fprintf(stream, "usage: %s {-v | --version}\n", program_name);
+  fprintf(stream, "usage: %s --help\n", program_name);
+}
+
+#if defined(__MSDOS__) || defined(__EMX__)
+static char *fix_program_name(char *arg, char *dflt)
+{
+  if (!arg)
+    return dflt;
+  char *prog = strchr(arg, '\0');
+  for (;;) {
+    if (prog == arg)
+      break;
+    --prog;
+    if (strchr("\\/:", *prog)) {
+      prog++;
+      break;
+    }
+  }	
+  char *ext = strchr(prog, '.');
+  if (ext)
+    *ext = '\0';
+  for (char *p = prog; *p; p++)
+    if ('A' <= *p && *p <= 'Z')
+      *p = 'a' + (*p - 'A');
+  return prog;
+}
+#endif /* __MSDOS__ || __EMX__ */
+
+int main(int argc, char **argv)
+{
+  setlocale(LC_NUMERIC, "C");
+#if defined(__MSDOS__) || defined(__EMX__)
+  argv[0] = fix_program_name(argv[0], "pic");
+#endif /* __MSDOS__ || __EMX__ */
+  program_name = argv[0];
+  static char stderr_buf[BUFSIZ];
+  setbuf(stderr, stderr_buf);
+  int opt;
+#ifdef TEX_SUPPORT
+  int tex_flag = 0;
+  int tpic_flag = 0;
+#endif
+#ifdef FIG_SUPPORT
+  int whole_file_flag = 0;
+  int fig_flag = 0;
+#endif
+  static const struct option long_options[] = {
+    { "help", no_argument, 0, CHAR_MAX + 1 },
+    { "version", no_argument, 0, 'v' },
+    { NULL, 0, 0, 0 }
+  };
+  while ((opt = getopt_long(argc, argv, "T:CDSUtcvnxzpf", long_options, NULL))
+	 != EOF)
+    switch (opt) {
+    case 'C':
+      compatible_flag = 1;
+      break;
+    case 'D':
+    case 'T':
+      break;
+    case 'S':
+      safer_flag = 1;
+      break;
+    case 'U':
+      safer_flag = 0;
+      break;
+    case 'f':
+#ifdef FIG_SUPPORT
+      whole_file_flag++;
+      fig_flag++;
+#else
+      fatal("fig support not included");
+#endif
+      break;
+    case 'n':
+      driver_extension_flag = 0;
+      break;
+    case 'p':
+    case 'x':
+      warning("-%1 option is obsolete", char(opt));
+      break;
+    case 't':
+#ifdef TEX_SUPPORT
+      tex_flag++;
+#else
+      fatal("TeX support not included");
+#endif
+      break;
+    case 'c':
+#ifdef TEX_SUPPORT
+      tpic_flag++;
+#else
+      fatal("TeX support not included");
+#endif
+      break;
+    case 'v':
+      {
+	printf("GNU pic (groff) version %s\n", Version_string);
+	exit(0);
+	break;
+      }
+    case 'z':
+      // zero length lines will be printed as dots
+      zero_length_line_flag++;
+      break;
+    case CHAR_MAX + 1: // --help
+      usage(stdout);
+      exit(0);
+      break;
+    case '?':
+      usage(stderr);
+      exit(1);
+      break;
+    default:
+      assert(0);
+    }
+  parse_init();
+#ifdef TEX_SUPPORT
+  if (tpic_flag) {
+    out = make_tpic_output();
+    lf_flag = 0;
+  }
+  else if (tex_flag) {
+    out = make_tex_output();
+    command_char = '\\';
+    lf_flag = 0;
+  }
+  else
+#endif
+#ifdef FIG_SUPPORT
+  if (fig_flag)
+    out = make_fig_output();
+  else
+#endif
+  {
+    out = make_troff_output();
+    printf(".do if !dPS .ds PS\n"
+	   ".do if !dPE .ds PE\n"
+	   ".do if !dPF .ds PF\n"
+	   ".do if !dPY .ds PY\n");
+  }
+#ifdef FIG_SUPPORT
+  if (whole_file_flag) {
+    if (optind >= argc)
+      do_whole_file("-");
+    else if (argc - optind > 1) {
+      usage(stderr);
+      exit(1);
+    } else
+      do_whole_file(argv[optind]);
+  }
+  else {
+#endif
+    if (optind >= argc)
+      do_file("-");
+    else
+      for (int i = optind; i < argc; i++)
+	do_file(argv[i]);
+#ifdef FIG_SUPPORT
+  }
+#endif
+  delete out;
+  if (ferror(stdout) || fflush(stdout) < 0)
+    fatal("output error");
+  return had_parse_error;
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/pic/object.cpp b/src/preproc/pic/object.cpp
new file mode 100644
index 0000000..e207fb1
--- /dev/null
+++ b/src/preproc/pic/object.cpp
@@ -0,0 +1,2079 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdlib.h>
+
+#include "pic.h"
+#include "ptable.h"
+#include "object.h"
+
+void print_object_list(object *);
+
+line_type::line_type()
+: type(solid), thickness(1.0)
+{
+}
+
+output::output() : args(0), desired_height(0.0), desired_width(0.0)
+{
+}
+
+output::~output()
+{
+  delete[] args;
+}
+
+void output::set_desired_width_height(double wid, double ht)
+{
+  desired_width = wid;
+  desired_height = ht;
+}
+
+void output::set_args(const char *s)
+{
+  delete[] args;
+  if (s == 0 || *s == '\0')
+    args = 0;
+  else
+    args = strsave(s);
+}
+
+int output::supports_filled_polygons()
+{
+  return 0;
+}
+
+void output::begin_block(const position &, const position &)
+{
+}
+
+void output::end_block()
+{
+}
+
+double output::compute_scale(double sc, const position &ll, const position &ur)
+{
+  distance dim = ur - ll;
+  if (desired_width != 0.0 || desired_height != 0.0) {
+    sc = 0.0;
+    if (desired_width != 0.0) {
+      if (dim.x == 0.0)
+	error("width specified for picture with zero width");
+      else
+	sc = dim.x/desired_width;
+    }
+    if (desired_height != 0.0) {
+      if (dim.y == 0.0)
+	error("height specified for picture with zero height");
+      else {
+	double tem = dim.y/desired_height;
+	if (tem > sc)
+	  sc = tem;
+      }
+    }
+    return sc == 0.0 ? 1.0 : sc;
+  }
+  else {
+    if (sc <= 0.0)
+      sc = 1.0;
+    distance sdim = dim/sc;
+    double max_width = 0.0;
+    lookup_variable("maxpswid", &max_width);
+    double max_height = 0.0;
+    lookup_variable("maxpsht", &max_height);
+    if ((max_width > 0.0 && sdim.x > max_width)
+	|| (max_height > 0.0 && sdim.y > max_height)) {
+      double xscale = dim.x/max_width;
+      double yscale = dim.y/max_height;
+      return xscale > yscale ? xscale : yscale;
+    }
+    else
+      return sc;
+  }
+}
+
+position::position(const place &pl)
+{
+  if (pl.obj != 0) {
+    // Use two statements to work around bug in SGI C++.
+    object *tem = pl.obj;
+    *this = tem->origin();
+  }
+  else {
+    x = pl.x;
+    y = pl.y;
+  }
+}
+
+position::position() : x(0.0), y(0.0)
+{
+}
+
+position::position(double a, double b) : x(a), y(b)
+{
+}
+
+
+int operator==(const position &a, const position &b)
+{
+  return a.x == b.x && a.y == b.y;
+}
+
+int operator!=(const position &a, const position &b)
+{
+  return a.x != b.x || a.y != b.y;
+}
+
+position &position::operator+=(const position &a)
+{
+  x += a.x;
+  y += a.y;
+  return *this;
+}
+
+position &position::operator-=(const position &a)
+{
+  x -= a.x;
+  y -= a.y;
+  return *this;
+}
+
+position &position::operator*=(double a)
+{
+  x *= a;
+  y *= a;
+  return *this;
+}
+
+position &position::operator/=(double a)
+{
+  x /= a;
+  y /= a;
+  return *this;
+}
+
+position operator-(const position &a)
+{
+  return position(-a.x, -a.y);
+}
+
+position operator+(const position &a, const position &b)
+{
+  return position(a.x + b.x, a.y + b.y);
+}
+
+position operator-(const position &a, const position &b)
+{
+  return position(a.x - b.x, a.y - b.y);
+}
+
+position operator/(const position &a, double n)
+{
+  return position(a.x/n, a.y/n);
+}
+
+position operator*(const position &a, double n)
+{
+  return position(a.x*n, a.y*n);
+}
+
+// dot product
+
+double operator*(const position &a, const position &b)
+{
+  return a.x*b.x + a.y*b.y;
+}
+
+double hypot(const position &a)
+{
+  return groff_hypot(a.x, a.y);
+}
+
+struct arrow_head_type {
+  double height;
+  double width;
+  int solid;
+};
+
+void draw_arrow(const position &pos, const distance &dir,
+		const arrow_head_type &aht, const line_type &lt,
+		char *outline_color_for_fill)
+{
+  double hyp = hypot(dir);
+  if (hyp == 0.0) {
+    error("cannot draw arrow on object with zero length");
+    return;
+  }
+  position base = -dir;
+  base *= aht.height/hyp;
+  position n(dir.y, -dir.x);
+  n *= aht.width/(hyp*2.0);
+  line_type slt = lt;
+  slt.type = line_type::solid;
+  if (aht.solid && out->supports_filled_polygons()) {
+    position v[3];
+    v[0] = pos;
+    v[1] = pos + base + n;
+    v[2] = pos + base - n;
+    // fill with outline color
+    out->set_color(outline_color_for_fill, outline_color_for_fill);
+    // make stroke thin to avoid arrow sticking
+    slt.thickness = 0.1;
+    out->polygon(v, 3, slt, 1);
+  }
+  else {
+    // use two line segments to avoid arrow sticking
+    out->line(pos + base - n, &pos, 1, slt);
+    out->line(pos + base + n, &pos, 1, slt);
+  }
+}
+
+object::object() : prev(0), next(0)
+{
+}
+
+object::~object()
+{
+}
+
+void object::move_by(const position &)
+{
+}
+
+void object::print()
+{
+}
+
+void object::print_text()
+{
+}
+
+int object::blank()
+{
+  return 0;
+}
+
+struct bounding_box {
+  int blank;
+  position ll;
+  position ur;
+
+  bounding_box();
+  void encompass(const position &);
+};
+
+bounding_box::bounding_box()
+: blank(1)
+{
+}
+
+void bounding_box::encompass(const position &pos)
+{
+  if (blank) {
+    ll = pos;
+    ur = pos;
+    blank = 0;
+  }
+  else {
+    if (pos.x < ll.x)
+      ll.x = pos.x;
+    if (pos.y < ll.y)
+      ll.y = pos.y;
+    if (pos.x > ur.x)
+      ur.x = pos.x;
+    if (pos.y > ur.y)
+      ur.y = pos.y;
+  }
+}
+
+void object::update_bounding_box(bounding_box *)
+{
+}
+
+position object::origin()
+{
+  return position(0.0,0.0);
+}
+
+position object::north()
+{
+  return origin();
+}
+
+position object::south()
+{
+  return origin();
+}
+
+position object::east()
+{
+  return origin();
+}
+
+position object::west()
+{
+  return origin();
+}
+
+position object::north_east()
+{
+  return origin();
+}
+
+position object::north_west()
+{
+  return origin();
+}
+
+position object::south_east()
+{
+  return origin();
+}
+
+position object::south_west()
+{
+  return origin();
+}
+
+position object::start()
+{
+  return origin();
+}
+
+position object::end()
+{
+  return origin();
+}
+
+position object::center()
+{
+  return origin();
+}
+
+double object::width()
+{
+  return 0.0;
+}
+
+double object::radius()
+{
+  return 0.0;
+}
+
+double object::height()
+{
+  return 0.0;
+}
+
+place *object::find_label(const char *)
+{
+  return 0;
+}
+
+segment::segment(const position &a, int n, segment *p)
+: is_absolute(n), pos(a), next(p)
+{
+}
+
+text_item::text_item(char *t, const char *fn, int ln)
+: next(0), text(t), filename(fn), lineno(ln) 
+{
+  adj.h = CENTER_ADJUST;
+  adj.v = NONE_ADJUST;
+}
+
+text_item::~text_item()
+{
+  delete[] text;
+}
+
+object_spec::object_spec(object_type t) : type(t)
+{
+  flags = 0;
+  tbl = 0;
+  segment_list = 0;
+  segment_width = segment_height = 0.0;
+  segment_is_absolute = 0;
+  text = 0;
+  shaded = 0;
+  xslanted = 0;
+  yslanted = 0;
+  outlined = 0;
+  with = 0;
+  dir = RIGHT_DIRECTION;
+}
+
+object_spec::~object_spec()
+{
+  delete tbl;
+  while (segment_list != 0) {
+    segment *tem = segment_list;
+    segment_list = segment_list->next;
+    delete tem;
+  }
+  object *p = oblist.head;
+  while (p != 0) {
+    object *tem = p;
+    p = p->next;
+    delete tem;
+  }
+  while (text != 0) {
+    text_item *tem = text;
+    text = text->next;
+    delete tem;
+  }
+  delete with;
+  delete[] shaded;
+  delete[] outlined;
+}
+
+class command_object : public object {
+  char *s;
+  const char *filename;
+  int lineno;
+public:
+  command_object(char *, const char *, int);
+  ~command_object();
+  object_type type() { return OTHER_OBJECT; }
+  void print();
+};
+
+command_object::command_object(char *p, const char *fn, int ln)
+: s(p), filename(fn), lineno(ln)
+{
+}
+
+command_object::~command_object()
+{
+  delete[] s;
+}
+
+void command_object::print()
+{
+  out->command(s, filename, lineno);
+}
+
+object *make_command_object(char *s, const char *fn, int ln)
+{
+  return new command_object(s, fn, ln);
+}
+
+class mark_object : public object {
+public:
+  mark_object();
+  object_type type();
+};
+
+object *make_mark_object()
+{
+  return new mark_object();
+}
+
+mark_object::mark_object()
+{
+}
+
+object_type mark_object::type()
+{
+  return MARK_OBJECT;
+}
+
+object_list::object_list() : head(0), tail(0)
+{
+}
+
+void object_list::append(object *obj)
+{
+  if (tail == 0) {
+    obj->next = obj->prev = 0;
+    head = tail = obj;
+  }
+  else {
+    obj->prev = tail;
+    obj->next = 0;
+    tail->next = obj;
+    tail = obj;
+  }
+}
+
+void object_list::wrap_up_block(object_list *ol)
+{
+  object *p;
+  for (p = tail; p && p->type() != MARK_OBJECT; p = p->prev)
+    ;
+  assert(p != 0);
+  ol->head = p->next;
+  if (ol->head) {
+    ol->tail = tail;
+    ol->head->prev = 0;
+  }
+  else
+    ol->tail = 0;
+  tail = p->prev;
+  if (tail)
+    tail->next = 0;
+  else
+    head = 0;
+  delete p;
+}
+
+text_piece::text_piece()
+: text(0), filename(0), lineno(-1)
+{
+  adj.h = CENTER_ADJUST;
+  adj.v = NONE_ADJUST;
+}
+
+text_piece::~text_piece()
+{
+  free(text);
+}
+
+class graphic_object : public object {
+  int ntext;
+  text_piece *text;
+  int aligned;
+protected:
+  line_type lt;
+  char *outline_color;
+  char *color_fill;
+public:
+  graphic_object();
+  ~graphic_object();
+  object_type type() = 0;
+  void print_text();
+  void add_text(text_item *, int);
+  void set_dotted(double);
+  void set_dashed(double);
+  void set_thickness(double);
+  void set_invisible();
+  void set_outline_color(char *);
+  char *get_outline_color();
+  virtual void set_fill(double);
+  virtual void set_xslanted(double);
+  virtual void set_yslanted(double);
+  virtual void set_fill_color(char *);
+};
+
+graphic_object::graphic_object()
+: ntext(0), text(0), aligned(0), outline_color(0), color_fill(0)
+{
+}
+
+void graphic_object::set_dotted(double wid)
+{
+  lt.type = line_type::dotted;
+  lt.dash_width = wid;
+}
+
+void graphic_object::set_dashed(double wid)
+{
+  lt.type = line_type::dashed;
+  lt.dash_width = wid;
+}
+
+void graphic_object::set_thickness(double th)
+{
+  lt.thickness = th;
+}
+
+void graphic_object::set_fill(double)
+{
+}
+
+void graphic_object::set_xslanted(double)
+{
+}
+
+void graphic_object::set_yslanted(double)
+{
+}
+
+void graphic_object::set_fill_color(char *c)
+{
+  color_fill = strsave(c);
+}
+
+void graphic_object::set_outline_color(char *c)
+{
+  outline_color = strsave(c);
+}
+
+char *graphic_object::get_outline_color()
+{
+  return outline_color;
+}
+
+void graphic_object::set_invisible()
+{
+  lt.type = line_type::invisible;
+}
+
+void graphic_object::add_text(text_item *t, int a)
+{
+  aligned = a;
+  int len = 0;
+  text_item *p;
+  for (p = t; p; p = p->next)
+    len++;
+  if (len == 0)
+    text = 0;
+  else {
+    text = new text_piece[len];
+    for (p = t, len = 0; p; p = p->next, len++) {
+      text[len].text = p->text;
+      p->text = 0;
+      text[len].adj = p->adj;
+      text[len].filename = p->filename;
+      text[len].lineno = p->lineno;
+    }
+  }
+  ntext = len;
+}
+
+void graphic_object::print_text()
+{
+  double angle = 0.0;
+  if (aligned) {
+    position d(end() - start());
+    if (d.x != 0.0 || d.y != 0.0)
+      angle = atan2(d.y, d.x);
+  }
+  if (text != 0) {
+    out->set_color(color_fill, get_outline_color());
+    out->text(center(), text, ntext, angle);
+    out->reset_color();
+  }
+}
+
+graphic_object::~graphic_object()
+{
+  if (text)
+    delete[] text;
+}
+
+class rectangle_object : public graphic_object {
+protected:
+  position cent;
+  position dim;
+public:
+  rectangle_object(const position &);
+  double width() { return dim.x; }
+  double height() { return dim.y; }
+  position origin() { return cent; }
+  position center() { return cent; }
+  position north() { return position(cent.x, cent.y + dim.y/2.0); }
+  position south() { return position(cent.x, cent.y - dim.y/2.0); }
+  position east() { return position(cent.x + dim.x/2.0, cent.y); }
+  position west() { return position(cent.x - dim.x/2.0, cent.y); }
+  position north_east() { return position(cent.x + dim.x/2.0, cent.y + dim.y/2.0); }
+  position north_west() { return position(cent.x - dim.x/2.0, cent.y + dim.y/2.0); }
+  position south_east() { return position(cent.x + dim.x/2.0, cent.y - dim.y/2.0); }
+  position south_west() { return position(cent.x - dim.x/2.0, cent.y - dim.y/2.0); }
+  object_type type() = 0;
+  void update_bounding_box(bounding_box *);
+  void move_by(const position &);
+};
+
+rectangle_object::rectangle_object(const position &d)
+: dim(d)
+{
+}
+
+void rectangle_object::update_bounding_box(bounding_box *p)
+{
+  p->encompass(cent - dim/2.0);
+  p->encompass(cent + dim/2.0);
+}
+
+void rectangle_object::move_by(const position &a)
+{
+  cent += a;
+}
+
+class closed_object : public rectangle_object {
+public:
+  closed_object(const position &);
+  object_type type() = 0;
+  void set_fill(double);
+  void set_xslanted(double);
+  void set_yslanted(double);
+  void set_fill_color(char *fill);
+protected:
+  double fill;			// < 0 if not filled
+  double xslanted;		// !=0 if x is slanted
+  double yslanted;		// !=0 if y is slanted
+  char *color_fill;		// = 0 if not colored
+};
+
+closed_object::closed_object(const position &pos)
+: rectangle_object(pos), fill(-1.0), xslanted(0), yslanted(0), color_fill(0)
+{
+}
+
+void closed_object::set_fill(double f)
+{
+  assert(f >= 0.0);
+  fill = f;
+}
+
+/* accept positive and negative values */ 
+void closed_object::set_xslanted(double s)
+{
+  //assert(s >= 0.0);
+  xslanted = s;
+}
+/* accept positive and negative values */ 
+void closed_object::set_yslanted(double s)
+{
+  //assert(s >= 0.0);
+  yslanted = s;
+}
+
+void closed_object::set_fill_color(char *f)
+{
+  color_fill = strsave(f);
+}
+
+class box_object : public closed_object {
+  double xrad;
+  double yrad;
+public:
+  box_object(const position &, double);
+  object_type type() { return BOX_OBJECT; }
+  void print();
+  position north_east();
+  position north_west();
+  position south_east();
+  position south_west();
+};
+
+box_object::box_object(const position &pos, double r)
+: closed_object(pos), xrad(dim.x > 0 ? r : -r), yrad(dim.y > 0 ? r : -r)
+{
+}
+
+const double CHOP_FACTOR = 1.0 - 1.0/M_SQRT2;
+
+position box_object::north_east()
+{
+  return position(cent.x + dim.x/2.0 - CHOP_FACTOR*xrad,
+		  cent.y + dim.y/2.0 - CHOP_FACTOR*yrad);
+}
+
+position box_object::north_west()
+{
+  return position(cent.x - dim.x/2.0 + CHOP_FACTOR*xrad,
+		  cent.y + dim.y/2.0 - CHOP_FACTOR*yrad);
+}
+
+position box_object::south_east()
+{
+  return position(cent.x + dim.x/2.0 - CHOP_FACTOR*xrad,
+		  cent.y - dim.y/2.0 + CHOP_FACTOR*yrad);
+}
+
+position box_object::south_west()
+{
+  return position(cent.x - dim.x/2.0 + CHOP_FACTOR*xrad,
+		  cent.y - dim.y/2.0 + CHOP_FACTOR*yrad);
+}
+
+void box_object::print()
+{
+  if (lt.type == line_type::invisible && fill < 0.0 && color_fill == 0)
+    return;
+  out->set_color(color_fill, graphic_object::get_outline_color());
+  if (xrad == 0.0) {
+    distance dim2 = dim/2.0;
+    position vec[4];
+    /* error("x slanted %1", xslanted); */
+    /* error("y slanted %1", yslanted); */
+    vec[0] = cent + position(dim2.x, -(dim2.y - yslanted));	     /* lr */
+    vec[1] = cent + position(dim2.x + xslanted, dim2.y + yslanted);  /* ur */
+    vec[2] = cent + position(-(dim2.x - xslanted), dim2.y);	     /* ul */
+    vec[3] = cent + position(-(dim2.x), -dim2.y);		     /* ll */
+    out->polygon(vec, 4, lt, fill);
+  }
+  else {
+    distance abs_dim(fabs(dim.x), fabs(dim.y));
+    out->rounded_box(cent, abs_dim, fabs(xrad), lt, fill, color_fill);
+  }
+  out->reset_color();
+}
+
+graphic_object *object_spec::make_box(position *curpos, direction *dirp)
+{
+  static double last_box_height;
+  static double last_box_width;
+  static double last_box_radius;
+  static int have_last_box = 0;
+  if (!(flags & HAS_HEIGHT)) {
+    if ((flags & IS_SAME) && have_last_box)
+      height = last_box_height;
+    else
+      lookup_variable("boxht", &height);
+  }
+  if (!(flags & HAS_WIDTH)) {
+    if ((flags & IS_SAME) && have_last_box)
+      width = last_box_width;
+    else
+      lookup_variable("boxwid", &width);
+  }
+  if (!(flags & HAS_RADIUS)) {
+    if ((flags & IS_SAME) && have_last_box)
+      radius = last_box_radius;
+    else
+      lookup_variable("boxrad", &radius);
+  }
+  last_box_width = width;
+  last_box_height = height;
+  last_box_radius = radius;
+  have_last_box = 1;
+  radius = fabs(radius);
+  if (radius*2.0 > fabs(width))
+    radius = fabs(width/2.0);
+  if (radius*2.0 > fabs(height))
+    radius = fabs(height/2.0);
+  box_object *p = new box_object(position(width, height), radius);
+  if (!position_rectangle(p, curpos, dirp)) {
+    delete p;
+    p = 0;
+  }
+  return p;
+}
+
+// return non-zero for success
+
+int object_spec::position_rectangle(rectangle_object *p,
+				    position *curpos, direction *dirp)
+{
+  position pos;
+  dir = *dirp;			// ignore any direction in attribute list
+  position motion;
+  switch (dir) {
+  case UP_DIRECTION:
+    motion.y = p->height()/2.0;
+    break;
+  case DOWN_DIRECTION:
+    motion.y = -p->height()/2.0;
+    break;
+  case LEFT_DIRECTION:
+    motion.x = -p->width()/2.0;
+    break;
+  case RIGHT_DIRECTION:
+    motion.x = p->width()/2.0;
+    break;
+  default:
+    assert(0);
+  }
+  if (flags & HAS_AT) {
+    pos = at;
+    if (flags & HAS_WITH) {
+      place offset;
+      place here;
+      here.obj = p;
+      if (!with->follow(here, &offset))
+	return 0;
+      pos -= offset;
+    }
+  }
+  else {
+    pos = *curpos;
+    pos += motion;
+  }
+  p->move_by(pos);
+  pos += motion;
+  *curpos = pos;
+  return 1;
+}
+
+class block_object : public rectangle_object {
+  object_list oblist;
+  PTABLE(place) *tbl;
+public:
+  block_object(const position &, const object_list &ol, PTABLE(place) *t);
+  ~block_object();
+  place *find_label(const char *);
+  object_type type();
+  void move_by(const position &);
+  void print();
+};
+
+block_object::block_object(const position &d, const object_list &ol,
+			   PTABLE(place) *t)
+: rectangle_object(d), oblist(ol), tbl(t)
+{
+}
+
+block_object::~block_object()
+{
+  delete tbl;
+  object *p = oblist.head;
+  while (p != 0) {
+    object *tem = p;
+    p = p->next;
+    delete tem;
+  }
+}
+
+void block_object::print()
+{
+  out->begin_block(south_west(), north_east());
+  print_object_list(oblist.head);
+  out->end_block();
+}
+
+static void adjust_objectless_places(PTABLE(place) *tbl, const position &a)
+{
+  // Adjust all the labels that aren't attached to objects.
+  PTABLE_ITERATOR(place) iter(tbl);
+  const char *key;
+  place *pl;
+  while (iter.next(&key, &pl))
+    if (key && csupper(key[0]) && pl->obj == 0) {
+      pl->x += a.x;
+      pl->y += a.y;
+    }
+}
+
+void block_object::move_by(const position &a)
+{
+  cent += a;
+  for (object *p = oblist.head; p; p = p->next)
+    p->move_by(a);
+  adjust_objectless_places(tbl, a);
+}
+
+
+place *block_object::find_label(const char *name)
+{
+  return tbl->lookup(name);
+}
+
+object_type block_object::type()
+{
+  return BLOCK_OBJECT;
+}
+
+graphic_object *object_spec::make_block(position *curpos, direction *dirp)
+{
+  bounding_box bb;
+  for (object *p = oblist.head; p; p = p->next)
+    p->update_bounding_box(&bb);
+  position dim;
+  if (!bb.blank) {
+    position m = -(bb.ll + bb.ur)/2.0;
+    for (object *p = oblist.head; p; p = p->next)
+      p->move_by(m);
+    adjust_objectless_places(tbl, m);
+    dim = bb.ur - bb.ll;
+  }
+  if (flags & HAS_WIDTH)
+    dim.x = width;
+  if (flags & HAS_HEIGHT)
+    dim.y = height;
+  block_object *block = new block_object(dim, oblist, tbl);
+  if (!position_rectangle(block, curpos, dirp)) {
+    delete block;
+    block = 0;
+  }
+  tbl = 0;
+  oblist.head = oblist.tail = 0;
+  return block;
+}
+
+class text_object : public rectangle_object {
+public:
+  text_object(const position &);
+  object_type type() { return TEXT_OBJECT; }
+};
+
+text_object::text_object(const position &d)
+: rectangle_object(d)
+{
+}
+
+graphic_object *object_spec::make_text(position *curpos, direction *dirp)
+{
+  if (!(flags & HAS_HEIGHT)) {
+    lookup_variable("textht", &height);
+    int nitems = 0;
+    for (text_item *t = text; t; t = t->next)
+      nitems++;
+    height *= nitems;
+  }
+  if (!(flags & HAS_WIDTH))
+    lookup_variable("textwid", &width);
+  text_object *p = new text_object(position(width, height));
+  if (!position_rectangle(p, curpos, dirp)) {
+    delete p;
+    p = 0;
+  }
+  return p;
+}
+
+
+class ellipse_object : public closed_object {
+public:
+  ellipse_object(const position &);
+  position north_east() { return position(cent.x + dim.x/(M_SQRT2*2.0),
+					  cent.y + dim.y/(M_SQRT2*2.0)); }
+  position north_west() { return position(cent.x - dim.x/(M_SQRT2*2.0),
+					  cent.y + dim.y/(M_SQRT2*2.0)); }
+  position south_east() { return position(cent.x + dim.x/(M_SQRT2*2.0),
+					  cent.y - dim.y/(M_SQRT2*2.0)); }
+  position south_west() { return position(cent.x - dim.x/(M_SQRT2*2.0),
+					  cent.y - dim.y/(M_SQRT2*2.0)); }
+  double radius() { return dim.x/2.0; }
+  object_type type() { return ELLIPSE_OBJECT; }
+  void print();
+};
+
+ellipse_object::ellipse_object(const position &d)
+: closed_object(d)
+{
+}
+
+void ellipse_object::print()
+{
+  if (lt.type == line_type::invisible && fill < 0.0 && color_fill == 0)
+    return;
+  out->set_color(color_fill, graphic_object::get_outline_color());
+  out->ellipse(cent, dim, lt, fill);
+  out->reset_color();
+}
+
+graphic_object *object_spec::make_ellipse(position *curpos, direction *dirp)
+{
+  static double last_ellipse_height;
+  static double last_ellipse_width;
+  static int have_last_ellipse = 0;
+  if (!(flags & HAS_HEIGHT)) {
+    if ((flags & IS_SAME) && have_last_ellipse)
+      height = last_ellipse_height;
+    else
+      lookup_variable("ellipseht", &height);
+  }
+  if (!(flags & HAS_WIDTH)) {
+    if ((flags & IS_SAME) && have_last_ellipse)
+      width = last_ellipse_width;
+    else
+      lookup_variable("ellipsewid", &width);
+  }
+  last_ellipse_width = width;
+  last_ellipse_height = height;
+  have_last_ellipse = 1;
+  ellipse_object *p = new ellipse_object(position(width, height));
+  if (!position_rectangle(p, curpos, dirp)) {
+    delete p;
+    return 0;
+  }
+  return p;
+}
+
+class circle_object : public ellipse_object {
+public:
+  circle_object(double);
+  object_type type() { return CIRCLE_OBJECT; }
+  void print();
+};
+
+circle_object::circle_object(double diam)
+: ellipse_object(position(diam, diam))
+{
+}
+
+void circle_object::print()
+{
+  if (lt.type == line_type::invisible && fill < 0.0 && color_fill == 0)
+    return;
+  out->set_color(color_fill, graphic_object::get_outline_color());
+  out->circle(cent, dim.x/2.0, lt, fill);
+  out->reset_color();
+}
+
+graphic_object *object_spec::make_circle(position *curpos, direction *dirp)
+{
+  static double last_circle_radius;
+  static int have_last_circle = 0;
+  if (!(flags & HAS_RADIUS)) {
+    if ((flags & IS_SAME) && have_last_circle)
+      radius = last_circle_radius;
+    else
+      lookup_variable("circlerad", &radius);
+  }
+  last_circle_radius = radius;
+  have_last_circle = 1;
+  circle_object *p = new circle_object(radius*2.0);
+  if (!position_rectangle(p, curpos, dirp)) {
+    delete p;
+    return 0;
+  }
+  return p;
+}
+
+class move_object : public graphic_object {
+  position strt;
+  position en;
+public:
+  move_object(const position &s, const position &e);
+  position origin() { return en; }
+  object_type type() { return MOVE_OBJECT; }
+  void update_bounding_box(bounding_box *);
+  void move_by(const position &);
+};
+
+move_object::move_object(const position &s, const position &e)
+: strt(s), en(e)
+{
+}
+
+void move_object::update_bounding_box(bounding_box *p)
+{
+  p->encompass(strt);
+  p->encompass(en);
+}
+
+void move_object::move_by(const position &a)
+{
+  strt += a;
+  en += a;
+}
+
+graphic_object *object_spec::make_move(position *curpos, direction *dirp)
+{
+  static position last_move;
+  static int have_last_move = 0;
+  *dirp = dir;
+  // No need to look at at since 'at' attribute sets 'from' attribute.
+  position startpos = (flags & HAS_FROM) ? from : *curpos;
+  if (!(flags & HAS_SEGMENT)) {
+    if ((flags & IS_SAME) && have_last_move)
+      segment_pos = last_move;
+    else {
+      switch (dir) {
+      case UP_DIRECTION:
+	segment_pos.y = segment_height;
+	break;
+      case DOWN_DIRECTION:
+	segment_pos.y = -segment_height;
+	break;
+      case LEFT_DIRECTION:
+	segment_pos.x = -segment_width;
+	break;
+      case RIGHT_DIRECTION:
+	segment_pos.x = segment_width;
+	break;
+      default:
+	assert(0);
+      }
+    }
+  }
+  segment_list = new segment(segment_pos, segment_is_absolute, segment_list);
+  // Reverse the segment_list so that it's in forward order.
+  segment *old = segment_list;
+  segment_list = 0;
+  while (old != 0) {
+    segment *tem = old->next;
+    old->next = segment_list;
+    segment_list = old;
+    old = tem;
+  }
+  // Compute the end position.
+  position endpos = startpos;
+  for (segment *s = segment_list; s; s = s->next)
+    if (s->is_absolute)
+      endpos = s->pos;
+    else 
+      endpos += s->pos;
+  have_last_move = 1;
+  last_move = endpos - startpos;
+  move_object *p = new move_object(startpos, endpos);
+  *curpos = endpos;
+  return p;
+}
+
+class linear_object : public graphic_object {
+protected:
+  char arrow_at_start;
+  char arrow_at_end;
+  arrow_head_type aht;
+  position strt;
+  position en;
+public:
+  linear_object(const position &s, const position &e);
+  position start() { return strt; }
+  position end() { return en; }
+  void move_by(const position &);
+  void update_bounding_box(bounding_box *) = 0;
+  object_type type() = 0;
+  void add_arrows(int at_start, int at_end, const arrow_head_type &);
+};
+
+class line_object : public linear_object {
+protected:
+  position *v;
+  int n;
+public:
+  line_object(const position &s, const position &e, position *, int);
+  ~line_object();
+  position origin() { return strt; }
+  position center() { return (strt + en)/2.0; }
+  position north() { return (en.y - strt.y) > 0 ? en : strt; }
+  position south() { return (en.y - strt.y) < 0 ? en : strt; }
+  position east() { return (en.x - strt.x) > 0 ? en : strt; }
+  position west() { return (en.x - strt.x) < 0 ? en : strt; }
+  object_type type() { return LINE_OBJECT; }
+  void update_bounding_box(bounding_box *);
+  void print();
+  void move_by(const position &);
+};
+
+class arrow_object : public line_object {
+public:
+  arrow_object(const position &, const position &, position *, int);
+  object_type type() { return ARROW_OBJECT; }
+};
+
+class spline_object : public line_object {
+public:
+  spline_object(const position &, const position &, position *, int);
+  object_type type() { return SPLINE_OBJECT; }
+  void print();
+  void update_bounding_box(bounding_box *);
+};
+
+linear_object::linear_object(const position &s, const position &e)
+: arrow_at_start(0), arrow_at_end(0), strt(s), en(e)
+{
+}
+
+void linear_object::move_by(const position &a)
+{
+  strt += a;
+  en += a;
+}
+
+void linear_object::add_arrows(int at_start, int at_end,
+			       const arrow_head_type &a)
+{
+  arrow_at_start = at_start;
+  arrow_at_end = at_end;
+  aht = a;
+}
+
+line_object::line_object(const position &s, const position &e,
+			 position *p, int i)
+: linear_object(s, e), v(p), n(i)
+{
+}
+
+void line_object::print()
+{
+  if (lt.type == line_type::invisible)
+    return;
+  out->set_color(0, graphic_object::get_outline_color());
+  // shorten line length to avoid arrow sticking.
+  position sp = strt;
+  if (arrow_at_start) {
+    position base = v[0] - strt;
+    double hyp = hypot(base);
+    if (hyp == 0.0) {
+      error("cannot draw arrow on object with zero length");
+      return;
+    }
+    if (aht.solid && out->supports_filled_polygons()) {
+      base *= aht.height / hyp;
+      draw_arrow(strt, strt - v[0], aht, lt,
+		 graphic_object::get_outline_color());
+      sp = strt + base;
+    } else {
+      base *= fabs(lt.thickness) / hyp / 72 / 4;
+      sp = strt + base;
+      draw_arrow(sp, sp - v[0], aht, lt,
+		 graphic_object::get_outline_color());
+    }
+  }
+  if (arrow_at_end) {
+    position base = v[n-1] - (n > 1 ? v[n-2] : strt);
+    double hyp = hypot(base);
+    if (hyp == 0.0) {
+      error("cannot draw arrow on object with zero length");
+      return;
+    }
+    if (aht.solid && out->supports_filled_polygons()) {
+      base *= aht.height / hyp;
+      draw_arrow(en, v[n-1] - (n > 1 ? v[n-2] : strt), aht, lt,
+		 graphic_object::get_outline_color());
+      v[n-1] = en - base;
+    } else {
+      base *= fabs(lt.thickness) / hyp / 72 / 4;
+      v[n-1] = en - base;
+      draw_arrow(v[n-1], v[n-1] - (n > 1 ? v[n-2] : strt), aht, lt,
+		 graphic_object::get_outline_color());
+    }
+  }
+  out->line(sp, v, n, lt);
+  out->reset_color();
+}
+
+void line_object::update_bounding_box(bounding_box *p)
+{
+  p->encompass(strt);
+  for (int i = 0; i < n; i++)
+    p->encompass(v[i]);
+}
+
+void line_object::move_by(const position &pos)
+{
+  linear_object::move_by(pos);
+  for (int i = 0; i < n; i++)
+    v[i] += pos;
+}
+  
+void spline_object::update_bounding_box(bounding_box *p)
+{
+  p->encompass(strt);
+  p->encompass(en);
+  /*
+
+  If
+
+  p1 = q1/2 + q2/2
+  p2 = q1/6 + q2*5/6
+  p3 = q2*5/6 + q3/6
+  p4 = q2/2 + q3/2
+  [ the points for the Bezier cubic ]
+
+  and
+
+  t = .5
+
+  then
+
+  (1-t)^3*p1 + 3*t*(t - 1)^2*p2 + 3*t^2*(1-t)*p3 + t^3*p4
+  [ the equation for the Bezier cubic ]
+
+  = .125*q1 + .75*q2 + .125*q3
+
+  */
+  for (int i = 1; i < n; i++)
+    p->encompass((i == 1 ? strt : v[i-2])*.125 + v[i-1]*.75 + v[i]*.125);
+}
+
+arrow_object::arrow_object(const position &s, const position &e,
+			   position *p, int i)
+: line_object(s, e, p, i)
+{
+}
+
+spline_object::spline_object(const position &s, const position &e,
+			     position *p, int i)
+: line_object(s, e, p, i)
+{
+}
+
+void spline_object::print()
+{
+  if (lt.type == line_type::invisible)
+    return;
+  out->set_color(0, graphic_object::get_outline_color());
+  // shorten line length for spline to avoid arrow sticking
+  position sp = strt;
+  if (arrow_at_start) {
+    position base = v[0] - strt;
+    double hyp = hypot(base);
+    if (hyp == 0.0) {
+      error("cannot draw arrow on object with zero length");
+      return;
+    }
+    if (aht.solid && out->supports_filled_polygons()) {
+      base *= aht.height / hyp;
+      draw_arrow(strt, strt - v[0], aht, lt,
+		 graphic_object::get_outline_color());
+      sp = strt + base*0.1; // to reserve spline shape
+    } else {
+      base *= fabs(lt.thickness) / hyp / 72 / 4;
+      sp = strt + base;
+      draw_arrow(sp, sp - v[0], aht, lt,
+		 graphic_object::get_outline_color());
+    }
+  }
+  if (arrow_at_end) {
+    position base = v[n-1] - (n > 1 ? v[n-2] : strt);
+    double hyp = hypot(base);
+    if (hyp == 0.0) {
+      error("cannot draw arrow on object with zero length");
+      return;
+    }
+    if (aht.solid && out->supports_filled_polygons()) {
+      base *= aht.height / hyp;
+      draw_arrow(en, v[n-1] - (n > 1 ? v[n-2] : strt), aht, lt,
+		 graphic_object::get_outline_color());
+      v[n-1] = en - base*0.1; // to reserve spline shape
+    } else {
+      base *= fabs(lt.thickness) / hyp / 72 / 4;
+      v[n-1] = en - base;
+      draw_arrow(v[n-1], v[n-1] - (n > 1 ? v[n-2] : strt), aht, lt,
+		 graphic_object::get_outline_color());
+    }
+  }
+  out->spline(sp, v, n, lt);
+  out->reset_color();
+}
+
+line_object::~line_object()
+{
+  delete[] v;
+}
+
+linear_object *object_spec::make_line(position *curpos, direction *dirp)
+{
+  static position last_line;
+  static int have_last_line = 0;
+  *dirp = dir;
+  // We handle 'at' only in conjunction with 'with', otherwise it is
+  // the same as the 'from' attribute.
+  position startpos;
+  if ((flags & HAS_AT) && (flags & HAS_WITH))
+    // handled later -- we need the end position
+    startpos = *curpos;
+  else if (flags & HAS_FROM)
+    startpos = from;
+  else
+    startpos = *curpos;
+  if (!(flags & HAS_SEGMENT)) {
+    if ((flags & IS_SAME) && (type == LINE_OBJECT || type == ARROW_OBJECT)
+	&& have_last_line)
+      segment_pos = last_line;
+    else 
+      switch (dir) {
+      case UP_DIRECTION:
+	segment_pos.y = segment_height;
+	break;
+      case DOWN_DIRECTION:
+	segment_pos.y = -segment_height;
+	break;
+      case LEFT_DIRECTION:
+	segment_pos.x = -segment_width;
+	break;
+      case RIGHT_DIRECTION:
+	segment_pos.x = segment_width;
+	break;
+      default:
+	assert(0);
+      }
+  }
+  segment_list = new segment(segment_pos, segment_is_absolute, segment_list);
+  // reverse the segment_list so that it's in forward order
+  segment *old = segment_list;
+  segment_list = 0;
+  while (old != 0) {
+    segment *tem = old->next;
+    old->next = segment_list;
+    segment_list = old;
+    old = tem;
+  }
+  // Absolutise all movements
+  position endpos = startpos;
+  int nsegments = 0;
+  segment *s;
+  for (s = segment_list; s; s = s->next, nsegments++)
+    if (s->is_absolute)
+      endpos = s->pos;
+    else {
+      endpos += s->pos;
+      s->pos = endpos;
+      s->is_absolute = 1;	// to avoid confusion
+    }
+  if ((flags & HAS_AT) && (flags & HAS_WITH)) {
+    // 'tmpobj' works for arrows and splines too -- we only need positions
+    line_object tmpobj(startpos, endpos, 0, 0);
+    position pos = at;
+    place offset;
+    place here;
+    here.obj = &tmpobj;
+    if (!with->follow(here, &offset))
+      return 0;
+    pos -= offset;
+    for (s = segment_list; s; s = s->next)
+      s->pos += pos;
+    startpos += pos;
+    endpos += pos;
+  }
+  // handle chop
+  line_object *p = 0;
+  position *v = new position[nsegments];
+  int i = 0;
+  for (s = segment_list; s; s = s->next, i++)
+    v[i] = s->pos;
+  if (flags & IS_DEFAULT_CHOPPED) {
+    lookup_variable("circlerad", &start_chop);
+    end_chop = start_chop;
+    flags |= IS_CHOPPED;
+  }
+  if (flags & IS_CHOPPED) {
+    position start_chop_vec, end_chop_vec;
+    if (start_chop != 0.0) {
+      start_chop_vec = v[0] - startpos;
+      start_chop_vec *= start_chop / hypot(start_chop_vec);
+    }
+    if (end_chop != 0.0) {
+      end_chop_vec = (v[nsegments - 1]
+		      - (nsegments > 1 ? v[nsegments - 2] : startpos));
+      end_chop_vec *= end_chop / hypot(end_chop_vec);
+    }
+    startpos += start_chop_vec;
+    v[nsegments - 1] -= end_chop_vec;
+    endpos -= end_chop_vec;
+  }
+  switch (type) {
+  case SPLINE_OBJECT:
+    p = new spline_object(startpos, endpos, v, nsegments);
+    break;
+  case ARROW_OBJECT:
+    p = new arrow_object(startpos, endpos, v, nsegments);
+    break;
+  case LINE_OBJECT:
+    p = new line_object(startpos, endpos, v, nsegments);
+    break;
+  default:
+    assert(0);
+  }
+  have_last_line = 1;
+  last_line = endpos - startpos;
+  *curpos = endpos;
+  return p;
+}
+
+class arc_object : public linear_object {
+  int clockwise;
+  position cent;
+  double rad;
+public:
+  arc_object(int, const position &, const position &, const position &);
+  position origin() { return cent; }
+  position center() { return cent; }
+  double radius() { return rad; }
+  position north();
+  position south();
+  position east();
+  position west();
+  position north_east();
+  position north_west();
+  position south_east();
+  position south_west();
+  void update_bounding_box(bounding_box *);
+  object_type type() { return ARC_OBJECT; }
+  void print();
+  void move_by(const position &pos);
+};
+
+arc_object::arc_object(int cw, const position &s, const position &e,
+		       const position &c)
+: linear_object(s, e), clockwise(cw), cent(c)
+{
+  rad = hypot(c - s);
+}
+
+void arc_object::move_by(const position &pos)
+{
+  linear_object::move_by(pos);
+  cent += pos;
+}
+
+// we get arc corners from the corresponding circle
+
+position arc_object::north()
+{
+  position result(cent);
+  result.y += rad;
+  return result;
+}
+
+position arc_object::south()
+{
+  position result(cent);
+  result.y -= rad;
+  return result;
+}
+
+position arc_object::east()
+{
+  position result(cent);
+  result.x += rad;
+  return result;
+}
+
+position arc_object::west()
+{
+  position result(cent);
+  result.x -= rad;
+  return result;
+}
+
+position arc_object::north_east()
+{
+  position result(cent);
+  result.x += rad/M_SQRT2;
+  result.y += rad/M_SQRT2;
+  return result;
+}
+
+position arc_object::north_west()
+{
+  position result(cent);
+  result.x -= rad/M_SQRT2;
+  result.y += rad/M_SQRT2;
+  return result;
+}
+
+position arc_object::south_east()
+{
+  position result(cent);
+  result.x += rad/M_SQRT2;
+  result.y -= rad/M_SQRT2;
+  return result;
+}
+
+position arc_object::south_west()
+{
+  position result(cent);
+  result.x -= rad/M_SQRT2;
+  result.y -= rad/M_SQRT2;
+  return result;
+}
+
+
+void arc_object::print()
+{
+  if (lt.type == line_type::invisible)
+    return;
+  out->set_color(0, graphic_object::get_outline_color());
+  // handle arrow direction; make shorter line for arc
+  position sp, ep, b;
+  if (clockwise) {
+    sp = en;
+    ep = strt;
+  } else {
+    sp = strt;
+    ep = en;
+  }
+  if (arrow_at_start) {
+    double theta = aht.height / rad;
+    if (clockwise)
+      theta = - theta;
+    b = strt - cent;
+    b = position(b.x*cos(theta) - b.y*sin(theta),
+		 b.x*sin(theta) + b.y*cos(theta)) + cent;
+    if (clockwise)
+      ep = b;
+    else
+      sp = b;
+    if (aht.solid && out->supports_filled_polygons()) {
+      draw_arrow(strt, strt - b, aht, lt,
+		 graphic_object::get_outline_color());
+    } else {
+      position v = b;
+      theta = fabs(lt.thickness) / 72 / 4 / rad;
+      if (clockwise)
+	theta = - theta;
+      b = strt - cent;
+      b = position(b.x*cos(theta) - b.y*sin(theta),
+		   b.x*sin(theta) + b.y*cos(theta)) + cent;
+      draw_arrow(b, b - v, aht, lt,
+		 graphic_object::get_outline_color());
+      out->line(b, &v, 1, lt);
+    }
+  }
+  if (arrow_at_end) {
+    double theta = aht.height / rad;
+    if (!clockwise)
+      theta = - theta;
+    b = en - cent;
+    b = position(b.x*cos(theta) - b.y*sin(theta),
+                 b.x*sin(theta) + b.y*cos(theta)) + cent;
+    if (clockwise)
+      sp = b;
+    else
+      ep = b;
+    if (aht.solid && out->supports_filled_polygons()) {
+      draw_arrow(en, en - b, aht, lt,
+		 graphic_object::get_outline_color());
+    } else {
+      position v = b;
+      theta = fabs(lt.thickness) / 72 / 4 / rad;
+      if (!clockwise)
+	theta = - theta;
+      b = en - cent;
+      b = position(b.x*cos(theta) - b.y*sin(theta),
+                   b.x*sin(theta) + b.y*cos(theta)) + cent;
+      draw_arrow(b, b - v, aht, lt,
+		 graphic_object::get_outline_color());
+      out->line(b, &v, 1, lt);
+    }
+  }
+  out->arc(sp, cent, ep, lt);
+  out->reset_color();
+}
+
+inline double max(double a, double b)
+{
+  return a > b ? a : b;
+}
+
+void arc_object::update_bounding_box(bounding_box *p)
+{
+  p->encompass(strt);
+  p->encompass(en);
+  position start_offset = strt - cent;
+  if (start_offset.x == 0.0 && start_offset.y == 0.0)
+    return;
+  position end_offset = en  - cent;
+  if (end_offset.x == 0.0 && end_offset.y == 0.0)
+    return;
+  double start_quad = atan2(start_offset.y, start_offset.x)/(M_PI/2.0);
+  double end_quad = atan2(end_offset.y, end_offset.x)/(M_PI/2.0);
+  if (clockwise) {
+    double temp = start_quad;
+    start_quad = end_quad;
+    end_quad = temp;
+  }
+  if (start_quad < 0.0)
+    start_quad += 4.0;
+  while (end_quad <= start_quad)
+    end_quad += 4.0;
+  double r = max(hypot(start_offset), hypot(end_offset));
+  for (int q = int(start_quad) + 1; q < end_quad; q++) {
+    position offset;
+    switch (q % 4) {
+    case 0:
+      offset.x = r;
+      break;
+    case 1:
+      offset.y = r;
+      break;
+    case 2:
+      offset.x = -r;
+      break;
+    case 3:
+      offset.y = -r;
+      break;
+    }
+    p->encompass(cent + offset);
+  }
+}
+
+// We ignore the with attribute. The at attribute always refers to the center.
+
+linear_object *object_spec::make_arc(position *curpos, direction *dirp)
+{
+  *dirp = dir;
+  int cw = (flags & IS_CLOCKWISE) != 0;
+  // compute the start
+  position startpos;
+  if (flags & HAS_FROM)
+    startpos = from;
+  else
+    startpos = *curpos;
+  if (!(flags & HAS_RADIUS))
+    lookup_variable("arcrad", &radius);
+  // compute the end
+  position endpos;
+  if (flags & HAS_TO)
+    endpos = to;
+  else {
+    position m(radius, radius);
+    // Adjust the signs.
+    if (cw) {
+      if (dir == DOWN_DIRECTION || dir == LEFT_DIRECTION)
+	m.x = -m.x;
+      if (dir == DOWN_DIRECTION || dir == RIGHT_DIRECTION)
+	m.y = -m.y;
+      *dirp = direction((dir + 3) % 4);
+    }
+    else {
+      if (dir == UP_DIRECTION || dir == LEFT_DIRECTION)
+	m.x = -m.x;
+      if (dir == DOWN_DIRECTION || dir == LEFT_DIRECTION)
+	m.y = -m.y;
+      *dirp = direction((dir + 1) % 4);
+    }
+    endpos = startpos + m;
+  }
+  // compute the center
+  position centerpos;
+  if (flags & HAS_AT)
+    centerpos = at;
+  else if (startpos == endpos)
+    centerpos = startpos;
+  else {
+    position h = (endpos - startpos)/2.0;
+    double d = hypot(h);
+    if (radius <= 0)
+      radius = .25;
+    // make the radius big enough
+    if (radius < d)
+      radius = d;
+    double alpha = acos(d/radius);
+    double theta = atan2(h.y, h.x);
+    if (cw)
+      theta -= alpha;
+    else
+      theta += alpha;
+    centerpos = position(cos(theta), sin(theta))*radius + startpos;
+  }
+  arc_object *p = new arc_object(cw, startpos, endpos, centerpos);
+  *curpos = endpos;
+  return p;
+}
+
+graphic_object *object_spec::make_linear(position *curpos, direction *dirp)
+{
+  linear_object *obj;
+  if (type == ARC_OBJECT)
+    obj = make_arc(curpos, dirp);
+  else
+    obj = make_line(curpos, dirp);
+  if (type == ARROW_OBJECT
+      && (flags & (HAS_LEFT_ARROW_HEAD|HAS_RIGHT_ARROW_HEAD)) == 0)
+    flags |= HAS_RIGHT_ARROW_HEAD;
+  if (obj && (flags & (HAS_LEFT_ARROW_HEAD|HAS_RIGHT_ARROW_HEAD))) {
+    arrow_head_type a;
+    int at_start = (flags & HAS_LEFT_ARROW_HEAD) != 0;
+    int at_end = (flags & HAS_RIGHT_ARROW_HEAD) != 0;
+    if (flags & HAS_HEIGHT)
+      a.height = height;
+    else
+      lookup_variable("arrowht", &a.height);
+    if (flags & HAS_WIDTH)
+      a.width = width;
+    else
+      lookup_variable("arrowwid", &a.width);
+    double solid;
+    lookup_variable("arrowhead", &solid);
+    a.solid = solid != 0.0;
+    obj->add_arrows(at_start, at_end, a);
+  }
+  return obj;
+}
+
+object *object_spec::make_object(position *curpos, direction *dirp)
+{
+  graphic_object *obj = 0;
+  switch (type) {
+  case BLOCK_OBJECT:
+    obj = make_block(curpos, dirp);
+    break;
+  case BOX_OBJECT:
+    obj = make_box(curpos, dirp);
+    break;
+  case TEXT_OBJECT:
+    obj = make_text(curpos, dirp);
+    break;
+  case ELLIPSE_OBJECT:
+    obj = make_ellipse(curpos, dirp);
+    break;
+  case CIRCLE_OBJECT:
+    obj = make_circle(curpos, dirp);
+    break;
+  case MOVE_OBJECT:
+    obj = make_move(curpos, dirp);
+    break;
+  case ARC_OBJECT:
+  case LINE_OBJECT:
+  case SPLINE_OBJECT:
+  case ARROW_OBJECT:
+    obj = make_linear(curpos, dirp);
+    break;
+  case MARK_OBJECT:
+  case OTHER_OBJECT:
+  default:
+    assert(0);
+    break;
+  }
+  if (obj) {
+    if (flags & IS_INVISIBLE)
+      obj->set_invisible();
+    if (text != 0)
+      obj->add_text(text, (flags & IS_ALIGNED) != 0);
+    if (flags & IS_DOTTED)
+      obj->set_dotted(dash_width);
+    else if (flags & IS_DASHED)
+      obj->set_dashed(dash_width);
+    double th;
+    if (flags & HAS_THICKNESS)
+      th = thickness;
+    else
+      lookup_variable("linethick", &th);
+    obj->set_thickness(th);
+    if (flags & IS_OUTLINED)
+      obj->set_outline_color(outlined);
+    if (flags & IS_XSLANTED)
+      obj->set_xslanted(xslanted);
+    if (flags & IS_YSLANTED)
+      obj->set_yslanted(yslanted);
+    if (flags & (IS_DEFAULT_FILLED | IS_FILLED)) {
+      if (flags & IS_SHADED)
+	obj->set_fill_color(shaded);
+      else {
+	if (flags & IS_DEFAULT_FILLED)
+	  lookup_variable("fillval", &fill);
+	if (fill < 0.0)
+	  error("bad fill value %1", fill);
+	else
+	  obj->set_fill(fill);
+      }
+    }
+  }
+  return obj;
+}
+
+struct string_list {
+  string_list *next;
+  char *str;
+  string_list(char *);
+  ~string_list();
+};
+
+string_list::string_list(char *s)
+: next(0), str(s)
+{
+}
+
+string_list::~string_list()
+{
+  free(str);
+}
+
+/* A path is used to hold the argument to the 'with' attribute.  For
+   example, '.nw' or '.A.s' or '.A'.  The major operation on a path is to
+   take a place and follow the path through the place to place within the
+   place.  Note that '.A.B.C.sw' will work.
+
+   For compatibility with DWB pic, 'with' accepts positions also (this
+   is incorrectly documented in CSTR 116). */
+
+path::path(corner c)
+: crn(c), label_list(0), ypath(0), is_position(0)
+{
+}
+
+path::path(position p)
+: crn(0), label_list(0), ypath(0), is_position(1)
+{
+  pos.x = p.x;
+  pos.y = p.y;
+}
+
+path::path(char *l, corner c)
+: crn(c), ypath(0), is_position(0)
+{
+  label_list = new string_list(l);
+}
+
+path::~path()
+{
+  while (label_list) {
+    string_list *tem = label_list;
+    label_list = label_list->next;
+    delete tem;
+  }
+  delete ypath;
+}
+
+void path::append(corner c)
+{
+  assert(crn == 0);
+  crn = c;
+}
+
+void path::append(char *s)
+{
+  string_list **p;
+  for (p = &label_list; *p; p = &(*p)->next)
+    ;
+  *p = new string_list(s);
+}
+
+void path::set_ypath(path *p)
+{
+  ypath = p;
+}
+
+// return non-zero for success
+
+int path::follow(const place &pl, place *result) const
+{
+  if (is_position) {
+    result->x = pos.x;
+    result->y = pos.y;
+    result->obj = 0;
+    return 1;
+  }
+  const place *p = &pl;
+  for (string_list *lb = label_list; lb; lb = lb->next)
+    if (p->obj == 0 || (p = p->obj->find_label(lb->str)) == 0) {
+      lex_error("object does not contain a place '%1'", lb->str);
+      return 0;
+    }
+  if (crn == 0 || p->obj == 0)
+    *result = *p;
+  else {
+    position ps = ((p->obj)->*(crn))();
+    result->x = ps.x;
+    result->y = ps.y;
+    result->obj = 0;
+  }
+  if (ypath) {
+    place tem;
+    if (!ypath->follow(pl, &tem))
+      return 0;
+    result->y = tem.y;
+    if (result->obj != tem.obj)
+      result->obj = 0;
+  }
+  return 1;
+}
+
+void print_object_list(object *p)
+{
+  for (; p; p = p->next) {
+    p->print();
+    p->print_text();
+  }
+}
+
+void print_picture(object *obj)
+{
+  bounding_box bb;
+  for (object *p = obj; p; p = p->next)
+    p->update_bounding_box(&bb);
+  double scale;
+  lookup_variable("scale", &scale);
+  out->start_picture(scale, bb.ll, bb.ur);
+  print_object_list(obj);
+  out->finish_picture();
+}
+
diff --git a/src/preproc/pic/object.h b/src/preproc/pic/object.h
new file mode 100644
index 0000000..e39b6a6
--- /dev/null
+++ b/src/preproc/pic/object.h
@@ -0,0 +1,227 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+struct place;
+
+enum object_type {
+  OTHER_OBJECT,
+  BOX_OBJECT,
+  CIRCLE_OBJECT,
+  ELLIPSE_OBJECT,
+  ARC_OBJECT,
+  SPLINE_OBJECT,
+  LINE_OBJECT,
+  ARROW_OBJECT,
+  MOVE_OBJECT,
+  TEXT_OBJECT,
+  BLOCK_OBJECT,
+  MARK_OBJECT
+  };
+
+struct bounding_box;
+
+struct object {
+  object *prev;
+  object *next;
+  object();
+  virtual ~object();
+  virtual position origin();
+  virtual double width();
+  virtual double radius();
+  virtual double height();
+  virtual position north();
+  virtual position south();
+  virtual position east();
+  virtual position west();
+  virtual position north_east();
+  virtual position north_west();
+  virtual position south_east();
+  virtual position south_west();
+  virtual position start();
+  virtual position end();
+  virtual position center();
+  virtual place *find_label(const char *);
+  virtual void move_by(const position &);
+  virtual int blank();
+  virtual void update_bounding_box(bounding_box *);
+  virtual object_type type() = 0;
+  virtual void print();
+  virtual void print_text();
+};
+
+typedef position (object::*corner)();
+
+struct place {
+  object *obj;
+  double x, y;
+};
+
+struct string_list;
+
+class path {
+  position pos;
+  corner crn;
+  string_list *label_list;
+  path *ypath;
+  int is_position;
+public:
+  path(corner = 0);
+  path(position);
+  path(char *, corner = 0);
+  ~path();
+  void append(corner);
+  void append(char *);
+  void set_ypath(path *);
+  int follow(const place &, place *) const;
+};
+
+struct object_list {
+  object *head;
+  object *tail;
+  object_list();
+  void append(object *);
+  void wrap_up_block(object_list *);
+};
+
+declare_ptable(place)
+
+// these go counterclockwise
+enum direction {
+  RIGHT_DIRECTION,
+  UP_DIRECTION,
+  LEFT_DIRECTION,
+  DOWN_DIRECTION
+  };
+
+struct graphics_state {
+  double x, y;
+  direction dir;
+};
+
+struct saved_state : public graphics_state {
+  saved_state *prev;
+  PTABLE(place) *tbl;
+};
+
+
+struct text_item {
+  text_item *next;
+  char *text;
+  adjustment adj;
+  const char *filename;
+  int lineno;
+
+  text_item(char *, const char *, int);
+  ~text_item();
+};
+
+const unsigned long IS_DOTTED          =         01;
+const unsigned long IS_DASHED          =         02;
+const unsigned long IS_CLOCKWISE       =         04;
+const unsigned long IS_INVISIBLE       =        020;
+const unsigned long HAS_LEFT_ARROW_HEAD =       040;
+const unsigned long HAS_RIGHT_ARROW_HEAD =     0100;
+const unsigned long HAS_SEGMENT        =       0200;
+const unsigned long IS_SAME            =       0400;
+const unsigned long HAS_FROM           =      01000;
+const unsigned long HAS_AT             =      02000;
+const unsigned long HAS_WITH           =      04000;
+const unsigned long HAS_HEIGHT         =     010000;
+const unsigned long HAS_WIDTH          =     020000;
+const unsigned long HAS_RADIUS         =     040000;
+const unsigned long HAS_TO             =    0100000;
+const unsigned long IS_CHOPPED         =    0200000;
+const unsigned long IS_DEFAULT_CHOPPED =    0400000;
+const unsigned long HAS_THICKNESS      =   01000000;
+const unsigned long IS_FILLED          =   02000000;
+const unsigned long IS_DEFAULT_FILLED  =   04000000;
+const unsigned long IS_ALIGNED         =  010000000;
+const unsigned long IS_SHADED          =  020000000;
+const unsigned long IS_OUTLINED        =  040000000;
+const unsigned long IS_XSLANTED        = 0100000000;
+const unsigned long IS_YSLANTED        = 0200000000;
+
+struct segment {
+  int is_absolute;
+  position pos;
+  segment *next;
+  segment(const position &, int, segment *);
+};
+
+class rectangle_object;
+class graphic_object;
+class linear_object;
+
+struct object_spec {
+  unsigned long flags;
+  object_type type;
+  object_list oblist;
+  PTABLE(place) *tbl;
+  double dash_width;
+  position from;
+  position to;
+  position at;
+  position by;
+  path *with;
+  text_item *text;
+  double height;
+  double radius;
+  double width;
+  double segment_width;
+  double segment_height;
+  double start_chop;
+  double end_chop;
+  double thickness;
+  double fill;
+  double xslanted;
+  double yslanted;
+  char *shaded;
+  char *outlined;
+  direction dir;
+  segment *segment_list;
+  position segment_pos;
+  int segment_is_absolute;
+
+  object_spec(object_type);
+  ~object_spec();
+  object *make_object(position *, direction *);
+  graphic_object *make_box(position *, direction *);
+  graphic_object *make_block(position *, direction *);
+  graphic_object *make_text(position *, direction *);
+  graphic_object *make_ellipse(position *, direction *);
+  graphic_object *make_circle(position *, direction *);
+  linear_object *make_line(position *, direction *);
+  linear_object *make_arc(position *, direction *);
+  graphic_object *make_linear(position *, direction *);
+  graphic_object *make_move(position *, direction *);
+  int position_rectangle(rectangle_object *p, position *curpos,
+			 direction *dirp);
+};
+
+
+object *make_object(object_spec *, position *, direction *);
+
+object *make_mark_object();
+object *make_command_object(char *, const char *, int);
+
+int lookup_variable(const char *name, double *val);
+void define_variable(const char *name, double val);
+
+void print_picture(object *);
+
diff --git a/src/preproc/pic/output.h b/src/preproc/pic/output.h
new file mode 100644
index 0000000..f01e0a1
--- /dev/null
+++ b/src/preproc/pic/output.h
@@ -0,0 +1,82 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+struct line_type {
+  enum { invisible, solid, dotted, dashed } type;
+  double dash_width;
+  double thickness;		// the thickness is in points
+
+  line_type();
+};
+
+
+class output {
+protected:
+  char *args;
+  double desired_height;	// zero if no height specified
+  double desired_width;		// zero if no depth specified
+  double compute_scale(double, const position &, const position &);
+public:
+  output();
+  virtual ~output();
+  void set_desired_width_height(double wid, double ht);
+  void set_args(const char *);
+  virtual void start_picture(double sc, const position &ll, const position &ur) = 0;
+  virtual void finish_picture() = 0;
+  virtual void circle(const position &, double rad,
+		      const line_type &, double) = 0;
+  virtual void text(const position &, text_piece *, int, double) = 0;
+  virtual void line(const position &, const position *, int n,
+		    const line_type &) = 0;
+  virtual void polygon(const position *, int n,
+		       const line_type &, double) = 0;
+  virtual void spline(const position &, const position *, int n,
+		      const line_type &) = 0;
+  virtual void arc(const position &, const position &, const position &,
+		   const line_type &) = 0;
+  virtual void ellipse(const position &, const distance &,
+		       const line_type &, double) = 0;
+  virtual void rounded_box(const position &, const distance &, double,
+			   const line_type &, double, char *) = 0;
+  virtual void command(const char *, const char *, int) = 0;
+  virtual void set_location(const char *, int) {}
+  virtual void set_color(char *, char *) = 0;
+  virtual void reset_color() = 0;
+  virtual char *get_last_filled() = 0;
+  virtual char *get_outline_color() = 0;
+  virtual int supports_filled_polygons();
+  virtual void begin_block(const position &ll, const position &ur);
+  virtual void end_block();
+};
+
+extern output *out;
+
+/* #define FIG_SUPPORT 1 */
+#define TEX_SUPPORT 1
+
+output *make_troff_output();
+
+#ifdef TEX_SUPPORT
+output *make_tex_output();
+output *make_tpic_output();
+#endif /* TEX_SUPPORT */
+
+#ifdef FIG_SUPPORT
+output *make_fig_output();
+#endif /* FIG_SUPPORT */
diff --git a/src/preproc/pic/pic.1.man b/src/preproc/pic/pic.1.man
new file mode 100644
index 0000000..727cbc3
--- /dev/null
+++ b/src/preproc/pic/pic.1.man
@@ -0,0 +1,1569 @@
+.TH @g@pic @MAN1EXT@ "@MDATE@" "groff @VERSION@"
+.SH Name
+@g@pic \- compile pictures for
+.I troff
+or TeX
+.
+.
+.\" ====================================================================
+.\" Legal Terms
+.\" ====================================================================
+.\"
+.\" Copyright (C) 1989-2020 Free Software Foundation, Inc.
+.\"
+.\" Permission is granted to make and distribute verbatim copies of this
+.\" manual provided the copyright notice and this permission notice are
+.\" preserved on all copies.
+.\"
+.\" Permission is granted to copy and distribute modified versions of
+.\" this manual under the conditions for verbatim copying, provided that
+.\" the entire resulting derived work is distributed under the terms of
+.\" a permission notice identical to this one.
+.\"
+.\" Permission is granted to copy and distribute translations of this
+.\" manual into another language, under the above conditions for
+.\" modified versions, except that this permission notice may be
+.\" included in translations approved by the Free Software Foundation
+.\" instead of in the original English.
+.
+.
+.\" Save and disable compatibility mode (for, e.g., Solaris 10/11).
+.do nr *groff_pic_1_man_C \n[.cp]
+.cp 0
+.
+.\" Define fallback for groff 1.23's MR macro if the system lacks it.
+.nr do-fallback 0
+.if !\n(.f           .nr do-fallback 1 \" mandoc
+.if  \n(.g .if !d MR .nr do-fallback 1 \" older groff
+.if !\n(.g           .nr do-fallback 1 \" non-groff *roff
+.if \n[do-fallback]  \{\
+.  de MR
+.    ie \\n(.$=1 \
+.      I \%\\$1
+.    el \
+.      IR \%\\$1 (\\$2)\\$3
+.  .
+.\}
+.rr do-fallback
+.
+.
+.\" ====================================================================
+.\" Definitions
+.\" ====================================================================
+.
+.ie t \{\
+.  ds tx T\h'-.1667m'\v'.224m'E\v'-.224m'\h'-.125m'X
+.  ds lx L\h'-0.36m'\v'-0.22v'\s-2A\s0\h'-0.15m'\v'0.22v'\*[tx]
+.\}
+.el \{\
+.  ds tx TeX
+.  ds lx LaTeX
+.\}
+.
+.ie \n(.g .ds ic \/
+.el       .ds ic \^
+.
+.
+.\" ====================================================================
+.SH Synopsis
+.\" ====================================================================
+.
+.SY @g@pic
+.RB [ \-CnSU ]
+.RI [ file\~ .\|.\|.]
+.YS
+.
+.
+.SY @g@pic
+.B \-t
+.RB [ \-cCSUz ]
+.RI [ file\~ .\|.\|.]
+.YS
+.
+.
+.SY @g@pic
+.B \-\-help
+.YS
+.
+.
+.SY @g@pic
+.B \-v
+.
+.SY @g@pic
+.B \-\-version
+.YS
+.
+.
+.\" ====================================================================
+.SH Description
+.\" ====================================================================
+.
+The GNU implementation of
+.I pic \" generic
+is part of the
+.MR groff @MAN1EXT@
+document formatting system.
+.
+.I @g@pic
+is a
+.MR @g@troff @MAN1EXT@
+preprocessor that translates descriptions of diagrammatic pictures
+embedded in
+.MR roff @MAN7EXT@
+or \*[tx] input files into the language understood by \*[tx] or
+.IR @g@troff .
+.
+It copies the contents of each
+.I file
+to the standard output stream,
+except that lines between
+.B .PS
+and any of
+.BR .PE ,
+.BR .PF ,
+or
+.B .PY
+are interpreted as picture descriptions in the
+.I pic
+language.
+.
+End a
+.I @g@pic
+picture with
+.B .PE
+to leave the drawing position at the bottom of the picture,
+and with
+.B .PF
+or
+.B .PY
+to leave it at the top.
+.
+Normally,
+.I @g@pic
+is not executed directly by the user,
+but invoked by specifying the
+.B \-p
+option to
+.MR groff @MAN1EXT@ .
+.
+If no
+.I file
+operands are given on the command line,
+or if
+.I file
+is
+.RB \[lq] \- \[rq],
+the standard input stream is read.
+.
+.
+.P
+It is the user's responsibility to provide appropriate definitions
+of the
+.BR PS ,
+.BR PE ,
+and one or both of the
+.B PF
+and
+.B PY
+macros.
+.
+When a macro package does not supply these,
+obtain simple definitions with the
+.I groff
+option
+.BR \-mpic ;
+these will center each picture.
+.
+.
+.P
+GNU
+.I pic \" GNU
+supports
+.B PY
+as a synonym of
+.B PF
+to work around a name space collision with the
+.I mm
+macro package,
+which defines
+.B PF
+as a page footer management macro.
+.
+Use
+.B PF
+preferentially unless a similar problem faces your document.
+.
+.
+.\" ====================================================================
+.SH Options
+.\" ====================================================================
+.
+.B \-\-help
+displays a usage message,
+while
+.B \-v
+and
+.B \-\-version
+show version information;
+all exit afterward.
+.
+.
+.TP
+.B \-c
+Be more compatible with
+.IR tpic ;
+implies
+.BR \-t .
+.
+Lines beginning with
+.B \[rs]
+are not passed through transparently.
+.
+Lines beginning with
+.B .\&
+are passed through with the initial
+.B .\&
+changed to
+.BR \[rs] .
+.
+A line beginning with
+.B .ps
+is given special treatment:
+it takes an optional integer argument specifying the line thickness
+(pen size)
+in milliinches;
+a missing argument restores the previous line thickness;
+the default line thickness is 8\~milliinches.
+.
+The line thickness thus specified takes effect only when a
+non-negative line thickness has not been specified by use of the
+.B \%thickness
+attribute or by setting the
+.B \%linethick
+variable.
+.
+.
+.TP
+.B \-C
+Recognize
+.BR .PS ,
+.BR .PE ,
+.BR .PF ,
+and
+.B .PY
+even when followed by a character other than space or newline.
+.
+.
+.TP
+.B \-n
+Don't use
+.I groff
+extensions to the
+.I troff \" generic
+drawing commands.
+.
+Specify this option if a postprocessor you're using doesn't support
+these extensions,
+described in
+.MR groff_out @MAN5EXT@ .
+.
+This option also causes
+.I @g@pic
+not to use zero-length lines to draw dots in
+.I troff \" generic
+mode.
+.
+.
+.TP
+.B \-S
+Operate in
+.I safer mode;
+.B sh
+commands are ignored.
+.
+This mode,
+enabled by default,
+can be useful when operating on untrustworthy input.
+.
+.
+.TP
+.B \-t
+Produce \*[tx] output.
+.
+.
+.TP
+.B \-U
+Operate in
+.I unsafe mode;
+.B sh
+commands are interpreted.
+.
+.
+.TP
+.B \-z
+In \*[tx] mode,
+draw dots using zero-length lines.
+.
+.
+.P
+The following options supported by other versions of
+.I pic \" generic
+are ignored.
+.
+.
+.TP
+.B \-D
+Draw all lines using the \[rs]D escape sequence.
+GNU
+.I pic \" GNU
+always does this.
+.
+.TP
+.BI \-T\~ dev
+Generate output for the
+.I troff \" generic
+device
+.IR dev .
+.
+This is unnecessary because the
+.I troff \" generic
+output generated by
+GNU
+.I pic \" GNU
+is device-independent.
+.
+.
+.\" ====================================================================
+.SH Usage
+.\" ====================================================================
+.
+This section primarily discusses the differences between GNU
+.I pic \" GNU
+and the Eighth Edition Research Unix version of AT&T
+.I pic \" AT&T
+(1985).
+.
+Many of these differences also apply to later versions of AT&T
+.IR pic .
+.
+.
+.\" ====================================================================
+.SS "\*[tx] mode"
+.\" ====================================================================
+.
+\*[tx]-compatible output is produced when the
+.B \-t
+option is specified.
+.
+You must use a \*[tx] driver that supports
+.I tpic
+version 2 specials.
+.
+.RI ( tpic
+was a fork of AT&T
+.I pic \" AT&T
+by Tim Morgan of the University of California at Irvine that diverged
+from its source around 1984.
+.
+It is best known today for lending its name to a group of
+.B \[rs]special
+commands it produced for \*[tx].)
+.\" http://ftp.cs.stanford.edu/tex/texhax/texhax90.019
+.
+.
+.P
+Lines beginning with
+.B \[rs]
+are passed through transparently;
+a
+.B %
+is added to the end of the line to avoid unwanted spaces.
+.
+You can safely use this feature to change fonts or the value of
+.BR \[rs]baselineskip .
+.
+Anything else may well produce undesirable results;
+use at your own risk.
+.
+By default,
+lines beginning with a dot are not treated specially\[em]but see the
+.B \-c
+option.
+.
+.
+.P
+In \*[tx] mode,
+.I @g@pic
+will define a vbox called
+.B \[rs]graph
+for each picture.
+.
+Use GNU
+.IR pic 's \" GNU
+.B figname
+command to change the name of the vbox.
+.
+You must print that vbox yourself using the command
+.
+.RS
+.EX
+\[rs]centerline{\[rs]box\[rs]graph}
+.EE
+.RE
+.
+for instance.
+.
+Since the vbox has a height of zero
+(it is defined with
+.BR \[rs]vtop )
+this will produce slightly more vertical space above the picture than
+below it;
+.
+.RS
+.EX
+\[rs]centerline{\[rs]raise 1em\[rs]box\[rs]graph}
+.EE
+.RE
+.
+would avoid this.
+.
+To give the vbox a positive height and a depth of zero
+(as used by \*[lx]'s
+.IR \%graphics.sty ,
+for example)
+define the following macro in your document.
+.
+.RS
+.EX
+\[rs]def\[rs]gpicbox#1{%
+  \[rs]vbox{\[rs]unvbox\[rs]csname #1\[rs]endcsname\[rs]kern 0pt}}
+.EE
+.RE
+.
+You can then simply say
+.B \[rs]gpicbox{graph}
+instead of
+.BR \[rs]box\[rs]graph .
+.
+.
+.\" ====================================================================
+.SS Commands
+.\" ====================================================================
+.
+Several commands new to GNU
+.I pic \" GNU
+accept delimiters,
+shown in their synopses as braces
+.BR "{ }" .
+.
+Nesting of braces is supported.
+.
+Any other characters
+(except a space,
+tab,
+or newline)
+.\" XXX even crazy control characters, ugh--src/preproc/pic/lex.cpp:1266
+may be used as alternative delimiters,
+in which case the members of a given pair must be identical.
+.
+Strings are recognized within delimiters of either kind;
+they may contain the delimiter character or unbalanced braces.
+.
+.
+.TP
+\fBfor\fR \fIvariable\fR \fB=\fR \fIexpr1\fR \fBto\fR \fIexpr2\fR \
+[\fBby\fR [\fB*\fR]\,\fIexpr3\/\fR] \fBdo\fR \fIX\fR \fIbody\fR \fIX\fR
+Set
+.I variable
+to
+.IR expr1 .
+.
+While the value of
+.I variable
+is less than or equal to
+.IR expr2 ,
+do
+.I body
+and increment
+.I variable
+by
+.IR expr3 ;
+if
+.B by
+is not given,
+increment
+.I variable
+by 1.
+.
+If
+.I expr3
+is prefixed by
+.B *
+then
+.I variable
+will instead be multiplied by
+.IR expr3 .
+.
+The value of
+.I expr3
+can be negative for the additive case;
+.I variable
+is then tested whether it is greater than or equal to
+.IR expr2 .
+.
+For the multiplicative case,
+.I expr3
+must be greater than zero.
+.
+If the constraints aren't met,
+the loop isn't executed.
+.
+.I X
+can be any character not occurring in
+.IR body .
+.
+.TP
+\fBif\fR \fIexpr\fR \fBthen\fR \fIX\fR \fIif-true\fR \fIX\fR \
+[\fBelse\fR \fIY\fR \fIif-false\fR \fIY\fR]
+Evaluate
+.IR expr ;
+if it is non-zero then do
+.IR if-true ,
+otherwise do
+.IR if-false .
+.
+.I X
+can be any character not occurring in
+.IR if-true .
+.
+.I Y
+can be any character not occurring in
+.IR if-false .
+.
+.TP
+.BI print\~ arg\c
+\~.\|.\|.
+Concatenate and write arguments to the standard error stream followed by
+a newline.
+.
+Each
+.I arg
+must be an expression,
+a position,
+or text.
+.
+This is useful for debugging.
+.
+.TP
+.BI command\~ arg\c
+\~.\|.\|.
+.\" Move right margin to indentation since we must indent more later.
+.RS
+Concatenate arguments
+and pass them as a line to
+.I troff \" generic
+or \*[tx].
+.
+Each
+.I arg
+must be an expression,
+a position,
+or text.
+.
+.B command
+allows the values of
+.I pic
+variables to be passed to the formatter.
+.
+For example,
+.
+.RS
+.EX
+\&.PS
+x = 14
+command ".ds string x is " x "."
+\&.PE
+\[rs]*[string]
+.EE
+.RE
+.
+produces
+.
+.RS
+.EX
+x is 14.
+.EE
+.RE
+when formatted with
+.IR troff . \" generic
+.RE
+.
+.
+.TP
+\fBsh\fR \fIX\fR \fIcommand\fR \fIX\fR
+Pass
+.I command
+to a shell.
+.
+.
+.TP
+\fBcopy\fR \fB"\,\fIfilename\/\fB"\fR
+Include
+.I filename
+at this point in the file.
+.
+.
+.TP
+.BR copy\~ [ \[dq]\c
+.IB filename \[dq]\c
+.RB ]\~ thru\~\c
+.IR "X body X" \~\c \" space in roman: we must use 2-font macro with \c
+.RB [ until\~ \[dq]\c
+.IB word \[dq]\c
+]
+.TQ
+.BR copy\~ [ \[dq]\c
+.IB filename \[dq]\c
+.RB ]\~ thru\~\c
+.IR macro \~\c \" space roman because we must use 2-font macro with \c
+.RB [ until\~ \[dq]\c
+.IB word \[dq]\c
+]
+.\" Move right margin to indentation since we must indent more later.
+.RS
+This construct does
+.I body
+once for each line of
+.IR filename ;
+the line is split into blank-delimited words,
+and occurrences of
+.BI $ i
+in
+.IR body ,
+for
+.I i
+between 1 and 9,
+are replaced by the
+.IR i -th
+word of the line.
+.
+If
+.I filename
+is not given,
+lines are taken from the current input up to
+.BR .PE .
+.
+If an
+.B until
+clause is specified,
+lines will be read only until a line the first word of which is
+.IR word ;
+that line will then be discarded.
+.
+.I X
+can be any character not occurring in
+.IR body .
+.
+For example,
+.
+.RS \" now move further
+.EX
+\&.PS
+copy thru % circle at ($1,$2) % until "END"
+1 2
+3 4
+5 6
+END
+box
+\&.PE
+.EE
+.RE
+.
+and
+.
+.RS
+.EX
+\&.PS
+circle at (1,2)
+circle at (3,4)
+circle at (5,6)
+box
+\&.PE
+.EE
+.RE
+.
+are equivalent.
+.
+The commands to be performed for each line can also be taken from a
+macro defined earlier by giving the name of the macro as the argument to
+.BR thru .
+.
+The argument after
+.B thru
+is looked up as a macro name first;
+if not defined,
+its first character is interpreted as a delimiter.
+.RE
+.
+.
+.TP
+.B reset
+.TQ
+.BI reset\~ pvar1\c
+.RB [ , ]\~\c
+.IR pvar2 \~.\|.\|.
+Reset predefined variables
+.IR pvar1 ,
+.I pvar2
+\&.\|.\|.\& to their default values;
+if no arguments are given,
+reset all predefined variables to their default values.
+.
+Variable names may be separated by commas,
+spaces,
+or both.
+.
+Assigning a value to
+.B scale
+also causes all predefined variables that control dimensions to be reset
+to their default values times the new value of
+.BR scale .
+.
+.
+.TP
+\fBplot\fR \fIexpr\fR [\fB"\,\fItext\*(ic\fB"\fR]
+This is a text object which is constructed by using
+.I text
+as a format string for sprintf
+with an argument of
+.IR expr .
+.
+If
+.I text
+is omitted a format string of
+.B \[dq]%g\[dq]
+is used.
+.
+Attributes can be specified in the same way as for a normal text
+object.
+Be very careful that you specify an appropriate format string;
+.I @g@pic
+does only very limited checking of the string.
+.
+This is deprecated in favour of
+.BR sprintf .
+.
+.TP
+.IB var \~:=\~ expr
+.RS
+This syntax resembles variable assignment with
+.B =
+except that
+.I var
+must already be defined,
+and
+.I expr
+will be assigned to
+.I var
+without creating a variable local to the current block.
+.
+(By contrast,
+.B =
+defines
+.I var
+in the current block if it is not already defined there,
+and then changes the value in the current block only.)
+.
+For example,
+.
+.RS
+.EX
+.B .PS
+.B x = 3
+.B y = 3
+.B [
+.B   x := 5
+.B   y = 5
+.B ]
+.B print x " " y
+.B .PE
+.EE
+.RE
+.
+writes
+.
+.RS
+.EX
+5 3
+.EE
+.RE
+.
+to the standard error stream.
+.RE
+.
+.
+.\" ====================================================================
+.SS Expressions
+.\" ====================================================================
+.
+The syntax for expressions has been significantly extended.
+.
+.
+.P
+.IB  x\  \[ha]\  y
+(exponentiation)
+.br
+.BI sin( x )
+.br
+.BI cos( x )
+.br
+.BI atan2( y , \ x )
+.br
+.BI log( x )
+(base 10)
+.br
+.BI exp( x )
+(base 10, i.e.\&
+.ie t 10\v'-.4m'\fIx\*(ic\fR\v'.4m')
+.el   10\[ha]\fIx\fR)
+.br
+.BI sqrt( x )
+.br
+.BI int( x )
+.br
+.B rand()
+(return a random number between 0 and 1)
+.br
+.BI rand( x )
+(return a random number between 1 and
+.IR x ;
+deprecated)
+.br
+.BI srand( x )
+(set the random number seed)
+.br
+.BI max( e1 , \ e2 )
+.br
+.BI min( e1 , \ e2 )
+.br
+.BI ! e
+.br
+\fIe1\fB && \fIe2\fR
+.br
+\fIe1\fB || \fIe2\fR
+.br
+\fIe1\fB == \fIe2\fR
+.br
+\fIe1\fB != \fIe2\fR
+.br
+\fIe1\fB >= \fIe2\fR
+.br
+\fIe1\fB > \fIe2\fR
+.br
+\fIe1\fB <= \fIe2\fR
+.br
+\fIe1\fB < \fIe2\fR
+.br
+\fB"\,\fIstr1\*(ic\fB" == "\,\fIstr2\*(ic\fB"\fR
+.br
+\fB"\,\fIstr1\*(ic\fB" != "\,\fIstr2\*(ic\fB"\fR
+.br
+.
+.
+.LP
+String comparison expressions must be parenthesised in some contexts
+to avoid ambiguity.
+.
+.
+.\" ====================================================================
+.SS "Other changes"
+.\" ====================================================================
+.
+A bare expression,
+.IR expr ,
+is acceptable as an attribute;
+it is equivalent to
+.IR dir\ expr ,
+where
+.I dir
+is the current direction.
+.
+For example
+.LP
+.RS
+.B line 2i
+.RE
+.LP
+means draw a line 2\ inches long in the current direction.
+.
+The \[oq]i\[cq]
+(or \[oq]I\[cq])
+character is ignored;
+to use another measurement unit,
+set the
+.I scale
+variable to an appropriate value.
+.
+.
+.LP
+The maximum width and height of the picture are taken from the variables
+.B maxpswid
+and
+.BR maxpsht .
+.
+Initially,
+these have values 8.5 and 11.
+.
+.
+.LP
+Scientific notation is allowed for numbers.
+For example
+.
+.
+.RS
+.LP
+.B
+x = 5e\-2
+.RE
+.
+.
+.LP
+Text attributes can be compounded.
+.
+For example,
+.
+.RS
+.LP
+.B
+"foo" above ljust
+.RE
+.
+.
+.LP
+is valid.
+.
+.
+.LP
+There is no limit to the depth to which blocks can be examined.
+.
+For example,
+.RS
+.LP
+.EX
+[A: [B: [C: box ]]] with .A.B.C.sw at 1,2
+circle at last [\^].A.B.C
+.EE
+.RE
+.
+.
+.LP
+is acceptable.
+.
+.
+.LP
+Arcs now have compass points determined by the circle of which the arc
+is a part.
+.
+.
+.LP
+Circles,
+ellipses,
+and arcs can be dotted or dashed.
+.
+In \*[tx] mode splines can be dotted or dashed also.
+.
+.
+.LP
+Boxes can have rounded corners.
+.
+The
+.B rad
+attribute specifies the radius of the quarter-circles at each corner.
+If no
+.B rad
+or
+.B diam
+attribute is given,
+a radius of
+.B boxrad
+is used.
+.
+Initially,
+.B boxrad
+has a value of\ 0.
+.
+A box with rounded corners can be dotted or dashed.
+.
+.
+.LP
+Boxes can have slanted sides.
+.
+This effectively changes the shape of a box from a rectangle to an
+arbitrary parallelogram.
+.
+The
+.B xslanted
+and
+.B yslanted
+attributes specify the x and y\~offset of the box's upper right
+corner from its default position.
+.
+.
+.LP
+The
+.B .PS
+line can have a second argument specifying a maximum height for
+the picture.
+.
+If the width of zero is specified the width will be ignored in computing
+the scaling factor for the picture.
+.
+GNU
+.I pic \" GNU
+will always scale a picture by the same amount vertically as well as
+horizontally.
+.
+This is different from DWB 2.0
+.I pic \" foreign
+which may scale a picture by a different amount vertically than
+horizontally if a height is specified.
+.
+.
+.LP
+Each text object has an invisible box associated with it.
+.
+The compass points of a text object are determined by this box.
+.
+The implicit motion associated with the object is also determined
+by this box.
+.
+The dimensions of this box are taken from the width and height
+attributes;
+if the width attribute is not supplied then the width will be taken to
+be
+.BR textwid ;
+if the height attribute is not supplied then the height will be taken to
+be the number of text strings associated with the object times
+.BR textht .
+.
+Initially,
+.B textwid
+and
+.B textht
+have a value of 0.
+.
+.
+.LP
+In
+(almost all)
+places where a quoted text string can be used,
+an expression of the form
+.
+.
+.IP
+.BI sprintf(\[dq] format \[dq],\~ arg ,\fR\~.\|.\|.\fB)
+.
+.
+.LP
+can also be used;
+this will produce the arguments formatted according to
+.IR format ,
+which should be a string as described in
+.MR printf 3
+appropriate for the number of arguments supplied.
+.
+Only the modifiers
+.RB \[lq] # \[rq],
+.RB \[lq] \- \[rq],
+.RB \[lq] + \[rq],
+and \[lq]\~\[rq] [space]),
+a minimum field width,
+an optional precision,
+and the conversion specifiers
+.BR %e ,
+.BR %E ,
+.BR %f ,
+.BR %g ,
+.BR %G ,
+and
+.B %%
+are supported.
+.
+.
+.LP
+The thickness of the lines used to draw objects is controlled by the
+.B linethick
+variable.
+.
+This gives the thickness of lines in points.
+.
+A negative value means use the default thickness:
+in \*[tx] output mode,
+this means use a thickness of 8 milliinches;
+in \*[tx] output mode with the
+.B \-c
+option,
+this means use the line thickness specified by
+.B .ps
+lines;
+in
+.I troff
+output mode,
+this means use a thickness proportional to the pointsize.
+.
+A zero value means draw the thinnest possible line supported by
+the output device.
+.
+Initially,
+it has a value of \-1.
+.
+There is also a
+.BR thick [ ness ]
+attribute.
+.
+For example,
+.
+.
+.RS
+.LP
+.B circle thickness 1.5
+.RE
+.
+.
+.LP
+would draw a circle using a line with a thickness of 1.5 points.
+.
+The thickness of lines is not affected by the
+value of the
+.B scale
+variable,
+nor by the width or height given in the
+.B .PS
+line.
+.
+.
+.LP
+Boxes
+(including boxes with rounded corners or slanted sides),
+circles and ellipses can be filled by giving them an attribute of
+.BR fill [ ed ].
+.
+This takes an optional argument of an expression with a value between
+0 and 1;
+0 will fill it with white,
+1 with black,
+values in between with a proportionally gray shade.
+.
+A value greater than 1 can also be used:
+this means fill with the
+shade of gray that is currently being used for text and lines.
+.
+Normally this will be black,
+but output devices may provide a mechanism for changing this.
+.
+Without an argument,
+then the value of the variable
+.B \%fillval
+will be used.
+.
+Initially,
+this has a value of 0.5.
+.
+The invisible attribute does not affect the filling of objects.
+.
+Any text associated with a filled object will be added after the object
+has been filled,
+so that the text will not be obscured by the filling.
+.
+.
+.P
+Additional modifiers are available to draw colored objects:
+.BR \%outline [ d ]
+sets the color of the outline,
+.B shaded
+the fill color,
+and
+.BR colo [ u ] r [ ed ]
+sets both.
+.
+All expect a subsequent string argument specifying the color.
+.
+.RS
+.EX
+circle shaded \[dq]green\[dq] outline \[dq]black\[dq]
+.EE
+.RE
+.
+Color is not yet supported in \*[tx] mode.
+.
+Device macro files like
+.I ps.tmac
+declare color names;
+you can define additional ones with the
+.B \%defcolor
+request
+(see
+.MR groff @MAN7EXT@ ).
+.
+.
+.LP
+To change the name of the vbox in \*[tx] mode,
+set the pseudo-variable
+.B \%figname
+(which is actually a specially parsed command)
+within a picture.
+.
+Example:
+.RS
+.LP
+.B .PS
+.br
+.B figname = foobar;
+.br
+.B ...
+.br
+.B .PE
+.RE
+.
+.
+.LP
+The picture is then available in the box
+.BR \[rs]foobar .
+.
+.
+.LP
+.I @g@pic
+assumes that at the beginning of a picture both glyph and fill color are
+set to the default value.
+.
+.
+.LP
+Arrow heads will be drawn as solid triangles if the variable
+.B arrowhead
+is non-zero and either \*[tx] mode is enabled or the
+.B \-n
+option has not been given.
+.
+Initially,
+.B arrowhead
+has a value of\ 1.
+.
+Solid arrow heads are always filled with the current outline color.
+.
+.
+.LP
+The
+.I troff
+output of
+.I @g@pic
+is device-independent.
+.
+The
+.B \-T
+option is therefore redundant.
+.
+All numbers are taken to be in inches;
+numbers are never interpreted to be in
+.I troff
+machine units.
+.
+.
+.LP
+Objects can have an
+.B aligned
+attribute.
+.
+This will only work if the postprocessor is
+.MR grops @MAN1EXT@
+or
+.MR gropdf @MAN1EXT@ .
+.
+Any text associated with an object having the
+.B aligned
+attribute will be rotated about the center of the object
+so that it is aligned in the direction from the start point
+to the end point of the object.
+.
+This attribute will have no effect on objects whose start and end points
+are coincident.
+.
+.
+.LP
+In places where
+.IB n th
+is allowed,
+.BI \[aq] expr \[aq]th
+is also allowed.
+.
+.RB \[lq] \[aq]th \[lq]
+is a single token:
+no space is allowed between the apostrophe and the
+.RB \[lq] th \[rq].
+.
+.
+For example,
+.IP
+.EX
+for i = 1 to 4 do {
+   line from \[aq]i\[aq]th box.nw to \[aq]i+1\[aq]th box.se
+}
+.EE
+.
+.
+.\" ====================================================================
+.SH Conversion
+.\" ====================================================================
+.
+To obtain a stand-alone picture from a
+.I @g@pic
+file,
+enclose your
+.I pic \" language
+code with
+.B .PS
+and
+.B .PE
+requests;
+.I roff
+configuration commands may be added at the beginning of the file,
+but no
+.I roff
+text.
+.
+.
+.LP
+It is necessary to feed this file into
+.I groff
+without adding any page information,
+so you must check which
+.B .PS
+and
+.B .PE
+requests are actually called.
+.
+For example,
+the
+.I mm
+macro package adds a page number,
+which is very annoying.
+.
+At the moment,
+calling standard
+.I groff
+without any macro package works.
+.
+Alternatively,
+you can define your own requests,
+e.g.,
+to do nothing:
+.
+.
+.LP
+.RS
+.EX
+\&.de PS
+\&..
+\&.de PE
+\&..
+.EE
+.RE
+.
+.
+.LP
+.I groff
+itself does not provide direct conversion into other graphics file
+formats.
+.
+But there are lots of possibilities if you first transform your
+picture into PostScript\*R format using the
+.I groff
+option
+.BR \-Tps .
+.
+Since this
+.IR ps -file
+lacks BoundingBox information it is not very useful by itself, but it
+may be fed into other conversion programs, usually named
+.BI ps2 other
+or
+.BI psto other
+or the like.
+.
+Moreover,
+the PostScript interpreter Ghostscript
+.RI ( gs (1))
+has built-in graphics conversion devices that are called with the option
+.
+.
+.LP
+.RS
+.BI "gs \-sDEVICE=" <devname>
+.RE
+.
+.
+.LP
+Call
+.
+.
+.LP
+.RS
+.B gs \-\-help
+.RE
+.
+.
+.LP
+for a list of the available devices.
+.
+.
+.LP
+An alternative may be to use the
+.B \-Tpdf
+option to convert your picture directly into
+.B PDF
+format.
+.
+The MediaBox of the file produced can be controlled by passing a
+.B \-P\-p
+papersize to
+.IR groff .
+.
+.
+.br
+.ne 3v
+.P
+As the Encapsulated PostScript File Format
+.B EPS
+is getting more and more important,
+and the conversion wasn't regarded trivial in the past you might be
+interested to know that there is a conversion tool named
+.I ps2eps
+which does the right job.
+.
+It is much better than the tool
+.I ps2epsi
+packaged with
+.IR gs .
+.
+.
+.LP
+For bitmapped graphic formats,
+you should use
+.IR pstopnm ;
+the resulting (intermediate)
+.MR pnm 5
+file can be then converted to virtually any graphics format using the
+tools of the
+.B netpbm
+package.
+.
+.
+.\" ====================================================================
+.SH Files
+.\" ====================================================================
+.
+.TP
+.I @MACRODIR@/pic.tmac
+offers simple definitions of the
+.BR PS ,
+.BR PE ,
+.BR PF ,
+and
+.B PY
+macros.
+.
+.
+.\" ====================================================================
+.SH Bugs
+.\" ====================================================================
+.
+Characters that are invalid as input to GNU
+.I troff \" GNU
+(see the
+.I groff
+Texinfo manual or
+.MR groff_char @MAN7EXT@
+for a list)
+are rejected even in \*[tx] mode.
+.
+.
+.LP
+The interpretation of
+.B \%fillval
+is incompatible with the
+.I pic \" AT&T
+in Tenth Edition Research Unix,
+which interprets 0 as black and 1 as white.
+.
+.
+.\" ====================================================================
+.SH "See also"
+.\" ====================================================================
+.
+.TP
+.I @DOCDIR@/\:pic\:.ps
+\[lq]Making Pictures with GNU pic\[rq],
+by Eric S.\& Raymond.
+.
+This file,
+together with its source,
+.IR pic.ms ,
+is part of the
+.I groff
+distribution.
+.
+.
+.P
+\[lq]PIC\[em]A Graphics Language for Typesetting: User Manual\[rq],
+by Brian W.\& Kernighan,
+1984
+(revised 1991),
+AT&T Bell Laboratories Computing Science Technical Report No.\& 116
+.
+.
+.P
+.I ps2eps
+is available from CTAN mirrors, e.g.,
+.UR ftp://\:ftp\:.dante\:.de/\:tex\-archive/\:support/\:ps2eps/
+.UE
+.
+.
+.LP
+W.\& Richard Stevens,
+.UR http://\:www\:.kohala\:.com/\:start/\:troff/\:pic2html\:.html
+.I Turning PIC into HTML
+.UE
+.
+.
+.LP
+W.\& Richard Stevens,
+.UR http://\:www\:.kohala\:.com/\:start/\:troff/\:pic\:.examples\:.ps
+.IR "Examples of " pic " Macros"
+.UE
+.
+.
+.LP
+.MR @g@troff @MAN1EXT@ ,
+.MR groff_out @MAN5EXT@ ,
+.MR tex 1 ,
+.MR gs 1 ,
+.MR ps2eps 1 ,
+.MR pstopnm 1 ,
+.MR ps2epsi 1 ,
+.MR pnm 5
+.
+.
+.\" Clean up.
+.rm tx
+.rm lx
+.rm ic
+.
+.\" Restore compatibility mode (for, e.g., Solaris 10/11).
+.cp \n[*groff_pic_1_man_C]
+.do rr *groff_pic_1_man_C
+.
+.
+.\" Local Variables:
+.\" fill-column: 72
+.\" mode: nroff
+.\" End:
+.\" vim: set filetype=groff textwidth=72:
diff --git a/src/preproc/pic/pic.am b/src/preproc/pic/pic.am
new file mode 100644
index 0000000..fae1372
--- /dev/null
+++ b/src/preproc/pic/pic.am
@@ -0,0 +1,56 @@
+# Copyright (C) 2014-2020 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+prefixexecbin_PROGRAMS += pic
+pic_CPPFLAGS = $(AM_CPPFLAGS) \
+  -I $(top_srcdir)/src/preproc/pic \
+  -I $(top_builddir)/src/preproc/pic
+pic_LDADD = libgroff.a $(LIBM) lib/libgnu.a
+pic_SOURCES = \
+  src/preproc/pic/pic.ypp \
+  src/preproc/pic/lex.cpp \
+  src/preproc/pic/main.cpp \
+  src/preproc/pic/object.cpp \
+  src/preproc/pic/common.cpp \
+  src/preproc/pic/troff.cpp \
+  src/preproc/pic/tex.cpp \
+  src/preproc/pic/pic.h \
+  src/preproc/pic/position.h \
+  src/preproc/pic/text.h \
+  src/preproc/pic/common.h \
+  src/preproc/pic/output.h \
+  src/preproc/pic/object.h
+
+PREFIXMAN1 += src/preproc/pic/pic.1
+EXTRA_DIST += \
+  src/preproc/pic/TODO \
+  src/preproc/pic/pic.1.man
+
+# Since pic_CPPFLAGS was set, all .o files have a 'pic-' prefix.
+src/preproc/pic/pic-lex.$(OBJEXT): src/preproc/pic/pic.hpp
+
+MAINTAINERCLEANFILES += \
+  src/preproc/pic/pic.cpp \
+  src/preproc/pic/pic.hpp \
+  src/preproc/pic/pic.output
+
+
+# Local Variables:
+# fill-column: 72
+# mode: makefile-automake
+# End:
+# vim: set autoindent filetype=automake textwidth=72:
diff --git a/src/preproc/pic/pic.cpp b/src/preproc/pic/pic.cpp
new file mode 100644
index 0000000..14b15e4
--- /dev/null
+++ b/src/preproc/pic/pic.cpp
@@ -0,0 +1,5080 @@
+/* A Bison parser, made by GNU Bison 3.8.2.  */
+
+/* Bison implementation for Yacc-like parsers in C
+
+   Copyright (C) 1984, 1989-1990, 2000-2015, 2018-2021 Free Software Foundation,
+   Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* As a special exception, you may create a larger work that contains
+   part or all of the Bison parser skeleton and distribute that work
+   under terms of your choice, so long as that work isn't itself a
+   parser generator using the skeleton or a modified version thereof
+   as a parser skeleton.  Alternatively, if you modify or redistribute
+   the parser skeleton itself, you may (at your option) remove this
+   special exception, which will cause the skeleton and the resulting
+   Bison output files to be licensed under the GNU General Public
+   License without this special exception.
+
+   This special exception was added by the Free Software Foundation in
+   version 2.2 of Bison.  */
+
+/* C LALR(1) parser skeleton written by Richard Stallman, by
+   simplifying the original so-called "semantic" parser.  */
+
+/* DO NOT RELY ON FEATURES THAT ARE NOT DOCUMENTED in the manual,
+   especially those whose name start with YY_ or yy_.  They are
+   private implementation details that can be changed or removed.  */
+
+/* All symbols defined below should begin with yy or YY, to avoid
+   infringing on user name space.  This should be done even for local
+   variables, as they might otherwise be expanded by user macros.
+   There are some unavoidable exceptions within include files to
+   define necessary library symbols; they are noted "INFRINGES ON
+   USER NAME SPACE" below.  */
+
+/* Identify Bison output, and Bison version.  */
+#define YYBISON 30802
+
+/* Bison version string.  */
+#define YYBISON_VERSION "3.8.2"
+
+/* Skeleton name.  */
+#define YYSKELETON_NAME "yacc.c"
+
+/* Pure parsers.  */
+#define YYPURE 0
+
+/* Push parsers.  */
+#define YYPUSH 0
+
+/* Pull parsers.  */
+#define YYPULL 1
+
+
+
+
+/* First part of user prologue.  */
+#line 19 "../src/preproc/pic/pic.ypp"
+
+#include "pic.h"
+#include "ptable.h"
+#include "object.h"
+
+extern int delim_flag;
+extern void copy_rest_thru(const char *, const char *);
+extern void copy_file_thru(const char *, const char *, const char *);
+extern void push_body(const char *);
+extern void do_for(char *var, double from, double to,
+		   int by_is_multiplicative, double by, char *body);
+extern void do_lookahead();
+
+/* Maximum number of characters produced by printf("%g") */
+#define GDIGITS 14
+
+int yylex();
+void yyerror(const char *);
+
+void reset(const char *nm);
+void reset_all();
+
+place *lookup_label(const char *);
+void define_label(const char *label, const place *pl);
+
+direction current_direction;
+position current_position;
+
+implement_ptable(place)
+
+PTABLE(place) top_table;
+
+PTABLE(place) *current_table = &top_table;
+saved_state *current_saved_state = 0;
+
+object_list olist;
+
+const char *ordinal_postfix(int n);
+const char *object_type_name(object_type type);
+char *format_number(const char *fmt, double n);
+char *do_sprintf(const char *fmt, const double *v, int nv);
+
+
+#line 115 "src/preproc/pic/pic.cpp"
+
+# ifndef YY_CAST
+#  ifdef __cplusplus
+#   define YY_CAST(Type, Val) static_cast<Type> (Val)
+#   define YY_REINTERPRET_CAST(Type, Val) reinterpret_cast<Type> (Val)
+#  else
+#   define YY_CAST(Type, Val) ((Type) (Val))
+#   define YY_REINTERPRET_CAST(Type, Val) ((Type) (Val))
+#  endif
+# endif
+# ifndef YY_NULLPTR
+#  if defined __cplusplus
+#   if 201103L <= __cplusplus
+#    define YY_NULLPTR nullptr
+#   else
+#    define YY_NULLPTR 0
+#   endif
+#  else
+#   define YY_NULLPTR ((void*)0)
+#  endif
+# endif
+
+/* Use api.header.include to #include this header
+   instead of duplicating it here.  */
+#ifndef YY_YY_SRC_PREPROC_PIC_PIC_HPP_INCLUDED
+# define YY_YY_SRC_PREPROC_PIC_PIC_HPP_INCLUDED
+/* Debug traces.  */
+#ifndef YYDEBUG
+# define YYDEBUG 0
+#endif
+#if YYDEBUG
+extern int yydebug;
+#endif
+
+/* Token kinds.  */
+#ifndef YYTOKENTYPE
+# define YYTOKENTYPE
+  enum yytokentype
+  {
+    YYEMPTY = -2,
+    YYEOF = 0,                     /* "end of file"  */
+    YYerror = 256,                 /* error  */
+    YYUNDEF = 257,                 /* "invalid token"  */
+    LABEL = 258,                   /* LABEL  */
+    VARIABLE = 259,                /* VARIABLE  */
+    NUMBER = 260,                  /* NUMBER  */
+    TEXT = 261,                    /* TEXT  */
+    COMMAND_LINE = 262,            /* COMMAND_LINE  */
+    DELIMITED = 263,               /* DELIMITED  */
+    ORDINAL = 264,                 /* ORDINAL  */
+    TH = 265,                      /* TH  */
+    LEFT_ARROW_HEAD = 266,         /* LEFT_ARROW_HEAD  */
+    RIGHT_ARROW_HEAD = 267,        /* RIGHT_ARROW_HEAD  */
+    DOUBLE_ARROW_HEAD = 268,       /* DOUBLE_ARROW_HEAD  */
+    LAST = 269,                    /* LAST  */
+    BOX = 270,                     /* BOX  */
+    CIRCLE = 271,                  /* CIRCLE  */
+    ELLIPSE = 272,                 /* ELLIPSE  */
+    ARC = 273,                     /* ARC  */
+    LINE = 274,                    /* LINE  */
+    ARROW = 275,                   /* ARROW  */
+    MOVE = 276,                    /* MOVE  */
+    SPLINE = 277,                  /* SPLINE  */
+    HEIGHT = 278,                  /* HEIGHT  */
+    RADIUS = 279,                  /* RADIUS  */
+    FIGNAME = 280,                 /* FIGNAME  */
+    WIDTH = 281,                   /* WIDTH  */
+    DIAMETER = 282,                /* DIAMETER  */
+    UP = 283,                      /* UP  */
+    DOWN = 284,                    /* DOWN  */
+    RIGHT = 285,                   /* RIGHT  */
+    LEFT = 286,                    /* LEFT  */
+    FROM = 287,                    /* FROM  */
+    TO = 288,                      /* TO  */
+    AT = 289,                      /* AT  */
+    WITH = 290,                    /* WITH  */
+    BY = 291,                      /* BY  */
+    THEN = 292,                    /* THEN  */
+    SOLID = 293,                   /* SOLID  */
+    DOTTED = 294,                  /* DOTTED  */
+    DASHED = 295,                  /* DASHED  */
+    CHOP = 296,                    /* CHOP  */
+    SAME = 297,                    /* SAME  */
+    INVISIBLE = 298,               /* INVISIBLE  */
+    LJUST = 299,                   /* LJUST  */
+    RJUST = 300,                   /* RJUST  */
+    ABOVE = 301,                   /* ABOVE  */
+    BELOW = 302,                   /* BELOW  */
+    OF = 303,                      /* OF  */
+    THE = 304,                     /* THE  */
+    WAY = 305,                     /* WAY  */
+    BETWEEN = 306,                 /* BETWEEN  */
+    AND = 307,                     /* AND  */
+    HERE = 308,                    /* HERE  */
+    DOT_N = 309,                   /* DOT_N  */
+    DOT_E = 310,                   /* DOT_E  */
+    DOT_W = 311,                   /* DOT_W  */
+    DOT_S = 312,                   /* DOT_S  */
+    DOT_NE = 313,                  /* DOT_NE  */
+    DOT_SE = 314,                  /* DOT_SE  */
+    DOT_NW = 315,                  /* DOT_NW  */
+    DOT_SW = 316,                  /* DOT_SW  */
+    DOT_C = 317,                   /* DOT_C  */
+    DOT_START = 318,               /* DOT_START  */
+    DOT_END = 319,                 /* DOT_END  */
+    DOT_X = 320,                   /* DOT_X  */
+    DOT_Y = 321,                   /* DOT_Y  */
+    DOT_HT = 322,                  /* DOT_HT  */
+    DOT_WID = 323,                 /* DOT_WID  */
+    DOT_RAD = 324,                 /* DOT_RAD  */
+    SIN = 325,                     /* SIN  */
+    COS = 326,                     /* COS  */
+    ATAN2 = 327,                   /* ATAN2  */
+    LOG = 328,                     /* LOG  */
+    EXP = 329,                     /* EXP  */
+    SQRT = 330,                    /* SQRT  */
+    K_MAX = 331,                   /* K_MAX  */
+    K_MIN = 332,                   /* K_MIN  */
+    INT = 333,                     /* INT  */
+    RAND = 334,                    /* RAND  */
+    SRAND = 335,                   /* SRAND  */
+    COPY = 336,                    /* COPY  */
+    THRU = 337,                    /* THRU  */
+    TOP = 338,                     /* TOP  */
+    BOTTOM = 339,                  /* BOTTOM  */
+    UPPER = 340,                   /* UPPER  */
+    LOWER = 341,                   /* LOWER  */
+    SH = 342,                      /* SH  */
+    PRINT = 343,                   /* PRINT  */
+    CW = 344,                      /* CW  */
+    CCW = 345,                     /* CCW  */
+    FOR = 346,                     /* FOR  */
+    DO = 347,                      /* DO  */
+    IF = 348,                      /* IF  */
+    ELSE = 349,                    /* ELSE  */
+    ANDAND = 350,                  /* ANDAND  */
+    OROR = 351,                    /* OROR  */
+    NOTEQUAL = 352,                /* NOTEQUAL  */
+    EQUALEQUAL = 353,              /* EQUALEQUAL  */
+    LESSEQUAL = 354,               /* LESSEQUAL  */
+    GREATEREQUAL = 355,            /* GREATEREQUAL  */
+    LEFT_CORNER = 356,             /* LEFT_CORNER  */
+    RIGHT_CORNER = 357,            /* RIGHT_CORNER  */
+    NORTH = 358,                   /* NORTH  */
+    SOUTH = 359,                   /* SOUTH  */
+    EAST = 360,                    /* EAST  */
+    WEST = 361,                    /* WEST  */
+    CENTER = 362,                  /* CENTER  */
+    END = 363,                     /* END  */
+    START = 364,                   /* START  */
+    RESET = 365,                   /* RESET  */
+    UNTIL = 366,                   /* UNTIL  */
+    PLOT = 367,                    /* PLOT  */
+    THICKNESS = 368,               /* THICKNESS  */
+    FILL = 369,                    /* FILL  */
+    COLORED = 370,                 /* COLORED  */
+    OUTLINED = 371,                /* OUTLINED  */
+    SHADED = 372,                  /* SHADED  */
+    XSLANTED = 373,                /* XSLANTED  */
+    YSLANTED = 374,                /* YSLANTED  */
+    ALIGNED = 375,                 /* ALIGNED  */
+    SPRINTF = 376,                 /* SPRINTF  */
+    COMMAND = 377,                 /* COMMAND  */
+    DEFINE = 378,                  /* DEFINE  */
+    UNDEF = 379                    /* UNDEF  */
+  };
+  typedef enum yytokentype yytoken_kind_t;
+#endif
+/* Token kinds.  */
+#define YYEMPTY -2
+#define YYEOF 0
+#define YYerror 256
+#define YYUNDEF 257
+#define LABEL 258
+#define VARIABLE 259
+#define NUMBER 260
+#define TEXT 261
+#define COMMAND_LINE 262
+#define DELIMITED 263
+#define ORDINAL 264
+#define TH 265
+#define LEFT_ARROW_HEAD 266
+#define RIGHT_ARROW_HEAD 267
+#define DOUBLE_ARROW_HEAD 268
+#define LAST 269
+#define BOX 270
+#define CIRCLE 271
+#define ELLIPSE 272
+#define ARC 273
+#define LINE 274
+#define ARROW 275
+#define MOVE 276
+#define SPLINE 277
+#define HEIGHT 278
+#define RADIUS 279
+#define FIGNAME 280
+#define WIDTH 281
+#define DIAMETER 282
+#define UP 283
+#define DOWN 284
+#define RIGHT 285
+#define LEFT 286
+#define FROM 287
+#define TO 288
+#define AT 289
+#define WITH 290
+#define BY 291
+#define THEN 292
+#define SOLID 293
+#define DOTTED 294
+#define DASHED 295
+#define CHOP 296
+#define SAME 297
+#define INVISIBLE 298
+#define LJUST 299
+#define RJUST 300
+#define ABOVE 301
+#define BELOW 302
+#define OF 303
+#define THE 304
+#define WAY 305
+#define BETWEEN 306
+#define AND 307
+#define HERE 308
+#define DOT_N 309
+#define DOT_E 310
+#define DOT_W 311
+#define DOT_S 312
+#define DOT_NE 313
+#define DOT_SE 314
+#define DOT_NW 315
+#define DOT_SW 316
+#define DOT_C 317
+#define DOT_START 318
+#define DOT_END 319
+#define DOT_X 320
+#define DOT_Y 321
+#define DOT_HT 322
+#define DOT_WID 323
+#define DOT_RAD 324
+#define SIN 325
+#define COS 326
+#define ATAN2 327
+#define LOG 328
+#define EXP 329
+#define SQRT 330
+#define K_MAX 331
+#define K_MIN 332
+#define INT 333
+#define RAND 334
+#define SRAND 335
+#define COPY 336
+#define THRU 337
+#define TOP 338
+#define BOTTOM 339
+#define UPPER 340
+#define LOWER 341
+#define SH 342
+#define PRINT 343
+#define CW 344
+#define CCW 345
+#define FOR 346
+#define DO 347
+#define IF 348
+#define ELSE 349
+#define ANDAND 350
+#define OROR 351
+#define NOTEQUAL 352
+#define EQUALEQUAL 353
+#define LESSEQUAL 354
+#define GREATEREQUAL 355
+#define LEFT_CORNER 356
+#define RIGHT_CORNER 357
+#define NORTH 358
+#define SOUTH 359
+#define EAST 360
+#define WEST 361
+#define CENTER 362
+#define END 363
+#define START 364
+#define RESET 365
+#define UNTIL 366
+#define PLOT 367
+#define THICKNESS 368
+#define FILL 369
+#define COLORED 370
+#define OUTLINED 371
+#define SHADED 372
+#define XSLANTED 373
+#define YSLANTED 374
+#define ALIGNED 375
+#define SPRINTF 376
+#define COMMAND 377
+#define DEFINE 378
+#define UNDEF 379
+
+/* Value type.  */
+#if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
+union YYSTYPE
+{
+#line 65 "../src/preproc/pic/pic.ypp"
+
+	char *str;
+	int n;
+	double x;
+	struct { double x, y; } pair;
+	struct { double x; char *body; } if_data;
+	struct { char *str; const char *filename; int lineno; } lstr;
+	struct { double *v; int nv; int maxv; } dv;
+	struct { double val; int is_multiplicative; } by;
+	place pl;
+	object *obj;
+	corner crn;
+	path *pth;
+	object_spec *spec;
+	saved_state *pstate;
+	graphics_state state;
+	object_type obtype;
+
+#line 435 "src/preproc/pic/pic.cpp"
+
+};
+typedef union YYSTYPE YYSTYPE;
+# define YYSTYPE_IS_TRIVIAL 1
+# define YYSTYPE_IS_DECLARED 1
+#endif
+
+
+extern YYSTYPE yylval;
+
+
+int yyparse (void);
+
+
+#endif /* !YY_YY_SRC_PREPROC_PIC_PIC_HPP_INCLUDED  */
+/* Symbol kind.  */
+enum yysymbol_kind_t
+{
+  YYSYMBOL_YYEMPTY = -2,
+  YYSYMBOL_YYEOF = 0,                      /* "end of file"  */
+  YYSYMBOL_YYerror = 1,                    /* error  */
+  YYSYMBOL_YYUNDEF = 2,                    /* "invalid token"  */
+  YYSYMBOL_LABEL = 3,                      /* LABEL  */
+  YYSYMBOL_VARIABLE = 4,                   /* VARIABLE  */
+  YYSYMBOL_NUMBER = 5,                     /* NUMBER  */
+  YYSYMBOL_TEXT = 6,                       /* TEXT  */
+  YYSYMBOL_COMMAND_LINE = 7,               /* COMMAND_LINE  */
+  YYSYMBOL_DELIMITED = 8,                  /* DELIMITED  */
+  YYSYMBOL_ORDINAL = 9,                    /* ORDINAL  */
+  YYSYMBOL_TH = 10,                        /* TH  */
+  YYSYMBOL_LEFT_ARROW_HEAD = 11,           /* LEFT_ARROW_HEAD  */
+  YYSYMBOL_RIGHT_ARROW_HEAD = 12,          /* RIGHT_ARROW_HEAD  */
+  YYSYMBOL_DOUBLE_ARROW_HEAD = 13,         /* DOUBLE_ARROW_HEAD  */
+  YYSYMBOL_LAST = 14,                      /* LAST  */
+  YYSYMBOL_BOX = 15,                       /* BOX  */
+  YYSYMBOL_CIRCLE = 16,                    /* CIRCLE  */
+  YYSYMBOL_ELLIPSE = 17,                   /* ELLIPSE  */
+  YYSYMBOL_ARC = 18,                       /* ARC  */
+  YYSYMBOL_LINE = 19,                      /* LINE  */
+  YYSYMBOL_ARROW = 20,                     /* ARROW  */
+  YYSYMBOL_MOVE = 21,                      /* MOVE  */
+  YYSYMBOL_SPLINE = 22,                    /* SPLINE  */
+  YYSYMBOL_HEIGHT = 23,                    /* HEIGHT  */
+  YYSYMBOL_RADIUS = 24,                    /* RADIUS  */
+  YYSYMBOL_FIGNAME = 25,                   /* FIGNAME  */
+  YYSYMBOL_WIDTH = 26,                     /* WIDTH  */
+  YYSYMBOL_DIAMETER = 27,                  /* DIAMETER  */
+  YYSYMBOL_UP = 28,                        /* UP  */
+  YYSYMBOL_DOWN = 29,                      /* DOWN  */
+  YYSYMBOL_RIGHT = 30,                     /* RIGHT  */
+  YYSYMBOL_LEFT = 31,                      /* LEFT  */
+  YYSYMBOL_FROM = 32,                      /* FROM  */
+  YYSYMBOL_TO = 33,                        /* TO  */
+  YYSYMBOL_AT = 34,                        /* AT  */
+  YYSYMBOL_WITH = 35,                      /* WITH  */
+  YYSYMBOL_BY = 36,                        /* BY  */
+  YYSYMBOL_THEN = 37,                      /* THEN  */
+  YYSYMBOL_SOLID = 38,                     /* SOLID  */
+  YYSYMBOL_DOTTED = 39,                    /* DOTTED  */
+  YYSYMBOL_DASHED = 40,                    /* DASHED  */
+  YYSYMBOL_CHOP = 41,                      /* CHOP  */
+  YYSYMBOL_SAME = 42,                      /* SAME  */
+  YYSYMBOL_INVISIBLE = 43,                 /* INVISIBLE  */
+  YYSYMBOL_LJUST = 44,                     /* LJUST  */
+  YYSYMBOL_RJUST = 45,                     /* RJUST  */
+  YYSYMBOL_ABOVE = 46,                     /* ABOVE  */
+  YYSYMBOL_BELOW = 47,                     /* BELOW  */
+  YYSYMBOL_OF = 48,                        /* OF  */
+  YYSYMBOL_THE = 49,                       /* THE  */
+  YYSYMBOL_WAY = 50,                       /* WAY  */
+  YYSYMBOL_BETWEEN = 51,                   /* BETWEEN  */
+  YYSYMBOL_AND = 52,                       /* AND  */
+  YYSYMBOL_HERE = 53,                      /* HERE  */
+  YYSYMBOL_DOT_N = 54,                     /* DOT_N  */
+  YYSYMBOL_DOT_E = 55,                     /* DOT_E  */
+  YYSYMBOL_DOT_W = 56,                     /* DOT_W  */
+  YYSYMBOL_DOT_S = 57,                     /* DOT_S  */
+  YYSYMBOL_DOT_NE = 58,                    /* DOT_NE  */
+  YYSYMBOL_DOT_SE = 59,                    /* DOT_SE  */
+  YYSYMBOL_DOT_NW = 60,                    /* DOT_NW  */
+  YYSYMBOL_DOT_SW = 61,                    /* DOT_SW  */
+  YYSYMBOL_DOT_C = 62,                     /* DOT_C  */
+  YYSYMBOL_DOT_START = 63,                 /* DOT_START  */
+  YYSYMBOL_DOT_END = 64,                   /* DOT_END  */
+  YYSYMBOL_DOT_X = 65,                     /* DOT_X  */
+  YYSYMBOL_DOT_Y = 66,                     /* DOT_Y  */
+  YYSYMBOL_DOT_HT = 67,                    /* DOT_HT  */
+  YYSYMBOL_DOT_WID = 68,                   /* DOT_WID  */
+  YYSYMBOL_DOT_RAD = 69,                   /* DOT_RAD  */
+  YYSYMBOL_SIN = 70,                       /* SIN  */
+  YYSYMBOL_COS = 71,                       /* COS  */
+  YYSYMBOL_ATAN2 = 72,                     /* ATAN2  */
+  YYSYMBOL_LOG = 73,                       /* LOG  */
+  YYSYMBOL_EXP = 74,                       /* EXP  */
+  YYSYMBOL_SQRT = 75,                      /* SQRT  */
+  YYSYMBOL_K_MAX = 76,                     /* K_MAX  */
+  YYSYMBOL_K_MIN = 77,                     /* K_MIN  */
+  YYSYMBOL_INT = 78,                       /* INT  */
+  YYSYMBOL_RAND = 79,                      /* RAND  */
+  YYSYMBOL_SRAND = 80,                     /* SRAND  */
+  YYSYMBOL_COPY = 81,                      /* COPY  */
+  YYSYMBOL_THRU = 82,                      /* THRU  */
+  YYSYMBOL_TOP = 83,                       /* TOP  */
+  YYSYMBOL_BOTTOM = 84,                    /* BOTTOM  */
+  YYSYMBOL_UPPER = 85,                     /* UPPER  */
+  YYSYMBOL_LOWER = 86,                     /* LOWER  */
+  YYSYMBOL_SH = 87,                        /* SH  */
+  YYSYMBOL_PRINT = 88,                     /* PRINT  */
+  YYSYMBOL_CW = 89,                        /* CW  */
+  YYSYMBOL_CCW = 90,                       /* CCW  */
+  YYSYMBOL_FOR = 91,                       /* FOR  */
+  YYSYMBOL_DO = 92,                        /* DO  */
+  YYSYMBOL_IF = 93,                        /* IF  */
+  YYSYMBOL_ELSE = 94,                      /* ELSE  */
+  YYSYMBOL_ANDAND = 95,                    /* ANDAND  */
+  YYSYMBOL_OROR = 96,                      /* OROR  */
+  YYSYMBOL_NOTEQUAL = 97,                  /* NOTEQUAL  */
+  YYSYMBOL_EQUALEQUAL = 98,                /* EQUALEQUAL  */
+  YYSYMBOL_LESSEQUAL = 99,                 /* LESSEQUAL  */
+  YYSYMBOL_GREATEREQUAL = 100,             /* GREATEREQUAL  */
+  YYSYMBOL_LEFT_CORNER = 101,              /* LEFT_CORNER  */
+  YYSYMBOL_RIGHT_CORNER = 102,             /* RIGHT_CORNER  */
+  YYSYMBOL_NORTH = 103,                    /* NORTH  */
+  YYSYMBOL_SOUTH = 104,                    /* SOUTH  */
+  YYSYMBOL_EAST = 105,                     /* EAST  */
+  YYSYMBOL_WEST = 106,                     /* WEST  */
+  YYSYMBOL_CENTER = 107,                   /* CENTER  */
+  YYSYMBOL_END = 108,                      /* END  */
+  YYSYMBOL_START = 109,                    /* START  */
+  YYSYMBOL_RESET = 110,                    /* RESET  */
+  YYSYMBOL_UNTIL = 111,                    /* UNTIL  */
+  YYSYMBOL_PLOT = 112,                     /* PLOT  */
+  YYSYMBOL_THICKNESS = 113,                /* THICKNESS  */
+  YYSYMBOL_FILL = 114,                     /* FILL  */
+  YYSYMBOL_COLORED = 115,                  /* COLORED  */
+  YYSYMBOL_OUTLINED = 116,                 /* OUTLINED  */
+  YYSYMBOL_SHADED = 117,                   /* SHADED  */
+  YYSYMBOL_XSLANTED = 118,                 /* XSLANTED  */
+  YYSYMBOL_YSLANTED = 119,                 /* YSLANTED  */
+  YYSYMBOL_ALIGNED = 120,                  /* ALIGNED  */
+  YYSYMBOL_SPRINTF = 121,                  /* SPRINTF  */
+  YYSYMBOL_COMMAND = 122,                  /* COMMAND  */
+  YYSYMBOL_DEFINE = 123,                   /* DEFINE  */
+  YYSYMBOL_UNDEF = 124,                    /* UNDEF  */
+  YYSYMBOL_125_ = 125,                     /* '.'  */
+  YYSYMBOL_126_ = 126,                     /* '('  */
+  YYSYMBOL_127_ = 127,                     /* '`'  */
+  YYSYMBOL_128_ = 128,                     /* '['  */
+  YYSYMBOL_129_ = 129,                     /* ','  */
+  YYSYMBOL_130_ = 130,                     /* '<'  */
+  YYSYMBOL_131_ = 131,                     /* '>'  */
+  YYSYMBOL_132_ = 132,                     /* '+'  */
+  YYSYMBOL_133_ = 133,                     /* '-'  */
+  YYSYMBOL_134_ = 134,                     /* '*'  */
+  YYSYMBOL_135_ = 135,                     /* '/'  */
+  YYSYMBOL_136_ = 136,                     /* '%'  */
+  YYSYMBOL_137_ = 137,                     /* '!'  */
+  YYSYMBOL_138_ = 138,                     /* '^'  */
+  YYSYMBOL_139_ = 139,                     /* ';'  */
+  YYSYMBOL_140_ = 140,                     /* '='  */
+  YYSYMBOL_141_ = 141,                     /* ':'  */
+  YYSYMBOL_142_ = 142,                     /* '{'  */
+  YYSYMBOL_143_ = 143,                     /* '}'  */
+  YYSYMBOL_144_ = 144,                     /* ']'  */
+  YYSYMBOL_145_ = 145,                     /* ')'  */
+  YYSYMBOL_YYACCEPT = 146,                 /* $accept  */
+  YYSYMBOL_top = 147,                      /* top  */
+  YYSYMBOL_element_list = 148,             /* element_list  */
+  YYSYMBOL_middle_element_list = 149,      /* middle_element_list  */
+  YYSYMBOL_optional_separator = 150,       /* optional_separator  */
+  YYSYMBOL_separator = 151,                /* separator  */
+  YYSYMBOL_placeless_element = 152,        /* placeless_element  */
+  YYSYMBOL_153_1 = 153,                    /* $@1  */
+  YYSYMBOL_154_2 = 154,                    /* $@2  */
+  YYSYMBOL_155_3 = 155,                    /* $@3  */
+  YYSYMBOL_156_4 = 156,                    /* $@4  */
+  YYSYMBOL_157_5 = 157,                    /* $@5  */
+  YYSYMBOL_158_6 = 158,                    /* $@6  */
+  YYSYMBOL_159_7 = 159,                    /* $@7  */
+  YYSYMBOL_macro_name = 160,               /* macro_name  */
+  YYSYMBOL_reset_variables = 161,          /* reset_variables  */
+  YYSYMBOL_print_args = 162,               /* print_args  */
+  YYSYMBOL_print_arg = 163,                /* print_arg  */
+  YYSYMBOL_simple_if = 164,                /* simple_if  */
+  YYSYMBOL_165_8 = 165,                    /* $@8  */
+  YYSYMBOL_until = 166,                    /* until  */
+  YYSYMBOL_any_expr = 167,                 /* any_expr  */
+  YYSYMBOL_text_expr = 168,                /* text_expr  */
+  YYSYMBOL_optional_by = 169,              /* optional_by  */
+  YYSYMBOL_element = 170,                  /* element  */
+  YYSYMBOL_171_9 = 171,                    /* @9  */
+  YYSYMBOL_172_10 = 172,                   /* $@10  */
+  YYSYMBOL_optional_element = 173,         /* optional_element  */
+  YYSYMBOL_object_spec = 174,              /* object_spec  */
+  YYSYMBOL_175_11 = 175,                   /* @11  */
+  YYSYMBOL_text = 176,                     /* text  */
+  YYSYMBOL_sprintf_args = 177,             /* sprintf_args  */
+  YYSYMBOL_position = 178,                 /* position  */
+  YYSYMBOL_position_not_place = 179,       /* position_not_place  */
+  YYSYMBOL_between = 180,                  /* between  */
+  YYSYMBOL_expr_pair = 181,                /* expr_pair  */
+  YYSYMBOL_place = 182,                    /* place  */
+  YYSYMBOL_label = 183,                    /* label  */
+  YYSYMBOL_ordinal = 184,                  /* ordinal  */
+  YYSYMBOL_optional_ordinal_last = 185,    /* optional_ordinal_last  */
+  YYSYMBOL_nth_primitive = 186,            /* nth_primitive  */
+  YYSYMBOL_object_type = 187,              /* object_type  */
+  YYSYMBOL_label_path = 188,               /* label_path  */
+  YYSYMBOL_relative_path = 189,            /* relative_path  */
+  YYSYMBOL_path = 190,                     /* path  */
+  YYSYMBOL_corner = 191,                   /* corner  */
+  YYSYMBOL_expr = 192,                     /* expr  */
+  YYSYMBOL_expr_lower_than = 193,          /* expr_lower_than  */
+  YYSYMBOL_expr_not_lower_than = 194       /* expr_not_lower_than  */
+};
+typedef enum yysymbol_kind_t yysymbol_kind_t;
+
+
+
+
+#ifdef short
+# undef short
+#endif
+
+/* On compilers that do not define __PTRDIFF_MAX__ etc., make sure
+   <limits.h> and (if available) <stdint.h> are included
+   so that the code can choose integer types of a good width.  */
+
+#ifndef __PTRDIFF_MAX__
+# include <limits.h> /* INFRINGES ON USER NAME SPACE */
+# if defined __STDC_VERSION__ && 199901 <= __STDC_VERSION__
+#  include <stdint.h> /* INFRINGES ON USER NAME SPACE */
+#  define YY_STDINT_H
+# endif
+#endif
+
+/* Narrow types that promote to a signed type and that can represent a
+   signed or unsigned integer of at least N bits.  In tables they can
+   save space and decrease cache pressure.  Promoting to a signed type
+   helps avoid bugs in integer arithmetic.  */
+
+#ifdef __INT_LEAST8_MAX__
+typedef __INT_LEAST8_TYPE__ yytype_int8;
+#elif defined YY_STDINT_H
+typedef int_least8_t yytype_int8;
+#else
+typedef signed char yytype_int8;
+#endif
+
+#ifdef __INT_LEAST16_MAX__
+typedef __INT_LEAST16_TYPE__ yytype_int16;
+#elif defined YY_STDINT_H
+typedef int_least16_t yytype_int16;
+#else
+typedef short yytype_int16;
+#endif
+
+/* Work around bug in HP-UX 11.23, which defines these macros
+   incorrectly for preprocessor constants.  This workaround can likely
+   be removed in 2023, as HPE has promised support for HP-UX 11.23
+   (aka HP-UX 11i v2) only through the end of 2022; see Table 2 of
+   <https://h20195.www2.hpe.com/V2/getpdf.aspx/4AA4-7673ENW.pdf>.  */
+#ifdef __hpux
+# undef UINT_LEAST8_MAX
+# undef UINT_LEAST16_MAX
+# define UINT_LEAST8_MAX 255
+# define UINT_LEAST16_MAX 65535
+#endif
+
+#if defined __UINT_LEAST8_MAX__ && __UINT_LEAST8_MAX__ <= __INT_MAX__
+typedef __UINT_LEAST8_TYPE__ yytype_uint8;
+#elif (!defined __UINT_LEAST8_MAX__ && defined YY_STDINT_H \
+       && UINT_LEAST8_MAX <= INT_MAX)
+typedef uint_least8_t yytype_uint8;
+#elif !defined __UINT_LEAST8_MAX__ && UCHAR_MAX <= INT_MAX
+typedef unsigned char yytype_uint8;
+#else
+typedef short yytype_uint8;
+#endif
+
+#if defined __UINT_LEAST16_MAX__ && __UINT_LEAST16_MAX__ <= __INT_MAX__
+typedef __UINT_LEAST16_TYPE__ yytype_uint16;
+#elif (!defined __UINT_LEAST16_MAX__ && defined YY_STDINT_H \
+       && UINT_LEAST16_MAX <= INT_MAX)
+typedef uint_least16_t yytype_uint16;
+#elif !defined __UINT_LEAST16_MAX__ && USHRT_MAX <= INT_MAX
+typedef unsigned short yytype_uint16;
+#else
+typedef int yytype_uint16;
+#endif
+
+#ifndef YYPTRDIFF_T
+# if defined __PTRDIFF_TYPE__ && defined __PTRDIFF_MAX__
+#  define YYPTRDIFF_T __PTRDIFF_TYPE__
+#  define YYPTRDIFF_MAXIMUM __PTRDIFF_MAX__
+# elif defined PTRDIFF_MAX
+#  ifndef ptrdiff_t
+#   include <stddef.h> /* INFRINGES ON USER NAME SPACE */
+#  endif
+#  define YYPTRDIFF_T ptrdiff_t
+#  define YYPTRDIFF_MAXIMUM PTRDIFF_MAX
+# else
+#  define YYPTRDIFF_T long
+#  define YYPTRDIFF_MAXIMUM LONG_MAX
+# endif
+#endif
+
+#ifndef YYSIZE_T
+# ifdef __SIZE_TYPE__
+#  define YYSIZE_T __SIZE_TYPE__
+# elif defined size_t
+#  define YYSIZE_T size_t
+# elif defined __STDC_VERSION__ && 199901 <= __STDC_VERSION__
+#  include <stddef.h> /* INFRINGES ON USER NAME SPACE */
+#  define YYSIZE_T size_t
+# else
+#  define YYSIZE_T unsigned
+# endif
+#endif
+
+#define YYSIZE_MAXIMUM                                  \
+  YY_CAST (YYPTRDIFF_T,                                 \
+           (YYPTRDIFF_MAXIMUM < YY_CAST (YYSIZE_T, -1)  \
+            ? YYPTRDIFF_MAXIMUM                         \
+            : YY_CAST (YYSIZE_T, -1)))
+
+#define YYSIZEOF(X) YY_CAST (YYPTRDIFF_T, sizeof (X))
+
+
+/* Stored state numbers (used for stacks). */
+typedef yytype_int16 yy_state_t;
+
+/* State numbers in computations.  */
+typedef int yy_state_fast_t;
+
+#ifndef YY_
+# if defined YYENABLE_NLS && YYENABLE_NLS
+#  if ENABLE_NLS
+#   include <libintl.h> /* INFRINGES ON USER NAME SPACE */
+#   define YY_(Msgid) dgettext ("bison-runtime", Msgid)
+#  endif
+# endif
+# ifndef YY_
+#  define YY_(Msgid) Msgid
+# endif
+#endif
+
+
+#ifndef YY_ATTRIBUTE_PURE
+# if defined __GNUC__ && 2 < __GNUC__ + (96 <= __GNUC_MINOR__)
+#  define YY_ATTRIBUTE_PURE __attribute__ ((__pure__))
+# else
+#  define YY_ATTRIBUTE_PURE
+# endif
+#endif
+
+#ifndef YY_ATTRIBUTE_UNUSED
+# if defined __GNUC__ && 2 < __GNUC__ + (7 <= __GNUC_MINOR__)
+#  define YY_ATTRIBUTE_UNUSED __attribute__ ((__unused__))
+# else
+#  define YY_ATTRIBUTE_UNUSED
+# endif
+#endif
+
+/* Suppress unused-variable warnings by "using" E.  */
+#if ! defined lint || defined __GNUC__
+# define YY_USE(E) ((void) (E))
+#else
+# define YY_USE(E) /* empty */
+#endif
+
+/* Suppress an incorrect diagnostic about yylval being uninitialized.  */
+#if defined __GNUC__ && ! defined __ICC && 406 <= __GNUC__ * 100 + __GNUC_MINOR__
+# if __GNUC__ * 100 + __GNUC_MINOR__ < 407
+#  define YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN                           \
+    _Pragma ("GCC diagnostic push")                                     \
+    _Pragma ("GCC diagnostic ignored \"-Wuninitialized\"")
+# else
+#  define YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN                           \
+    _Pragma ("GCC diagnostic push")                                     \
+    _Pragma ("GCC diagnostic ignored \"-Wuninitialized\"")              \
+    _Pragma ("GCC diagnostic ignored \"-Wmaybe-uninitialized\"")
+# endif
+# define YY_IGNORE_MAYBE_UNINITIALIZED_END      \
+    _Pragma ("GCC diagnostic pop")
+#else
+# define YY_INITIAL_VALUE(Value) Value
+#endif
+#ifndef YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+# define YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+# define YY_IGNORE_MAYBE_UNINITIALIZED_END
+#endif
+#ifndef YY_INITIAL_VALUE
+# define YY_INITIAL_VALUE(Value) /* Nothing. */
+#endif
+
+#if defined __cplusplus && defined __GNUC__ && ! defined __ICC && 6 <= __GNUC__
+# define YY_IGNORE_USELESS_CAST_BEGIN                          \
+    _Pragma ("GCC diagnostic push")                            \
+    _Pragma ("GCC diagnostic ignored \"-Wuseless-cast\"")
+# define YY_IGNORE_USELESS_CAST_END            \
+    _Pragma ("GCC diagnostic pop")
+#endif
+#ifndef YY_IGNORE_USELESS_CAST_BEGIN
+# define YY_IGNORE_USELESS_CAST_BEGIN
+# define YY_IGNORE_USELESS_CAST_END
+#endif
+
+
+#define YY_ASSERT(E) ((void) (0 && (E)))
+
+#if !defined yyoverflow
+
+/* The parser invokes alloca or malloc; define the necessary symbols.  */
+
+# ifdef YYSTACK_USE_ALLOCA
+#  if YYSTACK_USE_ALLOCA
+#   ifdef __GNUC__
+#    define YYSTACK_ALLOC __builtin_alloca
+#   elif defined __BUILTIN_VA_ARG_INCR
+#    include <alloca.h> /* INFRINGES ON USER NAME SPACE */
+#   elif defined _AIX
+#    define YYSTACK_ALLOC __alloca
+#   elif defined _MSC_VER
+#    include <malloc.h> /* INFRINGES ON USER NAME SPACE */
+#    define alloca _alloca
+#   else
+#    define YYSTACK_ALLOC alloca
+#    if ! defined _ALLOCA_H && ! defined EXIT_SUCCESS
+#     include <stdlib.h> /* INFRINGES ON USER NAME SPACE */
+      /* Use EXIT_SUCCESS as a witness for stdlib.h.  */
+#     ifndef EXIT_SUCCESS
+#      define EXIT_SUCCESS 0
+#     endif
+#    endif
+#   endif
+#  endif
+# endif
+
+# ifdef YYSTACK_ALLOC
+   /* Pacify GCC's 'empty if-body' warning.  */
+#  define YYSTACK_FREE(Ptr) do { /* empty */; } while (0)
+#  ifndef YYSTACK_ALLOC_MAXIMUM
+    /* The OS might guarantee only one guard page at the bottom of the stack,
+       and a page size can be as small as 4096 bytes.  So we cannot safely
+       invoke alloca (N) if N exceeds 4096.  Use a slightly smaller number
+       to allow for a few compiler-allocated temporary stack slots.  */
+#   define YYSTACK_ALLOC_MAXIMUM 4032 /* reasonable circa 2006 */
+#  endif
+# else
+#  define YYSTACK_ALLOC YYMALLOC
+#  define YYSTACK_FREE YYFREE
+#  ifndef YYSTACK_ALLOC_MAXIMUM
+#   define YYSTACK_ALLOC_MAXIMUM YYSIZE_MAXIMUM
+#  endif
+#  if (defined __cplusplus && ! defined EXIT_SUCCESS \
+       && ! ((defined YYMALLOC || defined malloc) \
+             && (defined YYFREE || defined free)))
+#   include <stdlib.h> /* INFRINGES ON USER NAME SPACE */
+#   ifndef EXIT_SUCCESS
+#    define EXIT_SUCCESS 0
+#   endif
+#  endif
+#  ifndef YYMALLOC
+#   define YYMALLOC malloc
+#   if ! defined malloc && ! defined EXIT_SUCCESS
+void *malloc (YYSIZE_T); /* INFRINGES ON USER NAME SPACE */
+#   endif
+#  endif
+#  ifndef YYFREE
+#   define YYFREE free
+#   if ! defined free && ! defined EXIT_SUCCESS
+void free (void *); /* INFRINGES ON USER NAME SPACE */
+#   endif
+#  endif
+# endif
+#endif /* !defined yyoverflow */
+
+#if (! defined yyoverflow \
+     && (! defined __cplusplus \
+         || (defined YYSTYPE_IS_TRIVIAL && YYSTYPE_IS_TRIVIAL)))
+
+/* A type that is properly aligned for any stack member.  */
+union yyalloc
+{
+  yy_state_t yyss_alloc;
+  YYSTYPE yyvs_alloc;
+};
+
+/* The size of the maximum gap between one aligned stack and the next.  */
+# define YYSTACK_GAP_MAXIMUM (YYSIZEOF (union yyalloc) - 1)
+
+/* The size of an array large to enough to hold all stacks, each with
+   N elements.  */
+# define YYSTACK_BYTES(N) \
+     ((N) * (YYSIZEOF (yy_state_t) + YYSIZEOF (YYSTYPE)) \
+      + YYSTACK_GAP_MAXIMUM)
+
+# define YYCOPY_NEEDED 1
+
+/* Relocate STACK from its old location to the new one.  The
+   local variables YYSIZE and YYSTACKSIZE give the old and new number of
+   elements in the stack, and YYPTR gives the new location of the
+   stack.  Advance YYPTR to a properly aligned location for the next
+   stack.  */
+# define YYSTACK_RELOCATE(Stack_alloc, Stack)                           \
+    do                                                                  \
+      {                                                                 \
+        YYPTRDIFF_T yynewbytes;                                         \
+        YYCOPY (&yyptr->Stack_alloc, Stack, yysize);                    \
+        Stack = &yyptr->Stack_alloc;                                    \
+        yynewbytes = yystacksize * YYSIZEOF (*Stack) + YYSTACK_GAP_MAXIMUM; \
+        yyptr += yynewbytes / YYSIZEOF (*yyptr);                        \
+      }                                                                 \
+    while (0)
+
+#endif
+
+#if defined YYCOPY_NEEDED && YYCOPY_NEEDED
+/* Copy COUNT objects from SRC to DST.  The source and destination do
+   not overlap.  */
+# ifndef YYCOPY
+#  if defined __GNUC__ && 1 < __GNUC__
+#   define YYCOPY(Dst, Src, Count) \
+      __builtin_memcpy (Dst, Src, YY_CAST (YYSIZE_T, (Count)) * sizeof (*(Src)))
+#  else
+#   define YYCOPY(Dst, Src, Count)              \
+      do                                        \
+        {                                       \
+          YYPTRDIFF_T yyi;                      \
+          for (yyi = 0; yyi < (Count); yyi++)   \
+            (Dst)[yyi] = (Src)[yyi];            \
+        }                                       \
+      while (0)
+#  endif
+# endif
+#endif /* !YYCOPY_NEEDED */
+
+/* YYFINAL -- State number of the termination state.  */
+#define YYFINAL  6
+/* YYLAST -- Last index in YYTABLE.  */
+#define YYLAST   2438
+
+/* YYNTOKENS -- Number of terminals.  */
+#define YYNTOKENS  146
+/* YYNNTS -- Number of nonterminals.  */
+#define YYNNTS  49
+/* YYNRULES -- Number of rules.  */
+#define YYNRULES  260
+/* YYNSTATES -- Number of states.  */
+#define YYNSTATES  454
+
+/* YYMAXUTOK -- Last valid token kind.  */
+#define YYMAXUTOK   379
+
+
+/* YYTRANSLATE(TOKEN-NUM) -- Symbol number corresponding to TOKEN-NUM
+   as returned by yylex, with out-of-bounds checking.  */
+#define YYTRANSLATE(YYX)                                \
+  (0 <= (YYX) && (YYX) <= YYMAXUTOK                     \
+   ? YY_CAST (yysymbol_kind_t, yytranslate[YYX])        \
+   : YYSYMBOL_YYUNDEF)
+
+/* YYTRANSLATE[TOKEN-NUM] -- Symbol number corresponding to TOKEN-NUM
+   as returned by yylex.  */
+static const yytype_uint8 yytranslate[] =
+{
+       0,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,   137,     2,     2,     2,   136,     2,     2,
+     126,   145,   134,   132,   129,   133,   125,   135,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,   141,   139,
+     130,   140,   131,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,   128,     2,   144,   138,     2,   127,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,   142,     2,   143,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     1,     2,     3,     4,
+       5,     6,     7,     8,     9,    10,    11,    12,    13,    14,
+      15,    16,    17,    18,    19,    20,    21,    22,    23,    24,
+      25,    26,    27,    28,    29,    30,    31,    32,    33,    34,
+      35,    36,    37,    38,    39,    40,    41,    42,    43,    44,
+      45,    46,    47,    48,    49,    50,    51,    52,    53,    54,
+      55,    56,    57,    58,    59,    60,    61,    62,    63,    64,
+      65,    66,    67,    68,    69,    70,    71,    72,    73,    74,
+      75,    76,    77,    78,    79,    80,    81,    82,    83,    84,
+      85,    86,    87,    88,    89,    90,    91,    92,    93,    94,
+      95,    96,    97,    98,    99,   100,   101,   102,   103,   104,
+     105,   106,   107,   108,   109,   110,   111,   112,   113,   114,
+     115,   116,   117,   118,   119,   120,   121,   122,   123,   124
+};
+
+#if YYDEBUG
+/* YYRLINE[YYN] -- Source line where rule number YYN was defined.  */
+static const yytype_int16 yyrline[] =
+{
+       0,   275,   275,   276,   285,   290,   292,   296,   298,   302,
+     303,   307,   315,   320,   332,   334,   336,   338,   340,   345,
+     350,   357,   356,   372,   380,   382,   379,   393,   395,   392,
+     405,   404,   413,   422,   421,   435,   436,   441,   442,   446,
+     451,   456,   464,   466,   485,   492,   494,   505,   504,   516,
+     517,   522,   524,   529,   535,   541,   543,   545,   547,   549,
+     551,   553,   560,   564,   569,   577,   591,   597,   605,   612,
+     618,   611,   627,   637,   638,   643,   645,   647,   649,   654,
+     661,   668,   675,   682,   687,   694,   702,   701,   728,   734,
+     740,   746,   752,   771,   778,   785,   792,   799,   806,   813,
+     820,   827,   834,   849,   861,   867,   876,   883,   908,   912,
+     918,   924,   930,   936,   941,   947,   953,   959,   966,   975,
+     982,   998,  1015,  1020,  1025,  1030,  1035,  1040,  1045,  1050,
+    1058,  1068,  1078,  1088,  1098,  1104,  1112,  1114,  1126,  1131,
+    1161,  1163,  1169,  1178,  1180,  1185,  1190,  1195,  1200,  1205,
+    1210,  1216,  1221,  1229,  1230,  1234,  1239,  1245,  1247,  1253,
+    1259,  1265,  1274,  1284,  1286,  1295,  1297,  1305,  1307,  1312,
+    1327,  1345,  1347,  1349,  1351,  1353,  1355,  1357,  1359,  1361,
+    1366,  1368,  1376,  1380,  1382,  1390,  1392,  1398,  1404,  1410,
+    1416,  1425,  1427,  1429,  1431,  1433,  1435,  1437,  1439,  1441,
+    1443,  1445,  1447,  1449,  1451,  1453,  1455,  1457,  1459,  1461,
+    1463,  1465,  1467,  1469,  1471,  1473,  1475,  1477,  1479,  1481,
+    1483,  1485,  1487,  1492,  1494,  1499,  1504,  1512,  1514,  1521,
+    1528,  1535,  1542,  1549,  1551,  1553,  1555,  1563,  1571,  1584,
+    1586,  1588,  1597,  1606,  1619,  1628,  1637,  1646,  1648,  1650,
+    1652,  1659,  1665,  1670,  1672,  1674,  1676,  1678,  1680,  1682,
+    1684
+};
+#endif
+
+/** Accessing symbol of state STATE.  */
+#define YY_ACCESSING_SYMBOL(State) YY_CAST (yysymbol_kind_t, yystos[State])
+
+#if YYDEBUG || 0
+/* The user-facing name of the symbol whose (internal) number is
+   YYSYMBOL.  No bounds checking.  */
+static const char *yysymbol_name (yysymbol_kind_t yysymbol) YY_ATTRIBUTE_UNUSED;
+
+/* YYTNAME[SYMBOL-NUM] -- String name of the symbol SYMBOL-NUM.
+   First, the terminals, then, starting at YYNTOKENS, nonterminals.  */
+static const char *const yytname[] =
+{
+  "\"end of file\"", "error", "\"invalid token\"", "LABEL", "VARIABLE",
+  "NUMBER", "TEXT", "COMMAND_LINE", "DELIMITED", "ORDINAL", "TH",
+  "LEFT_ARROW_HEAD", "RIGHT_ARROW_HEAD", "DOUBLE_ARROW_HEAD", "LAST",
+  "BOX", "CIRCLE", "ELLIPSE", "ARC", "LINE", "ARROW", "MOVE", "SPLINE",
+  "HEIGHT", "RADIUS", "FIGNAME", "WIDTH", "DIAMETER", "UP", "DOWN",
+  "RIGHT", "LEFT", "FROM", "TO", "AT", "WITH", "BY", "THEN", "SOLID",
+  "DOTTED", "DASHED", "CHOP", "SAME", "INVISIBLE", "LJUST", "RJUST",
+  "ABOVE", "BELOW", "OF", "THE", "WAY", "BETWEEN", "AND", "HERE", "DOT_N",
+  "DOT_E", "DOT_W", "DOT_S", "DOT_NE", "DOT_SE", "DOT_NW", "DOT_SW",
+  "DOT_C", "DOT_START", "DOT_END", "DOT_X", "DOT_Y", "DOT_HT", "DOT_WID",
+  "DOT_RAD", "SIN", "COS", "ATAN2", "LOG", "EXP", "SQRT", "K_MAX", "K_MIN",
+  "INT", "RAND", "SRAND", "COPY", "THRU", "TOP", "BOTTOM", "UPPER",
+  "LOWER", "SH", "PRINT", "CW", "CCW", "FOR", "DO", "IF", "ELSE", "ANDAND",
+  "OROR", "NOTEQUAL", "EQUALEQUAL", "LESSEQUAL", "GREATEREQUAL",
+  "LEFT_CORNER", "RIGHT_CORNER", "NORTH", "SOUTH", "EAST", "WEST",
+  "CENTER", "END", "START", "RESET", "UNTIL", "PLOT", "THICKNESS", "FILL",
+  "COLORED", "OUTLINED", "SHADED", "XSLANTED", "YSLANTED", "ALIGNED",
+  "SPRINTF", "COMMAND", "DEFINE", "UNDEF", "'.'", "'('", "'`'", "'['",
+  "','", "'<'", "'>'", "'+'", "'-'", "'*'", "'/'", "'%'", "'!'", "'^'",
+  "';'", "'='", "':'", "'{'", "'}'", "']'", "')'", "$accept", "top",
+  "element_list", "middle_element_list", "optional_separator", "separator",
+  "placeless_element", "$@1", "$@2", "$@3", "$@4", "$@5", "$@6", "$@7",
+  "macro_name", "reset_variables", "print_args", "print_arg", "simple_if",
+  "$@8", "until", "any_expr", "text_expr", "optional_by", "element", "@9",
+  "$@10", "optional_element", "object_spec", "@11", "text", "sprintf_args",
+  "position", "position_not_place", "between", "expr_pair", "place",
+  "label", "ordinal", "optional_ordinal_last", "nth_primitive",
+  "object_type", "label_path", "relative_path", "path", "corner", "expr",
+  "expr_lower_than", "expr_not_lower_than", YY_NULLPTR
+};
+
+static const char *
+yysymbol_name (yysymbol_kind_t yysymbol)
+{
+  return yytname[yysymbol];
+}
+#endif
+
+#define YYPACT_NINF (-240)
+
+#define yypact_value_is_default(Yyn) \
+  ((Yyn) == YYPACT_NINF)
+
+#define YYTABLE_NINF (-206)
+
+#define yytable_value_is_error(Yyn) \
+  0
+
+/* YYPACT[STATE-NUM] -- Index in YYTABLE of the portion describing
+   STATE-NUM.  */
+static const yytype_int16 yypact[] =
+{
+    -114,  -240,    20,  -240,   757,  -107,  -240,   -98,  -123,  -240,
+    -240,  -240,  -240,  -240,  -240,  -240,  -240,  -240,  -240,  -106,
+    -240,  -240,  -240,  -240,     9,  -240,  1087,    46,  1172,    49,
+    1597,   -70,  1087,  -240,  -240,  -114,  -240,     3,   -33,  -240,
+     877,  -240,  -240,  -114,  1172,   -60,    36,   -14,  -240,    74,
+    -240,  -240,  -240,  -240,  -240,  -240,  -240,  -240,  -240,  -240,
+    -240,  -240,  -240,  -240,  -240,  -240,  -240,  -240,  -240,   -34,
+     -18,     8,    38,    47,    51,    65,   101,   102,   112,   122,
+    -240,  -240,    21,   150,  -240,  -240,  -240,  -240,  -240,  -240,
+    -240,  -240,  -240,  1257,  1172,  1597,  1597,  1087,  -240,  -240,
+     -43,  -240,  -240,   357,  2242,    59,   258,  -240,    10,  2147,
+    -240,     1,     6,  1172,  1172,   145,    -1,     2,   357,  2273,
+    -240,  -240,   220,   249,  1087,  -114,  -114,  -240,   721,  -240,
+     252,  -240,  -240,  -240,  -240,  1597,  1597,  1597,  1597,  2024,
+    2024,  1853,  1939,  1682,  1682,  1682,  1427,  1767,  -240,  -240,
+    2024,  2024,  2024,  -240,  -240,  -240,  -240,  -240,  -240,  -240,
+    -240,  1597,  2024,    23,    23,    23,  1597,  1597,  -240,  -240,
+    2282,   593,  -240,  1172,  -240,  -240,  -240,  -240,   250,  -240,
+    1172,  1172,  1172,  1172,  1172,  1172,  1172,  1172,  1172,   458,
+    1172,  -240,  -240,  -240,  -240,  -240,  -240,  -240,  -240,   121,
+     107,   123,   256,  2157,   137,   261,   134,   134,  -240,  1767,
+    1767,  -240,  -240,  -240,  -240,  -240,   276,  -240,  -240,  -240,
+    -240,  -240,  -240,  -240,  -240,  -240,  -240,   138,  -240,  -240,
+      24,   156,   235,  -240,  1597,  1597,  1597,  1597,  1597,  1597,
+    1597,  1597,  1597,  1597,  1597,  1597,  1597,  1597,  1597,  1682,
+    1682,  1597,  -240,   134,  -240,  1172,  1172,    23,    23,  1172,
+    1172,  -240,  -240,   143,   757,   153,  -240,  -240,   280,  2282,
+    2282,  2282,  2282,  2282,  2282,  2282,  2282,   -43,  2147,   -43,
+     -43,  2253,   275,   275,   295,  1002,   -43,  2081,  -240,  -240,
+      10,  1342,  -240,   694,  2282,  2282,  2282,  2282,  2282,  -240,
+    -240,  -240,  2282,  2282,   -98,  -123,    16,    28,  -240,   -43,
+      56,   302,  -240,   291,  -240,   155,   160,   172,   161,   164,
+     167,   184,   185,   181,  -240,   186,   188,  -240,  1682,  1767,
+    1767,  -240,  -240,  1682,  1682,  -240,  -240,  -240,  -240,  -240,
+     156,   279,   314,  2291,   440,   440,   413,   413,  2282,   413,
+     413,   -72,   -72,   134,   134,   134,   134,   -49,   117,   343,
+     322,  -240,   314,   239,  2300,  -240,  -240,  -240,   314,   239,
+    2300,  -119,  -240,  -240,  -240,  -240,  -240,  2116,  2116,  -240,
+     206,   333,  -240,   123,  2131,  -240,   228,  -240,  -240,  1172,
+    -240,  -240,  -240,  1172,  1172,  -240,  -240,  -240,  -110,   195,
+     197,   -47,   128,   292,  1682,  1682,  1597,  -240,  1597,  -240,
+     757,  -240,  -240,  2116,  -240,   228,   338,  -240,   200,   202,
+     212,  -240,  -240,  -240,  1682,  1682,  -240,   -43,   -27,   360,
+    2282,  -240,  -240,   214,  -240,  -240,  -240,  -240,  -240,   -73,
+      30,  -240,  1512,   268,  -240,  -240,   216,  1597,  2282,  -240,
+    -240,  2282,   354,  -240
+};
+
+/* YYDEFACT[STATE-NUM] -- Default reduction number in state STATE-NUM.
+   Performed when YYTABLE does not specify something else to do.  Zero
+   means the default is an error.  */
+static const yytype_int16 yydefact[] =
+{
+       7,     9,     0,     3,     2,     8,     1,     0,     0,   136,
+      18,    75,    76,    77,    78,    79,    80,    81,    82,     0,
+      14,    15,    17,    16,     0,    21,     0,     0,     0,    36,
+       0,     0,     0,    86,    69,     7,    72,    35,    32,     5,
+      65,    83,    10,     7,     0,     0,     0,    23,    27,     0,
+     162,   226,   227,   165,   167,   205,   204,   161,   191,   192,
+     193,   194,   195,   196,   197,   198,   199,   200,   201,     0,
+       0,     0,     0,     0,     0,     0,     0,     0,     0,     0,
+     202,   203,     0,     0,   210,   211,   216,   217,   218,   219,
+     220,   222,   221,     0,     0,     0,     0,    20,    42,    45,
+      46,   140,   143,   141,   157,     0,     0,   163,     0,    44,
+     223,   224,     0,     0,     0,     0,    52,     0,     0,    51,
+     224,    39,    84,     0,    19,     7,     7,     4,     8,    40,
+       0,    33,   124,   125,   126,     0,     0,     0,     0,    93,
+      95,    97,    99,     0,     0,     0,     0,     0,   107,   108,
+     109,   111,   120,   122,   123,   130,   131,   132,   133,   127,
+     128,     0,   113,     0,     0,     0,     0,     0,   135,   129,
+      92,     0,    12,     0,    38,    37,    11,    24,     0,    22,
+       0,     0,     0,     0,     0,     0,     0,     0,     0,     0,
+       0,   208,   206,   212,   214,   209,   207,   213,   215,     0,
+       0,   143,   141,    51,   224,     0,   239,   260,    43,     0,
+       0,   228,   229,   230,   231,   232,     0,   158,   179,   168,
+     171,   172,   173,   174,   175,   176,   177,     0,   169,   170,
+       0,   159,     0,   153,     0,     0,     0,     0,     0,     0,
+       0,     0,     0,     0,     0,     0,     0,     0,     0,     0,
+       0,     0,    61,   260,    47,     0,     0,     0,     0,     0,
+       0,    85,   138,     0,     0,     0,     6,    41,     0,    88,
+      89,    90,    91,    94,    96,    98,   100,   101,     0,   102,
+     103,   162,   165,   167,     0,     0,   105,   183,   185,   104,
+     182,     0,   106,     0,   110,   112,   121,   134,   114,   118,
+     119,   117,   115,   116,   162,   226,   205,   204,    66,     0,
+      67,    68,    13,     0,    28,     0,     0,     0,     0,     0,
+       0,     0,     0,     0,   251,     0,     0,   240,     0,     0,
+       0,   156,   142,     0,     0,   166,   144,   146,   164,   178,
+     160,     0,   258,   259,   257,   256,   253,   255,   155,   225,
+     254,   233,   234,   235,   236,   237,   238,     0,     0,     0,
+       0,    55,    56,    58,    59,    54,    53,    57,   258,    60,
+     259,     0,    87,    70,    34,   190,   182,     0,     0,   180,
+       0,     0,   184,     0,    51,    25,    49,   241,   242,     0,
+     244,   245,   246,     0,     0,   249,   250,   252,     0,   144,
+     146,     0,     0,     0,     0,     0,     0,    48,     0,   137,
+      73,   189,   188,     0,   181,    49,     0,    29,     0,     0,
+       0,   148,   145,   147,     0,     0,   154,   149,     0,    62,
+     139,    74,    71,     0,    26,    50,   243,   247,   248,   149,
+       0,   151,     0,     0,   186,   150,   151,     0,    63,    30,
+     152,    64,     0,    31
+};
+
+/* YYPGOTO[NTERM-NUM].  */
+static const yytype_int16 yypgoto[] =
+{
+    -240,  -240,    17,  -240,    12,   329,  -240,  -240,  -240,  -240,
+    -240,  -240,  -240,  -240,  -240,  -240,   334,   -76,  -240,  -240,
+     -42,    13,  -103,  -240,  -127,  -240,  -240,  -240,  -240,  -240,
+       5,  -240,    99,   194,   169,   -44,     4,  -100,  -240,  -240,
+    -240,  -104,  -240,  -239,  -240,   -50,   -26,  -240,    61
+};
+
+/* YYDEFGOTO[NTERM-NUM].  */
+static const yytype_int16 yydefgoto[] =
+{
+       0,     2,     3,    35,   264,     5,    36,    49,   313,   415,
+     178,   386,   452,   268,   176,    37,    97,    98,    38,   360,
+     417,   199,   116,   443,    39,   126,   410,   432,    40,   125,
+     117,   371,   100,   101,   249,   102,   118,   104,   105,   106,
+     107,   228,   287,   288,   289,   108,   119,   110,   120
+};
+
+/* YYTABLE[YYPACT[STATE-NUM]] -- What to do in state STATE-NUM.  If
+   positive, shift that token.  If negative, reduce the rule whose
+   number is the opposite.  If YYTABLE_NINF, syntax error.  */
+static const yytype_int16 yytable[] =
+{
+     109,   266,   229,   404,   122,   424,   109,   129,   231,    41,
+     408,   252,     4,    50,   170,    47,   -17,    44,    45,    53,
+       6,   208,   209,   210,    54,     1,   409,    50,   -16,     9,
+     103,    99,    42,    53,    46,   421,   103,    99,    54,   174,
+     175,   115,   375,    43,   308,   169,   380,   127,   208,   201,
+     112,   191,   192,   121,   217,   171,   123,   172,   230,   209,
+     210,   131,   245,   246,   247,   218,   248,   203,   177,   206,
+     207,   109,   445,   219,   220,   221,   222,   223,   224,   225,
+     173,   226,   179,   209,   210,   209,   210,   111,   253,   209,
+     210,    48,   180,   111,   255,   256,   290,   202,   109,   257,
+     258,   103,    99,   292,   441,   209,   210,   205,   181,   269,
+     270,   271,   272,   273,   274,   275,   276,   278,   278,   278,
+     278,   293,   193,   194,   294,   295,   296,   261,   103,    99,
+     340,   250,   130,    41,   182,   297,   298,    94,   411,   412,
+     302,   303,   263,   265,    31,   278,   251,   103,   103,   103,
+     103,    94,   361,   363,   204,   -17,   367,   369,   111,   -17,
+     -17,   446,   209,   210,   183,   336,   337,   -16,   299,   300,
+     301,   -16,   -16,   184,   433,   311,    41,   185,   377,   378,
+     195,   196,   254,   293,   293,   111,   312,   227,  -140,  -140,
+     231,   186,   200,   315,   316,   317,   318,   319,   320,   321,
+     322,   323,   325,   326,   111,   111,   111,   111,   342,   343,
+     344,   345,   346,   347,   348,   349,   350,   351,   352,   353,
+     354,   355,   356,   278,   278,   359,     9,   187,   188,   362,
+     364,   376,   111,   368,   370,   290,   328,   382,   189,   329,
+     330,   201,   277,   279,   280,   286,   405,   383,   190,   209,
+     210,   197,   198,   103,   103,   262,   267,   425,   314,   203,
+     209,   210,   365,   366,   218,   384,   327,   334,   331,    41,
+     309,   335,   248,   220,   221,   222,   223,   224,   225,   338,
+     226,   216,   339,   431,   341,   399,   400,   372,   374,   202,
+     220,   221,   222,   223,   224,   225,   373,   226,   379,   385,
+     387,   389,   278,   293,   293,   388,   390,   278,   278,   391,
+     111,   111,   392,   393,   394,   234,   235,   236,   237,   238,
+     239,   211,   212,   213,   214,   215,   395,   376,   376,   403,
+     407,   396,   103,   397,   255,   413,   414,   103,   103,   416,
+     422,    31,   423,   426,   435,   436,   204,   437,   357,   358,
+     241,   242,   243,   244,   245,   246,   247,   438,   248,   444,
+     449,   450,   453,   376,   128,   310,   124,   211,   212,   213,
+     214,   215,   333,   434,     0,     0,   406,     0,   278,   278,
+     429,     0,   430,     0,   200,     0,   227,     0,     0,   111,
+       0,     0,     0,     0,   111,   111,   442,     0,   278,   278,
+       0,   332,   418,   227,     0,     0,   419,   420,   103,   103,
+       0,   236,   237,   238,   239,    41,   448,     0,     0,     0,
+       0,   451,   211,   212,   213,   214,   215,   398,   103,   103,
+       0,     0,   401,   402,  -141,  -141,     0,     0,   234,   235,
+     236,   237,   238,   239,   241,   242,   243,   244,   245,   246,
+     247,     0,   248,     0,     0,   234,   235,   236,   237,   238,
+     239,    50,    51,    52,     9,   111,   111,    53,     0,     0,
+       0,     0,    54,   241,   242,   243,   244,   245,   246,   247,
+       0,   248,     0,     0,     0,   111,   111,     0,    55,    56,
+     241,   242,   243,   244,   245,   246,   247,     0,   248,     0,
+       0,     0,     0,   427,   428,     0,     0,     0,     0,     0,
+       0,    57,    58,    59,    60,    61,    62,    63,    64,    65,
+      66,    67,    68,   439,   440,     0,     0,     0,    69,    70,
+      71,    72,    73,    74,    75,    76,    77,    78,    79,   238,
+     239,    80,    81,    82,    83,   243,   244,   245,   246,   247,
+       0,   248,     0,     0,     0,     0,     0,     0,     0,    84,
+      85,    86,    87,    88,    89,    90,    91,    92,     0,     0,
+     241,   242,   243,   244,   245,   246,   247,     0,   248,    31,
+       0,     0,     0,     0,   113,    94,     0,     0,     0,     0,
+       0,    95,     0,     0,     0,   114,   304,   305,    52,     9,
+      10,     0,    53,   324,     0,     0,     0,    54,    11,    12,
+      13,    14,    15,    16,    17,    18,     0,     0,    19,     0,
+       0,    20,    21,   306,   307,     0,     0,     0,     0,     0,
+       0,     0,     0,     0,     0,     0,     0,     0,     0,     0,
+       0,     0,     0,     0,     0,     0,    57,    58,    59,    60,
+      61,    62,    63,    64,    65,    66,    67,    68,     0,     0,
+       0,     0,     0,    69,    70,    71,    72,    73,    74,    75,
+      76,    77,    78,    79,    24,     0,    80,    81,    82,    83,
+      25,    26,     0,     0,    27,     0,    28,     0,     0,     0,
+       0,     0,     0,     0,    84,    85,    86,    87,    88,    89,
+      90,    91,    92,    29,     0,    30,     0,     0,     0,     0,
+       0,     0,     0,     0,    31,    32,     0,     0,     0,    93,
+      94,    33,     0,     0,     7,     8,    95,     9,    10,     0,
+      96,     0,     0,     0,     0,    34,    11,    12,    13,    14,
+      15,    16,    17,    18,     0,     0,    19,     0,     0,    20,
+      21,    22,    23,     0,     0,     0,     0,     0,     0,     0,
+       7,     8,     0,     9,    10,     0,     0,     0,     0,     0,
+       0,     0,    11,    12,    13,    14,    15,    16,    17,    18,
+       0,     0,    19,     0,     0,    20,    21,    22,    23,   234,
+     235,   236,   237,   238,   239,     0,     0,     0,     0,     0,
+       0,     0,    24,     0,     0,     0,     0,     0,    25,    26,
+       0,     0,    27,     0,    28,     0,     0,     0,     0,     0,
+       0,     0,     0,   240,   241,   242,   243,   244,   245,   246,
+     247,    29,   248,    30,     0,     0,     0,     0,    24,     0,
+       0,     0,    31,    32,    25,    26,     0,     0,    27,    33,
+      28,     0,     0,     0,     0,     0,     0,     0,     0,     0,
+      42,     0,     0,    34,     0,     0,     0,    29,     0,    30,
+       0,     0,     0,     0,     0,     0,     0,     0,    31,    32,
+      50,    51,    52,     9,     0,    33,    53,     0,   132,   133,
+     134,    54,     0,     0,     0,     0,     0,     0,     0,    34,
+     135,   136,     0,   137,   138,   139,   140,   141,   142,   143,
+     144,   145,   146,   147,   148,   149,   150,   151,   152,   153,
+     154,   155,   156,   157,   158,     0,     0,     0,     0,     0,
+      57,    58,    59,    60,    61,    62,    63,    64,    65,    66,
+      67,    68,     0,     0,     0,     0,     0,    69,    70,    71,
+      72,    73,    74,    75,    76,    77,    78,    79,     0,     0,
+      80,    81,    82,    83,     0,     0,   159,   160,     0,     0,
+       0,     0,     0,     0,     0,     0,     0,     0,    84,    85,
+      86,    87,    88,    89,    90,    91,    92,     0,     0,     0,
+     161,   162,   163,   164,   165,   166,   167,   168,    31,     0,
+       0,     0,     0,   113,    94,    50,    51,    52,     9,     0,
+      95,    53,     0,     0,    96,     0,    54,     0,     0,     0,
+       0,     0,     0,     0,     0,     0,     0,     0,     0,     0,
+       0,     0,    55,    56,     0,     0,     0,     0,     0,     0,
+       0,     0,     0,     0,     0,     0,     0,     0,     0,     0,
+       0,     0,     0,     0,     0,    57,    58,    59,    60,    61,
+      62,    63,    64,    65,    66,    67,    68,     0,     0,     0,
+       0,     0,    69,    70,    71,    72,    73,    74,    75,    76,
+      77,    78,    79,     0,     0,    80,    81,    82,    83,     0,
+      50,    51,    52,     9,     0,     0,    53,     0,     0,     0,
+       0,    54,     0,    84,    85,    86,    87,    88,    89,    90,
+      91,    92,     0,     0,     0,     0,     0,    55,    56,     0,
+       0,     0,     0,    31,     0,     0,     0,   284,    93,    94,
+       0,     0,     0,     0,     0,    95,     0,     0,     0,   114,
+      57,    58,    59,    60,    61,    62,    63,    64,    65,    66,
+      67,    68,     0,     0,     0,     0,     0,    69,    70,    71,
+      72,    73,    74,    75,    76,    77,    78,    79,     0,     0,
+      80,    81,    82,    83,     0,    50,    51,    52,     9,     0,
+       0,    53,     0,     0,     0,     0,    54,     0,    84,    85,
+      86,    87,    88,    89,    90,    91,    92,     0,     0,     0,
+       0,     0,    55,    56,     0,     0,     0,     0,    31,     0,
+       0,     0,     0,    93,    94,     0,     0,     0,     0,     0,
+      95,     0,     0,     0,    96,    57,    58,    59,    60,    61,
+      62,    63,    64,    65,    66,    67,    68,     0,     0,     0,
+       0,     0,    69,    70,    71,    72,    73,    74,    75,    76,
+      77,    78,    79,     0,     0,    80,    81,    82,    83,     0,
+      50,    51,    52,     9,     0,     0,    53,     0,     0,     0,
+       0,    54,     0,    84,    85,    86,    87,    88,    89,    90,
+      91,    92,     0,     0,     0,     0,     0,    55,    56,     0,
+       0,     0,     0,    31,     0,     0,     0,     0,   113,    94,
+       0,     0,     0,     0,     0,    95,     0,     0,     0,   114,
+      57,    58,    59,    60,    61,    62,    63,    64,    65,    66,
+      67,    68,     0,     0,     0,     0,     0,    69,    70,    71,
+      72,    73,    74,    75,    76,    77,    78,    79,     0,     0,
+      80,    81,    82,    83,     0,    50,    51,    52,     9,     0,
+       0,    53,     0,     0,     0,     0,    54,     0,    84,    85,
+      86,    87,    88,    89,    90,    91,    92,     0,     0,     0,
+       0,     0,    55,    56,     0,     0,     0,     0,    31,     0,
+       0,     0,     0,    93,    94,     0,     0,     0,     0,     0,
+      95,     0,     0,     0,   114,    57,    58,    59,    60,    61,
+      62,    63,    64,    65,    66,    67,    68,     0,     0,     0,
+       0,     0,    69,    70,    71,    72,    73,    74,    75,    76,
+      77,    78,    79,     0,     0,    80,    81,    82,    83,     0,
+     281,    51,    52,     0,     0,     0,   282,     0,     0,     0,
+       0,   283,     0,    84,    85,    86,    87,    88,    89,    90,
+      91,    92,     0,     0,     0,     0,     0,    55,    56,     0,
+       0,     0,     0,    31,     0,     0,     0,     0,   291,    94,
+       0,     0,     0,     0,     0,    95,     0,     0,     0,   114,
+      57,    58,    59,    60,    61,    62,    63,    64,    65,    66,
+      67,    68,     0,     0,     0,     0,     0,    69,    70,    71,
+      72,    73,    74,    75,    76,    77,    78,    79,     0,     0,
+      80,    81,    82,    83,     0,    50,    51,    52,     0,     0,
+       0,    53,     0,     0,     0,     0,    54,     0,    84,    85,
+      86,    87,    88,    89,    90,    91,    92,     0,     0,     0,
+       0,     0,    55,    56,     0,     0,     0,     0,     0,     0,
+       0,     0,   284,   285,    94,     0,     0,     0,     0,     0,
+      95,     0,     0,     0,    96,    57,    58,    59,    60,    61,
+      62,    63,    64,    65,    66,    67,    68,     0,     0,     0,
+       0,     0,    69,    70,    71,    72,    73,    74,    75,    76,
+      77,    78,    79,     0,     0,    80,    81,    82,    83,     0,
+      50,    51,    52,     0,     0,     0,    53,     0,     0,     0,
+       0,    54,     0,    84,    85,    86,    87,    88,    89,    90,
+      91,    92,     0,     0,     0,     0,     0,    55,    56,     0,
+       0,     0,     0,     0,     0,     0,     0,     0,   113,    94,
+       0,     0,     0,     0,     0,    95,   447,     0,     0,    96,
+      57,    58,    59,    60,    61,    62,    63,    64,    65,    66,
+      67,    68,     0,     0,     0,     0,     0,    69,    70,    71,
+      72,    73,    74,    75,    76,    77,    78,    79,     0,     0,
+      80,    81,    82,    83,     0,    50,    51,    52,     0,     0,
+       0,    53,     0,     0,     0,     0,    54,     0,    84,    85,
+      86,    87,    88,    89,    90,    91,    92,     0,     0,     0,
+       0,     0,    55,    56,     0,     0,     0,     0,     0,     0,
+       0,     0,     0,   113,    94,     0,     0,     0,     0,     0,
+      95,     0,     0,     0,    96,    57,    58,    59,    60,    61,
+      62,    63,    64,    65,    66,    67,    68,     0,     0,     0,
+       0,     0,    69,    70,    71,    72,    73,    74,    75,    76,
+      77,    78,    79,     0,     0,    80,    81,    82,    83,     0,
+      50,    51,    52,     0,     0,     0,    53,     0,     0,     0,
+       0,    54,     0,    84,    85,    86,    87,    88,    89,    90,
+      91,    92,     0,     0,     0,     0,     0,    55,    56,     0,
+       0,     0,     0,     0,     0,     0,     0,     0,    93,    94,
+       0,     0,     0,     0,     0,    95,     0,     0,     0,    96,
+      57,    58,    59,    60,    61,    62,    63,    64,    65,    66,
+      67,    68,     0,     0,     0,     0,     0,    69,    70,    71,
+      72,    73,    74,    75,    76,    77,    78,    79,     0,     0,
+      80,    81,    82,    83,     0,     0,    50,    51,    52,     0,
+       0,     0,    53,     0,     0,     0,     0,    54,    84,    85,
+      86,    87,    88,    89,    90,    91,    92,     0,     0,     0,
+       0,     0,     0,     0,     0,     0,     0,     0,     0,     0,
+       0,     0,     0,   291,    94,     0,     0,     0,     0,     0,
+      95,  -205,     0,     0,    96,     0,    57,    58,    59,    60,
+      61,    62,    63,    64,    65,    66,    67,    68,     0,     0,
+       0,     0,     0,    69,    70,    71,    72,    73,    74,    75,
+      76,    77,    78,    79,     0,     0,    80,    81,    82,    83,
+       0,     0,    50,    51,    52,     0,     0,     0,    53,     0,
+       0,     0,     0,    54,    84,    85,    86,    87,    88,    89,
+      90,    91,    92,     0,     0,     0,     0,     0,     0,     0,
+       0,     0,     0,     0,     0,     0,     0,     0,     0,   113,
+      94,     0,     0,     0,     0,     0,    95,  -204,     0,     0,
+      96,     0,    57,    58,    59,    60,    61,    62,    63,    64,
+      65,    66,    67,    68,     0,     0,     0,     0,     0,    69,
+      70,    71,    72,    73,    74,    75,    76,    77,    78,    79,
+       0,     0,    80,    81,    82,    83,     0,    50,    51,    52,
+       0,     0,     0,    53,     0,     0,     0,     0,    54,     0,
+      84,    85,    86,    87,    88,    89,    90,    91,    92,     0,
+       0,     0,     0,     0,     0,     0,     0,     0,     0,     0,
+       0,     0,     0,     0,     0,   113,    94,     0,     0,     0,
+       0,     0,    95,     0,     0,     0,    96,    57,    58,    59,
+      60,    61,    62,    63,    64,    65,    66,    67,    68,     0,
+       0,     0,     0,     0,    69,    70,    71,    72,    73,    74,
+      75,    76,    77,    78,    79,     0,     0,    80,    81,    82,
+      83,    55,    56,     0,     0,     0,     0,     0,     0,     0,
+       0,     0,     0,     0,     0,    84,    85,    86,    87,    88,
+      89,    90,    91,    92,     0,    58,    59,    60,    61,    62,
+      63,    64,    65,    66,    67,    68,    55,    56,     0,     0,
+     113,    94,     0,     0,     0,     0,     0,    95,     0,     0,
+       0,    96,     0,     0,    80,    81,    82,    83,     0,     0,
+      58,    59,    60,    61,    62,    63,    64,    65,    66,    67,
+      68,     0,    84,    85,    86,    87,    88,    89,    90,    91,
+      92,     0,     0,     0,     0,   232,     0,     0,   233,    80,
+      81,    82,    83,     0,     0,   232,   381,     0,   233,     0,
+       0,     0,     0,     0,     0,     0,     0,    84,    85,    86,
+      87,    88,    89,    90,    91,    92,   259,   260,   236,   237,
+     238,   239,     0,     0,     0,     0,     0,     0,     0,     0,
+       0,   284,   234,   235,   236,   237,   238,   239,     0,     0,
+       0,     0,   259,   260,   236,   237,   238,   239,     0,     0,
+     240,   241,   242,   243,   244,   245,   246,   247,     0,   248,
+       0,     0,     0,     0,     0,     0,   240,   241,   242,   243,
+     244,   245,   246,   247,     0,   248,   240,   241,   242,   243,
+     244,   245,   246,   247,     0,   248,    58,    59,    60,    61,
+      62,    63,    64,    65,    66,    67,    68,    58,    59,    60,
+      61,    62,    63,    64,    65,    66,    67,    68,     0,     0,
+       0,     0,     0,     0,     0,    80,    81,    82,    83,     0,
+       0,     0,     0,     0,     0,     0,    80,    81,    82,    83,
+       0,     0,     0,    84,    85,    86,    87,    88,    89,    90,
+      91,    92,     0,     0,    84,    85,    86,    87,    88,    89,
+      90,    91,    92,     0,     0,     0,     0,   216,   259,   260,
+     236,   237,   238,   239,     0,     0,     0,   234,   235,   236,
+     237,   238,   239,     0,     0,     0,   234,     0,   236,   237,
+     238,   239,     0,     0,     0,   259,     0,   236,   237,   238,
+     239,     0,     0,   241,   242,   243,   244,   245,   246,   247,
+       0,   248,   241,   242,   243,   244,   245,   246,   247,     0,
+     248,   241,   242,   243,   244,   245,   246,   247,     0,   248,
+     241,   242,   243,   244,   245,   246,   247,     0,   248
+};
+
+static const yytype_int16 yycheck[] =
+{
+      26,   128,   106,    52,    30,    52,    32,     4,   108,     4,
+     129,   114,     0,     3,    40,     6,     0,   140,   141,     9,
+       0,    97,   132,   133,    14,   139,   145,     3,     0,     6,
+      26,    26,   139,     9,   140,   145,    32,    32,    14,     3,
+       4,    28,   281,   141,   171,    40,   285,    35,   124,    93,
+       4,    30,    31,     4,   104,    43,   126,    44,    48,   132,
+     133,    94,   134,   135,   136,     6,   138,    93,    82,    95,
+      96,    97,   145,    14,    15,    16,    17,    18,    19,    20,
+     140,    22,     8,   132,   133,   132,   133,    26,   114,   132,
+     133,    82,   126,    32,    95,    96,   146,    93,   124,    97,
+      98,    97,    97,   147,   131,   132,   133,    94,   126,   135,
+     136,   137,   138,   139,   140,   141,   142,   143,   144,   145,
+     146,   147,   101,   102,   150,   151,   152,   122,   124,   124,
+     230,   130,   129,   128,   126,   161,   162,   127,   377,   378,
+     166,   167,   125,   126,   121,   171,   140,   143,   144,   145,
+     146,   127,   255,   256,    93,   139,   259,   260,    97,   143,
+     144,   131,   132,   133,   126,   209,   210,   139,   163,   164,
+     165,   143,   144,   126,   413,   171,   171,   126,   282,   283,
+      30,    31,    37,   209,   210,   124,   173,   128,   132,   133,
+     290,   126,    93,   180,   181,   182,   183,   184,   185,   186,
+     187,   188,   189,   190,   143,   144,   145,   146,   234,   235,
+     236,   237,   238,   239,   240,   241,   242,   243,   244,   245,
+     246,   247,   248,   249,   250,   251,     6,   126,   126,   255,
+     256,   281,   171,   259,   260,   285,   129,   287,   126,   132,
+     133,   285,   143,   144,   145,   146,   129,   291,   126,   132,
+     133,   101,   102,   249,   250,     6,     4,   129,     8,   285,
+     132,   133,   257,   258,     6,   291,   145,   130,   145,   264,
+     171,    10,   138,    15,    16,    17,    18,    19,    20,     3,
+      22,   125,   144,   410,    49,   329,   330,   144,     8,   285,
+      15,    16,    17,    18,    19,    20,   143,    22,     3,     8,
+     145,   129,   328,   329,   330,   145,   145,   333,   334,   145,
+     249,   250,   145,   129,   129,    95,    96,    97,    98,    99,
+     100,    65,    66,    67,    68,    69,   145,   377,   378,    50,
+       8,   145,   328,   145,    95,   129,     3,   333,   334,   111,
+     145,   121,   145,    51,     6,   145,   285,   145,   249,   250,
+     130,   131,   132,   133,   134,   135,   136,   145,   138,   145,
+      92,   145,     8,   413,    35,   171,    32,    65,    66,    67,
+      68,    69,   203,   415,    -1,    -1,    33,    -1,   404,   405,
+     406,    -1,   408,    -1,   285,    -1,   128,    -1,    -1,   328,
+      -1,    -1,    -1,    -1,   333,   334,    36,    -1,   424,   425,
+      -1,   145,   389,   128,    -1,    -1,   393,   394,   404,   405,
+      -1,    97,    98,    99,   100,   410,   442,    -1,    -1,    -1,
+      -1,   447,    65,    66,    67,    68,    69,   328,   424,   425,
+      -1,    -1,   333,   334,   132,   133,    -1,    -1,    95,    96,
+      97,    98,    99,   100,   130,   131,   132,   133,   134,   135,
+     136,    -1,   138,    -1,    -1,    95,    96,    97,    98,    99,
+     100,     3,     4,     5,     6,   404,   405,     9,    -1,    -1,
+      -1,    -1,    14,   130,   131,   132,   133,   134,   135,   136,
+      -1,   138,    -1,    -1,    -1,   424,   425,    -1,    30,    31,
+     130,   131,   132,   133,   134,   135,   136,    -1,   138,    -1,
+      -1,    -1,    -1,   404,   405,    -1,    -1,    -1,    -1,    -1,
+      -1,    53,    54,    55,    56,    57,    58,    59,    60,    61,
+      62,    63,    64,   424,   425,    -1,    -1,    -1,    70,    71,
+      72,    73,    74,    75,    76,    77,    78,    79,    80,    99,
+     100,    83,    84,    85,    86,   132,   133,   134,   135,   136,
+      -1,   138,    -1,    -1,    -1,    -1,    -1,    -1,    -1,   101,
+     102,   103,   104,   105,   106,   107,   108,   109,    -1,    -1,
+     130,   131,   132,   133,   134,   135,   136,    -1,   138,   121,
+      -1,    -1,    -1,    -1,   126,   127,    -1,    -1,    -1,    -1,
+      -1,   133,    -1,    -1,    -1,   137,     3,     4,     5,     6,
+       7,    -1,     9,   145,    -1,    -1,    -1,    14,    15,    16,
+      17,    18,    19,    20,    21,    22,    -1,    -1,    25,    -1,
+      -1,    28,    29,    30,    31,    -1,    -1,    -1,    -1,    -1,
+      -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,
+      -1,    -1,    -1,    -1,    -1,    -1,    53,    54,    55,    56,
+      57,    58,    59,    60,    61,    62,    63,    64,    -1,    -1,
+      -1,    -1,    -1,    70,    71,    72,    73,    74,    75,    76,
+      77,    78,    79,    80,    81,    -1,    83,    84,    85,    86,
+      87,    88,    -1,    -1,    91,    -1,    93,    -1,    -1,    -1,
+      -1,    -1,    -1,    -1,   101,   102,   103,   104,   105,   106,
+     107,   108,   109,   110,    -1,   112,    -1,    -1,    -1,    -1,
+      -1,    -1,    -1,    -1,   121,   122,    -1,    -1,    -1,   126,
+     127,   128,    -1,    -1,     3,     4,   133,     6,     7,    -1,
+     137,    -1,    -1,    -1,    -1,   142,    15,    16,    17,    18,
+      19,    20,    21,    22,    -1,    -1,    25,    -1,    -1,    28,
+      29,    30,    31,    -1,    -1,    -1,    -1,    -1,    -1,    -1,
+       3,     4,    -1,     6,     7,    -1,    -1,    -1,    -1,    -1,
+      -1,    -1,    15,    16,    17,    18,    19,    20,    21,    22,
+      -1,    -1,    25,    -1,    -1,    28,    29,    30,    31,    95,
+      96,    97,    98,    99,   100,    -1,    -1,    -1,    -1,    -1,
+      -1,    -1,    81,    -1,    -1,    -1,    -1,    -1,    87,    88,
+      -1,    -1,    91,    -1,    93,    -1,    -1,    -1,    -1,    -1,
+      -1,    -1,    -1,   129,   130,   131,   132,   133,   134,   135,
+     136,   110,   138,   112,    -1,    -1,    -1,    -1,    81,    -1,
+      -1,    -1,   121,   122,    87,    88,    -1,    -1,    91,   128,
+      93,    -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,
+     139,    -1,    -1,   142,    -1,    -1,    -1,   110,    -1,   112,
+      -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,   121,   122,
+       3,     4,     5,     6,    -1,   128,     9,    -1,    11,    12,
+      13,    14,    -1,    -1,    -1,    -1,    -1,    -1,    -1,   142,
+      23,    24,    -1,    26,    27,    28,    29,    30,    31,    32,
+      33,    34,    35,    36,    37,    38,    39,    40,    41,    42,
+      43,    44,    45,    46,    47,    -1,    -1,    -1,    -1,    -1,
+      53,    54,    55,    56,    57,    58,    59,    60,    61,    62,
+      63,    64,    -1,    -1,    -1,    -1,    -1,    70,    71,    72,
+      73,    74,    75,    76,    77,    78,    79,    80,    -1,    -1,
+      83,    84,    85,    86,    -1,    -1,    89,    90,    -1,    -1,
+      -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,   101,   102,
+     103,   104,   105,   106,   107,   108,   109,    -1,    -1,    -1,
+     113,   114,   115,   116,   117,   118,   119,   120,   121,    -1,
+      -1,    -1,    -1,   126,   127,     3,     4,     5,     6,    -1,
+     133,     9,    -1,    -1,   137,    -1,    14,    -1,    -1,    -1,
+      -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,
+      -1,    -1,    30,    31,    -1,    -1,    -1,    -1,    -1,    -1,
+      -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,
+      -1,    -1,    -1,    -1,    -1,    53,    54,    55,    56,    57,
+      58,    59,    60,    61,    62,    63,    64,    -1,    -1,    -1,
+      -1,    -1,    70,    71,    72,    73,    74,    75,    76,    77,
+      78,    79,    80,    -1,    -1,    83,    84,    85,    86,    -1,
+       3,     4,     5,     6,    -1,    -1,     9,    -1,    -1,    -1,
+      -1,    14,    -1,   101,   102,   103,   104,   105,   106,   107,
+     108,   109,    -1,    -1,    -1,    -1,    -1,    30,    31,    -1,
+      -1,    -1,    -1,   121,    -1,    -1,    -1,   125,   126,   127,
+      -1,    -1,    -1,    -1,    -1,   133,    -1,    -1,    -1,   137,
+      53,    54,    55,    56,    57,    58,    59,    60,    61,    62,
+      63,    64,    -1,    -1,    -1,    -1,    -1,    70,    71,    72,
+      73,    74,    75,    76,    77,    78,    79,    80,    -1,    -1,
+      83,    84,    85,    86,    -1,     3,     4,     5,     6,    -1,
+      -1,     9,    -1,    -1,    -1,    -1,    14,    -1,   101,   102,
+     103,   104,   105,   106,   107,   108,   109,    -1,    -1,    -1,
+      -1,    -1,    30,    31,    -1,    -1,    -1,    -1,   121,    -1,
+      -1,    -1,    -1,   126,   127,    -1,    -1,    -1,    -1,    -1,
+     133,    -1,    -1,    -1,   137,    53,    54,    55,    56,    57,
+      58,    59,    60,    61,    62,    63,    64,    -1,    -1,    -1,
+      -1,    -1,    70,    71,    72,    73,    74,    75,    76,    77,
+      78,    79,    80,    -1,    -1,    83,    84,    85,    86,    -1,
+       3,     4,     5,     6,    -1,    -1,     9,    -1,    -1,    -1,
+      -1,    14,    -1,   101,   102,   103,   104,   105,   106,   107,
+     108,   109,    -1,    -1,    -1,    -1,    -1,    30,    31,    -1,
+      -1,    -1,    -1,   121,    -1,    -1,    -1,    -1,   126,   127,
+      -1,    -1,    -1,    -1,    -1,   133,    -1,    -1,    -1,   137,
+      53,    54,    55,    56,    57,    58,    59,    60,    61,    62,
+      63,    64,    -1,    -1,    -1,    -1,    -1,    70,    71,    72,
+      73,    74,    75,    76,    77,    78,    79,    80,    -1,    -1,
+      83,    84,    85,    86,    -1,     3,     4,     5,     6,    -1,
+      -1,     9,    -1,    -1,    -1,    -1,    14,    -1,   101,   102,
+     103,   104,   105,   106,   107,   108,   109,    -1,    -1,    -1,
+      -1,    -1,    30,    31,    -1,    -1,    -1,    -1,   121,    -1,
+      -1,    -1,    -1,   126,   127,    -1,    -1,    -1,    -1,    -1,
+     133,    -1,    -1,    -1,   137,    53,    54,    55,    56,    57,
+      58,    59,    60,    61,    62,    63,    64,    -1,    -1,    -1,
+      -1,    -1,    70,    71,    72,    73,    74,    75,    76,    77,
+      78,    79,    80,    -1,    -1,    83,    84,    85,    86,    -1,
+       3,     4,     5,    -1,    -1,    -1,     9,    -1,    -1,    -1,
+      -1,    14,    -1,   101,   102,   103,   104,   105,   106,   107,
+     108,   109,    -1,    -1,    -1,    -1,    -1,    30,    31,    -1,
+      -1,    -1,    -1,   121,    -1,    -1,    -1,    -1,   126,   127,
+      -1,    -1,    -1,    -1,    -1,   133,    -1,    -1,    -1,   137,
+      53,    54,    55,    56,    57,    58,    59,    60,    61,    62,
+      63,    64,    -1,    -1,    -1,    -1,    -1,    70,    71,    72,
+      73,    74,    75,    76,    77,    78,    79,    80,    -1,    -1,
+      83,    84,    85,    86,    -1,     3,     4,     5,    -1,    -1,
+      -1,     9,    -1,    -1,    -1,    -1,    14,    -1,   101,   102,
+     103,   104,   105,   106,   107,   108,   109,    -1,    -1,    -1,
+      -1,    -1,    30,    31,    -1,    -1,    -1,    -1,    -1,    -1,
+      -1,    -1,   125,   126,   127,    -1,    -1,    -1,    -1,    -1,
+     133,    -1,    -1,    -1,   137,    53,    54,    55,    56,    57,
+      58,    59,    60,    61,    62,    63,    64,    -1,    -1,    -1,
+      -1,    -1,    70,    71,    72,    73,    74,    75,    76,    77,
+      78,    79,    80,    -1,    -1,    83,    84,    85,    86,    -1,
+       3,     4,     5,    -1,    -1,    -1,     9,    -1,    -1,    -1,
+      -1,    14,    -1,   101,   102,   103,   104,   105,   106,   107,
+     108,   109,    -1,    -1,    -1,    -1,    -1,    30,    31,    -1,
+      -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,   126,   127,
+      -1,    -1,    -1,    -1,    -1,   133,   134,    -1,    -1,   137,
+      53,    54,    55,    56,    57,    58,    59,    60,    61,    62,
+      63,    64,    -1,    -1,    -1,    -1,    -1,    70,    71,    72,
+      73,    74,    75,    76,    77,    78,    79,    80,    -1,    -1,
+      83,    84,    85,    86,    -1,     3,     4,     5,    -1,    -1,
+      -1,     9,    -1,    -1,    -1,    -1,    14,    -1,   101,   102,
+     103,   104,   105,   106,   107,   108,   109,    -1,    -1,    -1,
+      -1,    -1,    30,    31,    -1,    -1,    -1,    -1,    -1,    -1,
+      -1,    -1,    -1,   126,   127,    -1,    -1,    -1,    -1,    -1,
+     133,    -1,    -1,    -1,   137,    53,    54,    55,    56,    57,
+      58,    59,    60,    61,    62,    63,    64,    -1,    -1,    -1,
+      -1,    -1,    70,    71,    72,    73,    74,    75,    76,    77,
+      78,    79,    80,    -1,    -1,    83,    84,    85,    86,    -1,
+       3,     4,     5,    -1,    -1,    -1,     9,    -1,    -1,    -1,
+      -1,    14,    -1,   101,   102,   103,   104,   105,   106,   107,
+     108,   109,    -1,    -1,    -1,    -1,    -1,    30,    31,    -1,
+      -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,   126,   127,
+      -1,    -1,    -1,    -1,    -1,   133,    -1,    -1,    -1,   137,
+      53,    54,    55,    56,    57,    58,    59,    60,    61,    62,
+      63,    64,    -1,    -1,    -1,    -1,    -1,    70,    71,    72,
+      73,    74,    75,    76,    77,    78,    79,    80,    -1,    -1,
+      83,    84,    85,    86,    -1,    -1,     3,     4,     5,    -1,
+      -1,    -1,     9,    -1,    -1,    -1,    -1,    14,   101,   102,
+     103,   104,   105,   106,   107,   108,   109,    -1,    -1,    -1,
+      -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,
+      -1,    -1,    -1,   126,   127,    -1,    -1,    -1,    -1,    -1,
+     133,    48,    -1,    -1,   137,    -1,    53,    54,    55,    56,
+      57,    58,    59,    60,    61,    62,    63,    64,    -1,    -1,
+      -1,    -1,    -1,    70,    71,    72,    73,    74,    75,    76,
+      77,    78,    79,    80,    -1,    -1,    83,    84,    85,    86,
+      -1,    -1,     3,     4,     5,    -1,    -1,    -1,     9,    -1,
+      -1,    -1,    -1,    14,   101,   102,   103,   104,   105,   106,
+     107,   108,   109,    -1,    -1,    -1,    -1,    -1,    -1,    -1,
+      -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,   126,
+     127,    -1,    -1,    -1,    -1,    -1,   133,    48,    -1,    -1,
+     137,    -1,    53,    54,    55,    56,    57,    58,    59,    60,
+      61,    62,    63,    64,    -1,    -1,    -1,    -1,    -1,    70,
+      71,    72,    73,    74,    75,    76,    77,    78,    79,    80,
+      -1,    -1,    83,    84,    85,    86,    -1,     3,     4,     5,
+      -1,    -1,    -1,     9,    -1,    -1,    -1,    -1,    14,    -1,
+     101,   102,   103,   104,   105,   106,   107,   108,   109,    -1,
+      -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,
+      -1,    -1,    -1,    -1,    -1,   126,   127,    -1,    -1,    -1,
+      -1,    -1,   133,    -1,    -1,    -1,   137,    53,    54,    55,
+      56,    57,    58,    59,    60,    61,    62,    63,    64,    -1,
+      -1,    -1,    -1,    -1,    70,    71,    72,    73,    74,    75,
+      76,    77,    78,    79,    80,    -1,    -1,    83,    84,    85,
+      86,    30,    31,    -1,    -1,    -1,    -1,    -1,    -1,    -1,
+      -1,    -1,    -1,    -1,    -1,   101,   102,   103,   104,   105,
+     106,   107,   108,   109,    -1,    54,    55,    56,    57,    58,
+      59,    60,    61,    62,    63,    64,    30,    31,    -1,    -1,
+     126,   127,    -1,    -1,    -1,    -1,    -1,   133,    -1,    -1,
+      -1,   137,    -1,    -1,    83,    84,    85,    86,    -1,    -1,
+      54,    55,    56,    57,    58,    59,    60,    61,    62,    63,
+      64,    -1,   101,   102,   103,   104,   105,   106,   107,   108,
+     109,    -1,    -1,    -1,    -1,    48,    -1,    -1,    51,    83,
+      84,    85,    86,    -1,    -1,    48,   125,    -1,    51,    -1,
+      -1,    -1,    -1,    -1,    -1,    -1,    -1,   101,   102,   103,
+     104,   105,   106,   107,   108,   109,    95,    96,    97,    98,
+      99,   100,    -1,    -1,    -1,    -1,    -1,    -1,    -1,    -1,
+      -1,   125,    95,    96,    97,    98,    99,   100,    -1,    -1,
+      -1,    -1,    95,    96,    97,    98,    99,   100,    -1,    -1,
+     129,   130,   131,   132,   133,   134,   135,   136,    -1,   138,
+      -1,    -1,    -1,    -1,    -1,    -1,   129,   130,   131,   132,
+     133,   134,   135,   136,    -1,   138,   129,   130,   131,   132,
+     133,   134,   135,   136,    -1,   138,    54,    55,    56,    57,
+      58,    59,    60,    61,    62,    63,    64,    54,    55,    56,
+      57,    58,    59,    60,    61,    62,    63,    64,    -1,    -1,
+      -1,    -1,    -1,    -1,    -1,    83,    84,    85,    86,    -1,
+      -1,    -1,    -1,    -1,    -1,    -1,    83,    84,    85,    86,
+      -1,    -1,    -1,   101,   102,   103,   104,   105,   106,   107,
+     108,   109,    -1,    -1,   101,   102,   103,   104,   105,   106,
+     107,   108,   109,    -1,    -1,    -1,    -1,   125,    95,    96,
+      97,    98,    99,   100,    -1,    -1,    -1,    95,    96,    97,
+      98,    99,   100,    -1,    -1,    -1,    95,    -1,    97,    98,
+      99,   100,    -1,    -1,    -1,    95,    -1,    97,    98,    99,
+     100,    -1,    -1,   130,   131,   132,   133,   134,   135,   136,
+      -1,   138,   130,   131,   132,   133,   134,   135,   136,    -1,
+     138,   130,   131,   132,   133,   134,   135,   136,    -1,   138,
+     130,   131,   132,   133,   134,   135,   136,    -1,   138
+};
+
+/* YYSTOS[STATE-NUM] -- The symbol kind of the accessing symbol of
+   state STATE-NUM.  */
+static const yytype_uint8 yystos[] =
+{
+       0,   139,   147,   148,   150,   151,     0,     3,     4,     6,
+       7,    15,    16,    17,    18,    19,    20,    21,    22,    25,
+      28,    29,    30,    31,    81,    87,    88,    91,    93,   110,
+     112,   121,   122,   128,   142,   149,   152,   161,   164,   170,
+     174,   176,   139,   141,   140,   141,   140,     6,    82,   153,
+       3,     4,     5,     9,    14,    30,    31,    53,    54,    55,
+      56,    57,    58,    59,    60,    61,    62,    63,    64,    70,
+      71,    72,    73,    74,    75,    76,    77,    78,    79,    80,
+      83,    84,    85,    86,   101,   102,   103,   104,   105,   106,
+     107,   108,   109,   126,   127,   133,   137,   162,   163,   176,
+     178,   179,   181,   182,   183,   184,   185,   186,   191,   192,
+     193,   194,     4,   126,   137,   167,   168,   176,   182,   192,
+     194,     4,   192,   126,   162,   175,   171,   150,   151,     4,
+     129,    94,    11,    12,    13,    23,    24,    26,    27,    28,
+      29,    30,    31,    32,    33,    34,    35,    36,    37,    38,
+      39,    40,    41,    42,    43,    44,    45,    46,    47,    89,
+      90,   113,   114,   115,   116,   117,   118,   119,   120,   176,
+     192,   150,   167,   140,     3,     4,   160,    82,   156,     8,
+     126,   126,   126,   126,   126,   126,   126,   126,   126,   126,
+     126,    30,    31,   101,   102,    30,    31,   101,   102,   167,
+     178,   181,   182,   192,   194,   167,   192,   192,   163,   132,
+     133,    65,    66,    67,    68,    69,   125,   191,     6,    14,
+      15,    16,    17,    18,    19,    20,    22,   128,   187,   187,
+      48,   183,    48,    51,    95,    96,    97,    98,    99,   100,
+     129,   130,   131,   132,   133,   134,   135,   136,   138,   180,
+     130,   140,   168,   192,    37,    95,    96,    97,    98,    95,
+      96,   176,     6,   148,   150,   148,   170,     4,   159,   192,
+     192,   192,   192,   192,   192,   192,   192,   178,   192,   178,
+     178,     3,     9,    14,   125,   126,   178,   188,   189,   190,
+     191,   126,   181,   192,   192,   192,   192,   192,   192,   176,
+     176,   176,   192,   192,     3,     4,    30,    31,   170,   178,
+     179,   182,   167,   154,     8,   167,   167,   167,   167,   167,
+     167,   167,   167,   167,   145,   167,   167,   145,   129,   132,
+     133,   145,   145,   180,   130,    10,   181,   181,     3,   144,
+     183,    49,   192,   192,   192,   192,   192,   192,   192,   192,
+     192,   192,   192,   192,   192,   192,   192,   178,   178,   192,
+     165,   168,   192,   168,   192,   176,   176,   168,   192,   168,
+     192,   177,   144,   143,     8,   189,   191,   187,   187,     3,
+     189,   125,   191,   181,   192,     8,   157,   145,   145,   129,
+     145,   145,   145,   129,   129,   145,   145,   145,   178,   181,
+     181,   178,   178,    50,    52,   129,    33,     8,   129,   145,
+     172,   189,   189,   129,     3,   155,   111,   166,   167,   167,
+     167,   145,   145,   145,    52,   129,    51,   178,   178,   192,
+     192,   170,   173,   189,   166,     6,   145,   145,   145,   178,
+     178,   131,    36,   169,   145,   145,   131,   134,   192,    92,
+     145,   192,   158,     8
+};
+
+/* YYR1[RULE-NUM] -- Symbol kind of the left-hand side of rule RULE-NUM.  */
+static const yytype_uint8 yyr1[] =
+{
+       0,   146,   147,   147,   148,   149,   149,   150,   150,   151,
+     151,   152,   152,   152,   152,   152,   152,   152,   152,   152,
+     152,   153,   152,   152,   154,   155,   152,   156,   157,   152,
+     158,   152,   152,   159,   152,   152,   152,   160,   160,   161,
+     161,   161,   162,   162,   163,   163,   163,   165,   164,   166,
+     166,   167,   167,   168,   168,   168,   168,   168,   168,   168,
+     168,   168,   169,   169,   169,   170,   170,   170,   170,   171,
+     172,   170,   170,   173,   173,   174,   174,   174,   174,   174,
+     174,   174,   174,   174,   174,   174,   175,   174,   174,   174,
+     174,   174,   174,   174,   174,   174,   174,   174,   174,   174,
+     174,   174,   174,   174,   174,   174,   174,   174,   174,   174,
+     174,   174,   174,   174,   174,   174,   174,   174,   174,   174,
+     174,   174,   174,   174,   174,   174,   174,   174,   174,   174,
+     174,   174,   174,   174,   174,   174,   176,   176,   177,   177,
+     178,   178,   178,   179,   179,   179,   179,   179,   179,   179,
+     179,   179,   179,   180,   180,   181,   181,   182,   182,   182,
+     182,   182,   183,   183,   183,   184,   184,   185,   185,   186,
+     186,   187,   187,   187,   187,   187,   187,   187,   187,   187,
+     188,   188,   189,   189,   189,   190,   190,   190,   190,   190,
+     190,   191,   191,   191,   191,   191,   191,   191,   191,   191,
+     191,   191,   191,   191,   191,   191,   191,   191,   191,   191,
+     191,   191,   191,   191,   191,   191,   191,   191,   191,   191,
+     191,   191,   191,   192,   192,   193,   194,   194,   194,   194,
+     194,   194,   194,   194,   194,   194,   194,   194,   194,   194,
+     194,   194,   194,   194,   194,   194,   194,   194,   194,   194,
+     194,   194,   194,   194,   194,   194,   194,   194,   194,   194,
+     194
+};
+
+/* YYR2[RULE-NUM] -- Number of symbols on the right-hand side of rule RULE-NUM.  */
+static const yytype_int8 yyr2[] =
+{
+       0,     2,     1,     1,     3,     1,     3,     0,     1,     1,
+       2,     3,     3,     4,     1,     1,     1,     1,     1,     2,
+       2,     0,     3,     2,     0,     0,     7,     0,     0,     6,
+       0,    10,     1,     0,     4,     1,     1,     1,     1,     2,
+       2,     3,     1,     2,     1,     1,     1,     0,     5,     0,
+       2,     1,     1,     3,     3,     3,     3,     3,     3,     3,
+       3,     2,     0,     2,     3,     1,     4,     4,     4,     0,
+       0,     6,     1,     0,     1,     1,     1,     1,     1,     1,
+       1,     1,     1,     1,     2,     3,     0,     4,     3,     3,
+       3,     3,     2,     2,     3,     2,     3,     2,     3,     2,
+       3,     3,     3,     3,     3,     3,     3,     2,     2,     2,
+       3,     2,     3,     2,     3,     3,     3,     3,     3,     3,
+       2,     3,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     3,     2,     1,     5,     0,     3,
+       1,     1,     3,     1,     3,     5,     3,     5,     5,     5,
+       7,     6,     8,     1,     4,     3,     3,     1,     2,     2,
+       3,     1,     1,     1,     3,     1,     3,     1,     2,     2,
+       2,     1,     1,     1,     1,     1,     1,     1,     2,     1,
+       2,     3,     1,     1,     2,     1,     5,     4,     3,     3,
+       2,     1,     1,     1,     1,     1,     1,     1,     1,     1,
+       1,     1,     1,     1,     1,     1,     2,     2,     2,     2,
+       1,     1,     2,     2,     2,     2,     1,     1,     1,     1,
+       1,     1,     1,     1,     1,     3,     1,     1,     2,     2,
+       2,     2,     2,     3,     3,     3,     3,     3,     3,     2,
+       3,     4,     4,     6,     4,     4,     4,     6,     6,     4,
+       4,     3,     4,     3,     3,     3,     3,     3,     3,     3,
+       2
+};
+
+
+enum { YYENOMEM = -2 };
+
+#define yyerrok         (yyerrstatus = 0)
+#define yyclearin       (yychar = YYEMPTY)
+
+#define YYACCEPT        goto yyacceptlab
+#define YYABORT         goto yyabortlab
+#define YYERROR         goto yyerrorlab
+#define YYNOMEM         goto yyexhaustedlab
+
+
+#define YYRECOVERING()  (!!yyerrstatus)
+
+#define YYBACKUP(Token, Value)                                    \
+  do                                                              \
+    if (yychar == YYEMPTY)                                        \
+      {                                                           \
+        yychar = (Token);                                         \
+        yylval = (Value);                                         \
+        YYPOPSTACK (yylen);                                       \
+        yystate = *yyssp;                                         \
+        goto yybackup;                                            \
+      }                                                           \
+    else                                                          \
+      {                                                           \
+        yyerror (YY_("syntax error: cannot back up")); \
+        YYERROR;                                                  \
+      }                                                           \
+  while (0)
+
+/* Backward compatibility with an undocumented macro.
+   Use YYerror or YYUNDEF. */
+#define YYERRCODE YYUNDEF
+
+
+/* Enable debugging if requested.  */
+#if YYDEBUG
+
+# ifndef YYFPRINTF
+#  include <stdio.h> /* INFRINGES ON USER NAME SPACE */
+#  define YYFPRINTF fprintf
+# endif
+
+# define YYDPRINTF(Args)                        \
+do {                                            \
+  if (yydebug)                                  \
+    YYFPRINTF Args;                             \
+} while (0)
+
+
+
+
+# define YY_SYMBOL_PRINT(Title, Kind, Value, Location)                    \
+do {                                                                      \
+  if (yydebug)                                                            \
+    {                                                                     \
+      YYFPRINTF (stderr, "%s ", Title);                                   \
+      yy_symbol_print (stderr,                                            \
+                  Kind, Value); \
+      YYFPRINTF (stderr, "\n");                                           \
+    }                                                                     \
+} while (0)
+
+
+/*-----------------------------------.
+| Print this symbol's value on YYO.  |
+`-----------------------------------*/
+
+static void
+yy_symbol_value_print (FILE *yyo,
+                       yysymbol_kind_t yykind, YYSTYPE const * const yyvaluep)
+{
+  FILE *yyoutput = yyo;
+  YY_USE (yyoutput);
+  if (!yyvaluep)
+    return;
+  YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+  YY_USE (yykind);
+  YY_IGNORE_MAYBE_UNINITIALIZED_END
+}
+
+
+/*---------------------------.
+| Print this symbol on YYO.  |
+`---------------------------*/
+
+static void
+yy_symbol_print (FILE *yyo,
+                 yysymbol_kind_t yykind, YYSTYPE const * const yyvaluep)
+{
+  YYFPRINTF (yyo, "%s %s (",
+             yykind < YYNTOKENS ? "token" : "nterm", yysymbol_name (yykind));
+
+  yy_symbol_value_print (yyo, yykind, yyvaluep);
+  YYFPRINTF (yyo, ")");
+}
+
+/*------------------------------------------------------------------.
+| yy_stack_print -- Print the state stack from its BOTTOM up to its |
+| TOP (included).                                                   |
+`------------------------------------------------------------------*/
+
+static void
+yy_stack_print (yy_state_t *yybottom, yy_state_t *yytop)
+{
+  YYFPRINTF (stderr, "Stack now");
+  for (; yybottom <= yytop; yybottom++)
+    {
+      int yybot = *yybottom;
+      YYFPRINTF (stderr, " %d", yybot);
+    }
+  YYFPRINTF (stderr, "\n");
+}
+
+# define YY_STACK_PRINT(Bottom, Top)                            \
+do {                                                            \
+  if (yydebug)                                                  \
+    yy_stack_print ((Bottom), (Top));                           \
+} while (0)
+
+
+/*------------------------------------------------.
+| Report that the YYRULE is going to be reduced.  |
+`------------------------------------------------*/
+
+static void
+yy_reduce_print (yy_state_t *yyssp, YYSTYPE *yyvsp,
+                 int yyrule)
+{
+  int yylno = yyrline[yyrule];
+  int yynrhs = yyr2[yyrule];
+  int yyi;
+  YYFPRINTF (stderr, "Reducing stack by rule %d (line %d):\n",
+             yyrule - 1, yylno);
+  /* The symbols being reduced.  */
+  for (yyi = 0; yyi < yynrhs; yyi++)
+    {
+      YYFPRINTF (stderr, "   $%d = ", yyi + 1);
+      yy_symbol_print (stderr,
+                       YY_ACCESSING_SYMBOL (+yyssp[yyi + 1 - yynrhs]),
+                       &yyvsp[(yyi + 1) - (yynrhs)]);
+      YYFPRINTF (stderr, "\n");
+    }
+}
+
+# define YY_REDUCE_PRINT(Rule)          \
+do {                                    \
+  if (yydebug)                          \
+    yy_reduce_print (yyssp, yyvsp, Rule); \
+} while (0)
+
+/* Nonzero means print parse trace.  It is left uninitialized so that
+   multiple parsers can coexist.  */
+int yydebug;
+#else /* !YYDEBUG */
+# define YYDPRINTF(Args) ((void) 0)
+# define YY_SYMBOL_PRINT(Title, Kind, Value, Location)
+# define YY_STACK_PRINT(Bottom, Top)
+# define YY_REDUCE_PRINT(Rule)
+#endif /* !YYDEBUG */
+
+
+/* YYINITDEPTH -- initial size of the parser's stacks.  */
+#ifndef YYINITDEPTH
+# define YYINITDEPTH 200
+#endif
+
+/* YYMAXDEPTH -- maximum size the stacks can grow to (effective only
+   if the built-in stack extension method is used).
+
+   Do not make this value too large; the results are undefined if
+   YYSTACK_ALLOC_MAXIMUM < YYSTACK_BYTES (YYMAXDEPTH)
+   evaluated with infinite-precision integer arithmetic.  */
+
+#ifndef YYMAXDEPTH
+# define YYMAXDEPTH 10000
+#endif
+
+
+
+
+
+
+/*-----------------------------------------------.
+| Release the memory associated to this symbol.  |
+`-----------------------------------------------*/
+
+static void
+yydestruct (const char *yymsg,
+            yysymbol_kind_t yykind, YYSTYPE *yyvaluep)
+{
+  YY_USE (yyvaluep);
+  if (!yymsg)
+    yymsg = "Deleting";
+  YY_SYMBOL_PRINT (yymsg, yykind, yyvaluep, yylocationp);
+
+  YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+  YY_USE (yykind);
+  YY_IGNORE_MAYBE_UNINITIALIZED_END
+}
+
+
+/* Lookahead token kind.  */
+int yychar;
+
+/* The semantic value of the lookahead symbol.  */
+YYSTYPE yylval;
+/* Number of syntax errors so far.  */
+int yynerrs;
+
+
+
+
+/*----------.
+| yyparse.  |
+`----------*/
+
+int
+yyparse (void)
+{
+    yy_state_fast_t yystate = 0;
+    /* Number of tokens to shift before error messages enabled.  */
+    int yyerrstatus = 0;
+
+    /* Refer to the stacks through separate pointers, to allow yyoverflow
+       to reallocate them elsewhere.  */
+
+    /* Their size.  */
+    YYPTRDIFF_T yystacksize = YYINITDEPTH;
+
+    /* The state stack: array, bottom, top.  */
+    yy_state_t yyssa[YYINITDEPTH];
+    yy_state_t *yyss = yyssa;
+    yy_state_t *yyssp = yyss;
+
+    /* The semantic value stack: array, bottom, top.  */
+    YYSTYPE yyvsa[YYINITDEPTH];
+    YYSTYPE *yyvs = yyvsa;
+    YYSTYPE *yyvsp = yyvs;
+
+  int yyn;
+  /* The return value of yyparse.  */
+  int yyresult;
+  /* Lookahead symbol kind.  */
+  yysymbol_kind_t yytoken = YYSYMBOL_YYEMPTY;
+  /* The variables used to return semantic value and location from the
+     action routines.  */
+  YYSTYPE yyval;
+
+
+
+#define YYPOPSTACK(N)   (yyvsp -= (N), yyssp -= (N))
+
+  /* The number of symbols on the RHS of the reduced rule.
+     Keep to zero when no symbol should be popped.  */
+  int yylen = 0;
+
+  YYDPRINTF ((stderr, "Starting parse\n"));
+
+  yychar = YYEMPTY; /* Cause a token to be read.  */
+
+  goto yysetstate;
+
+
+/*------------------------------------------------------------.
+| yynewstate -- push a new state, which is found in yystate.  |
+`------------------------------------------------------------*/
+yynewstate:
+  /* In all cases, when you get here, the value and location stacks
+     have just been pushed.  So pushing a state here evens the stacks.  */
+  yyssp++;
+
+
+/*--------------------------------------------------------------------.
+| yysetstate -- set current state (the top of the stack) to yystate.  |
+`--------------------------------------------------------------------*/
+yysetstate:
+  YYDPRINTF ((stderr, "Entering state %d\n", yystate));
+  YY_ASSERT (0 <= yystate && yystate < YYNSTATES);
+  YY_IGNORE_USELESS_CAST_BEGIN
+  *yyssp = YY_CAST (yy_state_t, yystate);
+  YY_IGNORE_USELESS_CAST_END
+  YY_STACK_PRINT (yyss, yyssp);
+
+  if (yyss + yystacksize - 1 <= yyssp)
+#if !defined yyoverflow && !defined YYSTACK_RELOCATE
+    YYNOMEM;
+#else
+    {
+      /* Get the current used size of the three stacks, in elements.  */
+      YYPTRDIFF_T yysize = yyssp - yyss + 1;
+
+# if defined yyoverflow
+      {
+        /* Give user a chance to reallocate the stack.  Use copies of
+           these so that the &'s don't force the real ones into
+           memory.  */
+        yy_state_t *yyss1 = yyss;
+        YYSTYPE *yyvs1 = yyvs;
+
+        /* Each stack pointer address is followed by the size of the
+           data in use in that stack, in bytes.  This used to be a
+           conditional around just the two extra args, but that might
+           be undefined if yyoverflow is a macro.  */
+        yyoverflow (YY_("memory exhausted"),
+                    &yyss1, yysize * YYSIZEOF (*yyssp),
+                    &yyvs1, yysize * YYSIZEOF (*yyvsp),
+                    &yystacksize);
+        yyss = yyss1;
+        yyvs = yyvs1;
+      }
+# else /* defined YYSTACK_RELOCATE */
+      /* Extend the stack our own way.  */
+      if (YYMAXDEPTH <= yystacksize)
+        YYNOMEM;
+      yystacksize *= 2;
+      if (YYMAXDEPTH < yystacksize)
+        yystacksize = YYMAXDEPTH;
+
+      {
+        yy_state_t *yyss1 = yyss;
+        union yyalloc *yyptr =
+          YY_CAST (union yyalloc *,
+                   YYSTACK_ALLOC (YY_CAST (YYSIZE_T, YYSTACK_BYTES (yystacksize))));
+        if (! yyptr)
+          YYNOMEM;
+        YYSTACK_RELOCATE (yyss_alloc, yyss);
+        YYSTACK_RELOCATE (yyvs_alloc, yyvs);
+#  undef YYSTACK_RELOCATE
+        if (yyss1 != yyssa)
+          YYSTACK_FREE (yyss1);
+      }
+# endif
+
+      yyssp = yyss + yysize - 1;
+      yyvsp = yyvs + yysize - 1;
+
+      YY_IGNORE_USELESS_CAST_BEGIN
+      YYDPRINTF ((stderr, "Stack size increased to %ld\n",
+                  YY_CAST (long, yystacksize)));
+      YY_IGNORE_USELESS_CAST_END
+
+      if (yyss + yystacksize - 1 <= yyssp)
+        YYABORT;
+    }
+#endif /* !defined yyoverflow && !defined YYSTACK_RELOCATE */
+
+
+  if (yystate == YYFINAL)
+    YYACCEPT;
+
+  goto yybackup;
+
+
+/*-----------.
+| yybackup.  |
+`-----------*/
+yybackup:
+  /* Do appropriate processing given the current state.  Read a
+     lookahead token if we need one and don't already have one.  */
+
+  /* First try to decide what to do without reference to lookahead token.  */
+  yyn = yypact[yystate];
+  if (yypact_value_is_default (yyn))
+    goto yydefault;
+
+  /* Not known => get a lookahead token if don't already have one.  */
+
+  /* YYCHAR is either empty, or end-of-input, or a valid lookahead.  */
+  if (yychar == YYEMPTY)
+    {
+      YYDPRINTF ((stderr, "Reading a token\n"));
+      yychar = yylex ();
+    }
+
+  if (yychar <= YYEOF)
+    {
+      yychar = YYEOF;
+      yytoken = YYSYMBOL_YYEOF;
+      YYDPRINTF ((stderr, "Now at end of input.\n"));
+    }
+  else if (yychar == YYerror)
+    {
+      /* The scanner already issued an error message, process directly
+         to error recovery.  But do not keep the error token as
+         lookahead, it is too special and may lead us to an endless
+         loop in error recovery. */
+      yychar = YYUNDEF;
+      yytoken = YYSYMBOL_YYerror;
+      goto yyerrlab1;
+    }
+  else
+    {
+      yytoken = YYTRANSLATE (yychar);
+      YY_SYMBOL_PRINT ("Next token is", yytoken, &yylval, &yylloc);
+    }
+
+  /* If the proper action on seeing token YYTOKEN is to reduce or to
+     detect an error, take that action.  */
+  yyn += yytoken;
+  if (yyn < 0 || YYLAST < yyn || yycheck[yyn] != yytoken)
+    goto yydefault;
+  yyn = yytable[yyn];
+  if (yyn <= 0)
+    {
+      if (yytable_value_is_error (yyn))
+        goto yyerrlab;
+      yyn = -yyn;
+      goto yyreduce;
+    }
+
+  /* Count tokens shifted since error; after three, turn off error
+     status.  */
+  if (yyerrstatus)
+    yyerrstatus--;
+
+  /* Shift the lookahead token.  */
+  YY_SYMBOL_PRINT ("Shifting", yytoken, &yylval, &yylloc);
+  yystate = yyn;
+  YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+  *++yyvsp = yylval;
+  YY_IGNORE_MAYBE_UNINITIALIZED_END
+
+  /* Discard the shifted token.  */
+  yychar = YYEMPTY;
+  goto yynewstate;
+
+
+/*-----------------------------------------------------------.
+| yydefault -- do the default action for the current state.  |
+`-----------------------------------------------------------*/
+yydefault:
+  yyn = yydefact[yystate];
+  if (yyn == 0)
+    goto yyerrlab;
+  goto yyreduce;
+
+
+/*-----------------------------.
+| yyreduce -- do a reduction.  |
+`-----------------------------*/
+yyreduce:
+  /* yyn is the number of a rule to reduce with.  */
+  yylen = yyr2[yyn];
+
+  /* If YYLEN is nonzero, implement the default value of the action:
+     '$$ = $1'.
+
+     Otherwise, the following line sets YYVAL to garbage.
+     This behavior is undocumented and Bison
+     users should not rely upon it.  Assigning to YYVAL
+     unconditionally makes the parser a bit smaller, and it avoids a
+     GCC warning that YYVAL may be used uninitialized.  */
+  yyval = yyvsp[1-yylen];
+
+
+  YY_REDUCE_PRINT (yyn);
+  switch (yyn)
+    {
+  case 3: /* top: element_list  */
+#line 277 "../src/preproc/pic/pic.ypp"
+                {
+		  if (olist.head)
+		    print_picture(olist.head);
+		}
+#line 2343 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 4: /* element_list: optional_separator middle_element_list optional_separator  */
+#line 286 "../src/preproc/pic/pic.ypp"
+                { (yyval.pl) = (yyvsp[-1].pl); }
+#line 2349 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 5: /* middle_element_list: element  */
+#line 291 "../src/preproc/pic/pic.ypp"
+                { (yyval.pl) = (yyvsp[0].pl); }
+#line 2355 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 6: /* middle_element_list: middle_element_list separator element  */
+#line 293 "../src/preproc/pic/pic.ypp"
+                { (yyval.pl) = (yyvsp[-2].pl); }
+#line 2361 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 11: /* placeless_element: FIGNAME '=' macro_name  */
+#line 308 "../src/preproc/pic/pic.ypp"
+                {
+		  delete[] graphname;
+		  graphname = new char[strlen((yyvsp[0].str)) + 1];
+		  strcpy(graphname, (yyvsp[0].str));
+		  delete[] (yyvsp[0].str);
+		}
+#line 2372 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 12: /* placeless_element: VARIABLE '=' any_expr  */
+#line 316 "../src/preproc/pic/pic.ypp"
+                {
+		  define_variable((yyvsp[-2].str), (yyvsp[0].x));
+		  free((yyvsp[-2].str));
+		}
+#line 2381 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 13: /* placeless_element: VARIABLE ':' '=' any_expr  */
+#line 321 "../src/preproc/pic/pic.ypp"
+                {
+		  place *p = lookup_label((yyvsp[-3].str));
+		  if (!p) {
+		    lex_error("variable '%1' not defined", (yyvsp[-3].str));
+		    YYABORT;
+		  }
+		  p->obj = 0;
+		  p->x = (yyvsp[0].x);
+		  p->y = 0.0;
+		  free((yyvsp[-3].str));
+		}
+#line 2397 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 14: /* placeless_element: UP  */
+#line 333 "../src/preproc/pic/pic.ypp"
+                { current_direction = UP_DIRECTION; }
+#line 2403 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 15: /* placeless_element: DOWN  */
+#line 335 "../src/preproc/pic/pic.ypp"
+                { current_direction = DOWN_DIRECTION; }
+#line 2409 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 16: /* placeless_element: LEFT  */
+#line 337 "../src/preproc/pic/pic.ypp"
+                { current_direction = LEFT_DIRECTION; }
+#line 2415 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 17: /* placeless_element: RIGHT  */
+#line 339 "../src/preproc/pic/pic.ypp"
+                { current_direction = RIGHT_DIRECTION; }
+#line 2421 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 18: /* placeless_element: COMMAND_LINE  */
+#line 341 "../src/preproc/pic/pic.ypp"
+                {
+		  olist.append(make_command_object((yyvsp[0].lstr).str, (yyvsp[0].lstr).filename,
+						   (yyvsp[0].lstr).lineno));
+		}
+#line 2430 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 19: /* placeless_element: COMMAND print_args  */
+#line 346 "../src/preproc/pic/pic.ypp"
+                {
+		  olist.append(make_command_object((yyvsp[0].lstr).str, (yyvsp[0].lstr).filename,
+						   (yyvsp[0].lstr).lineno));
+		}
+#line 2439 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 20: /* placeless_element: PRINT print_args  */
+#line 351 "../src/preproc/pic/pic.ypp"
+                {
+		  fprintf(stderr, "%s\n", (yyvsp[0].lstr).str);
+		  delete[] (yyvsp[0].lstr).str;
+		  fflush(stderr);
+		}
+#line 2449 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 21: /* $@1: %empty  */
+#line 357 "../src/preproc/pic/pic.ypp"
+                { delim_flag = 1; }
+#line 2455 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 22: /* placeless_element: SH $@1 DELIMITED  */
+#line 359 "../src/preproc/pic/pic.ypp"
+                {
+		  delim_flag = 0;
+		  if (safer_flag)
+		    lex_error("unsafe to run command '%1'; ignoring",
+			      (yyvsp[0].str));
+		  else {
+		    int retval = system((yyvsp[0].str));
+		    if (retval < 0)
+		      lex_error("error running command '%1': system()"
+			" returned %2", (yyvsp[0].str), retval);
+		  }
+		  delete[] (yyvsp[0].str);
+		}
+#line 2473 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 23: /* placeless_element: COPY TEXT  */
+#line 373 "../src/preproc/pic/pic.ypp"
+                {
+		  if (yychar < 0)
+		    do_lookahead();
+		  do_copy((yyvsp[0].lstr).str);
+		  // do not delete the filename
+		}
+#line 2484 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 24: /* $@2: %empty  */
+#line 380 "../src/preproc/pic/pic.ypp"
+                { delim_flag = 2; }
+#line 2490 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 25: /* $@3: %empty  */
+#line 382 "../src/preproc/pic/pic.ypp"
+                { delim_flag = 0; }
+#line 2496 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 26: /* placeless_element: COPY TEXT THRU $@2 DELIMITED $@3 until  */
+#line 384 "../src/preproc/pic/pic.ypp"
+                {
+		  if (yychar < 0)
+		    do_lookahead();
+		  copy_file_thru((yyvsp[-5].lstr).str, (yyvsp[-2].str), (yyvsp[0].str));
+		  // do not delete the filename
+		  delete[] (yyvsp[-2].str);
+		  delete[] (yyvsp[0].str);
+		}
+#line 2509 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 27: /* $@4: %empty  */
+#line 393 "../src/preproc/pic/pic.ypp"
+                { delim_flag = 2; }
+#line 2515 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 28: /* $@5: %empty  */
+#line 395 "../src/preproc/pic/pic.ypp"
+                { delim_flag = 0; }
+#line 2521 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 29: /* placeless_element: COPY THRU $@4 DELIMITED $@5 until  */
+#line 397 "../src/preproc/pic/pic.ypp"
+                {
+		  if (yychar < 0)
+		    do_lookahead();
+		  copy_rest_thru((yyvsp[-2].str), (yyvsp[0].str));
+		  delete[] (yyvsp[-2].str);
+		  delete[] (yyvsp[0].str);
+		}
+#line 2533 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 30: /* $@6: %empty  */
+#line 405 "../src/preproc/pic/pic.ypp"
+                { delim_flag = 1; }
+#line 2539 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 31: /* placeless_element: FOR VARIABLE '=' expr TO expr optional_by DO $@6 DELIMITED  */
+#line 407 "../src/preproc/pic/pic.ypp"
+                {
+		  delim_flag = 0;
+		  if (yychar < 0)
+		    do_lookahead();
+		  do_for((yyvsp[-8].str), (yyvsp[-6].x), (yyvsp[-4].x), (yyvsp[-3].by).is_multiplicative, (yyvsp[-3].by).val, (yyvsp[0].str)); 
+		}
+#line 2550 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 32: /* placeless_element: simple_if  */
+#line 414 "../src/preproc/pic/pic.ypp"
+                {
+		  if (yychar < 0)
+		    do_lookahead();
+		  if ((yyvsp[0].if_data).x != 0.0)
+		    push_body((yyvsp[0].if_data).body);
+		  delete[] (yyvsp[0].if_data).body;
+		}
+#line 2562 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 33: /* $@7: %empty  */
+#line 422 "../src/preproc/pic/pic.ypp"
+                { delim_flag = 1; }
+#line 2568 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 34: /* placeless_element: simple_if ELSE $@7 DELIMITED  */
+#line 424 "../src/preproc/pic/pic.ypp"
+                {
+		  delim_flag = 0;
+		  if (yychar < 0)
+		    do_lookahead();
+		  if ((yyvsp[-3].if_data).x != 0.0)
+		    push_body((yyvsp[-3].if_data).body);
+		  else
+		    push_body((yyvsp[0].str));
+		  free((yyvsp[-3].if_data).body);
+		  free((yyvsp[0].str));
+		}
+#line 2584 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 36: /* placeless_element: RESET  */
+#line 437 "../src/preproc/pic/pic.ypp"
+                { define_variable("scale", 1.0); }
+#line 2590 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 39: /* reset_variables: RESET VARIABLE  */
+#line 447 "../src/preproc/pic/pic.ypp"
+                {
+		  reset((yyvsp[0].str));
+		  delete[] (yyvsp[0].str);
+		}
+#line 2599 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 40: /* reset_variables: reset_variables VARIABLE  */
+#line 452 "../src/preproc/pic/pic.ypp"
+                {
+		  reset((yyvsp[0].str));
+		  delete[] (yyvsp[0].str);
+		}
+#line 2608 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 41: /* reset_variables: reset_variables ',' VARIABLE  */
+#line 457 "../src/preproc/pic/pic.ypp"
+                {
+		  reset((yyvsp[0].str));
+		  delete[] (yyvsp[0].str);
+		}
+#line 2617 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 42: /* print_args: print_arg  */
+#line 465 "../src/preproc/pic/pic.ypp"
+                { (yyval.lstr) = (yyvsp[0].lstr); }
+#line 2623 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 43: /* print_args: print_args print_arg  */
+#line 467 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.lstr).str = new char[strlen((yyvsp[-1].lstr).str) + strlen((yyvsp[0].lstr).str) + 1];
+		  strcpy((yyval.lstr).str, (yyvsp[-1].lstr).str);
+		  strcat((yyval.lstr).str, (yyvsp[0].lstr).str);
+		  delete[] (yyvsp[-1].lstr).str;
+		  delete[] (yyvsp[0].lstr).str;
+		  if ((yyvsp[-1].lstr).filename) {
+		    (yyval.lstr).filename = (yyvsp[-1].lstr).filename;
+		    (yyval.lstr).lineno = (yyvsp[-1].lstr).lineno;
+		  }
+		  else if ((yyvsp[0].lstr).filename) {
+		    (yyval.lstr).filename = (yyvsp[0].lstr).filename;
+		    (yyval.lstr).lineno = (yyvsp[0].lstr).lineno;
+		  }
+		}
+#line 2643 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 44: /* print_arg: expr  */
+#line 486 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.lstr).str = new char[GDIGITS + 1];
+		  sprintf((yyval.lstr).str, "%g", (yyvsp[0].x));
+		  (yyval.lstr).filename = 0;
+		  (yyval.lstr).lineno = 0;
+		}
+#line 2654 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 45: /* print_arg: text  */
+#line 493 "../src/preproc/pic/pic.ypp"
+                { (yyval.lstr) = (yyvsp[0].lstr); }
+#line 2660 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 46: /* print_arg: position  */
+#line 495 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.lstr).str = new char[GDIGITS + 2 + GDIGITS + 1];
+		  sprintf((yyval.lstr).str, "%g, %g", (yyvsp[0].pair).x, (yyvsp[0].pair).y);
+		  (yyval.lstr).filename = 0;
+		  (yyval.lstr).lineno = 0;
+		}
+#line 2671 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 47: /* $@8: %empty  */
+#line 505 "../src/preproc/pic/pic.ypp"
+                { delim_flag = 1; }
+#line 2677 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 48: /* simple_if: IF any_expr THEN $@8 DELIMITED  */
+#line 507 "../src/preproc/pic/pic.ypp"
+                {
+		  delim_flag = 0;
+		  (yyval.if_data).x = (yyvsp[-3].x);
+		  (yyval.if_data).body = (yyvsp[0].str);
+		}
+#line 2687 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 49: /* until: %empty  */
+#line 516 "../src/preproc/pic/pic.ypp"
+                { (yyval.str) = 0; }
+#line 2693 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 50: /* until: UNTIL TEXT  */
+#line 518 "../src/preproc/pic/pic.ypp"
+                { (yyval.str) = (yyvsp[0].lstr).str; }
+#line 2699 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 51: /* any_expr: expr  */
+#line 523 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = (yyvsp[0].x); }
+#line 2705 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 52: /* any_expr: text_expr  */
+#line 525 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = (yyvsp[0].x); }
+#line 2711 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 53: /* text_expr: text EQUALEQUAL text  */
+#line 530 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.x) = strcmp((yyvsp[-2].lstr).str, (yyvsp[0].lstr).str) == 0;
+		  delete[] (yyvsp[-2].lstr).str;
+		  delete[] (yyvsp[0].lstr).str;
+		}
+#line 2721 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 54: /* text_expr: text NOTEQUAL text  */
+#line 536 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.x) = strcmp((yyvsp[-2].lstr).str, (yyvsp[0].lstr).str) != 0;
+		  delete[] (yyvsp[-2].lstr).str;
+		  delete[] (yyvsp[0].lstr).str;
+		}
+#line 2731 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 55: /* text_expr: text_expr ANDAND text_expr  */
+#line 542 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = ((yyvsp[-2].x) != 0.0 && (yyvsp[0].x) != 0.0); }
+#line 2737 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 56: /* text_expr: text_expr ANDAND expr  */
+#line 544 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = ((yyvsp[-2].x) != 0.0 && (yyvsp[0].x) != 0.0); }
+#line 2743 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 57: /* text_expr: expr ANDAND text_expr  */
+#line 546 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = ((yyvsp[-2].x) != 0.0 && (yyvsp[0].x) != 0.0); }
+#line 2749 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 58: /* text_expr: text_expr OROR text_expr  */
+#line 548 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = ((yyvsp[-2].x) != 0.0 || (yyvsp[0].x) != 0.0); }
+#line 2755 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 59: /* text_expr: text_expr OROR expr  */
+#line 550 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = ((yyvsp[-2].x) != 0.0 || (yyvsp[0].x) != 0.0); }
+#line 2761 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 60: /* text_expr: expr OROR text_expr  */
+#line 552 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = ((yyvsp[-2].x) != 0.0 || (yyvsp[0].x) != 0.0); }
+#line 2767 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 61: /* text_expr: '!' text_expr  */
+#line 554 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = ((yyvsp[0].x) == 0.0); }
+#line 2773 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 62: /* optional_by: %empty  */
+#line 560 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.by).val = 1.0;
+		  (yyval.by).is_multiplicative = 0;
+		}
+#line 2782 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 63: /* optional_by: BY expr  */
+#line 565 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.by).val = (yyvsp[0].x);
+		  (yyval.by).is_multiplicative = 0;
+		}
+#line 2791 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 64: /* optional_by: BY '*' expr  */
+#line 570 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.by).val = (yyvsp[0].x);
+		  (yyval.by).is_multiplicative = 1;
+		}
+#line 2800 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 65: /* element: object_spec  */
+#line 578 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pl).obj = (yyvsp[0].spec)->make_object(&current_position,
+					   &current_direction);
+		  if ((yyval.pl).obj == 0)
+		    YYABORT;
+		  delete (yyvsp[0].spec);
+		  if ((yyval.pl).obj)
+		    olist.append((yyval.pl).obj);
+		  else {
+		    (yyval.pl).x = current_position.x;
+		    (yyval.pl).y = current_position.y;
+		  }
+		}
+#line 2818 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 66: /* element: LABEL ':' optional_separator element  */
+#line 592 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pl) = (yyvsp[0].pl);
+		  define_label((yyvsp[-3].str), & (yyval.pl));
+		  free((yyvsp[-3].str));
+		}
+#line 2828 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 67: /* element: LABEL ':' optional_separator position_not_place  */
+#line 598 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pl).obj = 0;
+		  (yyval.pl).x = (yyvsp[0].pair).x;
+		  (yyval.pl).y = (yyvsp[0].pair).y;
+		  define_label((yyvsp[-3].str), & (yyval.pl));
+		  free((yyvsp[-3].str));
+		}
+#line 2840 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 68: /* element: LABEL ':' optional_separator place  */
+#line 606 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pl) = (yyvsp[0].pl);
+		  define_label((yyvsp[-3].str), & (yyval.pl));
+		  free((yyvsp[-3].str));
+		}
+#line 2850 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 69: /* @9: %empty  */
+#line 612 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.state).x = current_position.x;
+		  (yyval.state).y = current_position.y;
+		  (yyval.state).dir = current_direction;
+		}
+#line 2860 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 70: /* $@10: %empty  */
+#line 618 "../src/preproc/pic/pic.ypp"
+                {
+		  current_position.x = (yyvsp[-2].state).x;
+		  current_position.y = (yyvsp[-2].state).y;
+		  current_direction = (yyvsp[-2].state).dir;
+		}
+#line 2870 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 71: /* element: '{' @9 element_list '}' $@10 optional_element  */
+#line 624 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pl) = (yyvsp[-3].pl);
+		}
+#line 2878 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 72: /* element: placeless_element  */
+#line 628 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pl).obj = 0;
+		  (yyval.pl).x = current_position.x;
+		  (yyval.pl).y = current_position.y;
+		}
+#line 2888 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 73: /* optional_element: %empty  */
+#line 637 "../src/preproc/pic/pic.ypp"
+                {}
+#line 2894 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 74: /* optional_element: element  */
+#line 639 "../src/preproc/pic/pic.ypp"
+                {}
+#line 2900 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 75: /* object_spec: BOX  */
+#line 644 "../src/preproc/pic/pic.ypp"
+                { (yyval.spec) = new object_spec(BOX_OBJECT); }
+#line 2906 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 76: /* object_spec: CIRCLE  */
+#line 646 "../src/preproc/pic/pic.ypp"
+                { (yyval.spec) = new object_spec(CIRCLE_OBJECT); }
+#line 2912 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 77: /* object_spec: ELLIPSE  */
+#line 648 "../src/preproc/pic/pic.ypp"
+                { (yyval.spec) = new object_spec(ELLIPSE_OBJECT); }
+#line 2918 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 78: /* object_spec: ARC  */
+#line 650 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = new object_spec(ARC_OBJECT);
+		  (yyval.spec)->dir = current_direction;
+		}
+#line 2927 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 79: /* object_spec: LINE  */
+#line 655 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = new object_spec(LINE_OBJECT);
+		  lookup_variable("lineht", & (yyval.spec)->segment_height);
+		  lookup_variable("linewid", & (yyval.spec)->segment_width);
+		  (yyval.spec)->dir = current_direction;
+		}
+#line 2938 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 80: /* object_spec: ARROW  */
+#line 662 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = new object_spec(ARROW_OBJECT);
+		  lookup_variable("lineht", & (yyval.spec)->segment_height);
+		  lookup_variable("linewid", & (yyval.spec)->segment_width);
+		  (yyval.spec)->dir = current_direction;
+		}
+#line 2949 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 81: /* object_spec: MOVE  */
+#line 669 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = new object_spec(MOVE_OBJECT);
+		  lookup_variable("moveht", & (yyval.spec)->segment_height);
+		  lookup_variable("movewid", & (yyval.spec)->segment_width);
+		  (yyval.spec)->dir = current_direction;
+		}
+#line 2960 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 82: /* object_spec: SPLINE  */
+#line 676 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = new object_spec(SPLINE_OBJECT);
+		  lookup_variable("lineht", & (yyval.spec)->segment_height);
+		  lookup_variable("linewid", & (yyval.spec)->segment_width);
+		  (yyval.spec)->dir = current_direction;
+		}
+#line 2971 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 83: /* object_spec: text  */
+#line 683 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = new object_spec(TEXT_OBJECT);
+		  (yyval.spec)->text = new text_item((yyvsp[0].lstr).str, (yyvsp[0].lstr).filename, (yyvsp[0].lstr).lineno);
+		}
+#line 2980 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 84: /* object_spec: PLOT expr  */
+#line 688 "../src/preproc/pic/pic.ypp"
+                {
+		  lex_warning("'plot' is deprecated; use 'sprintf'"
+			      " instead");
+		  (yyval.spec) = new object_spec(TEXT_OBJECT);
+		  (yyval.spec)->text = new text_item(format_number(0, (yyvsp[0].x)), 0, -1);
+		}
+#line 2991 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 85: /* object_spec: PLOT expr text  */
+#line 695 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = new object_spec(TEXT_OBJECT);
+		  (yyval.spec)->text = new text_item(format_number((yyvsp[0].lstr).str, (yyvsp[-1].x)),
+					   (yyvsp[0].lstr).filename, (yyvsp[0].lstr).lineno);
+		  delete[] (yyvsp[0].lstr).str;
+		}
+#line 3002 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 86: /* @11: %empty  */
+#line 702 "../src/preproc/pic/pic.ypp"
+                {
+		  saved_state *p = new saved_state;
+		  (yyval.pstate) = p;
+		  p->x = current_position.x;
+		  p->y = current_position.y;
+		  p->dir = current_direction;
+		  p->tbl = current_table;
+		  p->prev = current_saved_state;
+		  current_position.x = 0.0;
+		  current_position.y = 0.0;
+		  current_table = new PTABLE(place);
+		  current_saved_state = p;
+		  olist.append(make_mark_object());
+		}
+#line 3021 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 87: /* object_spec: '[' @11 element_list ']'  */
+#line 717 "../src/preproc/pic/pic.ypp"
+                {
+		  current_position.x = (yyvsp[-2].pstate)->x;
+		  current_position.y = (yyvsp[-2].pstate)->y;
+		  current_direction = (yyvsp[-2].pstate)->dir;
+		  (yyval.spec) = new object_spec(BLOCK_OBJECT);
+		  olist.wrap_up_block(& (yyval.spec)->oblist);
+		  (yyval.spec)->tbl = current_table;
+		  current_table = (yyvsp[-2].pstate)->tbl;
+		  current_saved_state = (yyvsp[-2].pstate)->prev;
+		  delete (yyvsp[-2].pstate);
+		}
+#line 3037 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 88: /* object_spec: object_spec HEIGHT expr  */
+#line 729 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->height = (yyvsp[0].x);
+		  (yyval.spec)->flags |= HAS_HEIGHT;
+		}
+#line 3047 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 89: /* object_spec: object_spec RADIUS expr  */
+#line 735 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->radius = (yyvsp[0].x);
+		  (yyval.spec)->flags |= HAS_RADIUS;
+		}
+#line 3057 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 90: /* object_spec: object_spec WIDTH expr  */
+#line 741 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->width = (yyvsp[0].x);
+		  (yyval.spec)->flags |= HAS_WIDTH;
+		}
+#line 3067 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 91: /* object_spec: object_spec DIAMETER expr  */
+#line 747 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->radius = (yyvsp[0].x)/2.0;
+		  (yyval.spec)->flags |= HAS_RADIUS;
+		}
+#line 3077 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 92: /* object_spec: object_spec expr  */
+#line 753 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  (yyval.spec)->flags |= HAS_SEGMENT;
+		  switch ((yyval.spec)->dir) {
+		  case UP_DIRECTION:
+		    (yyval.spec)->segment_pos.y += (yyvsp[0].x);
+		    break;
+		  case DOWN_DIRECTION:
+		    (yyval.spec)->segment_pos.y -= (yyvsp[0].x);
+		    break;
+		  case RIGHT_DIRECTION:
+		    (yyval.spec)->segment_pos.x += (yyvsp[0].x);
+		    break;
+		  case LEFT_DIRECTION:
+		    (yyval.spec)->segment_pos.x -= (yyvsp[0].x);
+		    break;
+		  }
+		}
+#line 3100 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 93: /* object_spec: object_spec UP  */
+#line 772 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  (yyval.spec)->dir = UP_DIRECTION;
+		  (yyval.spec)->flags |= HAS_SEGMENT;
+		  (yyval.spec)->segment_pos.y += (yyval.spec)->segment_height;
+		}
+#line 3111 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 94: /* object_spec: object_spec UP expr  */
+#line 779 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->dir = UP_DIRECTION;
+		  (yyval.spec)->flags |= HAS_SEGMENT;
+		  (yyval.spec)->segment_pos.y += (yyvsp[0].x);
+		}
+#line 3122 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 95: /* object_spec: object_spec DOWN  */
+#line 786 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  (yyval.spec)->dir = DOWN_DIRECTION;
+		  (yyval.spec)->flags |= HAS_SEGMENT;
+		  (yyval.spec)->segment_pos.y -= (yyval.spec)->segment_height;
+		}
+#line 3133 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 96: /* object_spec: object_spec DOWN expr  */
+#line 793 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->dir = DOWN_DIRECTION;
+		  (yyval.spec)->flags |= HAS_SEGMENT;
+		  (yyval.spec)->segment_pos.y -= (yyvsp[0].x);
+		}
+#line 3144 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 97: /* object_spec: object_spec RIGHT  */
+#line 800 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  (yyval.spec)->dir = RIGHT_DIRECTION;
+		  (yyval.spec)->flags |= HAS_SEGMENT;
+		  (yyval.spec)->segment_pos.x += (yyval.spec)->segment_width;
+		}
+#line 3155 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 98: /* object_spec: object_spec RIGHT expr  */
+#line 807 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->dir = RIGHT_DIRECTION;
+		  (yyval.spec)->flags |= HAS_SEGMENT;
+		  (yyval.spec)->segment_pos.x += (yyvsp[0].x);
+		}
+#line 3166 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 99: /* object_spec: object_spec LEFT  */
+#line 814 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  (yyval.spec)->dir = LEFT_DIRECTION;
+		  (yyval.spec)->flags |= HAS_SEGMENT;
+		  (yyval.spec)->segment_pos.x -= (yyval.spec)->segment_width;
+		}
+#line 3177 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 100: /* object_spec: object_spec LEFT expr  */
+#line 821 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->dir = LEFT_DIRECTION;
+		  (yyval.spec)->flags |= HAS_SEGMENT;
+		  (yyval.spec)->segment_pos.x -= (yyvsp[0].x);
+		}
+#line 3188 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 101: /* object_spec: object_spec FROM position  */
+#line 828 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->flags |= HAS_FROM;
+		  (yyval.spec)->from.x = (yyvsp[0].pair).x;
+		  (yyval.spec)->from.y = (yyvsp[0].pair).y;
+		}
+#line 3199 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 102: /* object_spec: object_spec TO position  */
+#line 835 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  if ((yyval.spec)->flags & HAS_SEGMENT)
+		    (yyval.spec)->segment_list = new segment((yyval.spec)->segment_pos,
+						   (yyval.spec)->segment_is_absolute,
+						   (yyval.spec)->segment_list);
+		  (yyval.spec)->flags |= HAS_SEGMENT;
+		  (yyval.spec)->segment_pos.x = (yyvsp[0].pair).x;
+		  (yyval.spec)->segment_pos.y = (yyvsp[0].pair).y;
+		  (yyval.spec)->segment_is_absolute = 1;
+		  (yyval.spec)->flags |= HAS_TO;
+		  (yyval.spec)->to.x = (yyvsp[0].pair).x;
+		  (yyval.spec)->to.y = (yyvsp[0].pair).y;
+		}
+#line 3218 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 103: /* object_spec: object_spec AT position  */
+#line 850 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->flags |= HAS_AT;
+		  (yyval.spec)->at.x = (yyvsp[0].pair).x;
+		  (yyval.spec)->at.y = (yyvsp[0].pair).y;
+		  if ((yyval.spec)->type != ARC_OBJECT) {
+		    (yyval.spec)->flags |= HAS_FROM;
+		    (yyval.spec)->from.x = (yyvsp[0].pair).x;
+		    (yyval.spec)->from.y = (yyvsp[0].pair).y;
+		  }
+		}
+#line 3234 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 104: /* object_spec: object_spec WITH path  */
+#line 862 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->flags |= HAS_WITH;
+		  (yyval.spec)->with = (yyvsp[0].pth);
+		}
+#line 3244 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 105: /* object_spec: object_spec WITH position  */
+#line 868 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->flags |= HAS_WITH;
+		  position pos;
+		  pos.x = (yyvsp[0].pair).x;
+		  pos.y = (yyvsp[0].pair).y;
+		  (yyval.spec)->with = new path(pos);
+		}
+#line 3257 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 106: /* object_spec: object_spec BY expr_pair  */
+#line 877 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->flags |= HAS_SEGMENT;
+		  (yyval.spec)->segment_pos.x += (yyvsp[0].pair).x;
+		  (yyval.spec)->segment_pos.y += (yyvsp[0].pair).y;
+		}
+#line 3268 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 107: /* object_spec: object_spec THEN  */
+#line 884 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  if (!((yyval.spec)->flags & HAS_SEGMENT))
+		    switch ((yyval.spec)->dir) {
+		    case UP_DIRECTION:
+		      (yyval.spec)->segment_pos.y += (yyval.spec)->segment_width;
+		      break;
+		    case DOWN_DIRECTION:
+		      (yyval.spec)->segment_pos.y -= (yyval.spec)->segment_width;
+		      break;
+		    case RIGHT_DIRECTION:
+		      (yyval.spec)->segment_pos.x += (yyval.spec)->segment_width;
+		      break;
+		    case LEFT_DIRECTION:
+		      (yyval.spec)->segment_pos.x -= (yyval.spec)->segment_width;
+		      break;
+		    }
+		  (yyval.spec)->segment_list = new segment((yyval.spec)->segment_pos,
+						 (yyval.spec)->segment_is_absolute,
+						 (yyval.spec)->segment_list);
+		  (yyval.spec)->flags &= ~HAS_SEGMENT;
+		  (yyval.spec)->segment_pos.x = (yyval.spec)->segment_pos.y = 0.0;
+		  (yyval.spec)->segment_is_absolute = 0;
+		}
+#line 3297 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 108: /* object_spec: object_spec SOLID  */
+#line 909 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);	// nothing
+		}
+#line 3305 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 109: /* object_spec: object_spec DOTTED  */
+#line 913 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  (yyval.spec)->flags |= IS_DOTTED;
+		  lookup_variable("dashwid", & (yyval.spec)->dash_width);
+		}
+#line 3315 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 110: /* object_spec: object_spec DOTTED expr  */
+#line 919 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->flags |= IS_DOTTED;
+		  (yyval.spec)->dash_width = (yyvsp[0].x);
+		}
+#line 3325 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 111: /* object_spec: object_spec DASHED  */
+#line 925 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  (yyval.spec)->flags |= IS_DASHED;
+		  lookup_variable("dashwid", & (yyval.spec)->dash_width);
+		}
+#line 3335 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 112: /* object_spec: object_spec DASHED expr  */
+#line 931 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->flags |= IS_DASHED;
+		  (yyval.spec)->dash_width = (yyvsp[0].x);
+		}
+#line 3345 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 113: /* object_spec: object_spec FILL  */
+#line 937 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  (yyval.spec)->flags |= IS_DEFAULT_FILLED;
+		}
+#line 3354 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 114: /* object_spec: object_spec FILL expr  */
+#line 942 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->flags |= IS_FILLED;
+		  (yyval.spec)->fill = (yyvsp[0].x);
+		}
+#line 3364 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 115: /* object_spec: object_spec XSLANTED expr  */
+#line 948 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->flags |= IS_XSLANTED;
+		  (yyval.spec)->xslanted = (yyvsp[0].x);
+		}
+#line 3374 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 116: /* object_spec: object_spec YSLANTED expr  */
+#line 954 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->flags |= IS_YSLANTED;
+		  (yyval.spec)->yslanted = (yyvsp[0].x);
+		}
+#line 3384 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 117: /* object_spec: object_spec SHADED text  */
+#line 960 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->flags |= (IS_SHADED | IS_FILLED);
+		  (yyval.spec)->shaded = new char[strlen((yyvsp[0].lstr).str)+1];
+		  strcpy((yyval.spec)->shaded, (yyvsp[0].lstr).str);
+		}
+#line 3395 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 118: /* object_spec: object_spec COLORED text  */
+#line 967 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->flags |= (IS_SHADED | IS_OUTLINED | IS_FILLED);
+		  (yyval.spec)->shaded = new char[strlen((yyvsp[0].lstr).str)+1];
+		  strcpy((yyval.spec)->shaded, (yyvsp[0].lstr).str);
+		  (yyval.spec)->outlined = new char[strlen((yyvsp[0].lstr).str)+1];
+		  strcpy((yyval.spec)->outlined, (yyvsp[0].lstr).str);
+		}
+#line 3408 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 119: /* object_spec: object_spec OUTLINED text  */
+#line 976 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->flags |= IS_OUTLINED;
+		  (yyval.spec)->outlined = new char[strlen((yyvsp[0].lstr).str)+1];
+		  strcpy((yyval.spec)->outlined, (yyvsp[0].lstr).str);
+		}
+#line 3419 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 120: /* object_spec: object_spec CHOP  */
+#line 983 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  // line chop chop means line chop 0 chop 0
+		  if ((yyval.spec)->flags & IS_DEFAULT_CHOPPED) {
+		    (yyval.spec)->flags |= IS_CHOPPED;
+		    (yyval.spec)->flags &= ~IS_DEFAULT_CHOPPED;
+		    (yyval.spec)->start_chop = (yyval.spec)->end_chop = 0.0;
+		  }
+		  else if ((yyval.spec)->flags & IS_CHOPPED) {
+		    (yyval.spec)->end_chop = 0.0;
+		  }
+		  else {
+		    (yyval.spec)->flags |= IS_DEFAULT_CHOPPED;
+		  }
+		}
+#line 3439 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 121: /* object_spec: object_spec CHOP expr  */
+#line 999 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  if ((yyval.spec)->flags & IS_DEFAULT_CHOPPED) {
+		    (yyval.spec)->flags |= IS_CHOPPED;
+		    (yyval.spec)->flags &= ~IS_DEFAULT_CHOPPED;
+		    (yyval.spec)->start_chop = 0.0;
+		    (yyval.spec)->end_chop = (yyvsp[0].x);
+		  }
+		  else if ((yyval.spec)->flags & IS_CHOPPED) {
+		    (yyval.spec)->end_chop = (yyvsp[0].x);
+		  }
+		  else {
+		    (yyval.spec)->start_chop = (yyval.spec)->end_chop = (yyvsp[0].x);
+		    (yyval.spec)->flags |= IS_CHOPPED;
+		  }
+		}
+#line 3460 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 122: /* object_spec: object_spec SAME  */
+#line 1016 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  (yyval.spec)->flags |= IS_SAME;
+		}
+#line 3469 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 123: /* object_spec: object_spec INVISIBLE  */
+#line 1021 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  (yyval.spec)->flags |= IS_INVISIBLE;
+		}
+#line 3478 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 124: /* object_spec: object_spec LEFT_ARROW_HEAD  */
+#line 1026 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  (yyval.spec)->flags |= HAS_LEFT_ARROW_HEAD;
+		}
+#line 3487 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 125: /* object_spec: object_spec RIGHT_ARROW_HEAD  */
+#line 1031 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  (yyval.spec)->flags |= HAS_RIGHT_ARROW_HEAD;
+		}
+#line 3496 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 126: /* object_spec: object_spec DOUBLE_ARROW_HEAD  */
+#line 1036 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  (yyval.spec)->flags |= (HAS_LEFT_ARROW_HEAD|HAS_RIGHT_ARROW_HEAD);
+		}
+#line 3505 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 127: /* object_spec: object_spec CW  */
+#line 1041 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  (yyval.spec)->flags |= IS_CLOCKWISE;
+		}
+#line 3514 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 128: /* object_spec: object_spec CCW  */
+#line 1046 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  (yyval.spec)->flags &= ~IS_CLOCKWISE;
+		}
+#line 3523 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 129: /* object_spec: object_spec text  */
+#line 1051 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  text_item **p;
+		  for (p = & (yyval.spec)->text; *p; p = &(*p)->next)
+		    ;
+		  *p = new text_item((yyvsp[0].lstr).str, (yyvsp[0].lstr).filename, (yyvsp[0].lstr).lineno);
+		}
+#line 3535 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 130: /* object_spec: object_spec LJUST  */
+#line 1059 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  if ((yyval.spec)->text) {
+		    text_item *p;
+		    for (p = (yyval.spec)->text; p->next; p = p->next)
+		      ;
+		    p->adj.h = LEFT_ADJUST;
+		  }
+		}
+#line 3549 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 131: /* object_spec: object_spec RJUST  */
+#line 1069 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  if ((yyval.spec)->text) {
+		    text_item *p;
+		    for (p = (yyval.spec)->text; p->next; p = p->next)
+		      ;
+		    p->adj.h = RIGHT_ADJUST;
+		  }
+		}
+#line 3563 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 132: /* object_spec: object_spec ABOVE  */
+#line 1079 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  if ((yyval.spec)->text) {
+		    text_item *p;
+		    for (p = (yyval.spec)->text; p->next; p = p->next)
+		      ;
+		    p->adj.v = ABOVE_ADJUST;
+		  }
+		}
+#line 3577 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 133: /* object_spec: object_spec BELOW  */
+#line 1089 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  if ((yyval.spec)->text) {
+		    text_item *p;
+		    for (p = (yyval.spec)->text; p->next; p = p->next)
+		      ;
+		    p->adj.v = BELOW_ADJUST;
+		  }
+		}
+#line 3591 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 134: /* object_spec: object_spec THICKNESS expr  */
+#line 1099 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-2].spec);
+		  (yyval.spec)->flags |= HAS_THICKNESS;
+		  (yyval.spec)->thickness = (yyvsp[0].x);
+		}
+#line 3601 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 135: /* object_spec: object_spec ALIGNED  */
+#line 1105 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.spec) = (yyvsp[-1].spec);
+		  (yyval.spec)->flags |= IS_ALIGNED;
+		}
+#line 3610 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 136: /* text: TEXT  */
+#line 1113 "../src/preproc/pic/pic.ypp"
+                { (yyval.lstr) = (yyvsp[0].lstr); }
+#line 3616 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 137: /* text: SPRINTF '(' TEXT sprintf_args ')'  */
+#line 1115 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.lstr).filename = (yyvsp[-2].lstr).filename;
+		  (yyval.lstr).lineno = (yyvsp[-2].lstr).lineno;
+		  (yyval.lstr).str = do_sprintf((yyvsp[-2].lstr).str, (yyvsp[-1].dv).v, (yyvsp[-1].dv).nv);
+		  delete[] (yyvsp[-1].dv).v;
+		  free((yyvsp[-2].lstr).str);
+		}
+#line 3628 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 138: /* sprintf_args: %empty  */
+#line 1126 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.dv).v = 0;
+		  (yyval.dv).nv = 0;
+		  (yyval.dv).maxv = 0;
+		}
+#line 3638 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 139: /* sprintf_args: sprintf_args ',' expr  */
+#line 1132 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.dv) = (yyvsp[-2].dv);
+		  if ((yyval.dv).nv >= (yyval.dv).maxv) {
+		    if ((yyval.dv).nv == 0) {
+		      (yyval.dv).v = new double[4];
+		      (yyval.dv).maxv = 4;
+		    }
+		    else {
+		      double *oldv = (yyval.dv).v;
+		      (yyval.dv).maxv *= 2;
+#if 0
+		      (yyval.dv).v = new double[(yyval.dv).maxv];
+		      memcpy((yyval.dv).v, oldv, (yyval.dv).nv*sizeof(double));
+#else
+		      // workaround for bug in Compaq C++ V6.5-033
+		      // for Compaq Tru64 UNIX V5.1A (Rev. 1885)
+		      double *foo = new double[(yyval.dv).maxv];
+		      memcpy(foo, oldv, (yyval.dv).nv*sizeof(double));
+		      (yyval.dv).v = foo;
+#endif
+		      delete[] oldv;
+		    }
+		  }
+		  (yyval.dv).v[(yyval.dv).nv] = (yyvsp[0].x);
+		  (yyval.dv).nv += 1;
+		}
+#line 3669 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 140: /* position: position_not_place  */
+#line 1162 "../src/preproc/pic/pic.ypp"
+                { (yyval.pair) = (yyvsp[0].pair); }
+#line 3675 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 141: /* position: place  */
+#line 1164 "../src/preproc/pic/pic.ypp"
+                {
+		  position pos = (yyvsp[0].pl);
+		  (yyval.pair).x = pos.x;
+		  (yyval.pair).y = pos.y;
+		}
+#line 3685 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 142: /* position: '(' place ')'  */
+#line 1170 "../src/preproc/pic/pic.ypp"
+                {
+		  position pos = (yyvsp[-1].pl);
+		  (yyval.pair).x = pos.x;
+		  (yyval.pair).y = pos.y;
+		}
+#line 3695 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 143: /* position_not_place: expr_pair  */
+#line 1179 "../src/preproc/pic/pic.ypp"
+                { (yyval.pair) = (yyvsp[0].pair); }
+#line 3701 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 144: /* position_not_place: position '+' expr_pair  */
+#line 1181 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pair).x = (yyvsp[-2].pair).x + (yyvsp[0].pair).x;
+		  (yyval.pair).y = (yyvsp[-2].pair).y + (yyvsp[0].pair).y;
+		}
+#line 3710 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 145: /* position_not_place: '(' position '+' expr_pair ')'  */
+#line 1186 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pair).x = (yyvsp[-3].pair).x + (yyvsp[-1].pair).x;
+		  (yyval.pair).y = (yyvsp[-3].pair).y + (yyvsp[-1].pair).y;
+		}
+#line 3719 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 146: /* position_not_place: position '-' expr_pair  */
+#line 1191 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pair).x = (yyvsp[-2].pair).x - (yyvsp[0].pair).x;
+		  (yyval.pair).y = (yyvsp[-2].pair).y - (yyvsp[0].pair).y;
+		}
+#line 3728 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 147: /* position_not_place: '(' position '-' expr_pair ')'  */
+#line 1196 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pair).x = (yyvsp[-3].pair).x - (yyvsp[-1].pair).x;
+		  (yyval.pair).y = (yyvsp[-3].pair).y - (yyvsp[-1].pair).y;
+		}
+#line 3737 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 148: /* position_not_place: '(' position ',' position ')'  */
+#line 1201 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pair).x = (yyvsp[-3].pair).x;
+		  (yyval.pair).y = (yyvsp[-1].pair).y;
+		}
+#line 3746 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 149: /* position_not_place: expr between position AND position  */
+#line 1206 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pair).x = (1.0 - (yyvsp[-4].x))*(yyvsp[-2].pair).x + (yyvsp[-4].x)*(yyvsp[0].pair).x;
+		  (yyval.pair).y = (1.0 - (yyvsp[-4].x))*(yyvsp[-2].pair).y + (yyvsp[-4].x)*(yyvsp[0].pair).y;
+		}
+#line 3755 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 150: /* position_not_place: '(' expr between position AND position ')'  */
+#line 1211 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pair).x = (1.0 - (yyvsp[-5].x))*(yyvsp[-3].pair).x + (yyvsp[-5].x)*(yyvsp[-1].pair).x;
+		  (yyval.pair).y = (1.0 - (yyvsp[-5].x))*(yyvsp[-3].pair).y + (yyvsp[-5].x)*(yyvsp[-1].pair).y;
+		}
+#line 3764 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 151: /* position_not_place: expr_not_lower_than '<' position ',' position '>'  */
+#line 1217 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pair).x = (1.0 - (yyvsp[-5].x))*(yyvsp[-3].pair).x + (yyvsp[-5].x)*(yyvsp[-1].pair).x;
+		  (yyval.pair).y = (1.0 - (yyvsp[-5].x))*(yyvsp[-3].pair).y + (yyvsp[-5].x)*(yyvsp[-1].pair).y;
+		}
+#line 3773 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 152: /* position_not_place: '(' expr_not_lower_than '<' position ',' position '>' ')'  */
+#line 1222 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pair).x = (1.0 - (yyvsp[-6].x))*(yyvsp[-4].pair).x + (yyvsp[-6].x)*(yyvsp[-2].pair).x;
+		  (yyval.pair).y = (1.0 - (yyvsp[-6].x))*(yyvsp[-4].pair).y + (yyvsp[-6].x)*(yyvsp[-2].pair).y;
+		}
+#line 3782 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 155: /* expr_pair: expr ',' expr  */
+#line 1235 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pair).x = (yyvsp[-2].x);
+		  (yyval.pair).y = (yyvsp[0].x);
+		}
+#line 3791 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 156: /* expr_pair: '(' expr_pair ')'  */
+#line 1240 "../src/preproc/pic/pic.ypp"
+                { (yyval.pair) = (yyvsp[-1].pair); }
+#line 3797 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 157: /* place: label  */
+#line 1246 "../src/preproc/pic/pic.ypp"
+                { (yyval.pl) = (yyvsp[0].pl); }
+#line 3803 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 158: /* place: label corner  */
+#line 1248 "../src/preproc/pic/pic.ypp"
+                {
+		  path pth((yyvsp[0].crn));
+		  if (!pth.follow((yyvsp[-1].pl), & (yyval.pl)))
+		    YYABORT;
+		}
+#line 3813 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 159: /* place: corner label  */
+#line 1254 "../src/preproc/pic/pic.ypp"
+                {
+		  path pth((yyvsp[-1].crn));
+		  if (!pth.follow((yyvsp[0].pl), & (yyval.pl)))
+		    YYABORT;
+		}
+#line 3823 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 160: /* place: corner OF label  */
+#line 1260 "../src/preproc/pic/pic.ypp"
+                {
+		  path pth((yyvsp[-2].crn));
+		  if (!pth.follow((yyvsp[0].pl), & (yyval.pl)))
+		    YYABORT;
+		}
+#line 3833 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 161: /* place: HERE  */
+#line 1266 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pl).x = current_position.x;
+		  (yyval.pl).y = current_position.y;
+		  (yyval.pl).obj = 0;
+		}
+#line 3843 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 162: /* label: LABEL  */
+#line 1275 "../src/preproc/pic/pic.ypp"
+                {
+		  place *p = lookup_label((yyvsp[0].str));
+		  if (!p) {
+		    lex_error("there is no place '%1'", (yyvsp[0].str));
+		    YYABORT;
+		  }
+		  (yyval.pl) = *p;
+		  free((yyvsp[0].str));
+		}
+#line 3857 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 163: /* label: nth_primitive  */
+#line 1285 "../src/preproc/pic/pic.ypp"
+                { (yyval.pl).obj = (yyvsp[0].obj); }
+#line 3863 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 164: /* label: label '.' LABEL  */
+#line 1287 "../src/preproc/pic/pic.ypp"
+                {
+		  path pth((yyvsp[0].str));
+		  if (!pth.follow((yyvsp[-2].pl), & (yyval.pl)))
+		    YYABORT;
+		}
+#line 3873 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 165: /* ordinal: ORDINAL  */
+#line 1296 "../src/preproc/pic/pic.ypp"
+                { (yyval.n) = (yyvsp[0].n); }
+#line 3879 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 166: /* ordinal: '`' any_expr TH  */
+#line 1298 "../src/preproc/pic/pic.ypp"
+                {
+		  // XXX Check for overflow (and non-integers?).
+		  (yyval.n) = (int)(yyvsp[-1].x);
+		}
+#line 3888 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 167: /* optional_ordinal_last: LAST  */
+#line 1306 "../src/preproc/pic/pic.ypp"
+                { (yyval.n) = 1; }
+#line 3894 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 168: /* optional_ordinal_last: ordinal LAST  */
+#line 1308 "../src/preproc/pic/pic.ypp"
+                { (yyval.n) = (yyvsp[-1].n); }
+#line 3900 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 169: /* nth_primitive: ordinal object_type  */
+#line 1313 "../src/preproc/pic/pic.ypp"
+                {
+		  int count = 0;
+		  object *p;
+		  for (p = olist.head; p != 0; p = p->next)
+		    if (p->type() == (yyvsp[0].obtype) && ++count == (yyvsp[-1].n)) {
+		      (yyval.obj) = p;
+		      break;
+		    }
+		  if (p == 0) {
+		    lex_error("there is no %1%2 %3", (yyvsp[-1].n), ordinal_postfix((yyvsp[-1].n)),
+			      object_type_name((yyvsp[0].obtype)));
+		    YYABORT;
+		  }
+		}
+#line 3919 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 170: /* nth_primitive: optional_ordinal_last object_type  */
+#line 1328 "../src/preproc/pic/pic.ypp"
+                {
+		  int count = 0;
+		  object *p;
+		  for (p = olist.tail; p != 0; p = p->prev)
+		    if (p->type() == (yyvsp[0].obtype) && ++count == (yyvsp[-1].n)) {
+		      (yyval.obj) = p;
+		      break;
+		    }
+		  if (p == 0) {
+		    lex_error("there is no %1%2 last %3", (yyvsp[-1].n),
+			      ordinal_postfix((yyvsp[-1].n)), object_type_name((yyvsp[0].obtype)));
+		    YYABORT;
+		  }
+		}
+#line 3938 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 171: /* object_type: BOX  */
+#line 1346 "../src/preproc/pic/pic.ypp"
+                { (yyval.obtype) = BOX_OBJECT; }
+#line 3944 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 172: /* object_type: CIRCLE  */
+#line 1348 "../src/preproc/pic/pic.ypp"
+                { (yyval.obtype) = CIRCLE_OBJECT; }
+#line 3950 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 173: /* object_type: ELLIPSE  */
+#line 1350 "../src/preproc/pic/pic.ypp"
+                { (yyval.obtype) = ELLIPSE_OBJECT; }
+#line 3956 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 174: /* object_type: ARC  */
+#line 1352 "../src/preproc/pic/pic.ypp"
+                { (yyval.obtype) = ARC_OBJECT; }
+#line 3962 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 175: /* object_type: LINE  */
+#line 1354 "../src/preproc/pic/pic.ypp"
+                { (yyval.obtype) = LINE_OBJECT; }
+#line 3968 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 176: /* object_type: ARROW  */
+#line 1356 "../src/preproc/pic/pic.ypp"
+                { (yyval.obtype) = ARROW_OBJECT; }
+#line 3974 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 177: /* object_type: SPLINE  */
+#line 1358 "../src/preproc/pic/pic.ypp"
+                { (yyval.obtype) = SPLINE_OBJECT; }
+#line 3980 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 178: /* object_type: '[' ']'  */
+#line 1360 "../src/preproc/pic/pic.ypp"
+                { (yyval.obtype) = BLOCK_OBJECT; }
+#line 3986 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 179: /* object_type: TEXT  */
+#line 1362 "../src/preproc/pic/pic.ypp"
+                { (yyval.obtype) = TEXT_OBJECT; }
+#line 3992 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 180: /* label_path: '.' LABEL  */
+#line 1367 "../src/preproc/pic/pic.ypp"
+                { (yyval.pth) = new path((yyvsp[0].str)); }
+#line 3998 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 181: /* label_path: label_path '.' LABEL  */
+#line 1369 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pth) = (yyvsp[-2].pth);
+		  (yyval.pth)->append((yyvsp[0].str));
+		}
+#line 4007 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 182: /* relative_path: corner  */
+#line 1377 "../src/preproc/pic/pic.ypp"
+                { (yyval.pth) = new path((yyvsp[0].crn)); }
+#line 4013 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 183: /* relative_path: label_path  */
+#line 1381 "../src/preproc/pic/pic.ypp"
+                { (yyval.pth) = (yyvsp[0].pth); }
+#line 4019 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 184: /* relative_path: label_path corner  */
+#line 1383 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pth) = (yyvsp[-1].pth);
+		  (yyval.pth)->append((yyvsp[0].crn));
+		}
+#line 4028 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 185: /* path: relative_path  */
+#line 1391 "../src/preproc/pic/pic.ypp"
+                { (yyval.pth) = (yyvsp[0].pth); }
+#line 4034 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 186: /* path: '(' relative_path ',' relative_path ')'  */
+#line 1393 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.pth) = (yyvsp[-3].pth);
+		  (yyval.pth)->set_ypath((yyvsp[-1].pth));
+		}
+#line 4043 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 187: /* path: ORDINAL LAST object_type relative_path  */
+#line 1399 "../src/preproc/pic/pic.ypp"
+                {
+		  lex_warning("'%1%2 last %3' in 'with' argument ignored",
+			      (yyvsp[-3].n), ordinal_postfix((yyvsp[-3].n)), object_type_name((yyvsp[-1].obtype)));
+		  (yyval.pth) = (yyvsp[0].pth);
+		}
+#line 4053 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 188: /* path: LAST object_type relative_path  */
+#line 1405 "../src/preproc/pic/pic.ypp"
+                {
+		  lex_warning("'last %1' in 'with' argument ignored",
+			      object_type_name((yyvsp[-1].obtype)));
+		  (yyval.pth) = (yyvsp[0].pth);
+		}
+#line 4063 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 189: /* path: ORDINAL object_type relative_path  */
+#line 1411 "../src/preproc/pic/pic.ypp"
+                {
+		  lex_warning("'%1%2 %3' in 'with' argument ignored",
+			      (yyvsp[-2].n), ordinal_postfix((yyvsp[-2].n)), object_type_name((yyvsp[-1].obtype)));
+		  (yyval.pth) = (yyvsp[0].pth);
+		}
+#line 4073 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 190: /* path: LABEL relative_path  */
+#line 1417 "../src/preproc/pic/pic.ypp"
+                {
+		  lex_warning("initial '%1' in 'with' argument ignored", (yyvsp[-1].str));
+		  delete[] (yyvsp[-1].str);
+		  (yyval.pth) = (yyvsp[0].pth);
+		}
+#line 4083 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 191: /* corner: DOT_N  */
+#line 1426 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::north; }
+#line 4089 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 192: /* corner: DOT_E  */
+#line 1428 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::east; }
+#line 4095 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 193: /* corner: DOT_W  */
+#line 1430 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::west; }
+#line 4101 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 194: /* corner: DOT_S  */
+#line 1432 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::south; }
+#line 4107 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 195: /* corner: DOT_NE  */
+#line 1434 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::north_east; }
+#line 4113 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 196: /* corner: DOT_SE  */
+#line 1436 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object:: south_east; }
+#line 4119 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 197: /* corner: DOT_NW  */
+#line 1438 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::north_west; }
+#line 4125 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 198: /* corner: DOT_SW  */
+#line 1440 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::south_west; }
+#line 4131 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 199: /* corner: DOT_C  */
+#line 1442 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::center; }
+#line 4137 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 200: /* corner: DOT_START  */
+#line 1444 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::start; }
+#line 4143 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 201: /* corner: DOT_END  */
+#line 1446 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::end; }
+#line 4149 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 202: /* corner: TOP  */
+#line 1448 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::north; }
+#line 4155 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 203: /* corner: BOTTOM  */
+#line 1450 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::south; }
+#line 4161 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 204: /* corner: LEFT  */
+#line 1452 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::west; }
+#line 4167 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 205: /* corner: RIGHT  */
+#line 1454 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::east; }
+#line 4173 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 206: /* corner: UPPER LEFT  */
+#line 1456 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::north_west; }
+#line 4179 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 207: /* corner: LOWER LEFT  */
+#line 1458 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::south_west; }
+#line 4185 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 208: /* corner: UPPER RIGHT  */
+#line 1460 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::north_east; }
+#line 4191 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 209: /* corner: LOWER RIGHT  */
+#line 1462 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::south_east; }
+#line 4197 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 210: /* corner: LEFT_CORNER  */
+#line 1464 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::west; }
+#line 4203 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 211: /* corner: RIGHT_CORNER  */
+#line 1466 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::east; }
+#line 4209 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 212: /* corner: UPPER LEFT_CORNER  */
+#line 1468 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::north_west; }
+#line 4215 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 213: /* corner: LOWER LEFT_CORNER  */
+#line 1470 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::south_west; }
+#line 4221 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 214: /* corner: UPPER RIGHT_CORNER  */
+#line 1472 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::north_east; }
+#line 4227 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 215: /* corner: LOWER RIGHT_CORNER  */
+#line 1474 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::south_east; }
+#line 4233 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 216: /* corner: NORTH  */
+#line 1476 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::north; }
+#line 4239 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 217: /* corner: SOUTH  */
+#line 1478 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::south; }
+#line 4245 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 218: /* corner: EAST  */
+#line 1480 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::east; }
+#line 4251 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 219: /* corner: WEST  */
+#line 1482 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::west; }
+#line 4257 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 220: /* corner: CENTER  */
+#line 1484 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::center; }
+#line 4263 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 221: /* corner: START  */
+#line 1486 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::start; }
+#line 4269 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 222: /* corner: END  */
+#line 1488 "../src/preproc/pic/pic.ypp"
+                { (yyval.crn) = &object::end; }
+#line 4275 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 223: /* expr: expr_lower_than  */
+#line 1493 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = (yyvsp[0].x); }
+#line 4281 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 224: /* expr: expr_not_lower_than  */
+#line 1495 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = (yyvsp[0].x); }
+#line 4287 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 225: /* expr_lower_than: expr '<' expr  */
+#line 1500 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = ((yyvsp[-2].x) < (yyvsp[0].x)); }
+#line 4293 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 226: /* expr_not_lower_than: VARIABLE  */
+#line 1505 "../src/preproc/pic/pic.ypp"
+                {
+		  if (!lookup_variable((yyvsp[0].str), & (yyval.x))) {
+		    lex_error("there is no variable '%1'", (yyvsp[0].str));
+		    YYABORT;
+		  }
+		  free((yyvsp[0].str));
+		}
+#line 4305 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 227: /* expr_not_lower_than: NUMBER  */
+#line 1513 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = (yyvsp[0].x); }
+#line 4311 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 228: /* expr_not_lower_than: place DOT_X  */
+#line 1515 "../src/preproc/pic/pic.ypp"
+                {
+		  if ((yyvsp[-1].pl).obj != 0)
+		    (yyval.x) = (yyvsp[-1].pl).obj->origin().x;
+		  else
+		    (yyval.x) = (yyvsp[-1].pl).x;
+		}
+#line 4322 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 229: /* expr_not_lower_than: place DOT_Y  */
+#line 1522 "../src/preproc/pic/pic.ypp"
+                {
+		  if ((yyvsp[-1].pl).obj != 0)
+		    (yyval.x) = (yyvsp[-1].pl).obj->origin().y;
+		  else
+		    (yyval.x) = (yyvsp[-1].pl).y;
+		}
+#line 4333 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 230: /* expr_not_lower_than: place DOT_HT  */
+#line 1529 "../src/preproc/pic/pic.ypp"
+                {
+		  if ((yyvsp[-1].pl).obj != 0)
+		    (yyval.x) = (yyvsp[-1].pl).obj->height();
+		  else
+		    (yyval.x) = 0.0;
+		}
+#line 4344 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 231: /* expr_not_lower_than: place DOT_WID  */
+#line 1536 "../src/preproc/pic/pic.ypp"
+                {
+		  if ((yyvsp[-1].pl).obj != 0)
+		    (yyval.x) = (yyvsp[-1].pl).obj->width();
+		  else
+		    (yyval.x) = 0.0;
+		}
+#line 4355 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 232: /* expr_not_lower_than: place DOT_RAD  */
+#line 1543 "../src/preproc/pic/pic.ypp"
+                {
+		  if ((yyvsp[-1].pl).obj != 0)
+		    (yyval.x) = (yyvsp[-1].pl).obj->radius();
+		  else
+		    (yyval.x) = 0.0;
+		}
+#line 4366 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 233: /* expr_not_lower_than: expr '+' expr  */
+#line 1550 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = (yyvsp[-2].x) + (yyvsp[0].x); }
+#line 4372 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 234: /* expr_not_lower_than: expr '-' expr  */
+#line 1552 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = (yyvsp[-2].x) - (yyvsp[0].x); }
+#line 4378 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 235: /* expr_not_lower_than: expr '*' expr  */
+#line 1554 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = (yyvsp[-2].x) * (yyvsp[0].x); }
+#line 4384 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 236: /* expr_not_lower_than: expr '/' expr  */
+#line 1556 "../src/preproc/pic/pic.ypp"
+                {
+		  if ((yyvsp[0].x) == 0.0) {
+		    lex_error("division by zero");
+		    YYABORT;
+		  }
+		  (yyval.x) = (yyvsp[-2].x)/(yyvsp[0].x);
+		}
+#line 4396 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 237: /* expr_not_lower_than: expr '%' expr  */
+#line 1564 "../src/preproc/pic/pic.ypp"
+                {
+		  if ((yyvsp[0].x) == 0.0) {
+		    lex_error("modulus by zero");
+		    YYABORT;
+		  }
+		  (yyval.x) = fmod((yyvsp[-2].x), (yyvsp[0].x));
+		}
+#line 4408 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 238: /* expr_not_lower_than: expr '^' expr  */
+#line 1572 "../src/preproc/pic/pic.ypp"
+                {
+		  errno = 0;
+		  (yyval.x) = pow((yyvsp[-2].x), (yyvsp[0].x));
+		  if (errno == EDOM) {
+		    lex_error("arguments to '^' operator out of domain");
+		    YYABORT;
+		  }
+		  if (errno == ERANGE) {
+		    lex_error("result of '^' operator out of range");
+		    YYABORT;
+		  }
+		}
+#line 4425 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 239: /* expr_not_lower_than: '-' expr  */
+#line 1585 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = -(yyvsp[0].x); }
+#line 4431 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 240: /* expr_not_lower_than: '(' any_expr ')'  */
+#line 1587 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = (yyvsp[-1].x); }
+#line 4437 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 241: /* expr_not_lower_than: SIN '(' any_expr ')'  */
+#line 1589 "../src/preproc/pic/pic.ypp"
+                {
+		  errno = 0;
+		  (yyval.x) = sin((yyvsp[-1].x));
+		  if (errno == ERANGE) {
+		    lex_error("sin result out of range");
+		    YYABORT;
+		  }
+		}
+#line 4450 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 242: /* expr_not_lower_than: COS '(' any_expr ')'  */
+#line 1598 "../src/preproc/pic/pic.ypp"
+                {
+		  errno = 0;
+		  (yyval.x) = cos((yyvsp[-1].x));
+		  if (errno == ERANGE) {
+		    lex_error("cos result out of range");
+		    YYABORT;
+		  }
+		}
+#line 4463 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 243: /* expr_not_lower_than: ATAN2 '(' any_expr ',' any_expr ')'  */
+#line 1607 "../src/preproc/pic/pic.ypp"
+                {
+		  errno = 0;
+		  (yyval.x) = atan2((yyvsp[-3].x), (yyvsp[-1].x));
+		  if (errno == EDOM) {
+		    lex_error("atan2 argument out of domain");
+		    YYABORT;
+		  }
+		  if (errno == ERANGE) {
+		    lex_error("atan2 result out of range");
+		    YYABORT;
+		  }
+		}
+#line 4480 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 244: /* expr_not_lower_than: LOG '(' any_expr ')'  */
+#line 1620 "../src/preproc/pic/pic.ypp"
+                {
+		  errno = 0;
+		  (yyval.x) = log10((yyvsp[-1].x));
+		  if (errno == ERANGE) {
+		    lex_error("log result out of range");
+		    YYABORT;
+		  }
+		}
+#line 4493 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 245: /* expr_not_lower_than: EXP '(' any_expr ')'  */
+#line 1629 "../src/preproc/pic/pic.ypp"
+                {
+		  errno = 0;
+		  (yyval.x) = pow(10.0, (yyvsp[-1].x));
+		  if (errno == ERANGE) {
+		    lex_error("exp result out of range");
+		    YYABORT;
+		  }
+		}
+#line 4506 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 246: /* expr_not_lower_than: SQRT '(' any_expr ')'  */
+#line 1638 "../src/preproc/pic/pic.ypp"
+                {
+		  errno = 0;
+		  (yyval.x) = sqrt((yyvsp[-1].x));
+		  if (errno == EDOM) {
+		    lex_error("sqrt argument out of domain");
+		    YYABORT;
+		  }
+		}
+#line 4519 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 247: /* expr_not_lower_than: K_MAX '(' any_expr ',' any_expr ')'  */
+#line 1647 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = (yyvsp[-3].x) > (yyvsp[-1].x) ? (yyvsp[-3].x) : (yyvsp[-1].x); }
+#line 4525 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 248: /* expr_not_lower_than: K_MIN '(' any_expr ',' any_expr ')'  */
+#line 1649 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = (yyvsp[-3].x) < (yyvsp[-1].x) ? (yyvsp[-3].x) : (yyvsp[-1].x); }
+#line 4531 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 249: /* expr_not_lower_than: INT '(' any_expr ')'  */
+#line 1651 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = (yyvsp[-1].x) < 0 ? -floor(-(yyvsp[-1].x)) : floor((yyvsp[-1].x)); }
+#line 4537 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 250: /* expr_not_lower_than: RAND '(' any_expr ')'  */
+#line 1653 "../src/preproc/pic/pic.ypp"
+                {
+		  lex_error("use of 'rand' with an argument is"
+			    " deprecated; shift and scale 'rand()' with"
+			    " arithmetic instead");
+		  (yyval.x) = 1.0 + floor(((rand()&0x7fff)/double(0x7fff))*(yyvsp[-1].x));
+		}
+#line 4548 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 251: /* expr_not_lower_than: RAND '(' ')'  */
+#line 1660 "../src/preproc/pic/pic.ypp"
+                {
+		  /* return a random number in the range [0,1) */
+		  /* portable, but not very random */
+		  (yyval.x) = (rand() & 0x7fff) / double(0x8000);
+		}
+#line 4558 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 252: /* expr_not_lower_than: SRAND '(' any_expr ')'  */
+#line 1666 "../src/preproc/pic/pic.ypp"
+                {
+		  (yyval.x) = 0;
+		  srand((unsigned int)(yyvsp[-1].x));
+		}
+#line 4567 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 253: /* expr_not_lower_than: expr LESSEQUAL expr  */
+#line 1671 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = ((yyvsp[-2].x) <= (yyvsp[0].x)); }
+#line 4573 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 254: /* expr_not_lower_than: expr '>' expr  */
+#line 1673 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = ((yyvsp[-2].x) > (yyvsp[0].x)); }
+#line 4579 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 255: /* expr_not_lower_than: expr GREATEREQUAL expr  */
+#line 1675 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = ((yyvsp[-2].x) >= (yyvsp[0].x)); }
+#line 4585 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 256: /* expr_not_lower_than: expr EQUALEQUAL expr  */
+#line 1677 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = ((yyvsp[-2].x) == (yyvsp[0].x)); }
+#line 4591 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 257: /* expr_not_lower_than: expr NOTEQUAL expr  */
+#line 1679 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = ((yyvsp[-2].x) != (yyvsp[0].x)); }
+#line 4597 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 258: /* expr_not_lower_than: expr ANDAND expr  */
+#line 1681 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = ((yyvsp[-2].x) != 0.0 && (yyvsp[0].x) != 0.0); }
+#line 4603 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 259: /* expr_not_lower_than: expr OROR expr  */
+#line 1683 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = ((yyvsp[-2].x) != 0.0 || (yyvsp[0].x) != 0.0); }
+#line 4609 "src/preproc/pic/pic.cpp"
+    break;
+
+  case 260: /* expr_not_lower_than: '!' expr  */
+#line 1685 "../src/preproc/pic/pic.ypp"
+                { (yyval.x) = ((yyvsp[0].x) == 0.0); }
+#line 4615 "src/preproc/pic/pic.cpp"
+    break;
+
+
+#line 4619 "src/preproc/pic/pic.cpp"
+
+      default: break;
+    }
+  /* User semantic actions sometimes alter yychar, and that requires
+     that yytoken be updated with the new translation.  We take the
+     approach of translating immediately before every use of yytoken.
+     One alternative is translating here after every semantic action,
+     but that translation would be missed if the semantic action invokes
+     YYABORT, YYACCEPT, or YYERROR immediately after altering yychar or
+     if it invokes YYBACKUP.  In the case of YYABORT or YYACCEPT, an
+     incorrect destructor might then be invoked immediately.  In the
+     case of YYERROR or YYBACKUP, subsequent parser actions might lead
+     to an incorrect destructor call or verbose syntax error message
+     before the lookahead is translated.  */
+  YY_SYMBOL_PRINT ("-> $$ =", YY_CAST (yysymbol_kind_t, yyr1[yyn]), &yyval, &yyloc);
+
+  YYPOPSTACK (yylen);
+  yylen = 0;
+
+  *++yyvsp = yyval;
+
+  /* Now 'shift' the result of the reduction.  Determine what state
+     that goes to, based on the state we popped back to and the rule
+     number reduced by.  */
+  {
+    const int yylhs = yyr1[yyn] - YYNTOKENS;
+    const int yyi = yypgoto[yylhs] + *yyssp;
+    yystate = (0 <= yyi && yyi <= YYLAST && yycheck[yyi] == *yyssp
+               ? yytable[yyi]
+               : yydefgoto[yylhs]);
+  }
+
+  goto yynewstate;
+
+
+/*--------------------------------------.
+| yyerrlab -- here on detecting error.  |
+`--------------------------------------*/
+yyerrlab:
+  /* Make sure we have latest lookahead translation.  See comments at
+     user semantic actions for why this is necessary.  */
+  yytoken = yychar == YYEMPTY ? YYSYMBOL_YYEMPTY : YYTRANSLATE (yychar);
+  /* If not already recovering from an error, report this error.  */
+  if (!yyerrstatus)
+    {
+      ++yynerrs;
+      yyerror (YY_("syntax error"));
+    }
+
+  if (yyerrstatus == 3)
+    {
+      /* If just tried and failed to reuse lookahead token after an
+         error, discard it.  */
+
+      if (yychar <= YYEOF)
+        {
+          /* Return failure if at end of input.  */
+          if (yychar == YYEOF)
+            YYABORT;
+        }
+      else
+        {
+          yydestruct ("Error: discarding",
+                      yytoken, &yylval);
+          yychar = YYEMPTY;
+        }
+    }
+
+  /* Else will try to reuse lookahead token after shifting the error
+     token.  */
+  goto yyerrlab1;
+
+
+/*---------------------------------------------------.
+| yyerrorlab -- error raised explicitly by YYERROR.  |
+`---------------------------------------------------*/
+yyerrorlab:
+  /* Pacify compilers when the user code never invokes YYERROR and the
+     label yyerrorlab therefore never appears in user code.  */
+  if (0)
+    YYERROR;
+  ++yynerrs;
+
+  /* Do not reclaim the symbols of the rule whose action triggered
+     this YYERROR.  */
+  YYPOPSTACK (yylen);
+  yylen = 0;
+  YY_STACK_PRINT (yyss, yyssp);
+  yystate = *yyssp;
+  goto yyerrlab1;
+
+
+/*-------------------------------------------------------------.
+| yyerrlab1 -- common code for both syntax error and YYERROR.  |
+`-------------------------------------------------------------*/
+yyerrlab1:
+  yyerrstatus = 3;      /* Each real token shifted decrements this.  */
+
+  /* Pop stack until we find a state that shifts the error token.  */
+  for (;;)
+    {
+      yyn = yypact[yystate];
+      if (!yypact_value_is_default (yyn))
+        {
+          yyn += YYSYMBOL_YYerror;
+          if (0 <= yyn && yyn <= YYLAST && yycheck[yyn] == YYSYMBOL_YYerror)
+            {
+              yyn = yytable[yyn];
+              if (0 < yyn)
+                break;
+            }
+        }
+
+      /* Pop the current state because it cannot handle the error token.  */
+      if (yyssp == yyss)
+        YYABORT;
+
+
+      yydestruct ("Error: popping",
+                  YY_ACCESSING_SYMBOL (yystate), yyvsp);
+      YYPOPSTACK (1);
+      yystate = *yyssp;
+      YY_STACK_PRINT (yyss, yyssp);
+    }
+
+  YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+  *++yyvsp = yylval;
+  YY_IGNORE_MAYBE_UNINITIALIZED_END
+
+
+  /* Shift the error token.  */
+  YY_SYMBOL_PRINT ("Shifting", YY_ACCESSING_SYMBOL (yyn), yyvsp, yylsp);
+
+  yystate = yyn;
+  goto yynewstate;
+
+
+/*-------------------------------------.
+| yyacceptlab -- YYACCEPT comes here.  |
+`-------------------------------------*/
+yyacceptlab:
+  yyresult = 0;
+  goto yyreturnlab;
+
+
+/*-----------------------------------.
+| yyabortlab -- YYABORT comes here.  |
+`-----------------------------------*/
+yyabortlab:
+  yyresult = 1;
+  goto yyreturnlab;
+
+
+/*-----------------------------------------------------------.
+| yyexhaustedlab -- YYNOMEM (memory exhaustion) comes here.  |
+`-----------------------------------------------------------*/
+yyexhaustedlab:
+  yyerror (YY_("memory exhausted"));
+  yyresult = 2;
+  goto yyreturnlab;
+
+
+/*----------------------------------------------------------.
+| yyreturnlab -- parsing is finished, clean up and return.  |
+`----------------------------------------------------------*/
+yyreturnlab:
+  if (yychar != YYEMPTY)
+    {
+      /* Make sure we have latest lookahead translation.  See comments at
+         user semantic actions for why this is necessary.  */
+      yytoken = YYTRANSLATE (yychar);
+      yydestruct ("Cleanup: discarding lookahead",
+                  yytoken, &yylval);
+    }
+  /* Do not reclaim the symbols of the rule whose action triggered
+     this YYABORT or YYACCEPT.  */
+  YYPOPSTACK (yylen);
+  YY_STACK_PRINT (yyss, yyssp);
+  while (yyssp != yyss)
+    {
+      yydestruct ("Cleanup: popping",
+                  YY_ACCESSING_SYMBOL (+*yyssp), yyvsp);
+      YYPOPSTACK (1);
+    }
+#ifndef yyoverflow
+  if (yyss != yyssa)
+    YYSTACK_FREE (yyss);
+#endif
+
+  return yyresult;
+}
+
+#line 1689 "../src/preproc/pic/pic.ypp"
+
+
+/* bison defines const to be empty unless __STDC__ is defined, which it
+isn't under cfront */
+
+#ifdef const
+#undef const
+#endif
+
+static struct {
+  const char *name;
+  double val;
+  int scaled;		     // non-zero if val should be multiplied by scale
+} defaults_table[] = {
+  { "arcrad", .25, 1 },
+  { "arrowht", .1, 1 },
+  { "arrowwid", .05, 1 },
+  { "circlerad", .25, 1 },
+  { "boxht", .5, 1 },
+  { "boxwid", .75, 1 },
+  { "boxrad", 0.0, 1 },
+  { "dashwid", .05, 1 },
+  { "ellipseht", .5, 1 },
+  { "ellipsewid", .75, 1 },
+  { "moveht", .5, 1 },
+  { "movewid", .5, 1 },
+  { "lineht", .5, 1 },
+  { "linewid", .5, 1 },
+  { "textht", 0.0, 1 },
+  { "textwid", 0.0, 1 },
+  { "scale", 1.0, 0 },
+  { "linethick", -1.0, 0 },		// in points
+  { "fillval", .5, 0 },
+  { "arrowhead", 1.0, 0 },
+  { "maxpswid", 8.5, 0 },
+  { "maxpsht", 11.0, 0 },
+};
+
+place *lookup_label(const char *label)
+{
+  saved_state *state = current_saved_state;
+  PTABLE(place) *tbl = current_table;
+  for (;;) {
+    place *pl = tbl->lookup(label);
+    if (pl)
+      return pl;
+    if (!state)
+      return 0;
+    tbl = state->tbl;
+    state = state->prev;
+  }
+}
+
+void define_label(const char *label, const place *pl)
+{
+  place *p = new place[1];
+  *p = *pl;
+  current_table->define(label, p);
+}
+
+int lookup_variable(const char *name, double *val)
+{
+  place *pl = lookup_label(name);
+  if (pl) {
+    *val = pl->x;
+    return 1;
+  }
+  return 0;
+}
+
+void define_variable(const char *name, double val)
+{
+  place *p = new place[1];
+  p->obj = 0;
+  p->x = val;
+  p->y = 0.0;
+  current_table->define(name, p);
+  if (strcmp(name, "scale") == 0) {
+    // When the scale changes, reset all scaled predefined variables to
+    // their default values.
+    for (unsigned int i = 0;
+	 i < sizeof(defaults_table)/sizeof(defaults_table[0]); i++) 
+      if (defaults_table[i].scaled)
+	define_variable(defaults_table[i].name, val*defaults_table[i].val);
+  }
+}
+
+// called once only (not once per parse)
+
+void parse_init()
+{
+  current_direction = RIGHT_DIRECTION;
+  current_position.x = 0.0;
+  current_position.y = 0.0;
+  // This resets everything to its default value.
+  reset_all();
+}
+
+void reset(const char *nm)
+{
+  for (unsigned int i = 0;
+       i < sizeof(defaults_table)/sizeof(defaults_table[0]); i++)
+    if (strcmp(nm, defaults_table[i].name) == 0) {
+      double val = defaults_table[i].val;
+      if (defaults_table[i].scaled) {
+	double scale;
+	lookup_variable("scale", &scale);
+	val *= scale;
+      }
+      define_variable(defaults_table[i].name, val);
+      return;
+    }
+  lex_error("'%1' is not a predefined variable", nm);
+}
+
+void reset_all()
+{
+  // We only have to explicitly reset the predefined variables that
+  // aren't scaled because 'scale' is not scaled, and changing the
+  // value of 'scale' will reset all the predefined variables that
+  // are scaled.
+  for (unsigned int i = 0;
+       i < sizeof(defaults_table)/sizeof(defaults_table[0]); i++)
+    if (!defaults_table[i].scaled)
+      define_variable(defaults_table[i].name, defaults_table[i].val);
+}
+
+// called after each parse
+
+void parse_cleanup()
+{
+  while (current_saved_state != 0) {
+    delete current_table;
+    current_table = current_saved_state->tbl;
+    saved_state *tem = current_saved_state;
+    current_saved_state = current_saved_state->prev;
+    delete tem;
+  }
+  assert(current_table == &top_table);
+  PTABLE_ITERATOR(place) iter(current_table);
+  const char *key;
+  place *pl;
+  while (iter.next(&key, &pl))
+    if (pl->obj != 0) {
+      position pos = pl->obj->origin();
+      pl->obj = 0;
+      pl->x = pos.x;
+      pl->y = pos.y;
+    }
+  while (olist.head != 0) {
+    object *tem = olist.head;
+    olist.head = olist.head->next;
+    delete tem;
+  }
+  olist.tail = 0;
+  current_direction = RIGHT_DIRECTION;
+  current_position.x = 0.0;
+  current_position.y = 0.0;
+}
+
+const char *ordinal_postfix(int n)
+{
+  if (n < 10 || n > 20)
+    switch (n % 10) {
+    case 1:
+      return "st";
+    case 2:
+      return "nd";
+    case 3:
+      return "rd";
+    }
+  return "th";
+}
+
+const char *object_type_name(object_type type)
+{
+  switch (type) {
+  case BOX_OBJECT:
+    return "box";
+  case CIRCLE_OBJECT:
+    return "circle";
+  case ELLIPSE_OBJECT:
+    return "ellipse";
+  case ARC_OBJECT:
+    return "arc";
+  case SPLINE_OBJECT:
+    return "spline";
+  case LINE_OBJECT:
+    return "line";
+  case ARROW_OBJECT:
+    return "arrow";
+  case MOVE_OBJECT:
+    return "move";
+  case TEXT_OBJECT:
+    return "\"\"";
+  case BLOCK_OBJECT:
+    return "[]";
+  case OTHER_OBJECT:
+  case MARK_OBJECT:
+  default:
+    break;
+  }
+  return "object";
+}
+
+static char sprintf_buf[1024];
+
+char *format_number(const char *fmt, double n)
+{
+  if (0 /* nullptr */ == fmt)
+    fmt = "%g";
+  return do_sprintf(fmt, &n, 1);
+}
+
+char *do_sprintf(const char *fmt, const double *v, int nv)
+{
+  // Define valid conversion specifiers and modifiers.
+  static const char spcs[] = "eEfgG%";
+  static const char mods[] = "#-+ 0123456789.";
+  string result;
+  int i = 0;
+  string one_format;
+  while (*fmt) {
+    if ('%' == *fmt) {
+      one_format += *fmt++;
+      for (; *fmt != '\0' && strchr(mods, *fmt) != 0; fmt++)
+	one_format += *fmt;
+      if ('\0' == *fmt || strchr(spcs, *fmt) == 0) {
+	lex_error("invalid sprintf conversion specifier '%1'", *fmt);
+	result += one_format;
+	result += fmt;
+	break;
+      }
+      if ('%' == *fmt) {
+	fmt++;
+	snprintf(sprintf_buf, sizeof(sprintf_buf), "%%");
+      }
+      else {
+	if (i >= nv) {
+	  lex_error("too few arguments to sprintf");
+	  result += one_format;
+	  result += fmt;
+	  break;
+	}
+	one_format += *fmt++;
+	one_format += '\0';
+// We validated the format string above.  Most conversion specifiers are
+// rejected, including `n`.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wformat-nonliteral"
+	snprintf(sprintf_buf, sizeof(sprintf_buf),
+		 one_format.contents(), v[i++]);
+#pragma GCC diagnostic pop
+      }
+      one_format.clear();
+      result += sprintf_buf;
+    }
+    else
+      result += *fmt++;
+  }
+  result += '\0';
+  return strsave(result.contents());
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/pic/pic.h b/src/preproc/pic/pic.h
new file mode 100644
index 0000000..1a99498
--- /dev/null
+++ b/src/preproc/pic/pic.h
@@ -0,0 +1,122 @@
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "lib.h"
+
+#include <assert.h>
+#include <errno.h>
+#include <math.h>
+#include <stdlib.h>
+
+#ifdef NEED_DECLARATION_RAND
+#undef rand
+extern "C" {
+  int rand();
+}
+#endif /* NEED_DECLARATION_RAND */
+
+#ifdef NEED_DECLARATION_SRAND
+#undef srand
+extern "C" {
+#ifdef RET_TYPE_SRAND_IS_VOID
+  void srand(unsigned int);
+#else
+  int srand(unsigned int);
+#endif
+}
+#endif /* NEED_DECLARATION_SRAND */
+
+#ifndef HAVE_FMOD
+extern "C" {
+  double fmod(double, double);
+}
+#endif
+
+#include "cset.h"
+#include "stringclass.h"
+#include "lf.h"
+#include "errarg.h"
+#include "error.h"
+#include "position.h"
+#include "text.h"
+#include "output.h"
+
+#ifndef M_SQRT2
+#define M_SQRT2	1.41421356237309504880
+#endif
+
+#ifndef M_PI
+#define M_PI 3.14159265358979323846
+#endif
+
+class input {
+  input *next;
+public:
+  input();
+  virtual ~input();
+  virtual int get() = 0;
+  virtual int peek() = 0;
+  virtual int get_location(const char **, int *);
+  friend class input_stack;
+  friend class copy_rest_thru_input;
+};
+
+class file_input : public input {
+  FILE *fp;
+  const char *filename;
+  int lineno;
+  string line;
+  const char *ptr;
+  int read_line();
+public:
+  file_input(FILE *, const char *);
+  ~file_input();
+  int get();
+  int peek();
+  int get_location(const char **, int *);
+};
+
+void lex_init(input *);
+int get_location(char **, int *);
+
+void do_copy(const char *file);
+void parse_init();
+void parse_cleanup();
+
+void lex_error(const char *message,
+	       const errarg &arg1 = empty_errarg,
+	       const errarg &arg2 = empty_errarg,
+	       const errarg &arg3 = empty_errarg);
+
+void lex_warning(const char *message,
+		 const errarg &arg1 = empty_errarg,
+		 const errarg &arg2 = empty_errarg,
+		 const errarg &arg3 = empty_errarg);
+
+void lex_cleanup();
+
+extern bool want_flyback;
+extern bool want_alternate_flyback;
+extern int command_char;
+// zero_length_line_flag is non-zero if zero-length lines are drawn 
+// as dots by the output device
+extern int zero_length_line_flag;
+extern int driver_extension_flag;
+extern int compatible_flag;
+extern int safer_flag;
+extern char *graphname;
diff --git a/src/preproc/pic/pic.hpp b/src/preproc/pic/pic.hpp
new file mode 100644
index 0000000..c162496
--- /dev/null
+++ b/src/preproc/pic/pic.hpp
@@ -0,0 +1,348 @@
+/* A Bison parser, made by GNU Bison 3.8.2.  */
+
+/* Bison interface for Yacc-like parsers in C
+
+   Copyright (C) 1984, 1989-1990, 2000-2015, 2018-2021 Free Software Foundation,
+   Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* As a special exception, you may create a larger work that contains
+   part or all of the Bison parser skeleton and distribute that work
+   under terms of your choice, so long as that work isn't itself a
+   parser generator using the skeleton or a modified version thereof
+   as a parser skeleton.  Alternatively, if you modify or redistribute
+   the parser skeleton itself, you may (at your option) remove this
+   special exception, which will cause the skeleton and the resulting
+   Bison output files to be licensed under the GNU General Public
+   License without this special exception.
+
+   This special exception was added by the Free Software Foundation in
+   version 2.2 of Bison.  */
+
+/* DO NOT RELY ON FEATURES THAT ARE NOT DOCUMENTED in the manual,
+   especially those whose name start with YY_ or yy_.  They are
+   private implementation details that can be changed or removed.  */
+
+#ifndef YY_YY_SRC_PREPROC_PIC_PIC_HPP_INCLUDED
+# define YY_YY_SRC_PREPROC_PIC_PIC_HPP_INCLUDED
+/* Debug traces.  */
+#ifndef YYDEBUG
+# define YYDEBUG 0
+#endif
+#if YYDEBUG
+extern int yydebug;
+#endif
+
+/* Token kinds.  */
+#ifndef YYTOKENTYPE
+# define YYTOKENTYPE
+  enum yytokentype
+  {
+    YYEMPTY = -2,
+    YYEOF = 0,                     /* "end of file"  */
+    YYerror = 256,                 /* error  */
+    YYUNDEF = 257,                 /* "invalid token"  */
+    LABEL = 258,                   /* LABEL  */
+    VARIABLE = 259,                /* VARIABLE  */
+    NUMBER = 260,                  /* NUMBER  */
+    TEXT = 261,                    /* TEXT  */
+    COMMAND_LINE = 262,            /* COMMAND_LINE  */
+    DELIMITED = 263,               /* DELIMITED  */
+    ORDINAL = 264,                 /* ORDINAL  */
+    TH = 265,                      /* TH  */
+    LEFT_ARROW_HEAD = 266,         /* LEFT_ARROW_HEAD  */
+    RIGHT_ARROW_HEAD = 267,        /* RIGHT_ARROW_HEAD  */
+    DOUBLE_ARROW_HEAD = 268,       /* DOUBLE_ARROW_HEAD  */
+    LAST = 269,                    /* LAST  */
+    BOX = 270,                     /* BOX  */
+    CIRCLE = 271,                  /* CIRCLE  */
+    ELLIPSE = 272,                 /* ELLIPSE  */
+    ARC = 273,                     /* ARC  */
+    LINE = 274,                    /* LINE  */
+    ARROW = 275,                   /* ARROW  */
+    MOVE = 276,                    /* MOVE  */
+    SPLINE = 277,                  /* SPLINE  */
+    HEIGHT = 278,                  /* HEIGHT  */
+    RADIUS = 279,                  /* RADIUS  */
+    FIGNAME = 280,                 /* FIGNAME  */
+    WIDTH = 281,                   /* WIDTH  */
+    DIAMETER = 282,                /* DIAMETER  */
+    UP = 283,                      /* UP  */
+    DOWN = 284,                    /* DOWN  */
+    RIGHT = 285,                   /* RIGHT  */
+    LEFT = 286,                    /* LEFT  */
+    FROM = 287,                    /* FROM  */
+    TO = 288,                      /* TO  */
+    AT = 289,                      /* AT  */
+    WITH = 290,                    /* WITH  */
+    BY = 291,                      /* BY  */
+    THEN = 292,                    /* THEN  */
+    SOLID = 293,                   /* SOLID  */
+    DOTTED = 294,                  /* DOTTED  */
+    DASHED = 295,                  /* DASHED  */
+    CHOP = 296,                    /* CHOP  */
+    SAME = 297,                    /* SAME  */
+    INVISIBLE = 298,               /* INVISIBLE  */
+    LJUST = 299,                   /* LJUST  */
+    RJUST = 300,                   /* RJUST  */
+    ABOVE = 301,                   /* ABOVE  */
+    BELOW = 302,                   /* BELOW  */
+    OF = 303,                      /* OF  */
+    THE = 304,                     /* THE  */
+    WAY = 305,                     /* WAY  */
+    BETWEEN = 306,                 /* BETWEEN  */
+    AND = 307,                     /* AND  */
+    HERE = 308,                    /* HERE  */
+    DOT_N = 309,                   /* DOT_N  */
+    DOT_E = 310,                   /* DOT_E  */
+    DOT_W = 311,                   /* DOT_W  */
+    DOT_S = 312,                   /* DOT_S  */
+    DOT_NE = 313,                  /* DOT_NE  */
+    DOT_SE = 314,                  /* DOT_SE  */
+    DOT_NW = 315,                  /* DOT_NW  */
+    DOT_SW = 316,                  /* DOT_SW  */
+    DOT_C = 317,                   /* DOT_C  */
+    DOT_START = 318,               /* DOT_START  */
+    DOT_END = 319,                 /* DOT_END  */
+    DOT_X = 320,                   /* DOT_X  */
+    DOT_Y = 321,                   /* DOT_Y  */
+    DOT_HT = 322,                  /* DOT_HT  */
+    DOT_WID = 323,                 /* DOT_WID  */
+    DOT_RAD = 324,                 /* DOT_RAD  */
+    SIN = 325,                     /* SIN  */
+    COS = 326,                     /* COS  */
+    ATAN2 = 327,                   /* ATAN2  */
+    LOG = 328,                     /* LOG  */
+    EXP = 329,                     /* EXP  */
+    SQRT = 330,                    /* SQRT  */
+    K_MAX = 331,                   /* K_MAX  */
+    K_MIN = 332,                   /* K_MIN  */
+    INT = 333,                     /* INT  */
+    RAND = 334,                    /* RAND  */
+    SRAND = 335,                   /* SRAND  */
+    COPY = 336,                    /* COPY  */
+    THRU = 337,                    /* THRU  */
+    TOP = 338,                     /* TOP  */
+    BOTTOM = 339,                  /* BOTTOM  */
+    UPPER = 340,                   /* UPPER  */
+    LOWER = 341,                   /* LOWER  */
+    SH = 342,                      /* SH  */
+    PRINT = 343,                   /* PRINT  */
+    CW = 344,                      /* CW  */
+    CCW = 345,                     /* CCW  */
+    FOR = 346,                     /* FOR  */
+    DO = 347,                      /* DO  */
+    IF = 348,                      /* IF  */
+    ELSE = 349,                    /* ELSE  */
+    ANDAND = 350,                  /* ANDAND  */
+    OROR = 351,                    /* OROR  */
+    NOTEQUAL = 352,                /* NOTEQUAL  */
+    EQUALEQUAL = 353,              /* EQUALEQUAL  */
+    LESSEQUAL = 354,               /* LESSEQUAL  */
+    GREATEREQUAL = 355,            /* GREATEREQUAL  */
+    LEFT_CORNER = 356,             /* LEFT_CORNER  */
+    RIGHT_CORNER = 357,            /* RIGHT_CORNER  */
+    NORTH = 358,                   /* NORTH  */
+    SOUTH = 359,                   /* SOUTH  */
+    EAST = 360,                    /* EAST  */
+    WEST = 361,                    /* WEST  */
+    CENTER = 362,                  /* CENTER  */
+    END = 363,                     /* END  */
+    START = 364,                   /* START  */
+    RESET = 365,                   /* RESET  */
+    UNTIL = 366,                   /* UNTIL  */
+    PLOT = 367,                    /* PLOT  */
+    THICKNESS = 368,               /* THICKNESS  */
+    FILL = 369,                    /* FILL  */
+    COLORED = 370,                 /* COLORED  */
+    OUTLINED = 371,                /* OUTLINED  */
+    SHADED = 372,                  /* SHADED  */
+    XSLANTED = 373,                /* XSLANTED  */
+    YSLANTED = 374,                /* YSLANTED  */
+    ALIGNED = 375,                 /* ALIGNED  */
+    SPRINTF = 376,                 /* SPRINTF  */
+    COMMAND = 377,                 /* COMMAND  */
+    DEFINE = 378,                  /* DEFINE  */
+    UNDEF = 379                    /* UNDEF  */
+  };
+  typedef enum yytokentype yytoken_kind_t;
+#endif
+/* Token kinds.  */
+#define YYEMPTY -2
+#define YYEOF 0
+#define YYerror 256
+#define YYUNDEF 257
+#define LABEL 258
+#define VARIABLE 259
+#define NUMBER 260
+#define TEXT 261
+#define COMMAND_LINE 262
+#define DELIMITED 263
+#define ORDINAL 264
+#define TH 265
+#define LEFT_ARROW_HEAD 266
+#define RIGHT_ARROW_HEAD 267
+#define DOUBLE_ARROW_HEAD 268
+#define LAST 269
+#define BOX 270
+#define CIRCLE 271
+#define ELLIPSE 272
+#define ARC 273
+#define LINE 274
+#define ARROW 275
+#define MOVE 276
+#define SPLINE 277
+#define HEIGHT 278
+#define RADIUS 279
+#define FIGNAME 280
+#define WIDTH 281
+#define DIAMETER 282
+#define UP 283
+#define DOWN 284
+#define RIGHT 285
+#define LEFT 286
+#define FROM 287
+#define TO 288
+#define AT 289
+#define WITH 290
+#define BY 291
+#define THEN 292
+#define SOLID 293
+#define DOTTED 294
+#define DASHED 295
+#define CHOP 296
+#define SAME 297
+#define INVISIBLE 298
+#define LJUST 299
+#define RJUST 300
+#define ABOVE 301
+#define BELOW 302
+#define OF 303
+#define THE 304
+#define WAY 305
+#define BETWEEN 306
+#define AND 307
+#define HERE 308
+#define DOT_N 309
+#define DOT_E 310
+#define DOT_W 311
+#define DOT_S 312
+#define DOT_NE 313
+#define DOT_SE 314
+#define DOT_NW 315
+#define DOT_SW 316
+#define DOT_C 317
+#define DOT_START 318
+#define DOT_END 319
+#define DOT_X 320
+#define DOT_Y 321
+#define DOT_HT 322
+#define DOT_WID 323
+#define DOT_RAD 324
+#define SIN 325
+#define COS 326
+#define ATAN2 327
+#define LOG 328
+#define EXP 329
+#define SQRT 330
+#define K_MAX 331
+#define K_MIN 332
+#define INT 333
+#define RAND 334
+#define SRAND 335
+#define COPY 336
+#define THRU 337
+#define TOP 338
+#define BOTTOM 339
+#define UPPER 340
+#define LOWER 341
+#define SH 342
+#define PRINT 343
+#define CW 344
+#define CCW 345
+#define FOR 346
+#define DO 347
+#define IF 348
+#define ELSE 349
+#define ANDAND 350
+#define OROR 351
+#define NOTEQUAL 352
+#define EQUALEQUAL 353
+#define LESSEQUAL 354
+#define GREATEREQUAL 355
+#define LEFT_CORNER 356
+#define RIGHT_CORNER 357
+#define NORTH 358
+#define SOUTH 359
+#define EAST 360
+#define WEST 361
+#define CENTER 362
+#define END 363
+#define START 364
+#define RESET 365
+#define UNTIL 366
+#define PLOT 367
+#define THICKNESS 368
+#define FILL 369
+#define COLORED 370
+#define OUTLINED 371
+#define SHADED 372
+#define XSLANTED 373
+#define YSLANTED 374
+#define ALIGNED 375
+#define SPRINTF 376
+#define COMMAND 377
+#define DEFINE 378
+#define UNDEF 379
+
+/* Value type.  */
+#if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
+union YYSTYPE
+{
+#line 65 "../src/preproc/pic/pic.ypp"
+
+	char *str;
+	int n;
+	double x;
+	struct { double x, y; } pair;
+	struct { double x; char *body; } if_data;
+	struct { char *str; const char *filename; int lineno; } lstr;
+	struct { double *v; int nv; int maxv; } dv;
+	struct { double val; int is_multiplicative; } by;
+	place pl;
+	object *obj;
+	corner crn;
+	path *pth;
+	object_spec *spec;
+	saved_state *pstate;
+	graphics_state state;
+	object_type obtype;
+
+#line 334 "src/preproc/pic/pic.hpp"
+
+};
+typedef union YYSTYPE YYSTYPE;
+# define YYSTYPE_IS_TRIVIAL 1
+# define YYSTYPE_IS_DECLARED 1
+#endif
+
+
+extern YYSTYPE yylval;
+
+
+int yyparse (void);
+
+
+#endif /* !YY_YY_SRC_PREPROC_PIC_PIC_HPP_INCLUDED  */
diff --git a/src/preproc/pic/pic.ypp b/src/preproc/pic/pic.ypp
new file mode 100644
index 0000000..b2fa6dc
--- /dev/null
+++ b/src/preproc/pic/pic.ypp
@@ -0,0 +1,1957 @@
+/* Copyright (C) 1989-2022 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+%{
+#include "pic.h"
+#include "ptable.h"
+#include "object.h"
+
+extern int delim_flag;
+extern void copy_rest_thru(const char *, const char *);
+extern void copy_file_thru(const char *, const char *, const char *);
+extern void push_body(const char *);
+extern void do_for(char *var, double from, double to,
+		   int by_is_multiplicative, double by, char *body);
+extern void do_lookahead();
+
+/* Maximum number of characters produced by printf("%g") */
+#define GDIGITS 14
+
+int yylex();
+void yyerror(const char *);
+
+void reset(const char *nm);
+void reset_all();
+
+place *lookup_label(const char *);
+void define_label(const char *label, const place *pl);
+
+direction current_direction;
+position current_position;
+
+implement_ptable(place)
+
+PTABLE(place) top_table;
+
+PTABLE(place) *current_table = &top_table;
+saved_state *current_saved_state = 0;
+
+object_list olist;
+
+const char *ordinal_postfix(int n);
+const char *object_type_name(object_type type);
+char *format_number(const char *fmt, double n);
+char *do_sprintf(const char *fmt, const double *v, int nv);
+
+%}
+
+%expect 2
+
+%union {
+	char *str;
+	int n;
+	double x;
+	struct { double x, y; } pair;
+	struct { double x; char *body; } if_data;
+	struct { char *str; const char *filename; int lineno; } lstr;
+	struct { double *v; int nv; int maxv; } dv;
+	struct { double val; int is_multiplicative; } by;
+	place pl;
+	object *obj;
+	corner crn;
+	path *pth;
+	object_spec *spec;
+	saved_state *pstate;
+	graphics_state state;
+	object_type obtype;
+}
+
+%token <str> LABEL
+%token <str> VARIABLE
+%token <x> NUMBER
+%token <lstr> TEXT
+%token <lstr> COMMAND_LINE
+%token <str> DELIMITED
+%token <n> ORDINAL
+%token TH
+%token LEFT_ARROW_HEAD
+%token RIGHT_ARROW_HEAD
+%token DOUBLE_ARROW_HEAD
+%token LAST
+%token BOX
+%token CIRCLE
+%token ELLIPSE
+%token ARC
+%token LINE
+%token ARROW
+%token MOVE
+%token SPLINE
+%token HEIGHT
+%token RADIUS
+%token FIGNAME
+%token WIDTH
+%token DIAMETER
+%token UP
+%token DOWN
+%token RIGHT
+%token LEFT
+%token FROM
+%token TO
+%token AT
+%token WITH
+%token BY
+%token THEN
+%token SOLID
+%token DOTTED
+%token DASHED
+%token CHOP
+%token SAME
+%token INVISIBLE
+%token LJUST
+%token RJUST
+%token ABOVE
+%token BELOW
+%token OF
+%token THE
+%token WAY
+%token BETWEEN
+%token AND
+%token HERE
+%token DOT_N
+%token DOT_E	
+%token DOT_W
+%token DOT_S
+%token DOT_NE
+%token DOT_SE
+%token DOT_NW
+%token DOT_SW
+%token DOT_C
+%token DOT_START
+%token DOT_END
+%token DOT_X
+%token DOT_Y
+%token DOT_HT
+%token DOT_WID
+%token DOT_RAD
+%token SIN
+%token COS
+%token ATAN2
+%token LOG
+%token EXP
+%token SQRT
+%token K_MAX
+%token K_MIN
+%token INT
+%token RAND
+%token SRAND
+%token COPY
+%token THRU
+%token TOP
+%token BOTTOM
+%token UPPER
+%token LOWER
+%token SH
+%token PRINT
+%token CW
+%token CCW
+%token FOR
+%token DO
+%token IF
+%token ELSE
+%token ANDAND
+%token OROR
+%token NOTEQUAL
+%token EQUALEQUAL
+%token LESSEQUAL
+%token GREATEREQUAL
+%token LEFT_CORNER
+%token RIGHT_CORNER
+%token NORTH
+%token SOUTH
+%token EAST
+%token WEST
+%token CENTER
+%token END
+%token START
+%token RESET
+%token UNTIL
+%token PLOT
+%token THICKNESS
+%token FILL
+%token COLORED
+%token OUTLINED
+%token SHADED
+%token XSLANTED
+%token YSLANTED
+%token ALIGNED
+%token SPRINTF
+%token COMMAND
+
+%token DEFINE
+%token UNDEF
+
+%left '.'
+
+/* this ensures that plot 17 "%g" parses as (plot 17 "%g") */
+%left PLOT
+%left TEXT SPRINTF
+
+/* give text adjustments higher precedence than TEXT, so that
+box "foo" above ljust == box ("foo" above ljust)
+*/
+
+%left LJUST RJUST ABOVE BELOW
+
+%left LEFT RIGHT
+/* Give attributes that take an optional expression a higher
+precedence than left and right, so that, e.g., 'line chop left'
+parses properly. */
+%left CHOP SOLID DASHED DOTTED UP DOWN FILL COLORED OUTLINED
+%left XSLANTED YSLANTED
+%left LABEL
+
+%left VARIABLE NUMBER '(' SIN COS ATAN2 LOG EXP SQRT K_MAX K_MIN INT RAND SRAND LAST 
+%left ORDINAL HERE '`'
+
+%left BOX CIRCLE ELLIPSE ARC LINE ARROW SPLINE '['
+
+/* these need to be lower than '-' */
+%left HEIGHT RADIUS WIDTH DIAMETER FROM TO AT THICKNESS
+
+/* these must have higher precedence than CHOP so that 'label %prec CHOP'
+works */
+%left DOT_N DOT_E DOT_W DOT_S DOT_NE DOT_SE DOT_NW DOT_SW DOT_C
+%left DOT_START DOT_END TOP BOTTOM LEFT_CORNER RIGHT_CORNER
+%left UPPER LOWER NORTH SOUTH EAST WEST CENTER START END
+
+%left ','
+%left OROR
+%left ANDAND
+%left EQUALEQUAL NOTEQUAL
+%left '<' '>' LESSEQUAL GREATEREQUAL
+
+%left BETWEEN OF
+%left AND
+
+%left '+' '-'
+%left '*' '/' '%'
+%right '!'
+%right '^'
+
+%type <x> expr expr_lower_than expr_not_lower_than any_expr text_expr
+%type <by> optional_by
+%type <pair> expr_pair position_not_place
+%type <if_data> simple_if
+%type <obj> nth_primitive
+%type <crn> corner
+%type <pth> path label_path relative_path
+%type <pl> place label element element_list middle_element_list
+%type <spec> object_spec
+%type <pair> position
+%type <obtype> object_type
+%type <n> optional_ordinal_last ordinal
+%type <str> macro_name until
+%type <dv> sprintf_args
+%type <lstr> text print_args print_arg
+
+%%
+
+top:
+	optional_separator
+	| element_list
+		{
+		  if (olist.head)
+		    print_picture(olist.head);
+		}
+	;
+
+
+element_list:
+	optional_separator middle_element_list optional_separator
+		{ $$ = $2; }
+	;
+
+middle_element_list:
+	element
+		{ $$ = $1; }
+	| middle_element_list separator element
+		{ $$ = $1; }
+	;
+
+optional_separator:
+	/* empty */
+	| separator
+	;
+
+separator:
+	';'
+	| separator ';'
+	;
+
+placeless_element:
+	FIGNAME '=' macro_name
+		{
+		  delete[] graphname;
+		  graphname = new char[strlen($3) + 1];
+		  strcpy(graphname, $3);
+		  delete[] $3;
+		}
+	|
+	VARIABLE '=' any_expr
+		{
+		  define_variable($1, $3);
+		  free($1);
+		}
+	| VARIABLE ':' '=' any_expr
+		{
+		  place *p = lookup_label($1);
+		  if (!p) {
+		    lex_error("variable '%1' not defined", $1);
+		    YYABORT;
+		  }
+		  p->obj = 0;
+		  p->x = $4;
+		  p->y = 0.0;
+		  free($1);
+		}
+	| UP
+		{ current_direction = UP_DIRECTION; }
+	| DOWN
+		{ current_direction = DOWN_DIRECTION; }
+	| LEFT
+		{ current_direction = LEFT_DIRECTION; }
+	| RIGHT
+		{ current_direction = RIGHT_DIRECTION; }
+	| COMMAND_LINE
+		{
+		  olist.append(make_command_object($1.str, $1.filename,
+						   $1.lineno));
+		}
+	| COMMAND print_args
+		{
+		  olist.append(make_command_object($2.str, $2.filename,
+						   $2.lineno));
+		}
+	| PRINT print_args
+		{
+		  fprintf(stderr, "%s\n", $2.str);
+		  delete[] $2.str;
+		  fflush(stderr);
+		}
+	| SH
+		{ delim_flag = 1; }
+	  DELIMITED
+		{
+		  delim_flag = 0;
+		  if (safer_flag)
+		    lex_error("unsafe to run command '%1'; ignoring",
+			      $3);
+		  else {
+		    int retval = system($3);
+		    if (retval < 0)
+		      lex_error("error running command '%1': system()"
+			" returned %2", $3, retval);
+		  }
+		  delete[] $3;
+		}
+	| COPY TEXT
+		{
+		  if (yychar < 0)
+		    do_lookahead();
+		  do_copy($2.str);
+		  // do not delete the filename
+		}
+	| COPY TEXT THRU
+		{ delim_flag = 2; }
+	  DELIMITED 
+		{ delim_flag = 0; }
+	  until
+		{
+		  if (yychar < 0)
+		    do_lookahead();
+		  copy_file_thru($2.str, $5, $7);
+		  // do not delete the filename
+		  delete[] $5;
+		  delete[] $7;
+		}
+	| COPY THRU
+		{ delim_flag = 2; }
+	  DELIMITED
+		{ delim_flag = 0; }
+	  until
+		{
+		  if (yychar < 0)
+		    do_lookahead();
+		  copy_rest_thru($4, $6);
+		  delete[] $4;
+		  delete[] $6;
+		}
+	| FOR VARIABLE '=' expr TO expr optional_by DO
+	  	{ delim_flag = 1; }
+	  DELIMITED
+	  	{
+		  delim_flag = 0;
+		  if (yychar < 0)
+		    do_lookahead();
+		  do_for($2, $4, $6, $7.is_multiplicative, $7.val, $10); 
+		}
+	| simple_if
+		{
+		  if (yychar < 0)
+		    do_lookahead();
+		  if ($1.x != 0.0)
+		    push_body($1.body);
+		  delete[] $1.body;
+		}
+	| simple_if ELSE
+		{ delim_flag = 1; }
+	  DELIMITED
+		{
+		  delim_flag = 0;
+		  if (yychar < 0)
+		    do_lookahead();
+		  if ($1.x != 0.0)
+		    push_body($1.body);
+		  else
+		    push_body($4);
+		  free($1.body);
+		  free($4);
+		}
+	| reset_variables
+	| RESET
+		{ define_variable("scale", 1.0); }
+	;
+
+macro_name:
+	VARIABLE
+	| LABEL
+	;
+
+reset_variables:
+	RESET VARIABLE
+		{
+		  reset($2);
+		  delete[] $2;
+		}
+	| reset_variables VARIABLE
+		{
+		  reset($2);
+		  delete[] $2;
+		}
+	| reset_variables ',' VARIABLE
+		{
+		  reset($3);
+		  delete[] $3;
+		}
+	;
+
+print_args:
+	print_arg
+		{ $$ = $1; }
+	| print_args print_arg
+		{
+		  $$.str = new char[strlen($1.str) + strlen($2.str) + 1];
+		  strcpy($$.str, $1.str);
+		  strcat($$.str, $2.str);
+		  delete[] $1.str;
+		  delete[] $2.str;
+		  if ($1.filename) {
+		    $$.filename = $1.filename;
+		    $$.lineno = $1.lineno;
+		  }
+		  else if ($2.filename) {
+		    $$.filename = $2.filename;
+		    $$.lineno = $2.lineno;
+		  }
+		}
+	;
+
+print_arg:
+  	expr							%prec ','
+		{
+		  $$.str = new char[GDIGITS + 1];
+		  sprintf($$.str, "%g", $1);
+		  $$.filename = 0;
+		  $$.lineno = 0;
+		}
+	| text
+		{ $$ = $1; }
+	| position						%prec ','
+		{
+		  $$.str = new char[GDIGITS + 2 + GDIGITS + 1];
+		  sprintf($$.str, "%g, %g", $1.x, $1.y);
+		  $$.filename = 0;
+		  $$.lineno = 0;
+		}
+	;
+
+simple_if:
+	IF any_expr THEN
+		{ delim_flag = 1; }
+	DELIMITED
+		{
+		  delim_flag = 0;
+		  $$.x = $2;
+		  $$.body = $5;
+		}
+	;
+
+until:
+	/* empty */
+		{ $$ = 0; }
+	| UNTIL TEXT
+		{ $$ = $2.str; }
+	;
+	
+any_expr:
+	expr
+		{ $$ = $1; }
+	| text_expr
+		{ $$ = $1; }
+	;
+	
+text_expr:
+	text EQUALEQUAL text
+		{
+		  $$ = strcmp($1.str, $3.str) == 0;
+		  delete[] $1.str;
+		  delete[] $3.str;
+		}
+	| text NOTEQUAL text
+		{
+		  $$ = strcmp($1.str, $3.str) != 0;
+		  delete[] $1.str;
+		  delete[] $3.str;
+		}
+	| text_expr ANDAND text_expr
+		{ $$ = ($1 != 0.0 && $3 != 0.0); }
+	| text_expr ANDAND expr
+		{ $$ = ($1 != 0.0 && $3 != 0.0); }
+	| expr ANDAND text_expr
+		{ $$ = ($1 != 0.0 && $3 != 0.0); }
+	| text_expr OROR text_expr
+		{ $$ = ($1 != 0.0 || $3 != 0.0); }
+	| text_expr OROR expr
+		{ $$ = ($1 != 0.0 || $3 != 0.0); }
+	| expr OROR text_expr
+		{ $$ = ($1 != 0.0 || $3 != 0.0); }
+	| '!' text_expr
+		{ $$ = ($2 == 0.0); }
+	;
+
+
+optional_by:
+	/* empty */
+		{
+		  $$.val = 1.0;
+		  $$.is_multiplicative = 0;
+		}
+	| BY expr
+		{
+		  $$.val = $2;
+		  $$.is_multiplicative = 0;
+		}
+	| BY '*' expr
+		{
+		  $$.val = $3;
+		  $$.is_multiplicative = 1;
+		}
+	;
+
+element:
+	object_spec
+		{
+		  $$.obj = $1->make_object(&current_position,
+					   &current_direction);
+		  if ($$.obj == 0)
+		    YYABORT;
+		  delete $1;
+		  if ($$.obj)
+		    olist.append($$.obj);
+		  else {
+		    $$.x = current_position.x;
+		    $$.y = current_position.y;
+		  }
+		}
+	| LABEL ':' optional_separator element
+		{
+		  $$ = $4;
+		  define_label($1, & $$);
+		  free($1);
+		}
+	| LABEL ':' optional_separator position_not_place
+		{
+		  $$.obj = 0;
+		  $$.x = $4.x;
+		  $$.y = $4.y;
+		  define_label($1, & $$);
+		  free($1);
+		}
+	| LABEL ':' optional_separator place
+		{
+		  $$ = $4;
+		  define_label($1, & $$);
+		  free($1);
+		}
+	| '{'
+		{
+		  $<state>$.x = current_position.x;
+		  $<state>$.y = current_position.y;
+		  $<state>$.dir = current_direction;
+		}
+	  element_list '}'
+		{
+		  current_position.x = $<state>2.x;
+		  current_position.y = $<state>2.y;
+		  current_direction = $<state>2.dir;
+		}
+	  optional_element
+		{
+		  $$ = $3;
+		}
+	| placeless_element
+		{
+		  $$.obj = 0;
+		  $$.x = current_position.x;
+		  $$.y = current_position.y;
+		}
+	;
+
+optional_element:
+	/* empty */
+		{}
+	| element
+		{}
+	;
+
+object_spec:
+	BOX
+		{ $$ = new object_spec(BOX_OBJECT); }
+	| CIRCLE
+		{ $$ = new object_spec(CIRCLE_OBJECT); }
+	| ELLIPSE
+		{ $$ = new object_spec(ELLIPSE_OBJECT); }
+	| ARC
+		{
+		  $$ = new object_spec(ARC_OBJECT);
+		  $$->dir = current_direction;
+		}
+	| LINE
+		{
+		  $$ = new object_spec(LINE_OBJECT);
+		  lookup_variable("lineht", & $$->segment_height);
+		  lookup_variable("linewid", & $$->segment_width);
+		  $$->dir = current_direction;
+		}
+	| ARROW
+		{
+		  $$ = new object_spec(ARROW_OBJECT);
+		  lookup_variable("lineht", & $$->segment_height);
+		  lookup_variable("linewid", & $$->segment_width);
+		  $$->dir = current_direction;
+		}
+	| MOVE
+		{
+		  $$ = new object_spec(MOVE_OBJECT);
+		  lookup_variable("moveht", & $$->segment_height);
+		  lookup_variable("movewid", & $$->segment_width);
+		  $$->dir = current_direction;
+		}
+	| SPLINE
+		{
+		  $$ = new object_spec(SPLINE_OBJECT);
+		  lookup_variable("lineht", & $$->segment_height);
+		  lookup_variable("linewid", & $$->segment_width);
+		  $$->dir = current_direction;
+		}
+	| text							%prec TEXT
+		{
+		  $$ = new object_spec(TEXT_OBJECT);
+		  $$->text = new text_item($1.str, $1.filename, $1.lineno);
+		}
+	| PLOT expr
+		{
+		  lex_warning("'plot' is deprecated; use 'sprintf'"
+			      " instead");
+		  $$ = new object_spec(TEXT_OBJECT);
+		  $$->text = new text_item(format_number(0, $2), 0, -1);
+		}
+	| PLOT expr text
+		{
+		  $$ = new object_spec(TEXT_OBJECT);
+		  $$->text = new text_item(format_number($3.str, $2),
+					   $3.filename, $3.lineno);
+		  delete[] $3.str;
+		}
+	| '[' 
+		{
+		  saved_state *p = new saved_state;
+		  $<pstate>$ = p;
+		  p->x = current_position.x;
+		  p->y = current_position.y;
+		  p->dir = current_direction;
+		  p->tbl = current_table;
+		  p->prev = current_saved_state;
+		  current_position.x = 0.0;
+		  current_position.y = 0.0;
+		  current_table = new PTABLE(place);
+		  current_saved_state = p;
+		  olist.append(make_mark_object());
+		}
+	  element_list ']'
+		{
+		  current_position.x = $<pstate>2->x;
+		  current_position.y = $<pstate>2->y;
+		  current_direction = $<pstate>2->dir;
+		  $$ = new object_spec(BLOCK_OBJECT);
+		  olist.wrap_up_block(& $$->oblist);
+		  $$->tbl = current_table;
+		  current_table = $<pstate>2->tbl;
+		  current_saved_state = $<pstate>2->prev;
+		  delete $<pstate>2;
+		}
+	| object_spec HEIGHT expr
+		{
+		  $$ = $1;
+		  $$->height = $3;
+		  $$->flags |= HAS_HEIGHT;
+		}
+	| object_spec RADIUS expr
+		{
+		  $$ = $1;
+		  $$->radius = $3;
+		  $$->flags |= HAS_RADIUS;
+		}
+	| object_spec WIDTH expr
+		{
+		  $$ = $1;
+		  $$->width = $3;
+		  $$->flags |= HAS_WIDTH;
+		}
+	| object_spec DIAMETER expr
+		{
+		  $$ = $1;
+		  $$->radius = $3/2.0;
+		  $$->flags |= HAS_RADIUS;
+		}
+	| object_spec expr					%prec HEIGHT
+		{
+		  $$ = $1;
+		  $$->flags |= HAS_SEGMENT;
+		  switch ($$->dir) {
+		  case UP_DIRECTION:
+		    $$->segment_pos.y += $2;
+		    break;
+		  case DOWN_DIRECTION:
+		    $$->segment_pos.y -= $2;
+		    break;
+		  case RIGHT_DIRECTION:
+		    $$->segment_pos.x += $2;
+		    break;
+		  case LEFT_DIRECTION:
+		    $$->segment_pos.x -= $2;
+		    break;
+		  }
+		}
+	| object_spec UP
+		{
+		  $$ = $1;
+		  $$->dir = UP_DIRECTION;
+		  $$->flags |= HAS_SEGMENT;
+		  $$->segment_pos.y += $$->segment_height;
+		}
+	| object_spec UP expr
+		{
+		  $$ = $1;
+		  $$->dir = UP_DIRECTION;
+		  $$->flags |= HAS_SEGMENT;
+		  $$->segment_pos.y += $3;
+		}
+	| object_spec DOWN
+		{
+		  $$ = $1;
+		  $$->dir = DOWN_DIRECTION;
+		  $$->flags |= HAS_SEGMENT;
+		  $$->segment_pos.y -= $$->segment_height;
+		}
+	| object_spec DOWN expr
+		{
+		  $$ = $1;
+		  $$->dir = DOWN_DIRECTION;
+		  $$->flags |= HAS_SEGMENT;
+		  $$->segment_pos.y -= $3;
+		}
+	| object_spec RIGHT
+		{
+		  $$ = $1;
+		  $$->dir = RIGHT_DIRECTION;
+		  $$->flags |= HAS_SEGMENT;
+		  $$->segment_pos.x += $$->segment_width;
+		}
+	| object_spec RIGHT expr
+		{
+		  $$ = $1;
+		  $$->dir = RIGHT_DIRECTION;
+		  $$->flags |= HAS_SEGMENT;
+		  $$->segment_pos.x += $3;
+		}
+	| object_spec LEFT
+		{
+		  $$ = $1;
+		  $$->dir = LEFT_DIRECTION;
+		  $$->flags |= HAS_SEGMENT;
+		  $$->segment_pos.x -= $$->segment_width;
+		}
+	| object_spec LEFT expr
+		{
+		  $$ = $1;
+		  $$->dir = LEFT_DIRECTION;
+		  $$->flags |= HAS_SEGMENT;
+		  $$->segment_pos.x -= $3;
+		}
+	| object_spec FROM position
+		{
+		  $$ = $1;
+		  $$->flags |= HAS_FROM;
+		  $$->from.x = $3.x;
+		  $$->from.y = $3.y;
+		}
+	| object_spec TO position
+		{
+		  $$ = $1;
+		  if ($$->flags & HAS_SEGMENT)
+		    $$->segment_list = new segment($$->segment_pos,
+						   $$->segment_is_absolute,
+						   $$->segment_list);
+		  $$->flags |= HAS_SEGMENT;
+		  $$->segment_pos.x = $3.x;
+		  $$->segment_pos.y = $3.y;
+		  $$->segment_is_absolute = 1;
+		  $$->flags |= HAS_TO;
+		  $$->to.x = $3.x;
+		  $$->to.y = $3.y;
+		}
+	| object_spec AT position
+		{
+		  $$ = $1;
+		  $$->flags |= HAS_AT;
+		  $$->at.x = $3.x;
+		  $$->at.y = $3.y;
+		  if ($$->type != ARC_OBJECT) {
+		    $$->flags |= HAS_FROM;
+		    $$->from.x = $3.x;
+		    $$->from.y = $3.y;
+		  }
+		}
+	| object_spec WITH path
+		{
+		  $$ = $1;
+		  $$->flags |= HAS_WITH;
+		  $$->with = $3;
+		}
+	| object_spec WITH position				%prec ','
+		{
+		  $$ = $1;
+		  $$->flags |= HAS_WITH;
+		  position pos;
+		  pos.x = $3.x;
+		  pos.y = $3.y;
+		  $$->with = new path(pos);
+		}
+	| object_spec BY expr_pair
+		{
+		  $$ = $1;
+		  $$->flags |= HAS_SEGMENT;
+		  $$->segment_pos.x += $3.x;
+		  $$->segment_pos.y += $3.y;
+		}
+	| object_spec THEN
+  		{
+		  $$ = $1;
+		  if (!($$->flags & HAS_SEGMENT))
+		    switch ($$->dir) {
+		    case UP_DIRECTION:
+		      $$->segment_pos.y += $$->segment_width;
+		      break;
+		    case DOWN_DIRECTION:
+		      $$->segment_pos.y -= $$->segment_width;
+		      break;
+		    case RIGHT_DIRECTION:
+		      $$->segment_pos.x += $$->segment_width;
+		      break;
+		    case LEFT_DIRECTION:
+		      $$->segment_pos.x -= $$->segment_width;
+		      break;
+		    }
+		  $$->segment_list = new segment($$->segment_pos,
+						 $$->segment_is_absolute,
+						 $$->segment_list);
+		  $$->flags &= ~HAS_SEGMENT;
+		  $$->segment_pos.x = $$->segment_pos.y = 0.0;
+		  $$->segment_is_absolute = 0;
+		}
+	| object_spec SOLID
+		{
+		  $$ = $1;	// nothing
+		}
+	| object_spec DOTTED
+		{
+		  $$ = $1;
+		  $$->flags |= IS_DOTTED;
+		  lookup_variable("dashwid", & $$->dash_width);
+		}
+	| object_spec DOTTED expr
+		{
+		  $$ = $1;
+		  $$->flags |= IS_DOTTED;
+		  $$->dash_width = $3;
+		}
+	| object_spec DASHED
+		{
+		  $$ = $1;
+		  $$->flags |= IS_DASHED;
+		  lookup_variable("dashwid", & $$->dash_width);
+		}
+	| object_spec DASHED expr
+		{
+		  $$ = $1;
+		  $$->flags |= IS_DASHED;
+		  $$->dash_width = $3;
+		}
+	| object_spec FILL
+		{
+		  $$ = $1;
+		  $$->flags |= IS_DEFAULT_FILLED;
+		}
+	| object_spec FILL expr
+		{
+		  $$ = $1;
+		  $$->flags |= IS_FILLED;
+		  $$->fill = $3;
+		}
+	| object_spec XSLANTED expr
+		{
+		  $$ = $1;
+		  $$->flags |= IS_XSLANTED;
+		  $$->xslanted = $3;
+		}
+	| object_spec YSLANTED expr
+		{
+		  $$ = $1;
+		  $$->flags |= IS_YSLANTED;
+		  $$->yslanted = $3;
+		}
+	| object_spec SHADED text
+		{
+		  $$ = $1;
+		  $$->flags |= (IS_SHADED | IS_FILLED);
+		  $$->shaded = new char[strlen($3.str)+1];
+		  strcpy($$->shaded, $3.str);
+		}
+	| object_spec COLORED text
+		{
+		  $$ = $1;
+		  $$->flags |= (IS_SHADED | IS_OUTLINED | IS_FILLED);
+		  $$->shaded = new char[strlen($3.str)+1];
+		  strcpy($$->shaded, $3.str);
+		  $$->outlined = new char[strlen($3.str)+1];
+		  strcpy($$->outlined, $3.str);
+		}
+	| object_spec OUTLINED text
+		{
+		  $$ = $1;
+		  $$->flags |= IS_OUTLINED;
+		  $$->outlined = new char[strlen($3.str)+1];
+		  strcpy($$->outlined, $3.str);
+		}
+	| object_spec CHOP
+  		{
+		  $$ = $1;
+		  // line chop chop means line chop 0 chop 0
+		  if ($$->flags & IS_DEFAULT_CHOPPED) {
+		    $$->flags |= IS_CHOPPED;
+		    $$->flags &= ~IS_DEFAULT_CHOPPED;
+		    $$->start_chop = $$->end_chop = 0.0;
+		  }
+		  else if ($$->flags & IS_CHOPPED) {
+		    $$->end_chop = 0.0;
+		  }
+		  else {
+		    $$->flags |= IS_DEFAULT_CHOPPED;
+		  }
+		}
+	| object_spec CHOP expr
+		{
+		  $$ = $1;
+		  if ($$->flags & IS_DEFAULT_CHOPPED) {
+		    $$->flags |= IS_CHOPPED;
+		    $$->flags &= ~IS_DEFAULT_CHOPPED;
+		    $$->start_chop = 0.0;
+		    $$->end_chop = $3;
+		  }
+		  else if ($$->flags & IS_CHOPPED) {
+		    $$->end_chop = $3;
+		  }
+		  else {
+		    $$->start_chop = $$->end_chop = $3;
+		    $$->flags |= IS_CHOPPED;
+		  }
+		}
+	| object_spec SAME
+		{
+		  $$ = $1;
+		  $$->flags |= IS_SAME;
+		}
+	| object_spec INVISIBLE
+		{
+		  $$ = $1;
+		  $$->flags |= IS_INVISIBLE;
+		}
+	| object_spec LEFT_ARROW_HEAD
+		{
+		  $$ = $1;
+		  $$->flags |= HAS_LEFT_ARROW_HEAD;
+		}
+	| object_spec RIGHT_ARROW_HEAD
+		{
+		  $$ = $1;
+		  $$->flags |= HAS_RIGHT_ARROW_HEAD;
+		}
+	| object_spec DOUBLE_ARROW_HEAD
+		{
+		  $$ = $1;
+		  $$->flags |= (HAS_LEFT_ARROW_HEAD|HAS_RIGHT_ARROW_HEAD);
+		}
+	| object_spec CW
+		{
+		  $$ = $1;
+		  $$->flags |= IS_CLOCKWISE;
+		}
+	| object_spec CCW
+		{
+		  $$ = $1;
+		  $$->flags &= ~IS_CLOCKWISE;
+		}
+	| object_spec text					%prec TEXT
+		{
+		  $$ = $1;
+		  text_item **p;
+		  for (p = & $$->text; *p; p = &(*p)->next)
+		    ;
+		  *p = new text_item($2.str, $2.filename, $2.lineno);
+		}
+	| object_spec LJUST
+		{
+		  $$ = $1;
+		  if ($$->text) {
+		    text_item *p;
+		    for (p = $$->text; p->next; p = p->next)
+		      ;
+		    p->adj.h = LEFT_ADJUST;
+		  }
+		}
+	| object_spec RJUST
+		{
+		  $$ = $1;
+		  if ($$->text) {
+		    text_item *p;
+		    for (p = $$->text; p->next; p = p->next)
+		      ;
+		    p->adj.h = RIGHT_ADJUST;
+		  }
+		}
+	| object_spec ABOVE
+		{
+		  $$ = $1;
+		  if ($$->text) {
+		    text_item *p;
+		    for (p = $$->text; p->next; p = p->next)
+		      ;
+		    p->adj.v = ABOVE_ADJUST;
+		  }
+		}
+	| object_spec BELOW
+		{
+		  $$ = $1;
+		  if ($$->text) {
+		    text_item *p;
+		    for (p = $$->text; p->next; p = p->next)
+		      ;
+		    p->adj.v = BELOW_ADJUST;
+		  }
+		}
+	| object_spec THICKNESS expr
+		{
+		  $$ = $1;
+		  $$->flags |= HAS_THICKNESS;
+		  $$->thickness = $3;
+		}
+	| object_spec ALIGNED
+		{
+		  $$ = $1;
+		  $$->flags |= IS_ALIGNED;
+		}
+	;
+
+text:
+	TEXT
+		{ $$ = $1; }
+	| SPRINTF '(' TEXT sprintf_args ')'
+		{
+		  $$.filename = $3.filename;
+		  $$.lineno = $3.lineno;
+		  $$.str = do_sprintf($3.str, $4.v, $4.nv);
+		  delete[] $4.v;
+		  free($3.str);
+		}
+	;
+
+sprintf_args:
+	/* empty */
+		{
+		  $$.v = 0;
+		  $$.nv = 0;
+		  $$.maxv = 0;
+		}
+	| sprintf_args ',' expr
+		{
+		  $$ = $1;
+		  if ($$.nv >= $$.maxv) {
+		    if ($$.nv == 0) {
+		      $$.v = new double[4];
+		      $$.maxv = 4;
+		    }
+		    else {
+		      double *oldv = $$.v;
+		      $$.maxv *= 2;
+#if 0
+		      $$.v = new double[$$.maxv];
+		      memcpy($$.v, oldv, $$.nv*sizeof(double));
+#else
+		      // workaround for bug in Compaq C++ V6.5-033
+		      // for Compaq Tru64 UNIX V5.1A (Rev. 1885)
+		      double *foo = new double[$$.maxv];
+		      memcpy(foo, oldv, $$.nv*sizeof(double));
+		      $$.v = foo;
+#endif
+		      delete[] oldv;
+		    }
+		  }
+		  $$.v[$$.nv] = $3;
+		  $$.nv += 1;
+		}
+	;
+
+position:
+  	position_not_place
+		{ $$ = $1; }
+	| place
+  		{
+		  position pos = $1;
+		  $$.x = pos.x;
+		  $$.y = pos.y;
+		}
+	| '(' place ')'
+		{
+		  position pos = $2;
+		  $$.x = pos.x;
+		  $$.y = pos.y;
+		}
+	;
+
+position_not_place:
+	expr_pair
+		{ $$ = $1; }
+	| position '+' expr_pair
+		{
+		  $$.x = $1.x + $3.x;
+		  $$.y = $1.y + $3.y;
+		}
+	| '(' position '+' expr_pair ')'
+		{
+		  $$.x = $2.x + $4.x;
+		  $$.y = $2.y + $4.y;
+		}
+	| position '-' expr_pair
+		{
+		  $$.x = $1.x - $3.x;
+		  $$.y = $1.y - $3.y;
+		}
+	| '(' position '-' expr_pair ')'
+		{
+		  $$.x = $2.x - $4.x;
+		  $$.y = $2.y - $4.y;
+		}
+	| '(' position ',' position ')'
+		{
+		  $$.x = $2.x;
+		  $$.y = $4.y;
+		}
+	| expr between position AND position
+		{
+		  $$.x = (1.0 - $1)*$3.x + $1*$5.x;
+		  $$.y = (1.0 - $1)*$3.y + $1*$5.y;
+		}
+	| '(' expr between position AND position ')'
+		{
+		  $$.x = (1.0 - $2)*$4.x + $2*$6.x;
+		  $$.y = (1.0 - $2)*$4.y + $2*$6.y;
+		}
+	/* the next two rules cause harmless shift/reduce warnings */
+	| expr_not_lower_than '<' position ',' position '>'
+		{
+		  $$.x = (1.0 - $1)*$3.x + $1*$5.x;
+		  $$.y = (1.0 - $1)*$3.y + $1*$5.y;
+		}
+	| '(' expr_not_lower_than '<' position ',' position '>' ')'
+		{
+		  $$.x = (1.0 - $2)*$4.x + $2*$6.x;
+		  $$.y = (1.0 - $2)*$4.y + $2*$6.y;
+		}
+	;
+
+between:
+	BETWEEN
+	| OF THE WAY BETWEEN
+	;
+
+expr_pair:
+	expr ',' expr
+		{
+		  $$.x = $1;
+		  $$.y = $3;
+		}
+	| '(' expr_pair ')'
+		{ $$ = $2; }
+	;
+
+place:
+	/* line at A left == line (at A) left */
+	label							%prec CHOP
+		{ $$ = $1; }
+	| label corner
+		{
+		  path pth($2);
+		  if (!pth.follow($1, & $$))
+		    YYABORT;
+		}
+	| corner label
+		{
+		  path pth($1);
+		  if (!pth.follow($2, & $$))
+		    YYABORT;
+		}
+	| corner OF label
+		{
+		  path pth($1);
+		  if (!pth.follow($3, & $$))
+		    YYABORT;
+		}
+	| HERE
+		{
+		  $$.x = current_position.x;
+		  $$.y = current_position.y;
+		  $$.obj = 0;
+		}
+	;
+
+label:
+	LABEL
+		{
+		  place *p = lookup_label($1);
+		  if (!p) {
+		    lex_error("there is no place '%1'", $1);
+		    YYABORT;
+		  }
+		  $$ = *p;
+		  free($1);
+		}
+	| nth_primitive
+		{ $$.obj = $1; }
+	| label '.' LABEL
+		{
+		  path pth($3);
+		  if (!pth.follow($1, & $$))
+		    YYABORT;
+		}
+	;
+
+ordinal:
+	ORDINAL
+		{ $$ = $1; }
+	| '`' any_expr TH
+		{
+		  // XXX Check for overflow (and non-integers?).
+		  $$ = (int)$2;
+		}
+	;
+
+optional_ordinal_last:
+	LAST
+		{ $$ = 1; }
+  	| ordinal LAST
+		{ $$ = $1; }
+	;
+
+nth_primitive:
+	ordinal object_type
+		{
+		  int count = 0;
+		  object *p;
+		  for (p = olist.head; p != 0; p = p->next)
+		    if (p->type() == $2 && ++count == $1) {
+		      $$ = p;
+		      break;
+		    }
+		  if (p == 0) {
+		    lex_error("there is no %1%2 %3", $1, ordinal_postfix($1),
+			      object_type_name($2));
+		    YYABORT;
+		  }
+		}
+	| optional_ordinal_last object_type
+		{
+		  int count = 0;
+		  object *p;
+		  for (p = olist.tail; p != 0; p = p->prev)
+		    if (p->type() == $2 && ++count == $1) {
+		      $$ = p;
+		      break;
+		    }
+		  if (p == 0) {
+		    lex_error("there is no %1%2 last %3", $1,
+			      ordinal_postfix($1), object_type_name($2));
+		    YYABORT;
+		  }
+		}
+	;
+
+object_type:
+	BOX
+  		{ $$ = BOX_OBJECT; }
+	| CIRCLE
+		{ $$ = CIRCLE_OBJECT; }
+	| ELLIPSE
+		{ $$ = ELLIPSE_OBJECT; }
+	| ARC
+		{ $$ = ARC_OBJECT; }
+	| LINE
+		{ $$ = LINE_OBJECT; }
+	| ARROW
+		{ $$ = ARROW_OBJECT; }
+	| SPLINE
+		{ $$ = SPLINE_OBJECT; }
+	| '[' ']'
+		{ $$ = BLOCK_OBJECT; }
+	| TEXT
+		{ $$ = TEXT_OBJECT; }
+	;
+
+label_path:
+ 	'.' LABEL
+		{ $$ = new path($2); }
+	| label_path '.' LABEL
+		{
+		  $$ = $1;
+		  $$->append($3);
+		}
+	;
+
+relative_path:
+	corner							%prec CHOP
+		{ $$ = new path($1); }
+	/* give this a lower precedence than LEFT and RIGHT so that
+	   [A: box] with .A left == [A: box] with (.A left) */
+  	| label_path						%prec TEXT
+		{ $$ = $1; }
+	| label_path corner
+		{
+		  $$ = $1;
+		  $$->append($2);
+		}
+	;
+
+path:
+	relative_path
+		{ $$ = $1; }
+	| '(' relative_path ',' relative_path ')'
+		{
+		  $$ = $2;
+		  $$->set_ypath($4);
+		}
+	/* The rest of these rules are a compatibility sop. */
+	| ORDINAL LAST object_type relative_path
+		{
+		  lex_warning("'%1%2 last %3' in 'with' argument ignored",
+			      $1, ordinal_postfix($1), object_type_name($3));
+		  $$ = $4;
+		}
+	| LAST object_type relative_path
+		{
+		  lex_warning("'last %1' in 'with' argument ignored",
+			      object_type_name($2));
+		  $$ = $3;
+		}
+	| ORDINAL object_type relative_path
+		{
+		  lex_warning("'%1%2 %3' in 'with' argument ignored",
+			      $1, ordinal_postfix($1), object_type_name($2));
+		  $$ = $3;
+		}
+	| LABEL relative_path
+		{
+		  lex_warning("initial '%1' in 'with' argument ignored", $1);
+		  delete[] $1;
+		  $$ = $2;
+		}
+	;
+
+corner:
+	DOT_N
+		{ $$ = &object::north; }
+	| DOT_E	
+		{ $$ = &object::east; }
+	| DOT_W
+		{ $$ = &object::west; }
+	| DOT_S
+		{ $$ = &object::south; }
+	| DOT_NE
+		{ $$ = &object::north_east; }
+	| DOT_SE
+		{ $$ = &object:: south_east; }
+	| DOT_NW
+		{ $$ = &object::north_west; }
+	| DOT_SW
+		{ $$ = &object::south_west; }
+	| DOT_C
+		{ $$ = &object::center; }
+	| DOT_START
+		{ $$ = &object::start; }
+	| DOT_END
+		{ $$ = &object::end; }
+  	| TOP
+		{ $$ = &object::north; }
+	| BOTTOM
+		{ $$ = &object::south; }
+	| LEFT
+		{ $$ = &object::west; }
+	| RIGHT
+		{ $$ = &object::east; }
+	| UPPER LEFT
+		{ $$ = &object::north_west; }
+	| LOWER LEFT
+		{ $$ = &object::south_west; }
+	| UPPER RIGHT
+		{ $$ = &object::north_east; }
+	| LOWER RIGHT
+		{ $$ = &object::south_east; }
+	| LEFT_CORNER
+		{ $$ = &object::west; }
+	| RIGHT_CORNER
+		{ $$ = &object::east; }
+	| UPPER LEFT_CORNER
+		{ $$ = &object::north_west; }
+	| LOWER LEFT_CORNER
+		{ $$ = &object::south_west; }
+	| UPPER RIGHT_CORNER
+		{ $$ = &object::north_east; }
+	| LOWER RIGHT_CORNER
+		{ $$ = &object::south_east; }
+	| NORTH
+		{ $$ = &object::north; }
+	| SOUTH
+		{ $$ = &object::south; }
+	| EAST
+		{ $$ = &object::east; }
+	| WEST
+		{ $$ = &object::west; }
+	| CENTER
+		{ $$ = &object::center; }
+	| START
+		{ $$ = &object::start; }
+	| END
+		{ $$ = &object::end; }
+	;
+
+expr:
+	expr_lower_than
+		{ $$ = $1; }
+	| expr_not_lower_than
+		{ $$ = $1; }
+	;
+
+expr_lower_than:
+	expr '<' expr
+		{ $$ = ($1 < $3); }
+	;
+
+expr_not_lower_than:
+	VARIABLE
+		{
+		  if (!lookup_variable($1, & $$)) {
+		    lex_error("there is no variable '%1'", $1);
+		    YYABORT;
+		  }
+		  free($1);
+		}
+	| NUMBER
+		{ $$ = $1; }
+	| place DOT_X
+  		{
+		  if ($1.obj != 0)
+		    $$ = $1.obj->origin().x;
+		  else
+		    $$ = $1.x;
+		}			
+	| place DOT_Y
+		{
+		  if ($1.obj != 0)
+		    $$ = $1.obj->origin().y;
+		  else
+		    $$ = $1.y;
+		}
+	| place DOT_HT
+		{
+		  if ($1.obj != 0)
+		    $$ = $1.obj->height();
+		  else
+		    $$ = 0.0;
+		}
+	| place DOT_WID
+		{
+		  if ($1.obj != 0)
+		    $$ = $1.obj->width();
+		  else
+		    $$ = 0.0;
+		}
+	| place DOT_RAD
+		{
+		  if ($1.obj != 0)
+		    $$ = $1.obj->radius();
+		  else
+		    $$ = 0.0;
+		}
+	| expr '+' expr
+		{ $$ = $1 + $3; }
+	| expr '-' expr
+		{ $$ = $1 - $3; }
+	| expr '*' expr
+		{ $$ = $1 * $3; }
+	| expr '/' expr
+		{
+		  if ($3 == 0.0) {
+		    lex_error("division by zero");
+		    YYABORT;
+		  }
+		  $$ = $1/$3;
+		}
+	| expr '%' expr
+		{
+		  if ($3 == 0.0) {
+		    lex_error("modulus by zero");
+		    YYABORT;
+		  }
+		  $$ = fmod($1, $3);
+		}
+	| expr '^' expr
+		{
+		  errno = 0;
+		  $$ = pow($1, $3);
+		  if (errno == EDOM) {
+		    lex_error("arguments to '^' operator out of domain");
+		    YYABORT;
+		  }
+		  if (errno == ERANGE) {
+		    lex_error("result of '^' operator out of range");
+		    YYABORT;
+		  }
+		}
+	| '-' expr						%prec '!'
+		{ $$ = -$2; }
+	| '(' any_expr ')'
+		{ $$ = $2; }
+	| SIN '(' any_expr ')'
+		{
+		  errno = 0;
+		  $$ = sin($3);
+		  if (errno == ERANGE) {
+		    lex_error("sin result out of range");
+		    YYABORT;
+		  }
+		}
+	| COS '(' any_expr ')'
+		{
+		  errno = 0;
+		  $$ = cos($3);
+		  if (errno == ERANGE) {
+		    lex_error("cos result out of range");
+		    YYABORT;
+		  }
+		}
+	| ATAN2 '(' any_expr ',' any_expr ')'
+		{
+		  errno = 0;
+		  $$ = atan2($3, $5);
+		  if (errno == EDOM) {
+		    lex_error("atan2 argument out of domain");
+		    YYABORT;
+		  }
+		  if (errno == ERANGE) {
+		    lex_error("atan2 result out of range");
+		    YYABORT;
+		  }
+		}
+	| LOG '(' any_expr ')'
+		{
+		  errno = 0;
+		  $$ = log10($3);
+		  if (errno == ERANGE) {
+		    lex_error("log result out of range");
+		    YYABORT;
+		  }
+		}
+	| EXP '(' any_expr ')'
+		{
+		  errno = 0;
+		  $$ = pow(10.0, $3);
+		  if (errno == ERANGE) {
+		    lex_error("exp result out of range");
+		    YYABORT;
+		  }
+		}
+	| SQRT '(' any_expr ')'
+		{
+		  errno = 0;
+		  $$ = sqrt($3);
+		  if (errno == EDOM) {
+		    lex_error("sqrt argument out of domain");
+		    YYABORT;
+		  }
+		}
+	| K_MAX '(' any_expr ',' any_expr ')'
+		{ $$ = $3 > $5 ? $3 : $5; }
+	| K_MIN '(' any_expr ',' any_expr ')'
+		{ $$ = $3 < $5 ? $3 : $5; }
+	| INT '(' any_expr ')'
+		{ $$ = $3 < 0 ? -floor(-$3) : floor($3); }
+	| RAND '(' any_expr ')'
+		{
+		  lex_error("use of 'rand' with an argument is"
+			    " deprecated; shift and scale 'rand()' with"
+			    " arithmetic instead");
+		  $$ = 1.0 + floor(((rand()&0x7fff)/double(0x7fff))*$3);
+		}
+	| RAND '(' ')'
+		{
+		  /* return a random number in the range [0,1) */
+		  /* portable, but not very random */
+		  $$ = (rand() & 0x7fff) / double(0x8000);
+		}
+	| SRAND '(' any_expr ')'
+		{
+		  $$ = 0;
+		  srand((unsigned int)$3);
+		}
+	| expr LESSEQUAL expr
+		{ $$ = ($1 <= $3); }
+	| expr '>' expr
+		{ $$ = ($1 > $3); }
+	| expr GREATEREQUAL expr
+		{ $$ = ($1 >= $3); }
+	| expr EQUALEQUAL expr
+		{ $$ = ($1 == $3); }
+	| expr NOTEQUAL expr
+		{ $$ = ($1 != $3); }
+	| expr ANDAND expr
+		{ $$ = ($1 != 0.0 && $3 != 0.0); }
+	| expr OROR expr
+		{ $$ = ($1 != 0.0 || $3 != 0.0); }
+	| '!' expr
+		{ $$ = ($2 == 0.0); }
+
+	;
+
+%%
+
+/* bison defines const to be empty unless __STDC__ is defined, which it
+isn't under cfront */
+
+#ifdef const
+#undef const
+#endif
+
+static struct {
+  const char *name;
+  double val;
+  int scaled;		     // non-zero if val should be multiplied by scale
+} defaults_table[] = {
+  { "arcrad", .25, 1 },
+  { "arrowht", .1, 1 },
+  { "arrowwid", .05, 1 },
+  { "circlerad", .25, 1 },
+  { "boxht", .5, 1 },
+  { "boxwid", .75, 1 },
+  { "boxrad", 0.0, 1 },
+  { "dashwid", .05, 1 },
+  { "ellipseht", .5, 1 },
+  { "ellipsewid", .75, 1 },
+  { "moveht", .5, 1 },
+  { "movewid", .5, 1 },
+  { "lineht", .5, 1 },
+  { "linewid", .5, 1 },
+  { "textht", 0.0, 1 },
+  { "textwid", 0.0, 1 },
+  { "scale", 1.0, 0 },
+  { "linethick", -1.0, 0 },		// in points
+  { "fillval", .5, 0 },
+  { "arrowhead", 1.0, 0 },
+  { "maxpswid", 8.5, 0 },
+  { "maxpsht", 11.0, 0 },
+};
+
+place *lookup_label(const char *label)
+{
+  saved_state *state = current_saved_state;
+  PTABLE(place) *tbl = current_table;
+  for (;;) {
+    place *pl = tbl->lookup(label);
+    if (pl)
+      return pl;
+    if (!state)
+      return 0;
+    tbl = state->tbl;
+    state = state->prev;
+  }
+}
+
+void define_label(const char *label, const place *pl)
+{
+  place *p = new place[1];
+  *p = *pl;
+  current_table->define(label, p);
+}
+
+int lookup_variable(const char *name, double *val)
+{
+  place *pl = lookup_label(name);
+  if (pl) {
+    *val = pl->x;
+    return 1;
+  }
+  return 0;
+}
+
+void define_variable(const char *name, double val)
+{
+  place *p = new place[1];
+  p->obj = 0;
+  p->x = val;
+  p->y = 0.0;
+  current_table->define(name, p);
+  if (strcmp(name, "scale") == 0) {
+    // When the scale changes, reset all scaled predefined variables to
+    // their default values.
+    for (unsigned int i = 0;
+	 i < sizeof(defaults_table)/sizeof(defaults_table[0]); i++) 
+      if (defaults_table[i].scaled)
+	define_variable(defaults_table[i].name, val*defaults_table[i].val);
+  }
+}
+
+// called once only (not once per parse)
+
+void parse_init()
+{
+  current_direction = RIGHT_DIRECTION;
+  current_position.x = 0.0;
+  current_position.y = 0.0;
+  // This resets everything to its default value.
+  reset_all();
+}
+
+void reset(const char *nm)
+{
+  for (unsigned int i = 0;
+       i < sizeof(defaults_table)/sizeof(defaults_table[0]); i++)
+    if (strcmp(nm, defaults_table[i].name) == 0) {
+      double val = defaults_table[i].val;
+      if (defaults_table[i].scaled) {
+	double scale;
+	lookup_variable("scale", &scale);
+	val *= scale;
+      }
+      define_variable(defaults_table[i].name, val);
+      return;
+    }
+  lex_error("'%1' is not a predefined variable", nm);
+}
+
+void reset_all()
+{
+  // We only have to explicitly reset the predefined variables that
+  // aren't scaled because 'scale' is not scaled, and changing the
+  // value of 'scale' will reset all the predefined variables that
+  // are scaled.
+  for (unsigned int i = 0;
+       i < sizeof(defaults_table)/sizeof(defaults_table[0]); i++)
+    if (!defaults_table[i].scaled)
+      define_variable(defaults_table[i].name, defaults_table[i].val);
+}
+
+// called after each parse
+
+void parse_cleanup()
+{
+  while (current_saved_state != 0) {
+    delete current_table;
+    current_table = current_saved_state->tbl;
+    saved_state *tem = current_saved_state;
+    current_saved_state = current_saved_state->prev;
+    delete tem;
+  }
+  assert(current_table == &top_table);
+  PTABLE_ITERATOR(place) iter(current_table);
+  const char *key;
+  place *pl;
+  while (iter.next(&key, &pl))
+    if (pl->obj != 0) {
+      position pos = pl->obj->origin();
+      pl->obj = 0;
+      pl->x = pos.x;
+      pl->y = pos.y;
+    }
+  while (olist.head != 0) {
+    object *tem = olist.head;
+    olist.head = olist.head->next;
+    delete tem;
+  }
+  olist.tail = 0;
+  current_direction = RIGHT_DIRECTION;
+  current_position.x = 0.0;
+  current_position.y = 0.0;
+}
+
+const char *ordinal_postfix(int n)
+{
+  if (n < 10 || n > 20)
+    switch (n % 10) {
+    case 1:
+      return "st";
+    case 2:
+      return "nd";
+    case 3:
+      return "rd";
+    }
+  return "th";
+}
+
+const char *object_type_name(object_type type)
+{
+  switch (type) {
+  case BOX_OBJECT:
+    return "box";
+  case CIRCLE_OBJECT:
+    return "circle";
+  case ELLIPSE_OBJECT:
+    return "ellipse";
+  case ARC_OBJECT:
+    return "arc";
+  case SPLINE_OBJECT:
+    return "spline";
+  case LINE_OBJECT:
+    return "line";
+  case ARROW_OBJECT:
+    return "arrow";
+  case MOVE_OBJECT:
+    return "move";
+  case TEXT_OBJECT:
+    return "\"\"";
+  case BLOCK_OBJECT:
+    return "[]";
+  case OTHER_OBJECT:
+  case MARK_OBJECT:
+  default:
+    break;
+  }
+  return "object";
+}
+
+static char sprintf_buf[1024];
+
+char *format_number(const char *fmt, double n)
+{
+  if (0 /* nullptr */ == fmt)
+    fmt = "%g";
+  return do_sprintf(fmt, &n, 1);
+}
+
+char *do_sprintf(const char *fmt, const double *v, int nv)
+{
+  // Define valid conversion specifiers and modifiers.
+  static const char spcs[] = "eEfgG%";
+  static const char mods[] = "#-+ 0123456789.";
+  string result;
+  int i = 0;
+  string one_format;
+  while (*fmt) {
+    if ('%' == *fmt) {
+      one_format += *fmt++;
+      for (; *fmt != '\0' && strchr(mods, *fmt) != 0; fmt++)
+	one_format += *fmt;
+      if ('\0' == *fmt || strchr(spcs, *fmt) == 0) {
+	lex_error("invalid sprintf conversion specifier '%1'", *fmt);
+	result += one_format;
+	result += fmt;
+	break;
+      }
+      if ('%' == *fmt) {
+	fmt++;
+	snprintf(sprintf_buf, sizeof(sprintf_buf), "%%");
+      }
+      else {
+	if (i >= nv) {
+	  lex_error("too few arguments to sprintf");
+	  result += one_format;
+	  result += fmt;
+	  break;
+	}
+	one_format += *fmt++;
+	one_format += '\0';
+// We validated the format string above.  Most conversion specifiers are
+// rejected, including `n`.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wformat-nonliteral"
+	snprintf(sprintf_buf, sizeof(sprintf_buf),
+		 one_format.contents(), v[i++]);
+#pragma GCC diagnostic pop
+      }
+      one_format.clear();
+      result += sprintf_buf;
+    }
+    else
+      result += *fmt++;
+  }
+  result += '\0';
+  return strsave(result.contents());
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/pic/position.h b/src/preproc/pic/position.h
new file mode 100644
index 0000000..fb32737
--- /dev/null
+++ b/src/preproc/pic/position.h
@@ -0,0 +1,46 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+struct place;
+struct position {
+  double x;
+  double y;
+  position(double, double );
+  position();
+  position(const place &);
+  position &operator+=(const position &);
+  position &operator-=(const position &);
+  position &operator*=(double);
+  position &operator/=(double);
+};
+
+position operator-(const position &);
+position operator+(const position &, const position &);
+position operator-(const position &, const position &);
+position operator/(const position &, double);
+position operator*(const position &, double);
+// dot product
+double operator*(const position &, const position &);
+int operator==(const position &, const position &);
+int operator!=(const position &, const position &);
+
+double hypot(const position &a);
+
+typedef position distance;
+
diff --git a/src/preproc/pic/tex.cpp b/src/preproc/pic/tex.cpp
new file mode 100644
index 0000000..c6071af
--- /dev/null
+++ b/src/preproc/pic/tex.cpp
@@ -0,0 +1,458 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "pic.h"
+
+#ifdef TEX_SUPPORT
+
+#include "common.h"
+
+class tex_output : public common_output {
+public:
+  tex_output();
+  ~tex_output();
+  void start_picture(double, const position &ll, const position &ur);
+  void finish_picture();
+  void text(const position &, text_piece *, int, double);
+  void line(const position &, const position *, int n,
+	    const line_type &);
+  void polygon(const position *, int n,
+	       const line_type &, double);
+  void spline(const position &, const position *, int n,
+	      const line_type &);
+  void arc(const position &, const position &, const position &,
+	   const line_type &);
+  void circle(const position &, double rad, const line_type &, double);
+  void ellipse(const position &, const distance &, const line_type &, double);
+  void command(const char *, const char *, int);
+  void set_color(char *, char *);
+  void reset_color();
+  char *get_last_filled();
+  char *get_outline_color();
+  int supports_filled_polygons();
+private:
+  position upper_left;
+  double height;
+  double width;
+  double scale;
+  double pen_size;
+
+  void point(const position &);
+  void dot(const position &, const line_type &);
+  void solid_arc(const position &cent, double rad, double start_angle,
+		 double end_angle, const line_type &lt);
+  position transform(const position &);
+protected:
+  virtual void set_pen_size(double ps);
+};
+
+// convert inches to milliinches
+
+inline int milliinches(double x)
+{
+  return int(x*1000.0 + .5);
+}
+
+inline position tex_output::transform(const position &pos)
+{
+  return position((pos.x - upper_left.x)/scale,
+		  (upper_left.y - pos.y)/scale);
+}
+
+output *make_tex_output()
+{
+  return new tex_output;
+}
+
+tex_output::tex_output()
+{
+}
+
+tex_output::~tex_output()
+{
+}
+
+const int DEFAULT_PEN_SIZE = 8;
+
+void tex_output::set_pen_size(double ps)
+{
+  if (ps < 0.0)
+    ps = -1.0;
+  if (ps != pen_size) {
+    pen_size = ps;
+    printf("    \\special{pn %d}%%\n", 
+	   ps < 0.0 ? DEFAULT_PEN_SIZE : int(ps*(1000.0/72.0) + .5));
+  }
+}
+
+void tex_output::start_picture(double sc, const position &ll,
+			       const position &ur)
+{
+  upper_left.x = ll.x;
+  upper_left.y = ur.y;
+  scale = compute_scale(sc, ll, ur);
+  height = (ur.y - ll.y)/scale;
+  width = (ur.x - ll.x)/scale;
+  /* The point of \vskip 0pt is to ensure that the vtop gets
+     a height of 0 rather than the height of the hbox; this
+     might be non-zero if text from text attributes lies outside pic's
+     idea of the bounding box of the picture. */
+  /* \newbox and \newdimen are defined with \outer in plain.tex and can't
+     be used directly in an \if clause. */
+  printf("\\expandafter\\ifx\\csname %s\\endcsname\\relax\n"
+	 "   \\csname newbox\\expandafter\\endcsname\\csname %s\\endcsname\n"
+	 "\\fi\n"
+	 "\\ifx\\graphtemp\\undefined\n"
+	 "  \\csname newdimen\\endcsname\\graphtemp\n"
+	 "\\fi\n"
+	 "\\expandafter\\setbox\\csname %s\\endcsname\n"
+	 " =\\vtop{\\vskip 0pt\\hbox{%%\n",
+	 graphname, graphname, graphname);
+  pen_size = -2.0;
+}
+
+void tex_output::finish_picture()
+{
+  printf("    \\hbox{\\vrule depth%.3fin width0pt height 0pt}%%\n"
+	 "    \\kern %.3fin\n"
+	 "  }%%\n"
+	 "}%%\n",
+	 height, width);
+}
+
+void tex_output::text(const position &center, text_piece *v, int n, double)
+{
+  position c = transform(center);
+  for (int i = 0; i < n; i++)
+    if (v[i].text != 0 && *v[i].text != '\0') {
+      int j = 2*i - n + 1;
+      if (v[i].adj.v == ABOVE_ADJUST)
+	j--;
+      else if (v[i].adj.v == BELOW_ADJUST)
+	j++;
+      if (j == 0) {
+	printf("    \\graphtemp=.5ex\n"
+	       "    \\advance\\graphtemp by %.3fin\n", c.y);
+      }
+      else {
+	printf("    \\graphtemp=\\baselineskip\n"
+	       "    \\multiply\\graphtemp by %d\n"
+	       "    \\divide\\graphtemp by 2\n"
+	       "    \\advance\\graphtemp by .5ex\n"
+	       "    \\advance\\graphtemp by %.3fin\n",
+	       j, c.y);
+      }
+      printf("    \\rlap{\\kern %.3fin\\lower\\graphtemp", c.x);
+      fputs("\\hbox to 0pt{", stdout);
+      if (v[i].adj.h != LEFT_ADJUST)
+	fputs("\\hss ", stdout);
+      fputs(v[i].text, stdout);
+      if (v[i].adj.h != RIGHT_ADJUST)
+	fputs("\\hss", stdout);
+      fputs("}}%\n", stdout);
+    }
+}
+
+void tex_output::point(const position &pos)
+{
+  position p = transform(pos);
+  printf("    \\special{pa %d %d}%%\n", milliinches(p.x), milliinches(p.y));
+}
+
+void tex_output::line(const position &start, const position *v, int n,
+		      const line_type &lt)
+{
+  set_pen_size(lt.thickness);
+  point(start);
+  for (int i = 0; i < n; i++)
+    point(v[i]);
+  fputs("    \\special{", stdout);
+  switch(lt.type) {
+  case line_type::invisible:
+    fputs("ip", stdout);
+    break;
+  case line_type::solid:
+    fputs("fp", stdout);
+    break;
+  case line_type::dotted:
+    printf("dt %.3f", lt.dash_width/scale);
+    break;
+  case line_type::dashed:
+    printf("da %.3f", lt.dash_width/scale);
+    break;
+  }
+  fputs("}%\n", stdout);
+}
+
+void tex_output::polygon(const position *v, int n,
+			 const line_type &lt, double fill)
+{
+  if (fill >= 0.0) {
+    if (fill > 1.0)
+      fill = 1.0;
+    printf("    \\special{sh %.3f}%%\n", fill);
+  }
+  line(v[n-1], v, n, lt);
+}
+
+void tex_output::spline(const position &start, const position *v, int n,
+			const line_type &lt)
+{
+  if (lt.type == line_type::invisible)
+    return;
+  set_pen_size(lt.thickness);
+  point(start);
+  for (int i = 0; i < n; i++)
+    point(v[i]);
+  fputs("    \\special{sp", stdout);
+  switch(lt.type) {
+  case line_type::solid:
+    break;
+  case line_type::dotted:
+    printf(" %.3f", -lt.dash_width/scale);
+    break;
+  case line_type::dashed:
+    printf(" %.3f", lt.dash_width/scale);
+    break;
+  case line_type::invisible:
+    assert(0);
+  }
+  fputs("}%\n", stdout);
+}
+
+void tex_output::solid_arc(const position &cent, double rad,
+			   double start_angle, double end_angle,
+			   const line_type &lt)
+{
+  set_pen_size(lt.thickness);
+  position c = transform(cent);
+  printf("    \\special{ar %d %d %d %d %f %f}%%\n",
+	 milliinches(c.x),
+	 milliinches(c.y),
+	 milliinches(rad/scale),
+	 milliinches(rad/scale),
+	 -end_angle,
+	 (-end_angle > -start_angle) ? (double)M_PI * 2 - start_angle
+	 			     : -start_angle);
+}
+  
+void tex_output::arc(const position &start, const position &cent,
+		     const position &end, const line_type &lt)
+{
+  switch (lt.type) {
+  case line_type::invisible:
+    break;
+  case line_type::dashed:
+    dashed_arc(start, cent, end, lt);
+    break;
+  case line_type::dotted:
+    dotted_arc(start, cent, end, lt);
+    break;
+  case line_type::solid:
+    {
+      position c;
+      if (!compute_arc_center(start, cent, end, &c)) {
+	line(start, &end, 1, lt);
+	break;
+      }
+      solid_arc(c,
+		hypot(cent - start),
+		atan2(start.y - c.y, start.x - c.x),
+		atan2(end.y - c.y, end.x - c.x),
+		lt);
+      break;
+    }
+  }
+}
+
+void tex_output::circle(const position &cent, double rad,
+			const line_type &lt, double fill)
+{
+  if (fill >= 0.0 && lt.type != line_type::solid) {
+    if (fill > 1.0)
+      fill = 1.0;
+    line_type ilt;
+    ilt.type = line_type::invisible;
+    ellipse(cent, position(rad*2.0, rad*2.0), ilt, fill);
+  }
+  switch (lt.type) {
+  case line_type::dashed:
+    dashed_circle(cent, rad, lt);
+    break;
+  case line_type::invisible:
+    break;
+  case line_type::solid:
+    ellipse(cent, position(rad*2.0,rad*2.0), lt, fill);
+    break;
+  case line_type::dotted:
+    dotted_circle(cent, rad, lt);
+    break;
+  default:
+    assert(0);
+  }
+}
+
+void tex_output::ellipse(const position &cent, const distance &dim,
+			 const line_type &lt, double fill)
+{
+  if (lt.type == line_type::invisible) {
+    if (fill < 0.0)
+      return;
+  }
+  else
+    set_pen_size(lt.thickness);
+  if (fill >= 0.0) {
+    if (fill > 1.0)
+      fill = 1.0;
+    printf("    \\special{sh %.3f}%%\n", fill);
+  }
+  position c = transform(cent);
+  switch (lt.type) {
+  case line_type::solid:
+  case line_type::invisible:
+    printf("    \\special{%s %d %d %d %d 0 6.28319}%%\n",
+	   (lt.type == line_type::invisible ? "ia" : "ar"),
+	   milliinches(c.x),
+	   milliinches(c.y),
+	   milliinches(dim.x/(2.0*scale)),
+	   milliinches(dim.y/(2.0*scale)));
+    break;
+  case line_type::dashed:
+    dashed_ellipse(cent, dim / scale, lt);
+    break;
+  case line_type::dotted:
+    dotted_ellipse(cent, dim / scale, lt);
+    break;
+  default:
+    assert(0);
+  }
+}
+
+void tex_output::command(const char *s, const char *, int)
+{
+  fputs(s, stdout);
+  putchar('%');			// avoid unwanted spaces
+  putchar('\n');
+}
+
+int tex_output::supports_filled_polygons()
+{
+  return 1;
+}
+
+void tex_output::dot(const position &pos, const line_type &lt)
+{
+  if (zero_length_line_flag) {
+    line_type slt = lt;
+    slt.type = line_type::solid;
+    line(pos, &pos, 1, slt);
+  }
+  else {
+    int dot_rad = int(lt.thickness*(1000.0/(72.0*2)) + .5);
+    if (dot_rad == 0)
+      dot_rad = 1;
+    position p = transform(pos);
+    printf("    \\special{sh 1}%%\n"
+	   "    \\special{ia %d %d %d %d 0 6.28319}%%\n",
+	   milliinches(p.x), milliinches(p.y), dot_rad, dot_rad);
+  }
+}
+
+void tex_output::set_color(char *, char *)
+{
+  /* not implemented yet */
+}
+
+void tex_output::reset_color()
+{
+  /* not implemented yet */
+}
+
+char *tex_output::get_last_filled()
+{
+  /* not implemented yet */
+  return NULL;
+}
+
+char *tex_output::get_outline_color()
+{
+  /* not implemented yet */
+  return NULL;
+}
+
+class tpic_output : public tex_output {
+public:
+  tpic_output();
+  void command(const char *, const char *, int);
+private:
+  void set_pen_size(double ps);
+  int default_pen_size;
+  int prev_default_pen_size;
+};
+
+tpic_output::tpic_output()
+: default_pen_size(DEFAULT_PEN_SIZE), prev_default_pen_size(DEFAULT_PEN_SIZE)
+{
+}
+
+void tpic_output::command(const char *s, const char *filename, int lineno)
+{
+  assert(s[0] == '.');
+  if (s[1] == 'p' && s[2] == 's' && (s[3] == '\0' || !csalpha(s[3]))) {
+    const char *p = s + 3;
+    while (csspace(*p))
+      p++;
+    if (*p == '\0') {
+      int temp = default_pen_size;
+      default_pen_size = prev_default_pen_size;
+      prev_default_pen_size = temp;
+    }
+    else {
+      char *ptr;
+      int temp = (int)strtol(p, &ptr, 10);
+      if (temp == 0 && ptr == p)
+	error_with_file_and_line(filename, lineno,
+				 "argument to '.ps' not an integer");
+      else if (temp < 0)
+	error_with_file_and_line(filename, lineno,
+				 "negative pen size");
+      else {
+	prev_default_pen_size = default_pen_size;
+	default_pen_size = temp;
+      }
+    }
+  }
+  else
+    printf("\\%s%%\n", s + 1);
+}
+
+void tpic_output::set_pen_size(double ps)
+{
+  if (ps < 0.0)
+    printf("    \\special{pn %d}%%\n", default_pen_size);
+  else
+    tex_output::set_pen_size(ps);
+}
+
+output *make_tpic_output()
+{
+  return new tpic_output;
+}
+ 
+#endif
diff --git a/src/preproc/pic/text.h b/src/preproc/pic/text.h
new file mode 100644
index 0000000..9b9353f
--- /dev/null
+++ b/src/preproc/pic/text.h
@@ -0,0 +1,46 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+
+enum hadjustment {
+  CENTER_ADJUST,
+  LEFT_ADJUST,
+  RIGHT_ADJUST
+  };
+
+enum vadjustment {
+  NONE_ADJUST,
+  ABOVE_ADJUST,
+  BELOW_ADJUST
+  };
+
+struct adjustment {
+  hadjustment h;
+  vadjustment v;
+};
+
+struct text_piece {
+  char *text;
+  adjustment adj;
+  const char *filename;
+  int lineno;
+
+  text_piece();
+  ~text_piece();
+};
diff --git a/src/preproc/pic/troff.cpp b/src/preproc/pic/troff.cpp
new file mode 100644
index 0000000..3dc87a7
--- /dev/null
+++ b/src/preproc/pic/troff.cpp
@@ -0,0 +1,579 @@
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "pic.h"
+#include "common.h"
+
+
+const double RELATIVE_THICKNESS = -1.0;
+const double BAD_THICKNESS = -2.0;
+
+class simple_output : public common_output {
+  virtual void simple_line(const position &, const position &) = 0;
+  virtual void simple_spline(const position &, const position *, int n) = 0;
+  virtual void simple_arc(const position &, const position &,
+			  const position &) = 0;
+  virtual void simple_circle(int, const position &, double rad) = 0;
+  virtual void simple_ellipse(int, const position &, const distance &) = 0;
+  virtual void simple_polygon(int, const position *, int) = 0;
+  virtual void line_thickness(double) = 0;
+  virtual void set_fill(double) = 0;
+  virtual void set_color(char *, char *) = 0;
+  virtual void reset_color() = 0;
+  virtual char *get_last_filled() = 0;
+  void dot(const position &, const line_type &) = 0;
+public:
+  void start_picture(double sc, const position &ll, const position &ur) = 0;
+  void finish_picture() = 0;
+  void text(const position &, text_piece *, int, double) = 0;
+  void line(const position &, const position *, int n,
+	    const line_type &);
+  void polygon(const position *, int n,
+	       const line_type &, double);
+  void spline(const position &, const position *, int n,
+	      const line_type &);
+  void arc(const position &, const position &, const position &,
+	   const line_type &);
+  void circle(const position &, double rad, const line_type &, double);
+  void ellipse(const position &, const distance &, const line_type &, double);
+  int supports_filled_polygons();
+};
+
+int simple_output::supports_filled_polygons()
+{
+  return driver_extension_flag != 0;
+}
+
+void simple_output::arc(const position &start, const position &cent,
+			const position &end, const line_type &lt)
+{
+  switch (lt.type) {
+  case line_type::solid:
+    line_thickness(lt.thickness);
+    simple_arc(start, cent, end);
+    break;
+  case line_type::invisible:
+    break;
+  case line_type::dashed:
+    dashed_arc(start, cent, end, lt);
+    break;
+  case line_type::dotted:
+    dotted_arc(start, cent, end, lt);
+    break;
+  }
+}
+
+void simple_output::line(const position &start, const position *v, int n,
+			 const line_type &lt)
+{
+  position pos = start;
+  line_thickness(lt.thickness);
+  for (int i = 0; i < n; i++) {
+    switch (lt.type) {
+    case line_type::solid:
+      simple_line(pos, v[i]);
+      break;
+    case line_type::dotted:
+      {
+	distance vec(v[i] - pos);
+	double dist = hypot(vec);
+	int ndots = int(dist/lt.dash_width + .5);
+	if (ndots == 0)
+	  dot(pos, lt);
+	else {
+	  vec /= double(ndots);
+	  for (int j = 0; j <= ndots; j++)
+	    dot(pos + vec*j, lt);
+	}
+      }
+      break;
+    case line_type::dashed:
+      {
+	distance vec(v[i] - pos);
+	double dist = hypot(vec);
+	if (dist <= lt.dash_width*2.0)
+	  simple_line(pos, v[i]);
+	else {
+	  int ndashes = int((dist - lt.dash_width)/(lt.dash_width*2.0) + .5);
+	  distance dash_vec = vec*(lt.dash_width/dist);
+	  double dash_gap = (dist - lt.dash_width)/ndashes;
+	  distance dash_gap_vec = vec*(dash_gap/dist);
+	  for (int j = 0; j <= ndashes; j++) {
+	    position s(pos + dash_gap_vec*j);
+	    simple_line(s, s + dash_vec);
+	  }
+	}
+      }
+      break;
+    case line_type::invisible:
+      break;
+    default:
+      assert(0);
+    }
+    pos = v[i];
+  }
+}
+
+void simple_output::spline(const position &start, const position *v, int n,
+			   const line_type &lt)
+{
+  line_thickness(lt.thickness);
+  simple_spline(start, v, n);
+}
+
+void simple_output::polygon(const position *v, int n,
+			    const line_type &lt, double fill)
+{
+  if (driver_extension_flag && ((fill >= 0.0) || (get_last_filled() != 0))) {
+    if (get_last_filled() == 0)
+      set_fill(fill);
+    simple_polygon(1, v, n);
+  }
+  if (lt.type == line_type::solid && driver_extension_flag) {
+    line_thickness(lt.thickness);
+    simple_polygon(0, v, n);
+  }
+  else if (lt.type != line_type::invisible) {
+    line_thickness(lt.thickness);
+    line(v[n - 1], v, n, lt);
+  }
+}
+
+void simple_output::circle(const position &cent, double rad,
+			   const line_type &lt, double fill)
+{
+  if (driver_extension_flag && ((fill >= 0.0) || (get_last_filled() != 0))) {
+    if (get_last_filled() == 0)
+      set_fill(fill);
+    simple_circle(1, cent, rad);
+  }
+  line_thickness(lt.thickness);
+  switch (lt.type) {
+  case line_type::invisible:
+    break;
+  case line_type::dashed:
+    dashed_circle(cent, rad, lt);
+    break;
+  case line_type::dotted:
+    dotted_circle(cent, rad, lt);
+    break;
+  case line_type::solid:
+    simple_circle(0, cent, rad);
+    break;
+  default:
+    assert(0);
+  }
+}
+
+void simple_output::ellipse(const position &cent, const distance &dim,
+			    const line_type &lt, double fill)
+{
+  if (driver_extension_flag && ((fill >= 0.0) || (get_last_filled() != 0))) {
+    if (get_last_filled() == 0)
+      set_fill(fill);
+    simple_ellipse(1, cent, dim);
+  }
+  if (lt.type != line_type::invisible)
+    line_thickness(lt.thickness);
+  switch (lt.type) {
+  case line_type::invisible:
+    break;
+  case line_type::dotted:
+    dotted_ellipse(cent, dim, lt);
+    break;
+  case line_type::dashed:
+    dashed_ellipse(cent, dim, lt);
+    break;
+  case line_type::solid:
+    simple_ellipse(0, cent, dim);
+    break;
+  default:
+    assert(0);
+  }
+}
+
+class troff_output : public simple_output {
+  const char *last_filename;
+  position upper_left;
+  double height;
+  double scale;
+  double last_line_thickness;
+  double last_fill;
+  char *last_filled;		// color
+  char *last_outlined;		// color
+public:
+  troff_output();
+  ~troff_output();
+  void start_picture(double, const position &ll, const position &ur);
+  void finish_picture();
+  void text(const position &, text_piece *, int, double);
+  void dot(const position &, const line_type &);
+  void command(const char *, const char *, int);
+  void set_location(const char *, int);
+  void simple_line(const position &, const position &);
+  void simple_spline(const position &, const position *, int n);
+  void simple_arc(const position &, const position &, const position &);
+  void simple_circle(int, const position &, double rad);
+  void simple_ellipse(int, const position &, const distance &);
+  void simple_polygon(int, const position *, int);
+  void line_thickness(double p);
+  void set_fill(double);
+  void set_color(char *, char *);
+  void reset_color();
+  char *get_last_filled();
+  char *get_outline_color();
+  position transform(const position &);
+};
+
+output *make_troff_output()
+{
+  return new troff_output;
+}
+
+troff_output::troff_output()
+: last_filename(0), last_line_thickness(BAD_THICKNESS),
+  last_fill(-1.0), last_filled(0), last_outlined(0)
+{
+}
+
+troff_output::~troff_output()
+{
+  free((char *)last_filename);
+}
+
+inline position troff_output::transform(const position &pos)
+{
+  return position((pos.x - upper_left.x)/scale,
+		  (upper_left.y - pos.y)/scale);
+}
+
+#define FILL_REG "00"
+
+// If this register > 0, then pic will generate \X'ps: ...' commands
+// if the aligned attribute is used.
+#define GROPS_REG "0p"
+
+// If this register is defined, geqn won't produce '\x's.
+#define EQN_NO_EXTRA_SPACE_REG "0x"
+
+void troff_output::start_picture(double sc,
+				 const position &ll, const position &ur)
+{
+  upper_left.x = ll.x;
+  upper_left.y = ur.y;
+  scale = compute_scale(sc, ll, ur);
+  height = (ur.y - ll.y)/scale;
+  double width = (ur.x - ll.x)/scale;
+  printf(".PS %.3fi %.3fi", height, width);
+  if (args)
+    printf(" %s\n", args);
+  else
+    putchar('\n');
+  printf(".\\\" %g %g %g %g\n", ll.x, ll.y, ur.x, ur.y);
+  printf(".\\\" %.3fi %.3fi %.3fi %.3fi\n", 0.0, height, width, 0.0);
+  printf(".nr " FILL_REG " \\n(.u\n.nf\n");
+  printf(".nr " EQN_NO_EXTRA_SPACE_REG " 1\n");
+  // This guarantees that if the picture is used in a diversion it will
+  // have the right width.
+  printf("\\h'%.3fi'\n.sp -1\n", width);
+}
+
+void troff_output::finish_picture()
+{
+  line_thickness(BAD_THICKNESS);
+  last_fill = -1.0;		// force it to be reset for each picture
+  reset_color();
+  if (!(want_flyback || want_alternate_flyback))
+    printf(".sp %.3fi+1\n", height);
+  printf(".if \\n(" FILL_REG " .fi\n");
+  printf(".br\n");
+  printf(".nr " EQN_NO_EXTRA_SPACE_REG " 0\n");
+  // this is a little gross
+  set_location(current_filename, current_lineno);
+  if (want_flyback)
+    fputs(".PF\n", stdout);
+  else if (want_alternate_flyback)
+    fputs(".PY\n", stdout);
+  else
+    fputs(".PE\n", stdout);
+}
+
+void troff_output::command(const char *s,
+			   const char *filename, int lineno)
+{
+  if (filename != 0)
+    set_location(filename, lineno);
+  fputs(s, stdout);
+  putchar('\n');
+}
+
+void troff_output::simple_circle(int filled, const position &cent, double rad)
+{
+  position c = transform(cent);
+  printf("\\h'%.3fi'"
+	 "\\v'%.3fi'"
+	 "\\D'%c %.3fi'"
+	 "\n.sp -1\n",
+	 c.x - rad/scale,
+	 c.y,
+	 (filled ? 'C' : 'c'),
+	 rad*2.0/scale);
+}
+
+void troff_output::simple_ellipse(int filled, const position &cent,
+				  const distance &dim)
+{
+  position c = transform(cent);
+  printf("\\h'%.3fi'"
+	 "\\v'%.3fi'"
+	 "\\D'%c %.3fi %.3fi'"
+	 "\n.sp -1\n",
+	 c.x - dim.x/(2.0*scale),
+	 c.y,
+	 (filled ? 'E' : 'e'),
+	 dim.x/scale, dim.y/scale);
+}
+
+void troff_output::simple_arc(const position &start, const distance &cent,
+			      const distance &end)
+{
+  position s = transform(start);
+  position c = transform(cent);
+  distance cv = c - s;
+  distance ev = transform(end) - c;
+  printf("\\h'%.3fi'"
+	 "\\v'%.3fi'"
+	 "\\D'a %.3fi %.3fi %.3fi %.3fi'"
+	 "\n.sp -1\n",
+	 s.x, s.y, cv.x, cv.y, ev.x, ev.y);
+}
+
+void troff_output::simple_line(const position &start, const position &end)
+{
+  position s = transform(start);
+  distance ev = transform(end) - s;
+  printf("\\h'%.3fi'"
+	 "\\v'%.3fi'"
+	 "\\D'l %.3fi %.3fi'"
+	 "\n.sp -1\n",
+	 s.x, s.y, ev.x, ev.y);
+}
+
+void troff_output::simple_spline(const position &start,
+				 const position *v, int n)
+{
+  position pos = transform(start);
+  printf("\\h'%.3fi'"
+	 "\\v'%.3fi'",
+	 pos.x, pos.y);
+  fputs("\\D'~ ", stdout);
+  for (int i = 0; i < n; i++) {
+    position temp = transform(v[i]);
+    distance d = temp - pos;
+    pos = temp;
+    if (i != 0)
+      putchar(' ');
+    printf("%.3fi %.3fi", d.x, d.y);
+  }
+  printf("'\n.sp -1\n");
+}
+
+// a solid polygon
+
+void troff_output::simple_polygon(int filled, const position *v, int n)
+{
+  position pos = transform(v[0]);
+  printf("\\h'%.3fi'"
+	 "\\v'%.3fi'",
+	 pos.x, pos.y);
+  printf("\\D'%c ", (filled ? 'P' : 'p'));
+  for (int i = 1; i < n; i++) {
+    position temp = transform(v[i]);
+    distance d = temp - pos;
+    pos = temp;
+    if (i != 1)
+      putchar(' ');
+    printf("%.3fi %.3fi", d.x, d.y);
+  }
+  printf("'\n.sp -1\n");
+}
+
+const double TEXT_AXIS = 0.22;	// in ems
+
+static const char *choose_delimiter(const char *text)
+{
+  if (strchr(text, '\'') == 0)
+    return "'";
+  else
+    return "\\(ts";
+}
+
+void troff_output::text(const position &center, text_piece *v, int n,
+			double ang)
+{
+  line_thickness(BAD_THICKNESS); // text might use lines (e.g., in equations)
+  int rotate_flag = 0;
+  if (driver_extension_flag && ang != 0.0) {
+    rotate_flag = 1;
+    position c = transform(center);
+    printf(".if \\n(" GROPS_REG " \\{\\\n"
+	   "\\h'%.3fi'"
+	   "\\v'%.3fi'"
+	   "\\X'ps: exec gsave currentpoint 2 copy translate %.4f rotate neg exch neg exch translate'"
+	   "\n.sp -1\n"
+	   ".\\}\n",
+	   c.x, c.y, -ang*180.0/M_PI);
+  }
+  for (int i = 0; i < n; i++)
+    if (v[i].text != 0 && *v[i].text != '\0') {
+      position c = transform(center);
+      if (v[i].filename != 0)
+	set_location(v[i].filename, v[i].lineno);
+      printf("\\h'%.3fi", c.x);
+      const char *delim = choose_delimiter(v[i].text);
+      if (v[i].adj.h == RIGHT_ADJUST)
+	printf("-\\w%s%s%su", delim, v[i].text, delim);
+      else if (v[i].adj.h != LEFT_ADJUST)
+	printf("-(\\w%s%s%su/2u)", delim, v[i].text, delim);
+      putchar('\'');
+      printf("\\v'%.3fi-(%dv/2u)+%dv+%.2fm",
+	     c.y,
+	     n - 1,
+	     i,
+	     TEXT_AXIS);
+      if (v[i].adj.v == ABOVE_ADJUST)
+	printf("-.5v");
+      else if (v[i].adj.v == BELOW_ADJUST)
+	printf("+.5v");
+      putchar('\'');
+      fputs(v[i].text, stdout);
+      fputs("\n.sp -1\n", stdout);
+    }
+  if (rotate_flag)
+    printf(".if \\n(" GROPS_REG " \\{\\\n"
+	   "\\X'ps: exec grestore'\n.sp -1\n"
+	   ".\\}\n");
+}
+
+void troff_output::line_thickness(double p)
+{
+  if (p < 0.0)
+    p = RELATIVE_THICKNESS;
+  if (driver_extension_flag && p != last_line_thickness) {
+    printf("\\D't %.3fp'\\h'%.3fp'\n.sp -1\n", p, -p);
+    last_line_thickness = p;
+  }
+}
+
+void troff_output::set_fill(double f)
+{
+  if (driver_extension_flag && f != last_fill) {
+    // \D'Fg ...' emits a node only in compatibility mode,
+    // thus we add a dummy node
+    printf("\\&\\D'Fg %.3f'\n.sp -1\n", 1.0 - f);
+    last_fill = f;
+  }
+  if (last_filled) {
+    free(last_filled);
+    last_filled = 0;
+    printf(".fcolor\n");
+  }
+}
+
+void troff_output::set_color(char *color_fill, char *color_outlined)
+{
+  if (driver_extension_flag) {
+    if (last_filled || last_outlined) {
+      reset_color();
+    }
+    // .gcolor and .fcolor emit a node in compatibility mode only,
+    // but that won't work anyway
+    if (color_fill) {
+      printf(".fcolor %s\n", color_fill);
+      last_filled = strsave(color_fill);
+    }
+    if (color_outlined) {
+      printf(".gcolor %s\n", color_outlined);
+      last_outlined = strsave(color_outlined);
+    }
+  }
+}
+
+void troff_output::reset_color()
+{
+  if (driver_extension_flag) {
+    if (last_filled) {
+      printf(".fcolor\n");
+      free(last_filled);
+      last_filled = 0;
+    }
+    if (last_outlined) {
+      printf(".gcolor\n");
+      free(last_outlined);
+      last_outlined = 0;
+    }
+  }
+}
+
+char *troff_output::get_last_filled()
+{
+  return last_filled;
+}
+
+char *troff_output::get_outline_color()
+{
+  return last_outlined;
+}
+
+const double DOT_AXIS = .044;
+
+void troff_output::dot(const position &cent, const line_type &lt)
+{
+  if (driver_extension_flag) {
+    line_thickness(lt.thickness);
+    simple_line(cent, cent);
+  }
+  else {
+    position c = transform(cent);
+    printf("\\h'%.3fi-(\\w'.'u/2u)'"
+	   "\\v'%.3fi+%.2fm'"
+	   ".\n.sp -1\n",
+	   c.x,
+	   c.y, 
+	   DOT_AXIS);
+  }
+}
+
+void troff_output::set_location(const char *s, int n)
+{
+  if (last_filename != 0 && strcmp(s, last_filename) == 0)
+    printf(".lf %d\n", n);
+  else {
+    printf(".lf %d %s\n", n, s);
+    char *lfn = strdup(s);
+    if (0 == lfn)
+      fatal("memory allocation failure while copying file name");
+    last_filename = lfn;
+  }
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/preconv/preconv.1.man b/src/preproc/preconv/preconv.1.man
new file mode 100644
index 0000000..1535bae
--- /dev/null
+++ b/src/preproc/preconv/preconv.1.man
@@ -0,0 +1,559 @@
+.TH preconv @MAN1EXT@ "@MDATE@" "groff @VERSION@"
+.SH Name
+preconv \- prepare files for typesetting with
+.I groff
+.
+.
+.\" ====================================================================
+.\" Legal Terms
+.\" ====================================================================
+.\"
+.\" Copyright (C) 2006-2020 Free Software Foundation, Inc.
+.\"
+.\" Permission is granted to make and distribute verbatim copies of this
+.\" manual provided the copyright notice and this permission notice are
+.\" preserved on all copies.
+.\"
+.\" Permission is granted to copy and distribute modified versions of
+.\" this manual under the conditions for verbatim copying, provided that
+.\" the entire resulting derived work is distributed under the terms of
+.\" a permission notice identical to this one.
+.\"
+.\" Permission is granted to copy and distribute translations of this
+.\" manual into another language, under the above conditions for
+.\" modified versions, except that this permission notice may be
+.\" included in translations approved by the Free Software Foundation
+.\" instead of in the original English.
+.
+.
+.\" Save and disable compatibility mode (for, e.g., Solaris 10/11).
+.do nr *groff_preconv_1_man_C \n[.cp]
+.cp 0
+.
+.\" Define fallback for groff 1.23's MR macro if the system lacks it.
+.nr do-fallback 0
+.if !\n(.f           .nr do-fallback 1 \" mandoc
+.if  \n(.g .if !d MR .nr do-fallback 1 \" older groff
+.if !\n(.g           .nr do-fallback 1 \" non-groff *roff
+.if \n[do-fallback]  \{\
+.  de MR
+.    ie \\n(.$=1 \
+.      I \%\\$1
+.    el \
+.      IR \%\\$1 (\\$2)\\$3
+.  .
+.\}
+.rr do-fallback
+.
+.
+.\" ====================================================================
+.SH Synopsis
+.\" ====================================================================
+.
+.SY preconv
+.RB [ \-dr ]
+.RB [ \-D\~\c
+.IR fallback-encoding ]
+.RB [ \-e\~\c
+.IR encoding ]
+.RI [ file\~ .\|.\|.]
+.YS
+.
+.
+.SY preconv
+.B \-h
+.
+.SY preconv
+.B \-\-help
+.YS
+.
+.
+.SY preconv
+.B \-v
+.
+.SY preconv
+.B \-\-version
+.YS
+.
+.
+.\" ====================================================================
+.SH Description
+.\" ====================================================================
+.
+.I preconv
+reads each
+.IR file ,
+converts its encoded characters to a form
+.MR @g@troff @MAN1EXT@
+can interpret,
+and sends the result to the standard output stream.
+.
+Currently,
+this means that code points in the range 0\[en]127
+(in US-ASCII,
+ISO\~8859,
+or Unicode)
+remain as-is and the remainder are converted to the
+.I groff
+special character form
+.RB \[lq] \[rs][\c
+.BI u XXXX ]\c
+\[rq],
+where
+.I XXXX
+is a hexadecimal number of four to six digits corresponding to a Unicode
+code point.
+.
+By default,
+.I preconv
+also inserts a
+.I roff
+.B .lf
+request at the beginning of each
+.IR file ,
+identifying it for the benefit of later processing
+(including diagnostic messages);
+the
+.B \-r
+option suppresses this behavior.
+.
+.
+.PP
+In typical usage scenarios,
+.I preconv
+need not be run directly;
+instead it should be invoked with the
+.B \-k
+or
+.B \-K
+options of
+.IR groff .
+.
+If no
+.I file
+operands are given on the command line,
+or if
+.I file
+is
+.RB \[lq] \- \[rq],
+the standard input stream is read.
+.
+.
+.PP
+.I preconv
+tries to find the input encoding with the following algorithm,
+stopping at the first success.
+.
+.
+.IP 1. 4n
+If the input encoding has been explicitly specified with option
+.BR \-e ,
+use it.
+.
+.
+.IP 2.
+If the input starts with a Unicode Byte Order Mark,
+determine the encoding as UTF-8,
+UTF-16,
+or UTF-32 accordingly.
+.
+.
+.IP 3.
+If the input stream is seekable,
+check the first and second input lines for a recognized GNU\~Emacs
+file-local variable identifying the character encoding,
+here referred to as the \[lq]coding tag\[rq] for brevity.
+.
+If found,
+use it.
+.
+.
+.IP 4.
+If the input stream is seekable,
+and if the
+.I uchardet
+library is available on the system,
+use it to try to infer the encoding of the file.
+.
+.
+.IP 5.
+If the
+.B \-D
+option specifies an encoding,
+use it.
+.
+.
+.IP 6.
+Use the encoding specified by the current locale
+.RI ( LC_CTYPE ),
+unless the locale is
+\[lq]C\[rq],
+\[lq]POSIX\[rq],
+or empty,
+in which case assume Latin-1
+(ISO\~8859-1).
+.
+.
+.PP
+The coding tag and
+.I uchardet
+methods in the above procedure rely upon a seekable input stream;
+when
+.I preconv
+reads from a pipe,
+the stream is not seekable,
+and these detection methods are skipped.
+.
+If character encoding detection of your input files is unreliable,
+arrange for one of the other methods to succeed by using
+.IR preconv 's
+.B \-D
+or
+.B \-e
+options,
+or by configuring your locale appropriately.
+.
+.I groff
+also supports a
+.I \%GROFF_ENCODING
+environment variable,
+which can be overridden by its
+.B \-K
+option.
+.
+Valid values for
+(or parameters to)
+all of these are enumerated in the lists of recognized coding tags in
+the next subsection,
+and are further influenced by
+.I iconv
+library support.
+.
+.
+.\" ====================================================================
+.SS "Coding tags"
+.\" ====================================================================
+.
+Text editors that support more than a single character encoding need
+tags within the input files to mark the file's encoding.
+.
+While it is possible to guess the right input encoding with the help of
+heuristics that are reliable for a preponderance of natural language
+texts,
+they are not absolutely reliable.
+.
+Heuristics can fail on inputs that are too short or don't represent a
+natural language.
+.
+.
+.PP
+Consequently,
+.I preconv
+supports the coding tag convention used by GNU\~Emacs
+(with some restrictions).
+.
+This notation appears in specially marked regions of an input file
+designated for \[lq]file-local variables\[rq].
+.
+.
+.PP
+.I preconv
+interprets the following syntax if it occurs in a
+.I roff
+comment
+in the first or second line of the input file.
+.
+Both \[lq]\[rs]"\[rq] and \[lq]\[rs]#\[rq] comment forms are recognized,
+but the control
+(or no-break control)
+character must be the default and must begin the line.
+.
+Similarly,
+the escape character must be the default.
+.
+.
+.RS
+.EX
+.B \-*\- \c
+.RB [.\|.\|. ; ]\~\c
+.B coding: \c
+.I encoding\c
+.RB [ ;\~ .\|.\|.\&]\~\c
+.B \-*\-
+.EE
+.RE
+.
+.
+.PP
+The only variable
+.I preconv
+interprets is \[lq]coding\[rq],
+which can take the values listed below.
+.
+.
+.PP
+The following list comprises all MIME \[lq]charset\[rq] parameter values
+recognized,
+case-insensitively,
+by
+.IR preconv .
+.
+.RS
+\%big5,
+\%cp1047,
+\%euc\-jp,
+\%euc\-kr,
+\%gb2312,
+\%iso\-8859\-1,
+\%iso\-8859\-2,
+\%iso\-8859\-5,
+\%iso\-8859\-7,
+\%iso\-8859\-9,
+\%iso\-8859\-13,
+\%iso\-8859\-15,
+\%koi8\-r,
+\%us\-ascii,
+\%utf\-8,
+\%utf\-16,
+\%utf\-16be,
+\%utf\-16le
+.RE
+.
+.
+.PP
+In addition,
+the following list of other coding tags is recognized,
+each of which is mapped to an appropriate value from the list above.
+.
+.RS
+\%ascii,
+\%chinese\-big5,
+\%chinese\-euc,
+\%chinese\-iso\-8bit,
+\%cn\-big5,
+\%cn\-gb,
+\%cn\-gb\-2312,
+\%cp878,
+\%csascii,
+\%csisolatin1,
+\%cyrillic\-iso\-8bit,
+\%cyrillic\-koi8,
+\%euc\-china,
+\%euc\-cn,
+\%euc\-japan,
+\%euc\-japan\-1990,
+\%euc\-korea,
+\%greek\-iso\-8bit,
+\%iso\-10646/utf8,
+\%iso\-10646/utf\-8,
+\%iso\-latin\-1,
+\%iso\-latin\-2,
+\%iso\-latin\-5,
+\%iso\-latin\-7,
+\%iso\-latin\-9,
+\%japanese\-euc,
+\%japanese\-iso\-8bit,
+\%jis8,
+\%koi8,
+\%korean\-euc,
+\%korean\-iso\-8bit,
+\%latin\-0,
+\%latin1,
+\%latin\-1,
+\%latin\-2,
+\%latin\-5,
+\%latin\-7,
+\%latin\-9,
+\%mule\-utf\-8,
+\%mule\-utf\-16,
+\%mule\-utf\-16be,
+\%mule\-utf\-16\-be,
+\%mule\-utf\-16be\-with\-signature,
+\%mule\-utf\-16le,
+\%mule\-utf\-16\-le,
+\%mule\-utf\-16le\-with\-signature,
+\%utf8,
+\%utf\-16\-be,
+\%utf\-16\-be\-with\-signature,
+\%utf\-16be\-with\-signature,
+\%utf\-16\-le,
+\%utf\-16\-le\-with\-signature,
+\%utf\-16le\-with\-signature
+.RE
+.
+.
+.PP
+Trailing
+\[lq]\-dos\[rq],
+\[lq]\-unix\[rq],
+and
+\[lq]\-mac\[rq]
+suffixes on coding tags
+(which indicate the end-of-line convention used in the file)
+are disregarded for the purpose of comparison with the above tags.
+.
+.
+.\" ====================================================================
+.SS "\f[I]iconv\f[] support"
+.\" ====================================================================
+.
+While
+.I preconv
+recognizes all of the coding tags listed above,
+it is capable on its own of interpreting only three encodings:
+Latin-1,
+code page 1047,
+and UTF-8.
+.
+If
+.I iconv
+support is configured at compile time and available at run time,
+all others are passed to
+.I iconv
+library functions,
+which may recognize many additional encoding strings.
+.
+The command
+.RB \[lq] preconv\~\-v \[rq]
+discloses whether
+.I iconv
+support is configured.
+.
+.
+.PP
+The use of
+.I iconv
+means that characters in the input that encode invalid code points for
+that encoding may be dropped from the output stream or mapped to the
+Unicode replacement character
+(U+FFFD).
+.
+Compare the following examples using the input \[lq]caf\['e]\[rq]
+(note the \[lq]e\[rq] with an acute accent),
+which due to its short length challenges inference of the encoding used.
+.
+.RS
+.EX
+printf \[aq]caf\[rs]351\[rs]n\[aq] | LC_ALL=en_US.UTF\-8 preconv
+printf \[aq]caf\[rs]351\[rs]n\[aq] | preconv \-e us\-ascii
+printf \[aq]caf\[rs]351\[rs]n\[aq] | preconv \-e latin\-1
+.EE
+.RE
+.
+The fate of the accented \[lq]e\[rq] differs in each case.
+.
+In the first,
+.I uchardet
+fails to detect an encoding
+(though the library on your system may behave differently)
+and
+.I preconv
+falls back to the locale settings,
+where octal 351 starts an incomplete UTF-8 sequence and results in the
+Unicode replacement character.
+.
+In the second,
+it is not a representable character in the declared input encoding of
+US-ASCII and is discarded by
+.IR iconv .
+.
+In the last,
+it is correctly detected and mapped.
+.
+.
+.\" ====================================================================
+.SS Limitations
+.\" ====================================================================
+.
+.I preconv
+cannot perform any transformation on input that it cannot see.
+.
+Examples include files that are interpolated by preprocessors that run
+subsequently,
+including
+.MR @g@soelim @MAN1EXT@ ;
+files included by
+.I @g@troff
+itself through
+.RB \[lq] so \[rq]
+and similar requests;
+and string definitions passed to
+.I @g@troff
+through its
+.B \-d
+command-line option.
+.
+.
+.P
+.I preconv
+assumes that its input uses the default escape character,
+a backslash
+.BR \[rs] ,
+and writes special character escape sequences accordingly.
+.
+.
+.\" ====================================================================
+.SH Options
+.\" ====================================================================
+.
+.B \-h
+and
+.B \-\-help
+display a usage message,
+while
+.B \-v
+and
+.B \-\-version
+show version information;
+all exit afterward.
+.
+.
+.TP
+.B \-d
+Emit debugging messages to the standard error stream.
+.
+.
+.TP
+.BI \-D\~ fallback-encoding
+Report
+.I fallback-encoding
+if all detection methods fail.
+.
+.
+.TP
+.BI \-e\~ encoding
+Skip detection and assume
+.IR encoding ;
+see
+.IR groff 's
+.B \-K
+option.
+.
+.
+.TP
+.B \-r
+Write files \[lq]raw\[rq];
+do not add
+.B .lf
+requests.
+.
+.
+.\" ====================================================================
+.SH "See also"
+.\" ====================================================================
+.
+.MR groff @MAN1EXT@ ,
+.MR iconv 3 ,
+.MR locale 7
+.
+.
+.\" Restore compatibility mode (for, e.g., Solaris 10/11).
+.cp \n[*groff_preconv_1_man_C]
+.do rr *groff_preconv_1_man_C
+.
+.
+.\" Local Variables:
+.\" fill-column: 72
+.\" mode: nroff
+.\" End:
+.\" vim: set filetype=groff textwidth=72:
diff --git a/src/preproc/preconv/preconv.am b/src/preproc/preconv/preconv.am
new file mode 100644
index 0000000..199ff66
--- /dev/null
+++ b/src/preproc/preconv/preconv.am
@@ -0,0 +1,37 @@
+# Copyright (C) 2014-2020 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+bin_PROGRAMS += preconv
+preconv_LDADD = libgroff.a $(LIBM) $(LIBICONV) $(UCHARDET_LIBS) \
+  lib/libgnu.a
+preconv_SOURCES = src/preproc/preconv/preconv.cpp
+preconv_CPPFLAGS = $(AM_CPPFLAGS) $(UCHARDET_CFLAGS)
+man1_MANS += src/preproc/preconv/preconv.1
+EXTRA_DIST += src/preproc/preconv/preconv.1.man
+
+preconv_TESTS = \
+  src/preproc/preconv/tests/do-not-seek-the-unseekable.sh \
+  src/preproc/preconv/tests/smoke-test.sh
+TESTS += $(preconv_TESTS)
+EXTRA_DIST += $(preconv_TESTS)
+
+
+# Local Variables:
+# fill-column: 72
+# mode: makefile-automake
+# End:
+# vim: set autoindent filetype=automake textwidth=72:
diff --git a/src/preproc/preconv/preconv.cpp b/src/preproc/preconv/preconv.cpp
new file mode 100644
index 0000000..d403425
--- /dev/null
+++ b/src/preproc/preconv/preconv.cpp
@@ -0,0 +1,1318 @@
+/* Copyright (C) 2005-2020 Free Software Foundation, Inc.
+     Written by Werner Lemberg (wl@gnu.org)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "lib.h"
+
+#include <assert.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/stat.h>
+#ifdef HAVE_UCHARDET
+#include <uchardet/uchardet.h>
+#endif
+
+#include "errarg.h"
+#include "error.h"
+#include "localcharset.h"
+#include "nonposix.h"
+#include "stringclass.h"
+#include "lf.h"
+
+#include <locale.h>
+
+#if HAVE_ICONV
+# include <iconv.h>
+# ifdef WORDS_BIGENDIAN
+#  define UNICODE "UTF-32BE"
+# else
+#  define UNICODE "UTF-32LE"
+# endif
+#endif
+
+#define MAX_VAR_LEN 100
+
+extern "C" const char *Version_string;
+
+char fallback_encoding[MAX_VAR_LEN];
+char user_encoding[MAX_VAR_LEN];
+char encoding_string[MAX_VAR_LEN];
+bool is_debugging = false;
+int raw_flag = 0;
+
+struct conversion {
+  const char *from;
+  const char *to;
+};
+
+// The official list of MIME tags can be found at
+//
+//   http://www.iana.org/assignments/character-sets
+//
+// For encodings which don't have a MIME tag we use GNU iconv's encoding
+// names (which also work with the portable GNU libiconv package).  They
+// are marked with '*'.
+//
+// Encodings specific to XEmacs and Emacs are marked as such; no mark means
+// that they are used by both Emacs and XEmacs.
+//
+// Encodings marked with '--' are special to Emacs, XEmacs, or other
+// applications and shouldn't be used for data exchange.
+//
+// 'Not covered' means that the encoding can be handled neither by GNU iconv
+// nor by libiconv, or just one of them has support for it.
+//
+// A special case is VIQR encoding: Despite of having a MIME tag it is
+// missing in both libiconv 1.10 and iconv (coming with GNU libc 2.3.6).
+//
+// Finally, we add all aliases of GNU iconv for 'ascii', 'latin1', and
+// 'utf8' to catch those encoding names before iconv is called.
+//
+// Note that most entries are commented out -- only a small, (rather)
+// reliable and stable subset of encodings is recognized (for coding tags)
+// which are still in greater use today (January 2006).  Most notably, all
+// Windows-specific encodings are not selected because they lack stability:
+// Microsoft has changed the mappings instead of creating new versions.
+//
+// Please contact the groff list if you find the selection inadequate.
+
+static const conversion
+emacs_to_mime[] = {
+  {"ascii",				"US-ASCII"},	// Emacs
+  {"big5",				"Big5"},
+  {"chinese-big5",			"Big5"},	// Emacs
+  {"chinese-euc",			"GB2312"},	// XEmacs
+  {"chinese-iso-8bit",			"GB2312"},	// Emacs
+  {"cn-big5",				"Big5"},
+  {"cn-gb",				"GB2312"},	// Emacs
+  {"cn-gb-2312",			"GB2312"},
+  {"cp878",				"KOI8-R"},	// Emacs
+  {"cp1047",				"CP1047"},	// EBCDIC
+  {"csascii",				"US-ASCII"},	// alias
+  {"csisolatin1",			"ISO-8859-1"},	// alias
+  {"cyrillic-iso-8bit",			"ISO-8859-5"},	// Emacs
+  {"cyrillic-koi8",			"KOI8-R"},	// not KOI8!, Emacs
+  {"euc-china",				"GB2312"},	// Emacs
+  {"euc-cn",				"GB2312"},	// Emacs
+  {"euc-japan",				"EUC-JP"},
+  {"euc-japan-1990",			"EUC-JP"},	// Emacs
+  {"euc-jp",				"EUC-JP"},
+  {"euc-korea",				"EUC-KR"},
+  {"euc-kr",				"EUC-KR"},
+  {"gb2312",				"GB2312"},
+  {"greek-iso-8bit",			"ISO-8859-7"},
+  {"iso-10646/utf8",			"UTF-8"},	// alias
+  {"iso-10646/utf-8",			"UTF-8"},	// alias
+  {"iso-8859-1",			"ISO-8859-1"},
+  {"iso-8859-13",			"ISO-8859-13"},	// Emacs
+  {"iso-8859-15",			"ISO-8859-15"},
+  {"iso-8859-2",			"ISO-8859-2"},
+  {"iso-8859-5",			"ISO-8859-5"},
+  {"iso-8859-7",			"ISO-8859-7"},
+  {"iso-8859-9",			"ISO-8859-9"},
+  {"iso-latin-1",			"ISO-8859-1"},
+  {"iso-latin-2",			"ISO-8859-2"},	// Emacs
+  {"iso-latin-5",			"ISO-8859-9"},	// Emacs
+  {"iso-latin-7",			"ISO-8859-13"},	// Emacs
+  {"iso-latin-9",			"ISO-8859-15"},	// Emacs
+  {"japanese-iso-8bit",			"EUC-JP"},	// Emacs
+  {"japanese-euc",			"EUC-JP"},	// XEmacs
+  {"jis8",				"EUC-JP"},	// XEmacs
+  {"koi8",				"KOI8-R"},	// not KOI8!, Emacs
+  {"koi8-r",				"KOI8-R"},
+  {"korean-euc",			"EUC-KR"},	// XEmacs
+  {"korean-iso-8bit",			"EUC-KR"},	// Emacs
+  {"latin1",				"ISO-8859-1"},  // alias
+  {"latin-0",				"ISO-8859-15"},	// Emacs
+  {"latin-1",				"ISO-8859-1"},	// Emacs
+  {"latin-2",				"ISO-8859-2"},	// Emacs
+  {"latin-5",				"ISO-8859-9"},	// Emacs
+  {"latin-7",				"ISO-8859-13"},	// Emacs
+  {"latin-9",				"ISO-8859-15"},	// Emacs
+  {"mule-utf-16",			"UTF-16"},	// Emacs
+  {"mule-utf-16be",			"UTF-16BE"},	// Emacs
+  {"mule-utf-16-be",			"UTF-16BE"},	// Emacs
+  {"mule-utf-16be-with-signature",	"UTF-16"},	// Emacs, not UTF-16BE
+  {"mule-utf-16le",			"UTF-16LE"},	// Emacs
+  {"mule-utf-16-le",			"UTF-16LE"},	// Emacs
+  {"mule-utf-16le-with-signature",	"UTF-16"},	// Emacs, not UTF-16LE
+  {"mule-utf-8",			"UTF-8"},	// Emacs
+  {"us-ascii",				"US-ASCII"},	// Emacs
+  {"utf8",				"UTF-8"},	// alias
+  {"utf-16",				"UTF-16"},	// Emacs
+  {"utf-16be",				"UTF-16BE"},	// Emacs
+  {"utf-16-be",				"UTF-16BE"},	// Emacs
+  {"utf-16be-with-signature",		"UTF-16"},	// Emacs, not UTF-16BE
+  {"utf-16-be-with-signature",		"UTF-16"},	// Emacs, not UTF-16BE
+  {"utf-16le",				"UTF-16LE"},	// Emacs
+  {"utf-16-le",				"UTF-16LE"},	// Emacs
+  {"utf-16le-with-signature",		"UTF-16"},	// Emacs, not UTF-16LE
+  {"utf-16-le-with-signature",		"UTF-16"},	// Emacs, not UTF-16LE
+  {"utf-8",				"UTF-8"},	// Emacs
+
+//  {"alternativnyj",			""},		// ?
+//  {"arabic-iso-8bit",			"ISO-8859-6"},	// Emacs
+//  {"binary",				""},		// --
+//  {"chinese-hz",			"HZ-GB-2312"},	// Emacs
+//  {"chinese-iso-7bit",		"ISO-2022-CN"},	// Emacs
+//  {"chinese-iso-8bit-with-esc",	""},		// --
+//  {"compound-text",			""},		// --
+//  {"compound-text-with-extension",	""},		// --
+//  {"cp1125",				"cp1125"},	// *
+//  {"cp1250",				"windows-1250"},// Emacs
+//  {"cp1251",				"windows-1251"},// Emacs
+//  {"cp1252",				"windows-1252"},// Emacs
+//  {"cp1253",				"windows-1253"},// Emacs
+//  {"cp1254",				"windows-1254"},// Emacs
+//  {"cp1255",				"windows-1255"},// Emacs
+//  {"cp1256",				"windows-1256"},// Emacs
+//  {"cp1257",				"windows-1257"},// Emacs
+//  {"cp1258",				"windows-1258"},// Emacs
+//  {"cp437",				"cp437"},	// Emacs
+//  {"cp720",				""},		// not covered
+//  {"cp737",				"cp737"},	// *, Emacs
+//  {"cp775",				"cp775"},	// Emacs
+//  {"cp850",				"cp850"},	// Emacs
+//  {"cp851",				"cp851"},	// Emacs
+//  {"cp852",				"cp852"},	// Emacs
+//  {"cp855",				"cp855"},	// Emacs
+//  {"cp857",				"cp857"},	// Emacs
+//  {"cp860",				"cp860"},	// Emacs
+//  {"cp861",				"cp861"},	// Emacs
+//  {"cp862",				"cp862"},	// Emacs
+//  {"cp863",				"cp863"},	// Emacs
+//  {"cp864",				"cp864"},	// Emacs
+//  {"cp865",				"cp865"},	// Emacs
+//  {"cp866",				"cp866"},	// Emacs
+//  {"cp866u",				"cp1125"},	// *, Emacs
+//  {"cp869",				"cp869"},	// Emacs
+//  {"cp874",				"cp874"},	// *, Emacs
+//  {"cp932",				"cp932"},	// *, Emacs
+//  {"cp936",				"cp936"},	// Emacs
+//  {"cp949",				"cp949"},	// *, Emacs
+//  {"cp950",				"cp950"},	// *, Emacs
+//  {"ctext",				""},		// --
+//  {"ctext-no-compositions",		""},		// --
+//  {"ctext-with-extensions",		""},		// --
+//  {"cyrillic-alternativnyj",		""},		// ?, Emacs
+//  {"cyrillic-iso-8bit-with-esc",	""},		// --
+//  {"cyrillic-koi8-t",			"KOI8-T"},	// *, Emacs
+//  {"devanagari",			""},		// not covered
+//  {"dos",				""},		// --
+//  {"emacs-mule",			""},		// --
+//  {"euc-jisx0213",			"EUC-JISX0213"},// *, XEmacs?
+//  {"euc-jisx0213-with-esc",		""},		// XEmacs?
+//  {"euc-taiwan",			"EUC-TW"},	// *, Emacs
+//  {"euc-tw",				"EUC-TW"},	// *, Emacs
+//  {"georgian-ps",			"GEORGIAN-PS"},	// *, Emacs
+//  {"greek-iso-8bit-with-esc",		""},		// --
+//  {"hebrew-iso-8bit",			"ISO-8859-8"},	// Emacs
+//  {"hebrew-iso-8bit-with-esc",	""},		// --
+//  {"hz",				"HZ-GB-2312"},
+//  {"hz-gb-2312",			"HZ-GB-2312"},
+//  {"in-is13194",			""},		// not covered
+//  {"in-is13194-devanagari",		""},		// not covered
+//  {"in-is13194-with-esc",		""},		// --
+//  {"iso-2022-7",			""},		// XEmacs?
+//  {"iso-2022-7bit",			""},		// --
+//  {"iso-2022-7bit-lock",		""},		// --
+//  {"iso-2022-7bit-lock-ss2",		""},		// --
+//  {"iso-2022-7bit-ss2",		""},		// --
+//  {"iso-2022-8",			""},		// XEmacs?
+//  {"iso-2022-8bit",			""},		// XEmacs?
+//  {"iso-2022-8bit-lock",		""},		// XEmacs?
+//  {"iso-2022-8bit-lock-ss2",		""},		// XEmacs?
+//  {"iso-2022-8bit-ss2",		""},		// --
+//  {"iso-2022-cjk",			""},		// --
+//  {"iso-2022-cn",			"ISO-2022-CN"},	// Emacs
+//  {"iso-2022-cn-ext",			"ISO-2022-CN-EXT"},// Emacs
+//  {"iso-2022-int-1",			""},		// --
+//  {"iso-2022-jp",			"ISO-2022-JP"},
+//  {"iso-2022-jp-1978-irv",		"ISO-2022-JP"},
+//  {"iso-2022-jp-2",			"ISO-2022-JP-2"},
+//  {"iso-2022-jp-3",			"ISO-2022-JP-3"},// *, XEmacs?
+//  {"iso-2022-jp-3-compatible",	""},		// XEmacs?
+//  {"iso-2022-jp-3-strict",		"ISO-2022-JP-3"},// *, XEmacs?
+//  {"iso-2022-kr",			"ISO-2022-KR"},
+//  {"iso-2022-lock",			""},		// XEmacs?
+//  {"iso-8859-10",			"ISO-8859-10"},	// Emacs
+//  {"iso-8859-11",			"ISO-8859-11"},	// *, Emacs
+//  {"iso-8859-14",			"ISO-8859-14"},	// Emacs
+//  {"iso-8859-16",			"ISO-8859-16"},
+//  {"iso-8859-3",			"ISO-8859-3"},
+//  {"iso-8859-4",			"ISO-8859-4"},
+//  {"iso-8859-6",			"ISO-8859-6"},
+//  {"iso-8859-8",			"ISO-8859-8"},
+//  {"iso-8859-8-e",			"ISO-8859-8"},
+//  {"iso-8859-8-i",			"ISO-8859-8"},	// Emacs
+//  {"iso-latin-10",			"ISO-8859-16"},	// Emacs
+//  {"iso-latin-1-with-esc",		""},		// --
+//  {"iso-latin-2-with-esc",		""},		// --
+//  {"iso-latin-3",			"ISO-8859-3"},	// Emacs
+//  {"iso-latin-3-with-esc",		""},		// --
+//  {"iso-latin-4",			"ISO-8859-4"},	// Emacs
+//  {"iso-latin-4-with-esc",		""},		// --
+//  {"iso-latin-5-with-esc",		""},		// --
+//  {"iso-latin-6",			"ISO-8859-10"},	// Emacs
+//  {"iso-latin-8",			"ISO-8859-14"},	// Emacs
+//  {"iso-safe",				""},		// --
+//  {"japanese-iso-7bit-1978-irv",	"ISO-2022-JP"},	// Emacs
+//  {"japanese-iso-8bit-with-esc",	""},		// --
+//  {"japanese-shift-jis",		"Shift_JIS"},	// Emacs
+//  {"japanese-shift-jisx0213",		""},		// XEmacs?
+//  {"jis7",				"ISO-2022-JP"},	// Xemacs
+//  {"junet",				"ISO-2022-JP"},
+//  {"koi8-t",				"KOI8-T"},	// *, Emacs
+//  {"koi8-u",				"KOI8-U"},	// Emacs
+//  {"korean-iso-7bit-lock",		"ISO-2022-KR"},
+//  {"korean-iso-8bit-with-esc",	""},		// --
+//  {"lao",				""},		// not covered
+//  {"lao-with-esc",			""},		// --
+//  {"latin-10",			"ISO-8859-16"},	// Emacs
+//  {"latin-3",				"ISO-8859-3"},	// Emacs
+//  {"latin-4",				"ISO-8859-4"},	// Emacs
+//  {"latin-6",				"ISO-8859-10"},	// Emacs
+//  {"latin-8",				"ISO-8859-14"},	// Emacs
+//  {"mac",				""},		// --
+//  {"mac-roman",			"MACINTOSH"},	// Emacs
+//  {"mik",				""},		// not covered
+//  {"next",				"NEXTSTEP"},	// *, Emacs
+//  {"no-conversion",			""},		// --
+//  {"old-jis",				"ISO-2022-JP"},
+//  {"pt154",				"PT154"},	// Emacs
+//  {"raw-text",			""},		// --
+//  {"ruscii",				"cp1125"},	// *, Emacs
+//  {"shift-jis",			"Shift_JIS"},	// XEmacs
+//  {"shift_jis",			"Shift_JIS"},
+//  {"shift_jisx0213",			"Shift_JISX0213"},// *, XEmacs?
+//  {"sjis",				"Shift_JIS"},	// Emacs
+//  {"tcvn",				"TCVN"},	// *, Emacs
+//  {"tcvn-5712",			"TCVN"},	// *, Emacs
+//  {"thai-tis620",			"TIS-620"},
+//  {"thai-tis620-with-esc",		""},		// --
+//  {"th-tis620",			"TIS-620"},
+//  {"tibetan",				""},		// not covered
+//  {"tibetan-iso-8bit",		""},		// not covered
+//  {"tibetan-iso-8bit-with-esc",	""},		// --
+//  {"tis-620",				"TIS-620"},
+//  {"tis620",				"TIS-620"},
+//  {"undecided",			""},		// --
+//  {"unix",				""},		// --
+//  {"utf-7",				"UTF-7"},	// Emacs
+//  {"utf-7-safe",			""},		// XEmacs?
+//  {"utf-8-ws",			"UTF-8"},	// XEmacs?
+//  {"vietnamese-tcvn",			"TCVN"},	// *, Emacs
+//  {"vietnamese-viqr",			"VIQR"},	// not covered
+//  {"vietnamese-viscii",		"VISCII"},
+//  {"vietnamese-vscii",		""},		// not covered
+//  {"viqr",				"VIQR"},	// not covered
+//  {"viscii",				"VISCII"},
+//  {"vscii",				""},		// not covered
+//  {"windows-037",			""},		// not covered
+//  {"windows-10000",			""},		// not covered
+//  {"windows-10001",			""},		// not covered
+//  {"windows-10006",			""},		// not covered
+//  {"windows-10007",			""},		// not covered
+//  {"windows-10029",			""},		// not covered
+//  {"windows-10079",			""},		// not covered
+//  {"windows-10081",			""},		// not covered
+//  {"windows-1026",			""},		// not covered
+//  {"windows-1200",			""},		// not covered
+//  {"windows-1250",			"windows-1250"},
+//  {"windows-1251",			"windows-1251"},
+//  {"windows-1252",			"windows-1252"},
+//  {"windows-1253",			"windows-1253"},
+//  {"windows-1254",			"windows-1254"},
+//  {"windows-1255",			"windows-1255"},
+//  {"windows-1256",			"windows-1256"},
+//  {"windows-1257",			"windows-1257"},
+//  {"windows-1258",			"windows-1258"},
+//  {"windows-1361",			"cp1361"},	// *, XEmacs
+//  {"windows-437",			"cp437"},	// XEmacs
+//  {"windows-500",			""},		// not covered
+//  {"windows-708",			""},		// not covered
+//  {"windows-709",			""},		// not covered
+//  {"windows-710",			""},		// not covered
+//  {"windows-720",			""},		// not covered
+//  {"windows-737",			"cp737"},	// *, XEmacs
+//  {"windows-775",			"cp775"},	// XEmacs
+//  {"windows-850",			"cp850"},	// XEmacs
+//  {"windows-852",			"cp852"},	// XEmacs
+//  {"windows-855",			"cp855"},	// XEmacs
+//  {"windows-857",			"cp857"},	// XEmacs
+//  {"windows-860",			"cp860"},	// XEmacs
+//  {"windows-861",			"cp861"},	// XEmacs
+//  {"windows-862",			"cp862"},	// XEmacs
+//  {"windows-863",			"cp863"},	// XEmacs
+//  {"windows-864",			"cp864"},	// XEmacs
+//  {"windows-865",			"cp865"},	// XEmacs
+//  {"windows-866",			"cp866"},	// XEmacs
+//  {"windows-869",			"cp869"},	// XEmacs
+//  {"windows-874",			"cp874"},	// XEmacs
+//  {"windows-875",			""},		// not covered
+//  {"windows-932",			"cp932"},	// *, XEmacs
+//  {"windows-936",			"cp936"},	// XEmacs
+//  {"windows-949",			"cp949"},	// *, XEmacs
+//  {"windows-950",			"cp950"},	// *, XEmacs
+//  {"x-ctext",				""},		// --
+//  {"x-ctext-with-extensions",		""},		// --
+
+  {NULL,				NULL},
+};
+
+// ---------------------------------------------------------
+// Convert encoding name from emacs to mime.
+// ---------------------------------------------------------
+char *
+emacs2mime(char *emacs_enc)
+{
+  int emacs_enc_len = strlen(emacs_enc);
+  if (emacs_enc_len > 4
+      && !strcasecmp(emacs_enc + emacs_enc_len - 4, "-dos"))
+    emacs_enc[emacs_enc_len - 4] = 0;
+  if (emacs_enc_len > 4
+      && !strcasecmp(emacs_enc + emacs_enc_len - 4, "-mac"))
+    emacs_enc[emacs_enc_len - 4] = 0;
+  if (emacs_enc_len > 5
+      && !strcasecmp(emacs_enc + emacs_enc_len - 5, "-unix"))
+    emacs_enc[emacs_enc_len - 5] = 0;
+  for (const conversion *table = emacs_to_mime; table->from; table++)
+    if (!strcasecmp(emacs_enc, table->from))
+      return (char *)table->to;
+  return emacs_enc;
+}
+
+// ---------------------------------------------------------
+// Print out Unicode entity if value is greater than 0x7F.
+// ---------------------------------------------------------
+inline void
+unicode_entity(int u)
+{
+  if (u < 0x80)
+    putchar(u);
+  else {
+    // Handle no-break space and soft hyphen specially--they are input
+    // characters only, not glyphs.  See groff_char(7).
+    if (u == 0xA0) {
+      putchar('\\');
+      putchar('~');
+    }
+    else if (u == 0xAD) {
+      putchar('\\');
+      putchar('%');
+    }
+    else
+      printf("\\[u%04X]", u);
+  }
+}
+
+// ---------------------------------------------------------
+// Conversion functions.  All functions take 'data', which
+// normally holds the first two lines, and a file pointer.
+// ---------------------------------------------------------
+
+// Conversion from ISO-8859-1 (aka Latin-1) to Unicode.
+void
+conversion_latin1(FILE *fp, const string &data)
+{
+  int len = data.length();
+  const unsigned char *ptr = (const unsigned char *)data.contents();
+  for (int i = 0; i < len; i++)
+    unicode_entity(ptr[i]);
+  int c = -1;
+  while ((c = getc(fp)) != EOF)
+    unicode_entity(c);
+}
+
+// A future version of groff shall support UTF-8 natively.
+// In this case, the UTF-8 stuff here in this file will be
+// moved to the troff program.
+
+struct utf8 {
+  FILE *fp;
+  unsigned char s[6];
+  enum {
+    FIRST = 0,
+    SECOND,
+    THIRD,
+    FOURTH,
+    FIFTH,
+    SIXTH
+  } byte;
+  int expected_byte_count;
+  bool emit_invalid_utf8_warning;
+  bool emit_incomplete_utf8_warning;
+  utf8(FILE *);
+  ~utf8();
+  void add(unsigned char);
+  void invalid();
+  void incomplete();
+};
+
+utf8::utf8(FILE *f) : fp(f), byte(FIRST), expected_byte_count(1),
+		      emit_invalid_utf8_warning(true),
+		      emit_incomplete_utf8_warning(true)
+{
+  // empty
+}
+
+utf8::~utf8()
+{
+  if (byte != FIRST)
+    incomplete();
+}
+
+inline void
+utf8::add(unsigned char c)
+{
+  s[byte] = c;
+  if (byte == FIRST) {
+    if (c < 0x80)
+      unicode_entity(c);
+    else if (c < 0xC0)
+      invalid();
+    else if (c < 0xE0) {
+      expected_byte_count = 2;
+      byte = SECOND;
+    }
+    else if (c < 0xF0) {
+      expected_byte_count = 3;
+      byte = SECOND;
+    }
+    else if (c < 0xF8) {
+      expected_byte_count = 4;
+      byte = SECOND;
+    }
+    else if (c < 0xFC) {
+      expected_byte_count = 5;
+      byte = SECOND;
+    }
+    else if (c < 0xFE) {
+      expected_byte_count = 6;
+      byte = SECOND;
+    }
+    else
+      invalid();
+    return;
+  }
+  if (c < 0x80 || c > 0xBF) {
+    incomplete();
+    add(c);
+    return;
+  }
+  switch (byte) {
+  case FIRST:
+    // can't happen
+    break;
+  case SECOND:
+    if (expected_byte_count == 2) {
+      if (s[0] < 0xC2)
+	invalid();
+      else
+	unicode_entity(((s[0] & 0x1F) << 6)
+		       | (s[1] ^ 0x80));
+      byte = FIRST;
+    }
+    else
+      byte = THIRD;
+    break;
+  case THIRD:
+    if (expected_byte_count == 3) {
+      if (!(s[0] >= 0xE1 || s[1] >= 0xA0))
+	invalid();
+      else
+	unicode_entity(((s[0] & 0x1F) << 12)
+		       | ((s[1] ^ 0x80) << 6)
+		       | (s[2] ^ 0x80));
+      byte = FIRST;
+    }
+    else
+      byte = FOURTH;
+    break;
+  case FOURTH:
+    // We reject everything greater than 0x10FFFF.
+    if (expected_byte_count == 4) {
+      if (!((s[0] >= 0xF1 || s[1] >= 0x90)
+	    && (s[0] < 0xF4 || (s[0] == 0xF4 && s[1] < 0x90))))
+	invalid();
+      else
+	unicode_entity(((s[0] & 0x07) << 18)
+		       | ((s[1] ^ 0x80) << 12)
+		       | ((s[2] ^ 0x80) << 6)
+		       | (s[3] ^ 0x80));
+      byte = FIRST;
+    }
+    else
+      byte = FIFTH;
+    break;
+  case FIFTH:
+    if (expected_byte_count == 5) {
+      invalid();
+      byte = FIRST;
+    }
+    else
+      byte = SIXTH;
+    break;
+  case SIXTH:
+    invalid();
+    byte = FIRST;
+    break;
+  }
+}
+
+// We use fprintf(stderr) instead of libgroff's debug() because we need
+// to output longs, and libgroff's errprint() doesn't support that.
+
+void
+utf8::invalid()
+{
+  if (is_debugging && emit_invalid_utf8_warning) {
+    fprintf(stderr, "  invalid UTF-8 sequence(s) in input stream:"
+		    " replacing each such sequence with 0xFFFD\n");
+    emit_invalid_utf8_warning = false;
+  }
+  unicode_entity(0xFFFD);
+  byte = FIRST;
+}
+
+void
+utf8::incomplete()
+{
+  if (is_debugging && emit_incomplete_utf8_warning) {
+    fprintf(stderr, "  incomplete UTF-8 sequence(s) in input stream:"
+		    " replacing each such sequence with 0xFFFD\n");
+    emit_incomplete_utf8_warning = false;
+  }
+  unicode_entity(0xFFFD);
+  byte = FIRST;
+}
+
+// Conversion from UTF-8 to Unicode.
+void
+conversion_utf8(FILE *fp, const string &data)
+{
+  utf8 u(fp);
+  int len = data.length();
+  const unsigned char *ptr = (const unsigned char *)data.contents();
+  for (int i = 0; i < len; i++)
+    u.add(ptr[i]);
+  int c = -1;
+  while ((c = getc(fp)) != EOF)
+    u.add(c);
+  return;
+}
+
+// Conversion from cp1047 (EBCDIC) to UTF-8.
+void
+conversion_cp1047(FILE *fp, const string &data)
+{
+  static unsigned char cp1047[] = {
+    0x00, 0x01, 0x02, 0x03, 0x9C, 0x09, 0x86, 0x7F,	// 0x00
+    0x97, 0x8D, 0x8E, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
+    0x10, 0x11, 0x12, 0x13, 0x9D, 0x85, 0x08, 0x87,	// 0x10
+    0x18, 0x19, 0x92, 0x8F, 0x1C, 0x1D, 0x1E, 0x1F,
+    0x80, 0x81, 0x82, 0x83, 0x84, 0x0A, 0x17, 0x1B,	// 0x20
+    0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x05, 0x06, 0x07,
+    0x90, 0x91, 0x16, 0x93, 0x94, 0x95, 0x96, 0x04,	// 0x30
+    0x98, 0x99, 0x9A, 0x9B, 0x14, 0x15, 0x9E, 0x1A,
+    0x20, 0xA0, 0xE2, 0xE4, 0xE0, 0xE1, 0xE3, 0xE5,	// 0x40
+    0xE7, 0xF1, 0xA2, 0x2E, 0x3C, 0x28, 0x2B, 0x7C,
+    0x26, 0xE9, 0xEA, 0xEB, 0xE8, 0xED, 0xEE, 0xEF,	// 0x50
+    0xEC, 0xDF, 0x21, 0x24, 0x2A, 0x29, 0x3B, 0x5E,
+    0x2D, 0x2F, 0xC2, 0xC4, 0xC0, 0xC1, 0xC3, 0xC5,	// 0x60
+    0xC7, 0xD1, 0xA6, 0x2C, 0x25, 0x5F, 0x3E, 0x3F,
+    0xF8, 0xC9, 0xCA, 0xCB, 0xC8, 0xCD, 0xCE, 0xCF,	// 0x70
+    0xCC, 0x60, 0x3A, 0x23, 0x40, 0x27, 0x3D, 0x22,
+    0xD8, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,	// 0x80
+    0x68, 0x69, 0xAB, 0xBB, 0xF0, 0xFD, 0xFE, 0xB1,
+    0xB0, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70,	// 0x90
+    0x71, 0x72, 0xAA, 0xBA, 0xE6, 0xB8, 0xC6, 0xA4,
+    0xB5, 0x7E, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,	// 0xA0
+    0x79, 0x7A, 0xA1, 0xBF, 0xD0, 0x5B, 0xDE, 0xAE,
+    0xAC, 0xA3, 0xA5, 0xB7, 0xA9, 0xA7, 0xB6, 0xBC,	// 0xB0
+    0xBD, 0xBE, 0xDD, 0xA8, 0xAF, 0x5D, 0xB4, 0xD7,
+    0x7B, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,	// 0xC0
+    0x48, 0x49, 0xAD, 0xF4, 0xF6, 0xF2, 0xF3, 0xF5,
+    0x7D, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50,	// 0xD0
+    0x51, 0x52, 0xB9, 0xFB, 0xFC, 0xF9, 0xFA, 0xFF,
+    0x5C, 0xF7, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,	// 0xE0
+    0x59, 0x5A, 0xB2, 0xD4, 0xD6, 0xD2, 0xD3, 0xD5,
+    0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,	// 0xF0
+    0x38, 0x39, 0xB3, 0xDB, 0xDC, 0xD9, 0xDA, 0x9F,
+  };
+  int len = data.length();
+  const unsigned char *ptr = (const unsigned char *)data.contents();
+  for (int i = 0; i < len; i++)
+    unicode_entity(cp1047[ptr[i]]);
+  int c = -1;
+  while ((c = getc(fp)) != EOF)
+    unicode_entity(cp1047[c]);
+}
+
+// Locale-sensible conversion.
+#if HAVE_ICONV
+void
+conversion_iconv(FILE *fp, const string &data, char *enc)
+{
+  iconv_t handle = iconv_open(UNICODE, enc);
+  if (handle == (iconv_t)-1) {
+    if (errno == EINVAL) {
+      error("encoding system '%1' not supported by iconv()", enc);
+      return;
+    }
+    fatal("iconv_open failed");
+  }
+  char inbuf[BUFSIZ];
+  int outbuf[BUFSIZ];
+  char *outptr = (char *)outbuf;
+  size_t outbytes_left = BUFSIZ * sizeof (int);
+  // Handle 'data'.
+  char *inptr = (char *)data.contents();
+  size_t inbytes_left = data.length();
+  char *limit;
+  while (inbytes_left > 0) {
+    size_t status = iconv(handle,
+			  (ICONV_CONST char **)&inptr, &inbytes_left,
+			  &outptr, &outbytes_left);
+    if (status == (size_t)-1) {
+      if (errno == EILSEQ) {
+	// Invalid byte sequence.  XXX
+	inptr++;
+	inbytes_left--;
+      }
+      else if (errno == E2BIG) {
+	// Output buffer is full.
+	limit = (char *)outbuf + BUFSIZ * sizeof (int) - outbytes_left;
+	for (int *ptr = outbuf; (char *)ptr < limit; ptr++)
+	  unicode_entity(*ptr);
+	memmove(outbuf, outptr, outbytes_left);
+	outptr = (char *)outbuf + outbytes_left;
+	outbytes_left = BUFSIZ * sizeof (int) - outbytes_left;
+      }
+      else if (errno == EINVAL) {
+	// 'data' ends with partial input sequence.
+	memcpy(inbuf, inptr, inbytes_left);
+	break;
+      }
+    }
+  }
+  // Handle 'fp' and switch to 'inbuf'.
+  size_t read_bytes;
+  char *read_start = inbuf + inbytes_left;
+  while ((read_bytes = fread(read_start, 1, BUFSIZ - inbytes_left, fp)) > 0) {
+    inptr = inbuf;
+    inbytes_left += read_bytes;
+    while (inbytes_left > 0) {
+      size_t status = iconv(handle,
+			    (ICONV_CONST char **)&inptr, &inbytes_left,
+			    &outptr, &outbytes_left);
+      if (status == (size_t)-1) {
+	if (errno == EILSEQ) {
+	  // Invalid byte sequence.  XXX
+	  inptr++;
+	  inbytes_left--;
+	}
+	else if (errno == E2BIG) {
+	  // Output buffer is full.
+	  limit = (char *)outbuf + BUFSIZ * sizeof (int) - outbytes_left;
+	  for (int *ptr = outbuf; (char *)ptr < limit; ptr++)
+	    unicode_entity(*ptr);
+	  memmove(outbuf, outptr, outbytes_left);
+	  outptr = (char *)outbuf + outbytes_left;
+	  outbytes_left = BUFSIZ * sizeof (int) - outbytes_left;
+	}
+	else if (errno == EINVAL) {
+	  // 'inbuf' ends with partial input sequence.
+	  memmove(inbuf, inptr, inbytes_left);
+	  break;
+	}
+      }
+    }
+    read_start = inbuf + inbytes_left;
+  }
+  iconv_close(handle);
+  // XXX use ferror?
+  limit = (char *)outbuf + BUFSIZ * sizeof (int) - outbytes_left;
+  for (int *ptr = outbuf; (char *)ptr < limit; ptr++)
+    unicode_entity(*ptr);
+}
+#endif /* HAVE_ICONV */
+
+// ---------------------------------------------------------
+// Handle Byte Order Mark.
+//
+// Since we have a chicken-and-egg problem it's necessary
+// to handle the BOM manually if it is in the data stream.
+// As documented in the Unicode book it is very unlikely
+// that any normal text file (regardless of the encoding)
+// starts with the bytes which represent a BOM.
+//
+// Return the BOM in string 'BOM'; 'data' then starts with
+// the byte after the BOM.  This function reads (at most)
+// four bytes from the data stream.
+//
+// Return encoding if a BOM is found, NULL otherwise.
+// ---------------------------------------------------------
+const char *
+get_BOM(FILE *fp, string &BOM, string &data)
+{
+  // The BOM is U+FEFF.  We have thus the following possible
+  // representations.
+  //
+  //   UTF-8: 0xEFBBBF
+  //   UTF-16: 0xFEFF or 0xFFFE
+  //   UTF-32: 0x0000FEFF or 0xFFFE0000
+  static struct {
+    int len;
+    const char *str;
+    const char *name;
+  } BOM_table[] = {
+    {4, "\x00\x00\xFE\xFF", "UTF-32"},
+    {4, "\xFF\xFE\x00\x00", "UTF-32"},
+    {3, "\xEF\xBB\xBF", "UTF-8"},
+    {2, "\xFE\xFF", "UTF-16"},
+    {2, "\xFF\xFE", "UTF-16"},
+  };
+  const int BOM_table_len = sizeof (BOM_table) / sizeof (BOM_table[0]);
+  char BOM_string[4];
+  const char *retval = NULL;
+  int len;
+  for (len = 0; len < 4; len++) {
+    int c = getc(fp);
+    if (c == EOF)
+      break;
+    BOM_string[len] = char(c);
+  }
+  int i;
+  for (i = 0; i < BOM_table_len; i++) {
+    if (BOM_table[i].len <= len
+	&& memcmp(BOM_string, BOM_table[i].str, BOM_table[i].len) == 0)
+      break;
+  }
+  int j = 0;
+  if (i < BOM_table_len) {
+    for (; j < BOM_table[i].len; j++)
+      BOM += BOM_string[j];
+    retval = BOM_table[i].name;
+  }
+  for (; j < len; j++)
+    data += BOM_string[j];
+  return retval;
+}
+
+// ---------------------------------------------------------
+// Get first two lines from input stream.
+//
+// Return string (allocated with 'new') without zero bytes
+// or NULL in case no coding tag can occur in the data
+// (which is stored unmodified in 'data').
+// ---------------------------------------------------------
+char *
+get_tag_lines(FILE *fp, string &data)
+{
+  int newline_count = 0;
+  int c, prev = -1;
+  // Handle CR, LF, and CRLF as line separators.
+  for (int i = 0; i < data.length(); i++) {
+    c = data[i];
+    if (c == '\n' || c == '\r')
+      newline_count++;
+    if (c == '\n' && prev == '\r')
+      newline_count--;
+    prev = c;
+  }
+  if (newline_count > 1)
+    return NULL;
+  bool emit_warning = true;
+  for (int lines = newline_count; lines < 2; lines++) {
+    while ((c = getc(fp)) != EOF) {
+      if (c == '\0' && is_debugging && emit_warning) {
+	warning("null byte(s) found in input stream:"
+		" search for coding tag might return false result");
+	emit_warning = false;
+      }
+      data += char(c);
+      if (c == '\n' || c == '\r')
+	break;
+    }
+    // Handle CR, LF, and CRLF as line separators.
+    if (c == '\r') {
+      c = getc(fp);
+      if (c != EOF && c != '\n')
+	ungetc(c, fp);
+      else
+	data += char(c);
+    }
+  }
+  return data.extract();
+}
+
+// ---------------------------------------------------------
+// Check whether C string starts with a comment.
+//
+// Return 1 if true, 0 otherwise.
+// ---------------------------------------------------------
+int
+is_comment_line(char *s)
+{
+  if (!s || !*s)
+    return 0;
+  if (*s == '.' || *s == '\'')
+  {
+    s++;
+    while (*s == ' ' || *s == '\t')
+      s++;
+    if (*s && *s == '\\')
+    {
+      s++;
+      if (*s == '"' || *s == '#')
+	return 1;
+    }
+  }
+  else if (*s == '\\')
+  {
+    s++;
+    if (*s == '#')
+      return 1;
+  }
+  return 0;
+}
+
+// ---------------------------------------------------------
+// Get a value/variable pair from a local variables list
+// in a C string which look like this:
+//
+//   <variable1>: <value1>; <variable2>: <value2>; ...
+//
+// Leading and trailing blanks are ignored.  There might be
+// more than one blank after ':' and ';'.
+//
+// Return position of next value/variable pair or NULL if
+// at end of data.
+// ---------------------------------------------------------
+char *
+get_variable_value_pair(char *d1, char **variable, char **value)
+{
+  static char var[MAX_VAR_LEN], val[MAX_VAR_LEN];
+  *variable = var;
+  *value = val;
+  while (*d1 == ' ' || *d1 == '\t')
+    d1++;
+  // Get variable.
+  int l = 0;
+  while (l < MAX_VAR_LEN - 1 && *d1 && !strchr(";: \t", *d1))
+    var[l++] = *(d1++);
+  var[l] = 0;
+  // Skip everything until ':', ';', or end of data.
+  while (*d1 && *d1 != ':' && *d1 != ';')
+    d1++;
+  val[0] = 0;
+  if (!*d1)
+    return NULL;
+  if (*d1 == ';')
+    return d1 + 1;
+  d1++;
+  while (*d1 == ' ' || *d1 == '\t')
+    d1++;
+  // Get value.
+  l = 0;
+  while (l < MAX_VAR_LEN - 1 && *d1 && !strchr("; \t", *d1))
+    val[l++] = *(d1++);
+  val[l] = 0;
+  // Skip everything until ';' or end of data.
+  while (*d1 && *d1 != ';')
+    d1++;
+  if (*d1 == ';')
+    return d1 + 1;
+  return NULL;
+}
+
+// ---------------------------------------------------------
+// Check coding tag in the read buffer.
+//
+// We search for the following line:
+//
+//   <comment> ... -*-<local variables list>-*-
+//
+// ('...' might be anything).
+//
+// <comment> can be one of the following syntax forms at the
+// beginning of the line:
+//
+//   .\"   .\#   '\"   '\#   \#
+//
+// There can be whitespace after the leading '.' or "'".
+//
+// The local variables list must occur within the first
+// comment block at the very beginning of the data stream.
+//
+// Within the <local variables list>, we search for
+//
+//   coding: <value>
+//
+// which specifies the coding system used for the data
+// stream.
+//
+// Return <value> if found, NULL otherwise.
+//
+// Note that null bytes in the data are skipped before applying
+// the algorithm.  This should work even with files encoded as
+// UTF-16 or UTF-32 (or its siblings) in most cases.
+// ---------------------------------------------------------
+char *
+check_coding_tag(FILE *fp, string &data)
+{
+  char *inbuf = get_tag_lines(fp, data);
+  char *lineend;
+  for (char *p = inbuf; is_comment_line(p); p = lineend + 1) {
+    if ((lineend = strchr(p, '\n')) == NULL)
+      break;
+    *lineend = 0;		// switch temporarily to '\0'
+    char *d1 = strstr(p, "-*-");
+    char *d2 = 0;
+    if (d1)
+      d2 = strstr(d1 + 3, "-*-");
+    *lineend = '\n';		// restore newline
+    if (!d1 || !d2)
+      continue;
+    *d2 = 0;			// switch temporarily to '\0'
+    d1 += 3;
+    while (d1) {
+      char *variable, *value;
+      d1 = get_variable_value_pair(d1, &variable, &value);
+      if (!strcasecmp(variable, "coding")) {
+	*d2 = '-';		// restore '-'
+	free(inbuf);
+	return value;
+      }
+    }
+    *d2 = '-';			// restore '-'
+  }
+  free(inbuf);
+  return NULL;
+}
+
+char *
+detect_file_encoding(FILE *fp)
+{
+#ifdef HAVE_UCHARDET
+  uchardet_t ud = NULL;
+  struct stat stat_buf;
+  size_t len, read_bytes;
+  char *data = NULL;
+  int res, current_position;
+  const char *charset;
+  char *ret = NULL;
+
+  current_position = ftell(fp);
+  /* Due to BOM and tag detection, we are not at the beginning of the
+     file. */
+  rewind(fp);
+  if (fstat(fileno(fp), &stat_buf) != 0) {
+    error("fstat: %1", strerror(errno));
+    goto end;
+  }
+  len = stat_buf.st_size;
+  if (is_debugging)
+    fprintf(stderr, "  len: %lu\n", (unsigned long)len);
+  if (len == 0)
+    goto end;
+  data = (char *)calloc(len, 1);
+  read_bytes = fread(data, 1, len, fp);
+  if (read_bytes == 0) {
+    error("fread: %1", strerror(errno));
+    goto end;
+  }
+  /* We rewind back to the original position */
+  if (fseek(fp, current_position, SEEK_SET) != 0) {
+    fatal("fseek: %1", strerror(errno));
+    goto end;
+  }
+  ud = uchardet_new();
+  res = uchardet_handle_data(ud, data, len);
+  if (res != 0) {
+    debug("  uchardet_handle_data: error %1\n", res);
+    goto end;
+  }
+  if (is_debugging)
+    fprintf(stderr, "  uchardet read: %lu bytes\n",
+	    (unsigned long)read_bytes);
+  uchardet_data_end(ud);
+  charset = uchardet_get_charset(ud);
+  if (is_debugging) {
+    if (charset)
+       fprintf(stderr, "  charset: %s\n", charset);
+    else
+       fprintf(stderr, "  charset is NULL\n");
+  }
+  /* uchardet 0.0.1 could return an empty string instead of NULL */
+  if (charset && *charset) {
+    ret = (char *)malloc(strlen(charset) + 1);
+    strcpy(ret, charset);
+  }
+
+end:
+  if (ud)
+     uchardet_delete(ud);
+  if (data)
+     free(data);
+
+  return ret;
+#else /* not HAVE_UCHARDET */
+  return NULL;
+#endif /* not HAVE_UCHARDET */
+}
+
+// ---------------------------------------------------------
+// Handle an input file.  If `filename` is "-", read the
+// standard input stream.
+//
+// Return 1 on success, 0 otherwise.
+// ---------------------------------------------------------
+int
+do_file(const char *filename)
+{
+  FILE *fp;
+  string BOM, data;
+  bool is_seekable = false;
+  string reported_filename;
+
+  // TODO: Consider moving some of this into a `quoted_file_name`
+  // function in libgroff.
+  if (strcmp(filename, "-") == 0) {
+    fp = stdin;
+    reported_filename = string("<standard input>");
+  }
+  else {
+    fp = fopen(filename, FOPEN_RB);
+    reported_filename = "'" + string(filename) + "'";
+  }
+  if (!fp) {
+    error("can't open %1: %2", reported_filename.contents(),
+	  strerror(errno));
+    return 0;
+  }
+  if (is_debugging)
+    fprintf(stderr, "processing %s\n", reported_filename.contents());
+  if (fseek(fp, 0L, SEEK_SET) == 0)
+    is_seekable = true;
+  else {
+    SET_BINARY(fileno(fp));
+    if (is_debugging)
+      fprintf(stderr, "  stream is not seekable: %s\n",
+	      strerror(errno));
+  }
+  const char *BOM_encoding = get_BOM(fp, BOM, data);
+  // Determine the encoding.
+  char *encoding;
+  int must_free_encoding = 0;
+  if (user_encoding[0]) {
+    if (is_debugging) {
+      fprintf(stderr, "  user-specified encoding '%s', "
+		      "no search for coding tag\n",
+		      user_encoding);
+      if (BOM_encoding && strcmp(BOM_encoding, user_encoding))
+	fprintf(stderr, "  but BOM in data stream implies encoding '%s'!\n",
+			BOM_encoding);
+    }
+    encoding = (char *)user_encoding;
+  }
+  else if (BOM_encoding) {
+    if (is_debugging)
+      fprintf(stderr, "  found BOM, no search for coding tag\n");
+    encoding = (char *)BOM_encoding;
+  }
+  else {
+    // 'check_coding_tag' returns a pointer to a static array (or NULL).
+    char *file_encoding = check_coding_tag(fp, data);
+    if (!file_encoding) {
+      if (is_debugging)
+	fprintf(stderr, "  no coding tag\n");
+      if (is_seekable)
+         file_encoding = detect_file_encoding(fp);
+      if (!file_encoding) {
+        if (is_debugging)
+          fprintf(stderr, "  could not detect encoding with uchardet\n");
+        file_encoding = fallback_encoding;
+      }
+      else
+        must_free_encoding = 1;
+    }
+    else
+      if (is_debugging)
+	fprintf(stderr, "  coding tag: '%s'\n", file_encoding);
+    encoding = file_encoding;
+  }
+  strncpy(encoding_string, encoding, MAX_VAR_LEN - 1);
+  encoding_string[MAX_VAR_LEN - 1] = 0;
+  if (must_free_encoding)
+    free(encoding);
+  encoding = encoding_string;
+  // Translate from MIME & Emacs encoding names to locale encoding names.
+  encoding = emacs2mime(encoding_string);
+  if (encoding[0] == '\0') {
+    error("encoding '%1' not supported, not a portable encoding",
+	  encoding_string);
+    return 0;
+  }
+  if (is_debugging)
+    fprintf(stderr, "  encoding used: '%s'\n", encoding);
+  if (!raw_flag) {
+    string fn(filename);
+    fn += '\0';
+    normalize_for_lf(fn);
+    printf(".lf 1 %s\n", fn.contents());
+  }
+  int success = 1;
+  // Call converter (converters write to stdout).
+  if (!strcasecmp(encoding, "ISO-8859-1"))
+    conversion_latin1(fp, BOM + data);
+  else if (!strcasecmp(encoding, "UTF-8"))
+    conversion_utf8(fp, data);
+  else if (!strcasecmp(encoding, "cp1047"))
+    conversion_cp1047(fp, BOM + data);
+  else {
+#if HAVE_ICONV
+    conversion_iconv(fp, BOM + data, encoding);
+#else
+    error("encoding system '%1' not supported", encoding);
+    success = 0;
+#endif /* HAVE_ICONV */
+  }
+  if (fp != stdin)
+    fclose(fp);
+  return success;
+}
+
+// ---------------------------------------------------------
+// Print usage.
+// ---------------------------------------------------------
+void
+usage(FILE *stream)
+{
+  fprintf(stream,
+"usage: %s [-dr] [-D fallback-encoding] [-e encoding] [file ...]\n"
+"usage: %s {-v | --version}\n"
+"usage: %s {-h | --help}\n",
+	  program_name, program_name, program_name);
+  if (stdout == stream) {
+    fprintf(stream,
+"\n"
+"Read each file, convert its encoded characters to a form GNU"
+" troff(1)\n"
+"can interpret, and send the result to the standard output stream.\n"
+"The default fallback encoding is '%s'.  See the preconv(1) manual"
+" page.\n",
+	  fallback_encoding);
+    exit(EXIT_SUCCESS);
+  }
+}
+
+// ---------------------------------------------------------
+// Main routine.
+// ---------------------------------------------------------
+int
+main(int argc, char **argv)
+{
+  program_name = argv[0];
+  // Determine the fallback encoding.  This must be done before
+  // getopt() is called since the usage message shows the fallback
+  // encoding.
+  setlocale(LC_ALL, "");
+  char *locale = getlocale(LC_CTYPE);
+  if (!locale || !strcmp(locale, "C") || !strcmp(locale, "POSIX"))
+    strcpy(fallback_encoding, "latin1");
+  else {
+    strncpy(fallback_encoding, locale_charset(), MAX_VAR_LEN - 1);
+    fallback_encoding[MAX_VAR_LEN - 1] = 0;
+  }
+
+  program_name = argv[0];
+  int opt;
+  static const struct option long_options[] = {
+    { "help", no_argument, 0, 'h' },
+    { "version", no_argument, 0, 'v' },
+    { NULL, 0, 0, 0 }
+  };
+  // Parse the command-line options.
+  while ((opt = getopt_long(argc, argv,
+			    "dD:e:hrv", long_options, NULL)) != EOF)
+    switch (opt) {
+    case 'v':
+      printf("GNU preconv (groff) version %s %s iconv support and %s uchardet support\n",
+	     Version_string,
+#ifdef HAVE_ICONV
+	     "with",
+#else
+	     "without",
+#endif /* HAVE_ICONV */
+#ifdef HAVE_UCHARDET
+             "with"
+#else
+             "without"
+#endif /* HAVE_UCHARDET */
+	    );
+      exit(0);
+      break;
+    case 'd':
+      is_debugging = true;
+      break;
+    case 'e':
+      if (optarg) {
+	strncpy(user_encoding, optarg, MAX_VAR_LEN - 1);
+	user_encoding[MAX_VAR_LEN - 1] = 0;
+      }
+      else
+	user_encoding[0] = 0;
+      break;
+    case 'D':
+      if (optarg) {
+	strncpy(fallback_encoding, optarg, MAX_VAR_LEN - 1);
+	fallback_encoding[MAX_VAR_LEN - 1] = 0;
+      }
+      break;
+    case 'r':
+      raw_flag = 1;
+      break;
+    case 'h':
+      usage(stdout);
+      break;
+    case '?':
+      usage(stderr);
+      exit(1);
+      break;
+    default:
+      assert(0);
+    }
+  int nbad = 0;
+  if (is_debugging)
+    fprintf(stderr, "fallback encoding: '%s'\n", fallback_encoding);
+  if (optind >= argc)
+    nbad += !do_file("-");
+  else
+    for (int i = optind; i < argc; i++)
+      nbad += !do_file(argv[i]);
+  if (ferror(stdout) || fflush(stdout) < 0)
+    fatal("output error");
+  return nbad != 0;
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/preconv/tests/do-not-seek-the-unseekable.sh b/src/preproc/preconv/tests/do-not-seek-the-unseekable.sh
new file mode 100755
index 0000000..2b1142d
--- /dev/null
+++ b/src/preproc/preconv/tests/do-not-seek-the-unseekable.sh
@@ -0,0 +1,59 @@
+#!/bin/sh
+#
+# Copyright (C) 2022 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or (at your
+# option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+set -e
+
+preconv="${abs_top_builddir:-.}/preconv"
+
+fail=
+
+wail () {
+    echo FAILED >&2
+    fail=YES
+}
+
+# Scrape debugging output to see if we're skipping unseekable streams.
+# This is fragile, but we don't want to lock the language of diagnostic
+# messages (especially debugging ones).  If this test fails, check the
+# text of the command's debugging output for a mismatch before
+# investigating deeper problems.
+
+echo "testing seekability of file operand '-'" >&2
+output=$(printf '' | "$preconv" -d - 2>&1)
+echo "$output" | grep -q "stream is not seekable" || wail
+
+# /dev/stdin might not exist in a chroot.  Or, if it's not (a symbolic
+# link to) a character special device, the next test will not be valid,
+# as when using GNU Make's `-j` option.
+#
+# Similarly, we must have a controlling terminal.
+test -z "$fail"
+echo "skipping if /dev/stdin is not a character device" >&2
+test -c /dev/stdin || exit 77 # skip
+echo "skipping if there is no controlling terminal" >&2
+test "$(tty)" != "not a tty" || exit 77 # skip
+
+echo "testing seekability of standard input stream" >&2
+output=$(printf '' | "$preconv" -d /dev/stdin 2>&1)
+echo "$output" | grep -q "stream is not seekable" || wail
+
+test -z "$fail"
+
+# vim:set ai et sw=4 ts=4 tw=72:
diff --git a/src/preproc/preconv/tests/smoke-test.sh b/src/preproc/preconv/tests/smoke-test.sh
new file mode 100755
index 0000000..4131416
--- /dev/null
+++ b/src/preproc/preconv/tests/smoke-test.sh
@@ -0,0 +1,88 @@
+#!/bin/sh
+#
+# Copyright (C) 2020 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or (at your
+# option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+# Ensure a predictable character encoding.
+export LC_ALL=C
+
+set -e
+
+preconv="${abs_top_builddir:-.}/preconv"
+
+echo "testing -e flag override of BOM detection" >&2
+printf '\376\377\0\100\0\n' \
+    | "$preconv" -d -e euc-kr 2>&1 > /dev/null \
+    | grep -q "no search for coding tag"
+
+echo "testing detection of UTF-32BE BOM" >&2
+printf '\0\0\376\377\0\0\0\100\0\0\0\n' \
+    | "$preconv" -d 2>&1 > /dev/null \
+    | grep -q "found BOM"
+
+echo "testing detection of UTF-32LE BOM" >&2
+printf '\377\376\0\0\100\0\0\0\n\0\0\0' \
+    | "$preconv" -d 2>&1 > /dev/null \
+    | grep -q "found BOM"
+
+echo "testing detection of UTF-16BE BOM" >&2
+printf '\376\377\0\100\0\n' \
+    | "$preconv" -d 2>&1 > /dev/null \
+    | grep -q "found BOM"
+
+echo "testing detection of UTF-16LE BOM" >&2
+printf '\377\376\100\0\n\0' \
+    | "$preconv" -d 2>&1 > /dev/null \
+    | grep -q "found BOM"
+
+echo "testing detection of UTF-8 BOM" >&2
+printf '\357\273\277@\n' \
+    | "$preconv" -d 2>&1 > /dev/null \
+    | grep -q "found BOM"
+
+# We do not find a coding tag on piped input because it isn't seekable.
+echo "testing detection of Emacs coding tag in piped input" >&2
+printf '.\\" -*- coding: euc-kr; -*-\\n' \
+    | "$preconv" -d 2>&1 >/dev/null \
+    | grep -q "no coding tag"
+
+# We need uchardet to work to get past this point.
+echo "testing uchardet detection of encoding" >&2
+"$preconv" -v | grep -q 'with uchardet support' || exit 77
+
+# Instead of using temporary files, which in all fastidiousness means
+# cleaning them up even if we're interrupted, which in turn means
+# setting up signal handlers, we use files in the build tree.
+
+doc=contrib/mm/groff_mmse.7
+echo "testing uchardet detection on Latin-1 document $doc" >&2
+"$preconv" -d -D us-ascii 2>&1 >/dev/null $doc \
+    | grep -q 'charset: ISO-8859-1'
+
+# uchardet can't seek on a pipe either.
+echo "testing uchardet detection on pipe (expect fallback to -D)" >&2
+printf 'Eat at the caf\351.\n' \
+    | "$preconv" -d -D euc-kr 2>&1 > /dev/null \
+    | grep -q "encoding used: 'EUC-KR'"
+
+# Fall back to the locale.  preconv assumes Latin-1 for C instead of
+# US-ASCII.
+echo "testing fallback to locale setting in environment" >&2
+printf 'Eat at the caf\351.\n' \
+    | "$preconv" -d 2>&1 > /dev/null \
+    | grep -q "encoding used: 'ISO-8859-1'"
diff --git a/src/preproc/refer/TODO b/src/preproc/refer/TODO
new file mode 100644
index 0000000..36f4508
--- /dev/null
+++ b/src/preproc/refer/TODO
@@ -0,0 +1,124 @@
+inline references
+
+Some sort of macro/subroutine that can cover several references.
+
+move-punctuation should ignore multiple punctuation characters.
+
+Make the index files machine independent.
+
+Allow search keys to be negated (with !) to indicate that the
+reference should not contain the key.  Ignore negated keys during
+indexed searching.
+
+Provide an option with lkbib and lookbib that prints the location
+(filename, position) of each reference.  Need to map filename_id's
+back to filenames.
+
+Rename join-authors to join-fields.  Have a separate label-join-fields
+command used by @ and #.
+
+Have some sort of quantifier: e.g., $.n#A means execute '$.n' for each
+instance of an A field, setting $ to that field, and then join the
+results using the join-authors command.
+
+no-text-in-bracket command which says not to allow post_text and
+pre_text when the [] flags has been given. Useful for superscripted
+footnotes.
+
+Make it possible to translate - to \(en in page ranges.
+
+Trim eign a bit.
+
+In indexed searching discard all numeric keys except dates.
+
+Allow '\ ' to separate article from first word.
+
+%also
+
+Option automatically to supply [] flags in every reference.
+
+See if we can avoid requiring a comma before jr. and so on
+in find_last_name().
+
+Cache sortified authors in authors string during tentative evaluation of
+label specification.
+
+Possibly don't allow * and % expressions in the first part of ?:, | or
+& expressions.
+
+Handle better the case where <> occurs inside functions and in the
+first operand of ~. Or perhaps implement <> using some magic character
+in the string.
+
+Should special treatment be given to lines beginning with . in
+references?  (Unix refer seems to treat them like '%').
+
+Add global flag to control whether all files should be stat-ed after
+loading, and whether they should be stat-ed before each search.
+Perhaps make this dependent on the number of files there are.
+
+Option to truncate keys to truncate_len in linear searching.
+
+Allow multiple -f options in indxbib.
+
+In indxbib, possibly store common words rather than common words
+filename.  In this case store only words that are actually present in
+the file.
+
+Perhaps we should put out an obnoxious copyright message when lookbib
+starts up.
+
+Provide an option that writes a file containing just the references
+actually used.  Useful if you want to distribute a document.
+
+Have a magic token such that
+%A <sort stuff><magic token><print stuff>
+will print as though it were
+%A <print stuff>
+but sort as though it were
+%A <sort stuff>
+Do we need this if we can specify author alternatives for sorting?
+No, provided we have separate alternatives for @.
+
+In consider_authors when last names are ambiguous we might be able to
+use just the first name and not Jr. bit. Or we might be able to
+abbreviate the author.
+
+It ought to be possible to specify an alternative field to sort on
+instead of date. (ie if there's a field giving the type of document --
+these references should sort after any years)
+
+Provide a way to execute a command using a command-line option.
+
+Option to set the label-spec as a command-line option (-L).
+
+Command to specify which fields can occur multiple times:
+multiple AE
+
+Command to specify how various fields sort:
+aort-as-name A
+sort-as-date D
+sort-as-title T
+sort-as-other O
+
+Command to specify which fields are author fields:
+# if we don't have A use field Q
+author-fields AQ
+
+Commands to set properties of tokens.
+sortify-token \(ae ae
+uppercase-token \[ae] \[AE]
+
+Command to set the names of months:
+months january february march april may ...
+
+Perhaps provide some sort of macro capability:
+# perhaps a macro capability
+defmacro foo
+annotation-field $1
+endef
+
+Command to control strings used in capitalization
+capitalize-start \s+2
+capitalize-end \s-2
+(perhaps make these arguments to the capitalize command.)
diff --git a/src/preproc/refer/command.cpp b/src/preproc/refer/command.cpp
new file mode 100644
index 0000000..b49e2be
--- /dev/null
+++ b/src/preproc/refer/command.cpp
@@ -0,0 +1,814 @@
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "refer.h"
+#include "refid.h"
+#include "search.h"
+#include "command.h"
+
+cset cs_field_name = csalpha;
+
+class input_item {
+  input_item *next;
+  char *filename;
+  int first_lineno;
+  string buffer;
+  const char *ptr;
+  const char *end;
+public:
+  input_item(string &, const char *, int = 1);
+  ~input_item();
+  int get_char();
+  int peek_char();
+  void skip_char();
+  void get_location(const char **, int *);
+
+  friend class input_stack;
+};
+
+input_item::input_item(string &s, const char *fn, int ln)
+: filename(strsave(fn)), first_lineno(ln)
+{
+  buffer.move(s);
+  ptr = buffer.contents();
+  end = ptr + buffer.length();
+}
+
+input_item::~input_item()
+{
+  delete[] filename;
+}
+
+inline int input_item::peek_char()
+{
+  if (ptr >= end)
+    return EOF;
+  else
+    return (unsigned char)*ptr;
+}
+
+inline int input_item::get_char()
+{
+  if (ptr >= end)
+    return EOF;
+  else
+    return (unsigned char)*ptr++;
+}
+
+inline void input_item::skip_char()
+{
+  ptr++;
+}
+
+void input_item::get_location(const char **filenamep, int *linenop)
+{
+  *filenamep = filename;
+  if (ptr == buffer.contents())
+    *linenop = first_lineno;
+  else {
+    int ln = first_lineno;
+    const char *e = ptr - 1;
+    for (const char *p = buffer.contents(); p < e; p++)
+      if (*p == '\n')
+	ln++;
+    ln--; // Back up to identify line number _before_ last seen newline.
+    *linenop = ln;
+  }
+  return;
+}
+
+class input_stack {
+  static input_item *top;
+public:
+  static void init();
+  static int get_char();
+  static int peek_char();
+  static void skip_char() { top->skip_char(); }
+  static void push_file(const char *);
+  static void push_string(string &, const char *, int);
+  static void error(const char *format,
+		    const errarg &arg1 = empty_errarg,
+		    const errarg &arg2 = empty_errarg,
+		    const errarg &arg3 = empty_errarg);
+};
+
+input_item *input_stack::top = 0;
+
+void input_stack::init()
+{
+  while (top) {
+    input_item *tem = top;
+    top = top->next;
+    delete tem;
+  }
+}
+
+int input_stack::get_char()
+{
+  while (top) {
+    int c = top->get_char();
+    if (c >= 0)
+      return c;
+    input_item *tem = top;
+    top = top->next;
+    delete tem;
+  }
+  return -1;
+}
+
+int input_stack::peek_char()
+{
+  while (top) {
+    int c = top->peek_char();
+    if (c >= 0)
+      return c;
+    input_item *tem = top;
+    top = top->next;
+    delete tem;
+  }
+  return -1;
+}
+
+void input_stack::push_file(const char *fn)
+{
+  FILE *fp;
+  if (strcmp(fn, "-") == 0) {
+    fp = stdin;
+    fn = "<standard input>";
+  }
+  else {
+    errno = 0;
+    fp = fopen(fn, "r");
+    if (fp == 0) {
+      error("can't open '%1': %2", fn, strerror(errno));
+      return;
+    }
+  }
+  string buf;
+  bool is_at_beginning_of_line = true;
+  int lineno = 1;
+  for (;;) {
+    int c = getc(fp);
+    if (is_at_beginning_of_line && c == '.') {
+      // replace lines beginning with .R1 or .R2 with a blank line
+      c = getc(fp);
+      if (c == 'R') {
+	c = getc(fp);
+	if (c == '1' || c == '2') {
+	  int cc = c;
+	  c = getc(fp);
+	  if (compatible_flag || c == ' ' || c == '\n' || c == EOF) {
+	    while (c != '\n' && c != EOF)
+	      c = getc(fp);
+	  }
+	  else {
+	    buf += '.';
+	    buf += 'R';
+	    buf += cc;
+	  }
+	}
+	else {
+	  buf += '.';
+	  buf += 'R';
+	}
+      }
+      else
+	buf += '.';
+    }
+    if (c == EOF)
+      break;
+    if (is_invalid_input_char(c))
+      error_with_file_and_line(fn, lineno,
+			       "invalid input character code %1", c);
+    else {
+      buf += c;
+      if (c == '\n') {
+	is_at_beginning_of_line = true;
+	lineno++;
+      }
+      else
+	is_at_beginning_of_line = false;
+    }
+  }
+  if (fp != stdin)
+    fclose(fp);
+  if (buf.length() > 0 && buf[buf.length() - 1] != '\n')
+    buf += '\n';
+  input_item *it = new input_item(buf, fn);
+  it->next = top;
+  top = it;
+}
+
+void input_stack::push_string(string &s, const char *filename, int lineno)
+{
+  input_item *it = new input_item(s, filename, lineno);
+  it->next = top;
+  top = it;
+}
+
+void input_stack::error(const char *format, const errarg &arg1,
+			const errarg &arg2, const errarg &arg3)
+{
+  const char *filename;
+  int lineno;
+  for (input_item *it = top; it; it = it->next) {
+    it->get_location(&filename, &lineno);
+    error_with_file_and_line(filename, lineno, format, arg1, arg2, arg3);
+    return;
+  }
+  ::error(format, arg1, arg2, arg3);
+}
+
+void command_error(const char *format, const errarg &arg1,
+		   const errarg &arg2, const errarg &arg3)
+{
+  input_stack::error(format, arg1, arg2, arg3);
+}
+
+// # not recognized in ""
+// \<newline> is recognized in ""
+// # does not conceal newline
+// if missing closing quote, word extends to end of line
+// no special treatment of \ other than before newline
+// \<newline> not recognized after #
+// ; allowed as alternative to newline
+// ; not recognized in ""
+// don't clear word_buffer; just append on
+// return -1 for EOF, 0 for newline, 1 for word
+
+int get_word(string &word_buffer)
+{
+  int c = input_stack::get_char();
+  for (;;) {
+    if (c == '#') {
+      do {
+	c = input_stack::get_char();
+      } while (c != '\n' && c != EOF);
+      break;
+    }
+    if (c == '\\' && input_stack::peek_char() == '\n')
+      input_stack::skip_char();
+    else if (c != ' ' && c != '\t')
+      break;
+    c = input_stack::get_char();
+  }
+  if (c == EOF)
+    return -1;
+  if (c == '\n' || c == ';')
+    return 0;
+  if (c == '"') {
+    for (;;) {
+      c = input_stack::peek_char();
+      if (c == EOF || c == '\n')
+	break;
+      input_stack::skip_char();
+      if (c == '"') {
+	int d = input_stack::peek_char();
+	if (d == '"')
+	  input_stack::skip_char();
+	else
+	  break;
+      }
+      else if (c == '\\') {
+	int d = input_stack::peek_char();
+	if (d == '\n')
+	  input_stack::skip_char();
+	else
+	  word_buffer += '\\';
+      }
+      else
+	word_buffer += c;
+    }
+    return 1;
+  }
+  word_buffer += c;
+  for (;;) {
+    c = input_stack::peek_char();
+    if (c == ' ' || c == '\t' || c == '\n' || c == '#' || c == ';')
+      break;
+    input_stack::skip_char();
+    if (c == '\\') {
+      int d = input_stack::peek_char();
+      if (d == '\n')
+	input_stack::skip_char();
+      else
+	word_buffer += '\\';
+    }
+    else
+      word_buffer += c;
+  }
+  return 1;
+}
+
+union argument {
+  const char *s;
+  int n;
+};
+
+// This is for debugging.
+
+static void echo_command(int argc, argument *argv)
+{
+  for (int i = 0; i < argc; i++)
+    fprintf(stderr, "%s\n", argv[i].s);
+}
+
+static void include_command(int argc, argument *argv)
+{
+  assert(argc == 1);
+  input_stack::push_file(argv[0].s);
+}
+
+static void capitalize_command(int argc, argument *argv)
+{
+  if (argc > 0)
+    capitalize_fields = argv[0].s;
+  else
+    capitalize_fields.clear();
+}
+
+static void accumulate_command(int, argument *)
+{
+  accumulate = 1;
+}
+
+static void no_accumulate_command(int, argument *)
+{
+  accumulate = 0;
+}
+
+static void move_punctuation_command(int, argument *)
+{
+  move_punctuation = 1;
+}
+
+static void no_move_punctuation_command(int, argument *)
+{
+  move_punctuation = 0;
+}
+
+static void sort_command(int argc, argument *argv)
+{
+  if (argc == 0)
+    sort_fields = "AD";
+  else
+    sort_fields = argv[0].s;
+  accumulate = 1;
+}
+
+static void no_sort_command(int, argument *)
+{
+  sort_fields.clear();
+}
+
+static void articles_command(int argc, argument *argv)
+{
+  articles.clear();
+  int i;
+  for (i = 0; i < argc; i++) {
+    articles += argv[i].s;
+    articles += '\0';
+  }
+  int len = articles.length();
+  for (i = 0; i < len; i++)
+    articles[i] = cmlower(articles[i]);
+}
+
+static void database_command(int argc, argument *argv)
+{
+  for (int i = 0; i < argc; i++)
+    database_list.add_file(argv[i].s);
+}
+
+static void default_database_command(int, argument *)
+{
+  search_default = 1;
+}
+
+static void no_default_database_command(int, argument *)
+{
+  search_default = 0;
+}
+
+static void bibliography_command(int argc, argument *argv)
+{
+  have_bibliography = 1;
+  const char *saved_filename = current_filename;
+  int saved_lineno = current_lineno;
+  int saved_label_in_text = label_in_text;
+  label_in_text = 0;
+  if (!accumulate)
+    fputs(".]<\n", stdout);
+  for (int i = 0; i < argc; i++)
+    do_bib(argv[i].s);
+  if (accumulate)
+    output_references();
+  else
+    fputs(".]>\n", stdout);
+  current_filename = saved_filename;
+  current_lineno = saved_lineno;
+  label_in_text = saved_label_in_text;
+}
+
+static void annotate_command(int argc, argument *argv)
+{
+  if (argc > 0)
+    annotation_field = argv[0].s[0];
+  else
+    annotation_field = 'X';
+  if (argc == 2)
+    annotation_macro = argv[1].s;
+  else
+    annotation_macro = "AP";
+}
+
+static void no_annotate_command(int, argument *)
+{
+  annotation_macro.clear();
+  annotation_field = -1;
+}
+
+static void reverse_command(int, argument *argv)
+{
+  reverse_fields = argv[0].s;
+}
+
+static void no_reverse_command(int, argument *)
+{
+  reverse_fields.clear();
+}
+
+static void abbreviate_command(int argc, argument *argv)
+{
+  abbreviate_fields = argv[0].s;
+  period_before_initial = argc > 1 ? argv[1].s : ". ";
+  period_before_last_name = argc > 2 ? argv[2].s : ". ";
+  period_before_other = argc > 3 ? argv[3].s : ". ";
+  period_before_hyphen = argc > 4 ? argv[4].s : ".";
+}
+
+static void no_abbreviate_command(int, argument *)
+{
+  abbreviate_fields.clear();
+}
+
+string search_ignore_fields;
+
+static void search_ignore_command(int argc, argument *argv)
+{
+  if (argc > 0)
+    search_ignore_fields = argv[0].s;
+  else
+    search_ignore_fields = "XYZ";
+  search_ignore_fields += '\0';
+  linear_ignore_fields = search_ignore_fields.contents();
+}
+
+static void no_search_ignore_command(int, argument *)
+{
+  linear_ignore_fields = "";
+}
+
+static void search_truncate_command(int argc, argument *argv)
+{
+  if (argc > 0)
+    linear_truncate_len = argv[0].n;
+  else
+    linear_truncate_len = 6;
+}
+
+static void no_search_truncate_command(int, argument *)
+{
+  linear_truncate_len = -1;
+}
+
+static void discard_command(int argc, argument *argv)
+{
+  if (argc == 0)
+    discard_fields = "XYZ";
+  else
+    discard_fields = argv[0].s;
+  accumulate = 1;
+}
+
+static void no_discard_command(int, argument *)
+{
+  discard_fields.clear();
+}
+
+static void label_command(int, argument *argv)
+{
+  set_label_spec(argv[0].s);
+}
+
+static void abbreviate_label_ranges_command(int argc, argument *argv)
+{
+  abbreviate_label_ranges = 1;
+  label_range_indicator = argc > 0 ? argv[0].s : "-";
+}
+
+static void no_abbreviate_label_ranges_command(int, argument *)
+{
+  abbreviate_label_ranges = 0;
+}
+
+static void label_in_reference_command(int, argument *)
+{
+  label_in_reference = 1;
+}
+
+static void no_label_in_reference_command(int, argument *)
+{
+  label_in_reference = 0;
+}
+
+static void label_in_text_command(int, argument *)
+{
+  label_in_text = 1;
+}
+
+static void no_label_in_text_command(int, argument *)
+{
+  label_in_text = 0;
+}
+
+static void sort_adjacent_labels_command(int, argument *)
+{
+  sort_adjacent_labels = 1;
+}
+
+static void no_sort_adjacent_labels_command(int, argument *)
+{
+  sort_adjacent_labels = 0;
+}
+
+static void date_as_label_command(int argc, argument *argv)
+{
+  if (set_date_label_spec(argc > 0 ? argv[0].s : "D%a*"))
+    date_as_label = 1;
+}
+
+static void no_date_as_label_command(int, argument *)
+{
+  date_as_label = 0;
+}
+
+static void short_label_command(int, argument *argv)
+{
+  if (set_short_label_spec(argv[0].s))
+    short_label_flag = 1;
+}
+
+static void no_short_label_command(int, argument *)
+{
+  short_label_flag = 0;
+}
+
+static void compatible_command(int, argument *)
+{
+  compatible_flag = 1;
+}
+
+static void no_compatible_command(int, argument *)
+{
+  compatible_flag = 0;
+}
+
+static void join_authors_command(int argc, argument *argv)
+{
+  join_authors_exactly_two = argv[0].s;
+  join_authors_default = argc > 1 ? argv[1].s : argv[0].s;
+  join_authors_last_two = argc == 3 ? argv[2].s : argv[0].s;
+}
+
+static void bracket_label_command(int, argument *argv)
+{
+  pre_label = argv[0].s;
+  post_label = argv[1].s;
+  sep_label = argv[2].s;
+}
+
+static void separate_label_second_parts_command(int, argument *argv)
+{
+  separate_label_second_parts = argv[0].s;
+}
+
+static void et_al_command(int argc, argument *argv)
+{
+  et_al = argv[0].s;
+  et_al_min_elide = argv[1].n;
+  if (et_al_min_elide < 1)
+    et_al_min_elide = 1;
+  et_al_min_total = argc >= 3 ? argv[2].n : 0;
+}
+
+static void no_et_al_command(int, argument *)
+{
+  et_al.clear();
+  et_al_min_elide = 0;
+}
+
+typedef void (*command_t)(int, argument *);
+
+/* arg_types is a string describing the numbers and types of arguments.
+s means a string, i means an integer, f is a list of fields, F is
+a single field,
+? means that the previous argument is optional, * means that the
+previous argument can occur any number of times. */
+
+struct S {
+  const char *name;
+  command_t func;
+  const char *arg_types;
+} command_table[] = {
+  { "include", include_command, "s" },
+  { "echo", echo_command, "s*" },
+  { "capitalize", capitalize_command, "f?" },
+  { "accumulate", accumulate_command, "" },
+  { "no-accumulate", no_accumulate_command, "" },
+  { "move-punctuation", move_punctuation_command, "" },
+  { "no-move-punctuation", no_move_punctuation_command, "" },
+  { "sort", sort_command, "s?" },
+  { "no-sort", no_sort_command, "" },
+  { "articles", articles_command, "s*" },
+  { "database", database_command, "ss*" },
+  { "default-database", default_database_command, "" },
+  { "no-default-database", no_default_database_command, "" },
+  { "bibliography", bibliography_command, "ss*" },
+  { "annotate", annotate_command, "F?s?" },
+  { "no-annotate", no_annotate_command, "" },
+  { "reverse", reverse_command, "s" },
+  { "no-reverse", no_reverse_command, "" },
+  { "abbreviate", abbreviate_command, "ss?s?s?s?" },
+  { "no-abbreviate", no_abbreviate_command, "" },
+  { "search-ignore", search_ignore_command, "f?" },
+  { "no-search-ignore", no_search_ignore_command, "" },
+  { "search-truncate", search_truncate_command, "i?" },
+  { "no-search-truncate", no_search_truncate_command, "" },
+  { "discard", discard_command, "f?" },
+  { "no-discard", no_discard_command, "" },
+  { "label", label_command, "s" },
+  { "abbreviate-label-ranges", abbreviate_label_ranges_command, "s?" },
+  { "no-abbreviate-label-ranges", no_abbreviate_label_ranges_command, "" },
+  { "label-in-reference", label_in_reference_command, "" },
+  { "no-label-in-reference", no_label_in_reference_command, "" },
+  { "label-in-text", label_in_text_command, "" },
+  { "no-label-in-text", no_label_in_text_command, "" },
+  { "sort-adjacent-labels", sort_adjacent_labels_command, "" },
+  { "no-sort-adjacent-labels", no_sort_adjacent_labels_command, "" },
+  { "date-as-label", date_as_label_command, "s?" },
+  { "no-date-as-label", no_date_as_label_command, "" },
+  { "short-label", short_label_command, "s" },
+  { "no-short-label", no_short_label_command, "" },
+  { "compatible", compatible_command, "" },
+  { "no-compatible", no_compatible_command, "" },
+  { "join-authors", join_authors_command, "sss?" },
+  { "bracket-label", bracket_label_command, "sss" },
+  { "separate-label-second-parts", separate_label_second_parts_command, "s" },
+  { "et-al", et_al_command, "sii?" },
+  { "no-et-al", no_et_al_command, "" },
+};
+
+static int check_args(const char *types, const char *name,
+		      int argc, argument *argv)
+{
+  int argno = 0;
+  while (*types) {
+    if (argc == 0) {
+      if (types[1] == '?')
+	break;
+      else if (types[1] == '*') {
+	assert(types[2] == '\0');
+	break;
+      }
+      else {
+	input_stack::error("missing argument for command '%1'", name);
+	return 0;
+      }
+    }
+    switch (*types) {
+    case 's':
+      break;
+    case 'i':
+      {
+	char *ptr;
+	long n = strtol(argv->s, &ptr, 10);
+	if ((n == 0 && ptr == argv->s)
+	    || *ptr != '\0') {
+	  input_stack::error("argument %1 for command '%2' must be an integer",
+			     argno + 1, name);
+	  return 0;
+	}
+	argv->n = (int)n;
+	break;
+      }
+    case 'f':
+      {
+	for (const char *ptr = argv->s; *ptr != '\0'; ptr++)
+	  if (!cs_field_name(*ptr)) {
+	    input_stack::error("argument %1 for command '%2' must be a list of fields",
+			     argno + 1, name);
+	    return 0;
+	  }
+	break;
+      }
+    case 'F':
+      if (argv->s[0] == '\0' || argv->s[1] != '\0'
+	  || !cs_field_name(argv->s[0])) {
+	input_stack::error("argument %1 for command '%2' must be a field name",
+			   argno + 1, name);
+	return 0;
+      }
+      break;
+    default:
+      assert(0);
+    }
+    if (types[1] == '?')
+      types += 2;
+    else if (types[1] != '*')
+      types += 1;
+    --argc;
+    ++argv;
+    ++argno;
+  }
+  if (argc > 0) {
+    input_stack::error("too many arguments for command '%1'", name);
+    return 0;
+  }
+  return 1;
+}
+
+static void execute_command(const char *name, int argc, argument *argv)
+{
+  for (unsigned int i = 0;
+       i < sizeof(command_table)/sizeof(command_table[0]); i++)
+    if (strcmp(name, command_table[i].name) == 0) {
+      if (check_args(command_table[i].arg_types, name, argc, argv))
+	(*command_table[i].func)(argc, argv);
+      return;
+    }
+  input_stack::error("unknown command '%1'", name);
+}
+
+static void command_loop()
+{
+  string command;
+  for (;;) {
+    command.clear();
+    int res = get_word(command);
+    if (res != 1) {
+      if (res == 0)
+	continue;
+      break;
+    }
+    int argc = 0;
+    command += '\0';
+    while ((res = get_word(command)) == 1) {
+      argc++;
+      command += '\0';
+    }
+    argument *argv = new argument[argc];
+    const char *ptr = command.contents();
+    for (int i = 0; i < argc; i++)
+      argv[i].s = ptr = strchr(ptr, '\0') + 1;
+    execute_command(command.contents(), argc, argv);
+    delete[] argv;
+    if (res == -1)
+      break;
+  }
+}
+
+void process_commands(string &s, const char *file, int lineno)
+{
+  const char *saved_filename = current_filename;
+  int saved_lineno = current_lineno;
+  input_stack::init();
+  current_filename = file;
+  // Report diagnostics with respect to line _before_ last newline seen.
+  current_lineno = lineno - 1;
+  input_stack::push_string(s, file, lineno);
+  command_loop();
+  current_filename = saved_filename;
+  current_lineno = saved_lineno;
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/refer/command.h b/src/preproc/refer/command.h
new file mode 100644
index 0000000..db850f4
--- /dev/null
+++ b/src/preproc/refer/command.h
@@ -0,0 +1,35 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+void process_commands(string &s, const char *file, int lineno);
+
+extern int have_bibliography;
+extern int accumulate;
+extern int move_punctuation;
+extern int search_default;
+extern search_list database_list;
+extern int label_in_text;
+extern int label_in_reference;
+extern int sort_adjacent_labels;
+extern string pre_label;
+extern string post_label;
+extern string sep_label;
+
+extern void do_bib(const char *);
+extern void output_references();
diff --git a/src/preproc/refer/label.cpp b/src/preproc/refer/label.cpp
new file mode 100644
index 0000000..f8c1645
--- /dev/null
+++ b/src/preproc/refer/label.cpp
@@ -0,0 +1,2607 @@
+/* A Bison parser, made by GNU Bison 3.8.2.  */
+
+/* Bison implementation for Yacc-like parsers in C
+
+   Copyright (C) 1984, 1989-1990, 2000-2015, 2018-2021 Free Software Foundation,
+   Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* As a special exception, you may create a larger work that contains
+   part or all of the Bison parser skeleton and distribute that work
+   under terms of your choice, so long as that work isn't itself a
+   parser generator using the skeleton or a modified version thereof
+   as a parser skeleton.  Alternatively, if you modify or redistribute
+   the parser skeleton itself, you may (at your option) remove this
+   special exception, which will cause the skeleton and the resulting
+   Bison output files to be licensed under the GNU General Public
+   License without this special exception.
+
+   This special exception was added by the Free Software Foundation in
+   version 2.2 of Bison.  */
+
+/* C LALR(1) parser skeleton written by Richard Stallman, by
+   simplifying the original so-called "semantic" parser.  */
+
+/* DO NOT RELY ON FEATURES THAT ARE NOT DOCUMENTED in the manual,
+   especially those whose name start with YY_ or yy_.  They are
+   private implementation details that can be changed or removed.  */
+
+/* All symbols defined below should begin with yy or YY, to avoid
+   infringing on user name space.  This should be done even for local
+   variables, as they might otherwise be expanded by user macros.
+   There are some unavoidable exceptions within include files to
+   define necessary library symbols; they are noted "INFRINGES ON
+   USER NAME SPACE" below.  */
+
+/* Identify Bison output, and Bison version.  */
+#define YYBISON 30802
+
+/* Bison version string.  */
+#define YYBISON_VERSION "3.8.2"
+
+/* Skeleton name.  */
+#define YYSKELETON_NAME "yacc.c"
+
+/* Pure parsers.  */
+#define YYPURE 0
+
+/* Push parsers.  */
+#define YYPUSH 0
+
+/* Pull parsers.  */
+#define YYPULL 1
+
+
+
+
+/* First part of user prologue.  */
+#line 19 "../src/preproc/refer/label.ypp"
+
+
+#include "refer.h"
+#include "refid.h"
+#include "ref.h"
+#include "token.h"
+
+int yylex();
+void yyerror(const char *);
+
+static const char *format_serial(char c, int n);
+
+struct label_info {
+  int start;
+  int length;
+  int count;
+  int total;
+  label_info(const string &);
+};
+
+label_info *lookup_label(const string &label);
+
+struct expression {
+  enum {
+    // Does the tentative label depend on the reference?
+    CONTAINS_VARIABLE = 01, 
+    CONTAINS_STAR = 02,
+    CONTAINS_FORMAT = 04,
+    CONTAINS_AT = 010
+  };
+  virtual ~expression() { }
+  virtual void evaluate(int, const reference &, string &,
+			substring_position &) = 0;
+  virtual unsigned analyze() { return 0; }
+};
+
+class at_expr : public expression {
+public:
+  at_expr() { }
+  void evaluate(int, const reference &, string &, substring_position &);
+  unsigned analyze() { return CONTAINS_VARIABLE|CONTAINS_AT; }
+};
+
+class format_expr : public expression {
+  char type;
+  int width;
+  int first_number;
+public:
+  format_expr(char c, int w = 0, int f = 1)
+    : type(c), width(w), first_number(f) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+  unsigned analyze() { return CONTAINS_FORMAT; }
+};
+
+class field_expr : public expression {
+  int number;
+  char name;
+public:
+  field_expr(char nm, int num) : number(num), name(nm) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+  unsigned analyze() { return CONTAINS_VARIABLE; }
+};
+
+class literal_expr : public expression {
+  string s;
+public:
+  literal_expr(const char *ptr, int len) : s(ptr, len) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+};
+
+class unary_expr : public expression {
+protected:
+  expression *expr;
+public:
+  unary_expr(expression *e) : expr(e) { }
+  ~unary_expr() { delete expr; }
+  void evaluate(int, const reference &, string &, substring_position &) = 0;
+  unsigned analyze() { return expr ? expr->analyze() : 0; }
+};
+
+// This caches the analysis of an expression.
+
+class analyzed_expr : public unary_expr {
+  unsigned flags;
+public:
+  analyzed_expr(expression *);
+  void evaluate(int, const reference &, string &, substring_position &);
+  unsigned analyze() { return flags; }
+};
+
+class star_expr : public unary_expr {
+public:
+  star_expr(expression *e) : unary_expr(e) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+  unsigned analyze() {
+    return ((expr ? (expr->analyze() & ~CONTAINS_VARIABLE) : 0)
+	    | CONTAINS_STAR);
+  }
+};
+
+typedef void map_func(const char *, const char *, string &);
+
+class map_expr : public unary_expr {
+  map_func *func;
+public:
+  map_expr(expression *e, map_func *f) : unary_expr(e), func(f) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+};
+  
+typedef const char *extractor_func(const char *, const char *, const char **);
+
+class extractor_expr : public unary_expr {
+  int part;
+  extractor_func *func;
+public:
+  enum { BEFORE = +1, MATCH = 0, AFTER = -1 };
+  extractor_expr(expression *e, extractor_func *f, int pt)
+    : unary_expr(e), part(pt), func(f) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+};
+
+class truncate_expr : public unary_expr {
+  int n;
+public:
+  truncate_expr(expression *e, int i) : unary_expr(e), n(i) { } 
+  void evaluate(int, const reference &, string &, substring_position &);
+};
+
+class separator_expr : public unary_expr {
+public:
+  separator_expr(expression *e) : unary_expr(e) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+};
+
+class binary_expr : public expression {
+protected:
+  expression *expr1;
+  expression *expr2;
+public:
+  binary_expr(expression *e1, expression *e2) : expr1(e1), expr2(e2) { }
+  ~binary_expr() { delete expr1; delete expr2; }
+  void evaluate(int, const reference &, string &, substring_position &) = 0;
+  unsigned analyze() {
+    return (expr1 ? expr1->analyze() : 0) | (expr2 ? expr2->analyze() : 0);
+  }
+};
+
+class alternative_expr : public binary_expr {
+public:
+  alternative_expr(expression *e1, expression *e2) : binary_expr(e1, e2) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+};
+
+class list_expr : public binary_expr {
+public:
+  list_expr(expression *e1, expression *e2) : binary_expr(e1, e2) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+};
+
+class substitute_expr : public binary_expr {
+public:
+  substitute_expr(expression *e1, expression *e2) : binary_expr(e1, e2) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+};
+
+class ternary_expr : public expression {
+protected:
+  expression *expr1;
+  expression *expr2;
+  expression *expr3;
+public:
+  ternary_expr(expression *e1, expression *e2, expression *e3)
+    : expr1(e1), expr2(e2), expr3(e3) { }
+  ~ternary_expr() { delete expr1; delete expr2; delete expr3; }
+  void evaluate(int, const reference &, string &, substring_position &) = 0;
+  unsigned analyze() {
+    return ((expr1 ? expr1->analyze() : 0)
+	    | (expr2 ? expr2->analyze() : 0)
+	    | (expr3 ? expr3->analyze() : 0));
+  }
+};
+
+class conditional_expr : public ternary_expr {
+public:
+  conditional_expr(expression *e1, expression *e2, expression *e3)
+    : ternary_expr(e1, e2, e3) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+};
+
+static expression *parsed_label = 0;
+static expression *parsed_date_label = 0;
+static expression *parsed_short_label = 0;
+
+static expression *parse_result;
+
+string literals;
+
+
+#line 270 "src/preproc/refer/label.cpp"
+
+# ifndef YY_CAST
+#  ifdef __cplusplus
+#   define YY_CAST(Type, Val) static_cast<Type> (Val)
+#   define YY_REINTERPRET_CAST(Type, Val) reinterpret_cast<Type> (Val)
+#  else
+#   define YY_CAST(Type, Val) ((Type) (Val))
+#   define YY_REINTERPRET_CAST(Type, Val) ((Type) (Val))
+#  endif
+# endif
+# ifndef YY_NULLPTR
+#  if defined __cplusplus
+#   if 201103L <= __cplusplus
+#    define YY_NULLPTR nullptr
+#   else
+#    define YY_NULLPTR 0
+#   endif
+#  else
+#   define YY_NULLPTR ((void*)0)
+#  endif
+# endif
+
+/* Use api.header.include to #include this header
+   instead of duplicating it here.  */
+#ifndef YY_YY_SRC_PREPROC_REFER_LABEL_HPP_INCLUDED
+# define YY_YY_SRC_PREPROC_REFER_LABEL_HPP_INCLUDED
+/* Debug traces.  */
+#ifndef YYDEBUG
+# define YYDEBUG 0
+#endif
+#if YYDEBUG
+extern int yydebug;
+#endif
+
+/* Token kinds.  */
+#ifndef YYTOKENTYPE
+# define YYTOKENTYPE
+  enum yytokentype
+  {
+    YYEMPTY = -2,
+    YYEOF = 0,                     /* "end of file"  */
+    YYerror = 256,                 /* error  */
+    YYUNDEF = 257,                 /* "invalid token"  */
+    TOKEN_LETTER = 258,            /* TOKEN_LETTER  */
+    TOKEN_LITERAL = 259,           /* TOKEN_LITERAL  */
+    TOKEN_DIGIT = 260              /* TOKEN_DIGIT  */
+  };
+  typedef enum yytokentype yytoken_kind_t;
+#endif
+/* Token kinds.  */
+#define YYEMPTY -2
+#define YYEOF 0
+#define YYerror 256
+#define YYUNDEF 257
+#define TOKEN_LETTER 258
+#define TOKEN_LITERAL 259
+#define TOKEN_DIGIT 260
+
+/* Value type.  */
+#if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
+union YYSTYPE
+{
+#line 218 "../src/preproc/refer/label.ypp"
+
+  int num;
+  expression *expr;
+  struct { int ndigits; int val; } dig;
+  struct { int start; int len; } str;
+
+#line 340 "src/preproc/refer/label.cpp"
+
+};
+typedef union YYSTYPE YYSTYPE;
+# define YYSTYPE_IS_TRIVIAL 1
+# define YYSTYPE_IS_DECLARED 1
+#endif
+
+
+extern YYSTYPE yylval;
+
+
+int yyparse (void);
+
+
+#endif /* !YY_YY_SRC_PREPROC_REFER_LABEL_HPP_INCLUDED  */
+/* Symbol kind.  */
+enum yysymbol_kind_t
+{
+  YYSYMBOL_YYEMPTY = -2,
+  YYSYMBOL_YYEOF = 0,                      /* "end of file"  */
+  YYSYMBOL_YYerror = 1,                    /* error  */
+  YYSYMBOL_YYUNDEF = 2,                    /* "invalid token"  */
+  YYSYMBOL_TOKEN_LETTER = 3,               /* TOKEN_LETTER  */
+  YYSYMBOL_TOKEN_LITERAL = 4,              /* TOKEN_LITERAL  */
+  YYSYMBOL_TOKEN_DIGIT = 5,                /* TOKEN_DIGIT  */
+  YYSYMBOL_6_ = 6,                         /* '?'  */
+  YYSYMBOL_7_ = 7,                         /* ':'  */
+  YYSYMBOL_8_ = 8,                         /* '|'  */
+  YYSYMBOL_9_ = 9,                         /* '&'  */
+  YYSYMBOL_10_ = 10,                       /* '~'  */
+  YYSYMBOL_11_ = 11,                       /* '@'  */
+  YYSYMBOL_12_ = 12,                       /* '%'  */
+  YYSYMBOL_13_ = 13,                       /* '.'  */
+  YYSYMBOL_14_ = 14,                       /* '+'  */
+  YYSYMBOL_15_ = 15,                       /* '-'  */
+  YYSYMBOL_16_ = 16,                       /* '*'  */
+  YYSYMBOL_17_ = 17,                       /* '('  */
+  YYSYMBOL_18_ = 18,                       /* ')'  */
+  YYSYMBOL_19_ = 19,                       /* '<'  */
+  YYSYMBOL_20_ = 20,                       /* '>'  */
+  YYSYMBOL_YYACCEPT = 21,                  /* $accept  */
+  YYSYMBOL_expr = 22,                      /* expr  */
+  YYSYMBOL_conditional = 23,               /* conditional  */
+  YYSYMBOL_optional_conditional = 24,      /* optional_conditional  */
+  YYSYMBOL_alternative = 25,               /* alternative  */
+  YYSYMBOL_list = 26,                      /* list  */
+  YYSYMBOL_substitute = 27,                /* substitute  */
+  YYSYMBOL_string = 28,                    /* string  */
+  YYSYMBOL_optional_number = 29,           /* optional_number  */
+  YYSYMBOL_number = 30,                    /* number  */
+  YYSYMBOL_digits = 31,                    /* digits  */
+  YYSYMBOL_flag = 32                       /* flag  */
+};
+typedef enum yysymbol_kind_t yysymbol_kind_t;
+
+
+
+
+#ifdef short
+# undef short
+#endif
+
+/* On compilers that do not define __PTRDIFF_MAX__ etc., make sure
+   <limits.h> and (if available) <stdint.h> are included
+   so that the code can choose integer types of a good width.  */
+
+#ifndef __PTRDIFF_MAX__
+# include <limits.h> /* INFRINGES ON USER NAME SPACE */
+# if defined __STDC_VERSION__ && 199901 <= __STDC_VERSION__
+#  include <stdint.h> /* INFRINGES ON USER NAME SPACE */
+#  define YY_STDINT_H
+# endif
+#endif
+
+/* Narrow types that promote to a signed type and that can represent a
+   signed or unsigned integer of at least N bits.  In tables they can
+   save space and decrease cache pressure.  Promoting to a signed type
+   helps avoid bugs in integer arithmetic.  */
+
+#ifdef __INT_LEAST8_MAX__
+typedef __INT_LEAST8_TYPE__ yytype_int8;
+#elif defined YY_STDINT_H
+typedef int_least8_t yytype_int8;
+#else
+typedef signed char yytype_int8;
+#endif
+
+#ifdef __INT_LEAST16_MAX__
+typedef __INT_LEAST16_TYPE__ yytype_int16;
+#elif defined YY_STDINT_H
+typedef int_least16_t yytype_int16;
+#else
+typedef short yytype_int16;
+#endif
+
+/* Work around bug in HP-UX 11.23, which defines these macros
+   incorrectly for preprocessor constants.  This workaround can likely
+   be removed in 2023, as HPE has promised support for HP-UX 11.23
+   (aka HP-UX 11i v2) only through the end of 2022; see Table 2 of
+   <https://h20195.www2.hpe.com/V2/getpdf.aspx/4AA4-7673ENW.pdf>.  */
+#ifdef __hpux
+# undef UINT_LEAST8_MAX
+# undef UINT_LEAST16_MAX
+# define UINT_LEAST8_MAX 255
+# define UINT_LEAST16_MAX 65535
+#endif
+
+#if defined __UINT_LEAST8_MAX__ && __UINT_LEAST8_MAX__ <= __INT_MAX__
+typedef __UINT_LEAST8_TYPE__ yytype_uint8;
+#elif (!defined __UINT_LEAST8_MAX__ && defined YY_STDINT_H \
+       && UINT_LEAST8_MAX <= INT_MAX)
+typedef uint_least8_t yytype_uint8;
+#elif !defined __UINT_LEAST8_MAX__ && UCHAR_MAX <= INT_MAX
+typedef unsigned char yytype_uint8;
+#else
+typedef short yytype_uint8;
+#endif
+
+#if defined __UINT_LEAST16_MAX__ && __UINT_LEAST16_MAX__ <= __INT_MAX__
+typedef __UINT_LEAST16_TYPE__ yytype_uint16;
+#elif (!defined __UINT_LEAST16_MAX__ && defined YY_STDINT_H \
+       && UINT_LEAST16_MAX <= INT_MAX)
+typedef uint_least16_t yytype_uint16;
+#elif !defined __UINT_LEAST16_MAX__ && USHRT_MAX <= INT_MAX
+typedef unsigned short yytype_uint16;
+#else
+typedef int yytype_uint16;
+#endif
+
+#ifndef YYPTRDIFF_T
+# if defined __PTRDIFF_TYPE__ && defined __PTRDIFF_MAX__
+#  define YYPTRDIFF_T __PTRDIFF_TYPE__
+#  define YYPTRDIFF_MAXIMUM __PTRDIFF_MAX__
+# elif defined PTRDIFF_MAX
+#  ifndef ptrdiff_t
+#   include <stddef.h> /* INFRINGES ON USER NAME SPACE */
+#  endif
+#  define YYPTRDIFF_T ptrdiff_t
+#  define YYPTRDIFF_MAXIMUM PTRDIFF_MAX
+# else
+#  define YYPTRDIFF_T long
+#  define YYPTRDIFF_MAXIMUM LONG_MAX
+# endif
+#endif
+
+#ifndef YYSIZE_T
+# ifdef __SIZE_TYPE__
+#  define YYSIZE_T __SIZE_TYPE__
+# elif defined size_t
+#  define YYSIZE_T size_t
+# elif defined __STDC_VERSION__ && 199901 <= __STDC_VERSION__
+#  include <stddef.h> /* INFRINGES ON USER NAME SPACE */
+#  define YYSIZE_T size_t
+# else
+#  define YYSIZE_T unsigned
+# endif
+#endif
+
+#define YYSIZE_MAXIMUM                                  \
+  YY_CAST (YYPTRDIFF_T,                                 \
+           (YYPTRDIFF_MAXIMUM < YY_CAST (YYSIZE_T, -1)  \
+            ? YYPTRDIFF_MAXIMUM                         \
+            : YY_CAST (YYSIZE_T, -1)))
+
+#define YYSIZEOF(X) YY_CAST (YYPTRDIFF_T, sizeof (X))
+
+
+/* Stored state numbers (used for stacks). */
+typedef yytype_int8 yy_state_t;
+
+/* State numbers in computations.  */
+typedef int yy_state_fast_t;
+
+#ifndef YY_
+# if defined YYENABLE_NLS && YYENABLE_NLS
+#  if ENABLE_NLS
+#   include <libintl.h> /* INFRINGES ON USER NAME SPACE */
+#   define YY_(Msgid) dgettext ("bison-runtime", Msgid)
+#  endif
+# endif
+# ifndef YY_
+#  define YY_(Msgid) Msgid
+# endif
+#endif
+
+
+#ifndef YY_ATTRIBUTE_PURE
+# if defined __GNUC__ && 2 < __GNUC__ + (96 <= __GNUC_MINOR__)
+#  define YY_ATTRIBUTE_PURE __attribute__ ((__pure__))
+# else
+#  define YY_ATTRIBUTE_PURE
+# endif
+#endif
+
+#ifndef YY_ATTRIBUTE_UNUSED
+# if defined __GNUC__ && 2 < __GNUC__ + (7 <= __GNUC_MINOR__)
+#  define YY_ATTRIBUTE_UNUSED __attribute__ ((__unused__))
+# else
+#  define YY_ATTRIBUTE_UNUSED
+# endif
+#endif
+
+/* Suppress unused-variable warnings by "using" E.  */
+#if ! defined lint || defined __GNUC__
+# define YY_USE(E) ((void) (E))
+#else
+# define YY_USE(E) /* empty */
+#endif
+
+/* Suppress an incorrect diagnostic about yylval being uninitialized.  */
+#if defined __GNUC__ && ! defined __ICC && 406 <= __GNUC__ * 100 + __GNUC_MINOR__
+# if __GNUC__ * 100 + __GNUC_MINOR__ < 407
+#  define YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN                           \
+    _Pragma ("GCC diagnostic push")                                     \
+    _Pragma ("GCC diagnostic ignored \"-Wuninitialized\"")
+# else
+#  define YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN                           \
+    _Pragma ("GCC diagnostic push")                                     \
+    _Pragma ("GCC diagnostic ignored \"-Wuninitialized\"")              \
+    _Pragma ("GCC diagnostic ignored \"-Wmaybe-uninitialized\"")
+# endif
+# define YY_IGNORE_MAYBE_UNINITIALIZED_END      \
+    _Pragma ("GCC diagnostic pop")
+#else
+# define YY_INITIAL_VALUE(Value) Value
+#endif
+#ifndef YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+# define YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+# define YY_IGNORE_MAYBE_UNINITIALIZED_END
+#endif
+#ifndef YY_INITIAL_VALUE
+# define YY_INITIAL_VALUE(Value) /* Nothing. */
+#endif
+
+#if defined __cplusplus && defined __GNUC__ && ! defined __ICC && 6 <= __GNUC__
+# define YY_IGNORE_USELESS_CAST_BEGIN                          \
+    _Pragma ("GCC diagnostic push")                            \
+    _Pragma ("GCC diagnostic ignored \"-Wuseless-cast\"")
+# define YY_IGNORE_USELESS_CAST_END            \
+    _Pragma ("GCC diagnostic pop")
+#endif
+#ifndef YY_IGNORE_USELESS_CAST_BEGIN
+# define YY_IGNORE_USELESS_CAST_BEGIN
+# define YY_IGNORE_USELESS_CAST_END
+#endif
+
+
+#define YY_ASSERT(E) ((void) (0 && (E)))
+
+#if !defined yyoverflow
+
+/* The parser invokes alloca or malloc; define the necessary symbols.  */
+
+# ifdef YYSTACK_USE_ALLOCA
+#  if YYSTACK_USE_ALLOCA
+#   ifdef __GNUC__
+#    define YYSTACK_ALLOC __builtin_alloca
+#   elif defined __BUILTIN_VA_ARG_INCR
+#    include <alloca.h> /* INFRINGES ON USER NAME SPACE */
+#   elif defined _AIX
+#    define YYSTACK_ALLOC __alloca
+#   elif defined _MSC_VER
+#    include <malloc.h> /* INFRINGES ON USER NAME SPACE */
+#    define alloca _alloca
+#   else
+#    define YYSTACK_ALLOC alloca
+#    if ! defined _ALLOCA_H && ! defined EXIT_SUCCESS
+#     include <stdlib.h> /* INFRINGES ON USER NAME SPACE */
+      /* Use EXIT_SUCCESS as a witness for stdlib.h.  */
+#     ifndef EXIT_SUCCESS
+#      define EXIT_SUCCESS 0
+#     endif
+#    endif
+#   endif
+#  endif
+# endif
+
+# ifdef YYSTACK_ALLOC
+   /* Pacify GCC's 'empty if-body' warning.  */
+#  define YYSTACK_FREE(Ptr) do { /* empty */; } while (0)
+#  ifndef YYSTACK_ALLOC_MAXIMUM
+    /* The OS might guarantee only one guard page at the bottom of the stack,
+       and a page size can be as small as 4096 bytes.  So we cannot safely
+       invoke alloca (N) if N exceeds 4096.  Use a slightly smaller number
+       to allow for a few compiler-allocated temporary stack slots.  */
+#   define YYSTACK_ALLOC_MAXIMUM 4032 /* reasonable circa 2006 */
+#  endif
+# else
+#  define YYSTACK_ALLOC YYMALLOC
+#  define YYSTACK_FREE YYFREE
+#  ifndef YYSTACK_ALLOC_MAXIMUM
+#   define YYSTACK_ALLOC_MAXIMUM YYSIZE_MAXIMUM
+#  endif
+#  if (defined __cplusplus && ! defined EXIT_SUCCESS \
+       && ! ((defined YYMALLOC || defined malloc) \
+             && (defined YYFREE || defined free)))
+#   include <stdlib.h> /* INFRINGES ON USER NAME SPACE */
+#   ifndef EXIT_SUCCESS
+#    define EXIT_SUCCESS 0
+#   endif
+#  endif
+#  ifndef YYMALLOC
+#   define YYMALLOC malloc
+#   if ! defined malloc && ! defined EXIT_SUCCESS
+void *malloc (YYSIZE_T); /* INFRINGES ON USER NAME SPACE */
+#   endif
+#  endif
+#  ifndef YYFREE
+#   define YYFREE free
+#   if ! defined free && ! defined EXIT_SUCCESS
+void free (void *); /* INFRINGES ON USER NAME SPACE */
+#   endif
+#  endif
+# endif
+#endif /* !defined yyoverflow */
+
+#if (! defined yyoverflow \
+     && (! defined __cplusplus \
+         || (defined YYSTYPE_IS_TRIVIAL && YYSTYPE_IS_TRIVIAL)))
+
+/* A type that is properly aligned for any stack member.  */
+union yyalloc
+{
+  yy_state_t yyss_alloc;
+  YYSTYPE yyvs_alloc;
+};
+
+/* The size of the maximum gap between one aligned stack and the next.  */
+# define YYSTACK_GAP_MAXIMUM (YYSIZEOF (union yyalloc) - 1)
+
+/* The size of an array large to enough to hold all stacks, each with
+   N elements.  */
+# define YYSTACK_BYTES(N) \
+     ((N) * (YYSIZEOF (yy_state_t) + YYSIZEOF (YYSTYPE)) \
+      + YYSTACK_GAP_MAXIMUM)
+
+# define YYCOPY_NEEDED 1
+
+/* Relocate STACK from its old location to the new one.  The
+   local variables YYSIZE and YYSTACKSIZE give the old and new number of
+   elements in the stack, and YYPTR gives the new location of the
+   stack.  Advance YYPTR to a properly aligned location for the next
+   stack.  */
+# define YYSTACK_RELOCATE(Stack_alloc, Stack)                           \
+    do                                                                  \
+      {                                                                 \
+        YYPTRDIFF_T yynewbytes;                                         \
+        YYCOPY (&yyptr->Stack_alloc, Stack, yysize);                    \
+        Stack = &yyptr->Stack_alloc;                                    \
+        yynewbytes = yystacksize * YYSIZEOF (*Stack) + YYSTACK_GAP_MAXIMUM; \
+        yyptr += yynewbytes / YYSIZEOF (*yyptr);                        \
+      }                                                                 \
+    while (0)
+
+#endif
+
+#if defined YYCOPY_NEEDED && YYCOPY_NEEDED
+/* Copy COUNT objects from SRC to DST.  The source and destination do
+   not overlap.  */
+# ifndef YYCOPY
+#  if defined __GNUC__ && 1 < __GNUC__
+#   define YYCOPY(Dst, Src, Count) \
+      __builtin_memcpy (Dst, Src, YY_CAST (YYSIZE_T, (Count)) * sizeof (*(Src)))
+#  else
+#   define YYCOPY(Dst, Src, Count)              \
+      do                                        \
+        {                                       \
+          YYPTRDIFF_T yyi;                      \
+          for (yyi = 0; yyi < (Count); yyi++)   \
+            (Dst)[yyi] = (Src)[yyi];            \
+        }                                       \
+      while (0)
+#  endif
+# endif
+#endif /* !YYCOPY_NEEDED */
+
+/* YYFINAL -- State number of the termination state.  */
+#define YYFINAL  21
+/* YYLAST -- Last index in YYTABLE.  */
+#define YYLAST   39
+
+/* YYNTOKENS -- Number of terminals.  */
+#define YYNTOKENS  21
+/* YYNNTS -- Number of nonterminals.  */
+#define YYNNTS  12
+/* YYNRULES -- Number of rules.  */
+#define YYNRULES  34
+/* YYNSTATES -- Number of states.  */
+#define YYNSTATES  49
+
+/* YYMAXUTOK -- Last valid token kind.  */
+#define YYMAXUTOK   260
+
+
+/* YYTRANSLATE(TOKEN-NUM) -- Symbol number corresponding to TOKEN-NUM
+   as returned by yylex, with out-of-bounds checking.  */
+#define YYTRANSLATE(YYX)                                \
+  (0 <= (YYX) && (YYX) <= YYMAXUTOK                     \
+   ? YY_CAST (yysymbol_kind_t, yytranslate[YYX])        \
+   : YYSYMBOL_YYUNDEF)
+
+/* YYTRANSLATE[TOKEN-NUM] -- Symbol number corresponding to TOKEN-NUM
+   as returned by yylex.  */
+static const yytype_int8 yytranslate[] =
+{
+       0,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,    12,     9,     2,
+      17,    18,    16,    14,     2,    15,    13,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     7,     2,
+      19,     2,    20,     6,    11,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     8,     2,    10,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     2,     2,     2,     2,     1,     2,     3,     4,
+       5
+};
+
+#if YYDEBUG
+/* YYRLINE[YYN] -- Source line where rule number YYN was defined.  */
+static const yytype_int16 yyrline[] =
+{
+       0,   246,   246,   251,   253,   259,   260,   265,   267,   269,
+     274,   276,   281,   283,   288,   290,   295,   297,   299,   315,
+     319,   350,   352,   354,   356,   358,   364,   365,   370,   372,
+     377,   379,   386,   387,   389
+};
+#endif
+
+/** Accessing symbol of state STATE.  */
+#define YY_ACCESSING_SYMBOL(State) YY_CAST (yysymbol_kind_t, yystos[State])
+
+#if YYDEBUG || 0
+/* The user-facing name of the symbol whose (internal) number is
+   YYSYMBOL.  No bounds checking.  */
+static const char *yysymbol_name (yysymbol_kind_t yysymbol) YY_ATTRIBUTE_UNUSED;
+
+/* YYTNAME[SYMBOL-NUM] -- String name of the symbol SYMBOL-NUM.
+   First, the terminals, then, starting at YYNTOKENS, nonterminals.  */
+static const char *const yytname[] =
+{
+  "\"end of file\"", "error", "\"invalid token\"", "TOKEN_LETTER",
+  "TOKEN_LITERAL", "TOKEN_DIGIT", "'?'", "':'", "'|'", "'&'", "'~'", "'@'",
+  "'%'", "'.'", "'+'", "'-'", "'*'", "'('", "')'", "'<'", "'>'", "$accept",
+  "expr", "conditional", "optional_conditional", "alternative", "list",
+  "substitute", "string", "optional_number", "number", "digits", "flag", YY_NULLPTR
+};
+
+static const char *
+yysymbol_name (yysymbol_kind_t yysymbol)
+{
+  return yytname[yysymbol];
+}
+#endif
+
+#define YYPACT_NINF (-26)
+
+#define yypact_value_is_default(Yyn) \
+  ((Yyn) == YYPACT_NINF)
+
+#define YYTABLE_NINF (-1)
+
+#define yytable_value_is_error(Yyn) \
+  0
+
+/* YYPACT[STATE-NUM] -- Index in YYTABLE of the portion describing
+   STATE-NUM.  */
+static const yytype_int8 yypact[] =
+{
+       2,    11,   -26,   -26,    12,     2,     2,    24,   -26,   -26,
+      21,     2,    18,    -6,   -26,    26,   -26,   -26,    27,    15,
+      14,   -26,     2,     2,     2,    18,     2,    -3,    11,    11,
+     -26,   -26,   -26,   -26,   -26,    28,     2,     2,    -6,   -26,
+     -26,    33,    26,    26,     2,    11,   -26,   -26,    26
+};
+
+/* YYDEFACT[STATE-NUM] -- Default reduction number in state STATE-NUM.
+   Performed when YYTABLE does not specify something else to do.  Zero
+   means the default is an error.  */
+static const yytype_int8 yydefact[] =
+{
+       5,    16,    15,    14,     0,     5,     5,     0,     6,     2,
+       3,     7,    10,    12,    28,    17,    18,    30,    19,     0,
+       0,     1,     5,     0,     0,    11,     0,    32,     0,     0,
+      23,    29,    31,    24,    25,     0,     8,     9,    13,    33,
+      34,     0,    21,    22,     0,    26,     4,    20,    27
+};
+
+/* YYPGOTO[NTERM-NUM].  */
+static const yytype_int8 yypgoto[] =
+{
+     -26,   -26,    -7,    -4,   -26,    -1,   -11,    13,   -26,   -25,
+     -26,   -26
+};
+
+/* YYDEFGOTO[NTERM-NUM].  */
+static const yytype_int8 yydefgoto[] =
+{
+       0,     7,     8,     9,    10,    11,    12,    13,    47,    15,
+      18,    41
+};
+
+/* YYTABLE[YYPACT[STATE-NUM]] -- What to do in state STATE-NUM.  If
+   positive, shift that token.  If negative, reduce the rule whose
+   number is the opposite.  If YYTABLE_NINF, syntax error.  */
+static const yytype_int8 yytable[] =
+{
+      25,    19,    20,    42,    43,     1,     2,    27,    28,    29,
+      30,    39,    40,     3,     4,    16,    14,    17,    35,     5,
+      48,     6,    36,    37,    21,    25,    25,    22,    26,    23,
+      24,    31,    32,    33,    34,    44,    45,    46,     0,    38
+};
+
+static const yytype_int8 yycheck[] =
+{
+      11,     5,     6,    28,    29,     3,     4,    13,    14,    15,
+      16,    14,    15,    11,    12,     3,     5,     5,    22,    17,
+      45,    19,    23,    24,     0,    36,    37,     6,    10,     8,
+       9,     5,     5,    18,    20,     7,     3,    44,    -1,    26
+};
+
+/* YYSTOS[STATE-NUM] -- The symbol kind of the accessing symbol of
+   state STATE-NUM.  */
+static const yytype_int8 yystos[] =
+{
+       0,     3,     4,    11,    12,    17,    19,    22,    23,    24,
+      25,    26,    27,    28,     5,    30,     3,     5,    31,    24,
+      24,     0,     6,     8,     9,    27,    10,    13,    14,    15,
+      16,     5,     5,    18,    20,    24,    26,    26,    28,    14,
+      15,    32,    30,    30,     7,     3,    23,    29,    30
+};
+
+/* YYR1[RULE-NUM] -- Symbol kind of the left-hand side of rule RULE-NUM.  */
+static const yytype_int8 yyr1[] =
+{
+       0,    21,    22,    23,    23,    24,    24,    25,    25,    25,
+      26,    26,    27,    27,    28,    28,    28,    28,    28,    28,
+      28,    28,    28,    28,    28,    28,    29,    29,    30,    30,
+      31,    31,    32,    32,    32
+};
+
+/* YYR2[RULE-NUM] -- Number of symbols on the right-hand side of rule RULE-NUM.  */
+static const yytype_int8 yyr2[] =
+{
+       0,     2,     1,     1,     5,     0,     1,     1,     3,     3,
+       1,     2,     1,     3,     1,     1,     1,     2,     2,     2,
+       5,     3,     3,     2,     3,     3,     0,     1,     1,     2,
+       1,     2,     0,     1,     1
+};
+
+
+enum { YYENOMEM = -2 };
+
+#define yyerrok         (yyerrstatus = 0)
+#define yyclearin       (yychar = YYEMPTY)
+
+#define YYACCEPT        goto yyacceptlab
+#define YYABORT         goto yyabortlab
+#define YYERROR         goto yyerrorlab
+#define YYNOMEM         goto yyexhaustedlab
+
+
+#define YYRECOVERING()  (!!yyerrstatus)
+
+#define YYBACKUP(Token, Value)                                    \
+  do                                                              \
+    if (yychar == YYEMPTY)                                        \
+      {                                                           \
+        yychar = (Token);                                         \
+        yylval = (Value);                                         \
+        YYPOPSTACK (yylen);                                       \
+        yystate = *yyssp;                                         \
+        goto yybackup;                                            \
+      }                                                           \
+    else                                                          \
+      {                                                           \
+        yyerror (YY_("syntax error: cannot back up")); \
+        YYERROR;                                                  \
+      }                                                           \
+  while (0)
+
+/* Backward compatibility with an undocumented macro.
+   Use YYerror or YYUNDEF. */
+#define YYERRCODE YYUNDEF
+
+
+/* Enable debugging if requested.  */
+#if YYDEBUG
+
+# ifndef YYFPRINTF
+#  include <stdio.h> /* INFRINGES ON USER NAME SPACE */
+#  define YYFPRINTF fprintf
+# endif
+
+# define YYDPRINTF(Args)                        \
+do {                                            \
+  if (yydebug)                                  \
+    YYFPRINTF Args;                             \
+} while (0)
+
+
+
+
+# define YY_SYMBOL_PRINT(Title, Kind, Value, Location)                    \
+do {                                                                      \
+  if (yydebug)                                                            \
+    {                                                                     \
+      YYFPRINTF (stderr, "%s ", Title);                                   \
+      yy_symbol_print (stderr,                                            \
+                  Kind, Value); \
+      YYFPRINTF (stderr, "\n");                                           \
+    }                                                                     \
+} while (0)
+
+
+/*-----------------------------------.
+| Print this symbol's value on YYO.  |
+`-----------------------------------*/
+
+static void
+yy_symbol_value_print (FILE *yyo,
+                       yysymbol_kind_t yykind, YYSTYPE const * const yyvaluep)
+{
+  FILE *yyoutput = yyo;
+  YY_USE (yyoutput);
+  if (!yyvaluep)
+    return;
+  YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+  YY_USE (yykind);
+  YY_IGNORE_MAYBE_UNINITIALIZED_END
+}
+
+
+/*---------------------------.
+| Print this symbol on YYO.  |
+`---------------------------*/
+
+static void
+yy_symbol_print (FILE *yyo,
+                 yysymbol_kind_t yykind, YYSTYPE const * const yyvaluep)
+{
+  YYFPRINTF (yyo, "%s %s (",
+             yykind < YYNTOKENS ? "token" : "nterm", yysymbol_name (yykind));
+
+  yy_symbol_value_print (yyo, yykind, yyvaluep);
+  YYFPRINTF (yyo, ")");
+}
+
+/*------------------------------------------------------------------.
+| yy_stack_print -- Print the state stack from its BOTTOM up to its |
+| TOP (included).                                                   |
+`------------------------------------------------------------------*/
+
+static void
+yy_stack_print (yy_state_t *yybottom, yy_state_t *yytop)
+{
+  YYFPRINTF (stderr, "Stack now");
+  for (; yybottom <= yytop; yybottom++)
+    {
+      int yybot = *yybottom;
+      YYFPRINTF (stderr, " %d", yybot);
+    }
+  YYFPRINTF (stderr, "\n");
+}
+
+# define YY_STACK_PRINT(Bottom, Top)                            \
+do {                                                            \
+  if (yydebug)                                                  \
+    yy_stack_print ((Bottom), (Top));                           \
+} while (0)
+
+
+/*------------------------------------------------.
+| Report that the YYRULE is going to be reduced.  |
+`------------------------------------------------*/
+
+static void
+yy_reduce_print (yy_state_t *yyssp, YYSTYPE *yyvsp,
+                 int yyrule)
+{
+  int yylno = yyrline[yyrule];
+  int yynrhs = yyr2[yyrule];
+  int yyi;
+  YYFPRINTF (stderr, "Reducing stack by rule %d (line %d):\n",
+             yyrule - 1, yylno);
+  /* The symbols being reduced.  */
+  for (yyi = 0; yyi < yynrhs; yyi++)
+    {
+      YYFPRINTF (stderr, "   $%d = ", yyi + 1);
+      yy_symbol_print (stderr,
+                       YY_ACCESSING_SYMBOL (+yyssp[yyi + 1 - yynrhs]),
+                       &yyvsp[(yyi + 1) - (yynrhs)]);
+      YYFPRINTF (stderr, "\n");
+    }
+}
+
+# define YY_REDUCE_PRINT(Rule)          \
+do {                                    \
+  if (yydebug)                          \
+    yy_reduce_print (yyssp, yyvsp, Rule); \
+} while (0)
+
+/* Nonzero means print parse trace.  It is left uninitialized so that
+   multiple parsers can coexist.  */
+int yydebug;
+#else /* !YYDEBUG */
+# define YYDPRINTF(Args) ((void) 0)
+# define YY_SYMBOL_PRINT(Title, Kind, Value, Location)
+# define YY_STACK_PRINT(Bottom, Top)
+# define YY_REDUCE_PRINT(Rule)
+#endif /* !YYDEBUG */
+
+
+/* YYINITDEPTH -- initial size of the parser's stacks.  */
+#ifndef YYINITDEPTH
+# define YYINITDEPTH 200
+#endif
+
+/* YYMAXDEPTH -- maximum size the stacks can grow to (effective only
+   if the built-in stack extension method is used).
+
+   Do not make this value too large; the results are undefined if
+   YYSTACK_ALLOC_MAXIMUM < YYSTACK_BYTES (YYMAXDEPTH)
+   evaluated with infinite-precision integer arithmetic.  */
+
+#ifndef YYMAXDEPTH
+# define YYMAXDEPTH 10000
+#endif
+
+
+
+
+
+
+/*-----------------------------------------------.
+| Release the memory associated to this symbol.  |
+`-----------------------------------------------*/
+
+static void
+yydestruct (const char *yymsg,
+            yysymbol_kind_t yykind, YYSTYPE *yyvaluep)
+{
+  YY_USE (yyvaluep);
+  if (!yymsg)
+    yymsg = "Deleting";
+  YY_SYMBOL_PRINT (yymsg, yykind, yyvaluep, yylocationp);
+
+  YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+  YY_USE (yykind);
+  YY_IGNORE_MAYBE_UNINITIALIZED_END
+}
+
+
+/* Lookahead token kind.  */
+int yychar;
+
+/* The semantic value of the lookahead symbol.  */
+YYSTYPE yylval;
+/* Number of syntax errors so far.  */
+int yynerrs;
+
+
+
+
+/*----------.
+| yyparse.  |
+`----------*/
+
+int
+yyparse (void)
+{
+    yy_state_fast_t yystate = 0;
+    /* Number of tokens to shift before error messages enabled.  */
+    int yyerrstatus = 0;
+
+    /* Refer to the stacks through separate pointers, to allow yyoverflow
+       to reallocate them elsewhere.  */
+
+    /* Their size.  */
+    YYPTRDIFF_T yystacksize = YYINITDEPTH;
+
+    /* The state stack: array, bottom, top.  */
+    yy_state_t yyssa[YYINITDEPTH];
+    yy_state_t *yyss = yyssa;
+    yy_state_t *yyssp = yyss;
+
+    /* The semantic value stack: array, bottom, top.  */
+    YYSTYPE yyvsa[YYINITDEPTH];
+    YYSTYPE *yyvs = yyvsa;
+    YYSTYPE *yyvsp = yyvs;
+
+  int yyn;
+  /* The return value of yyparse.  */
+  int yyresult;
+  /* Lookahead symbol kind.  */
+  yysymbol_kind_t yytoken = YYSYMBOL_YYEMPTY;
+  /* The variables used to return semantic value and location from the
+     action routines.  */
+  YYSTYPE yyval;
+
+
+
+#define YYPOPSTACK(N)   (yyvsp -= (N), yyssp -= (N))
+
+  /* The number of symbols on the RHS of the reduced rule.
+     Keep to zero when no symbol should be popped.  */
+  int yylen = 0;
+
+  YYDPRINTF ((stderr, "Starting parse\n"));
+
+  yychar = YYEMPTY; /* Cause a token to be read.  */
+
+  goto yysetstate;
+
+
+/*------------------------------------------------------------.
+| yynewstate -- push a new state, which is found in yystate.  |
+`------------------------------------------------------------*/
+yynewstate:
+  /* In all cases, when you get here, the value and location stacks
+     have just been pushed.  So pushing a state here evens the stacks.  */
+  yyssp++;
+
+
+/*--------------------------------------------------------------------.
+| yysetstate -- set current state (the top of the stack) to yystate.  |
+`--------------------------------------------------------------------*/
+yysetstate:
+  YYDPRINTF ((stderr, "Entering state %d\n", yystate));
+  YY_ASSERT (0 <= yystate && yystate < YYNSTATES);
+  YY_IGNORE_USELESS_CAST_BEGIN
+  *yyssp = YY_CAST (yy_state_t, yystate);
+  YY_IGNORE_USELESS_CAST_END
+  YY_STACK_PRINT (yyss, yyssp);
+
+  if (yyss + yystacksize - 1 <= yyssp)
+#if !defined yyoverflow && !defined YYSTACK_RELOCATE
+    YYNOMEM;
+#else
+    {
+      /* Get the current used size of the three stacks, in elements.  */
+      YYPTRDIFF_T yysize = yyssp - yyss + 1;
+
+# if defined yyoverflow
+      {
+        /* Give user a chance to reallocate the stack.  Use copies of
+           these so that the &'s don't force the real ones into
+           memory.  */
+        yy_state_t *yyss1 = yyss;
+        YYSTYPE *yyvs1 = yyvs;
+
+        /* Each stack pointer address is followed by the size of the
+           data in use in that stack, in bytes.  This used to be a
+           conditional around just the two extra args, but that might
+           be undefined if yyoverflow is a macro.  */
+        yyoverflow (YY_("memory exhausted"),
+                    &yyss1, yysize * YYSIZEOF (*yyssp),
+                    &yyvs1, yysize * YYSIZEOF (*yyvsp),
+                    &yystacksize);
+        yyss = yyss1;
+        yyvs = yyvs1;
+      }
+# else /* defined YYSTACK_RELOCATE */
+      /* Extend the stack our own way.  */
+      if (YYMAXDEPTH <= yystacksize)
+        YYNOMEM;
+      yystacksize *= 2;
+      if (YYMAXDEPTH < yystacksize)
+        yystacksize = YYMAXDEPTH;
+
+      {
+        yy_state_t *yyss1 = yyss;
+        union yyalloc *yyptr =
+          YY_CAST (union yyalloc *,
+                   YYSTACK_ALLOC (YY_CAST (YYSIZE_T, YYSTACK_BYTES (yystacksize))));
+        if (! yyptr)
+          YYNOMEM;
+        YYSTACK_RELOCATE (yyss_alloc, yyss);
+        YYSTACK_RELOCATE (yyvs_alloc, yyvs);
+#  undef YYSTACK_RELOCATE
+        if (yyss1 != yyssa)
+          YYSTACK_FREE (yyss1);
+      }
+# endif
+
+      yyssp = yyss + yysize - 1;
+      yyvsp = yyvs + yysize - 1;
+
+      YY_IGNORE_USELESS_CAST_BEGIN
+      YYDPRINTF ((stderr, "Stack size increased to %ld\n",
+                  YY_CAST (long, yystacksize)));
+      YY_IGNORE_USELESS_CAST_END
+
+      if (yyss + yystacksize - 1 <= yyssp)
+        YYABORT;
+    }
+#endif /* !defined yyoverflow && !defined YYSTACK_RELOCATE */
+
+
+  if (yystate == YYFINAL)
+    YYACCEPT;
+
+  goto yybackup;
+
+
+/*-----------.
+| yybackup.  |
+`-----------*/
+yybackup:
+  /* Do appropriate processing given the current state.  Read a
+     lookahead token if we need one and don't already have one.  */
+
+  /* First try to decide what to do without reference to lookahead token.  */
+  yyn = yypact[yystate];
+  if (yypact_value_is_default (yyn))
+    goto yydefault;
+
+  /* Not known => get a lookahead token if don't already have one.  */
+
+  /* YYCHAR is either empty, or end-of-input, or a valid lookahead.  */
+  if (yychar == YYEMPTY)
+    {
+      YYDPRINTF ((stderr, "Reading a token\n"));
+      yychar = yylex ();
+    }
+
+  if (yychar <= YYEOF)
+    {
+      yychar = YYEOF;
+      yytoken = YYSYMBOL_YYEOF;
+      YYDPRINTF ((stderr, "Now at end of input.\n"));
+    }
+  else if (yychar == YYerror)
+    {
+      /* The scanner already issued an error message, process directly
+         to error recovery.  But do not keep the error token as
+         lookahead, it is too special and may lead us to an endless
+         loop in error recovery. */
+      yychar = YYUNDEF;
+      yytoken = YYSYMBOL_YYerror;
+      goto yyerrlab1;
+    }
+  else
+    {
+      yytoken = YYTRANSLATE (yychar);
+      YY_SYMBOL_PRINT ("Next token is", yytoken, &yylval, &yylloc);
+    }
+
+  /* If the proper action on seeing token YYTOKEN is to reduce or to
+     detect an error, take that action.  */
+  yyn += yytoken;
+  if (yyn < 0 || YYLAST < yyn || yycheck[yyn] != yytoken)
+    goto yydefault;
+  yyn = yytable[yyn];
+  if (yyn <= 0)
+    {
+      if (yytable_value_is_error (yyn))
+        goto yyerrlab;
+      yyn = -yyn;
+      goto yyreduce;
+    }
+
+  /* Count tokens shifted since error; after three, turn off error
+     status.  */
+  if (yyerrstatus)
+    yyerrstatus--;
+
+  /* Shift the lookahead token.  */
+  YY_SYMBOL_PRINT ("Shifting", yytoken, &yylval, &yylloc);
+  yystate = yyn;
+  YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+  *++yyvsp = yylval;
+  YY_IGNORE_MAYBE_UNINITIALIZED_END
+
+  /* Discard the shifted token.  */
+  yychar = YYEMPTY;
+  goto yynewstate;
+
+
+/*-----------------------------------------------------------.
+| yydefault -- do the default action for the current state.  |
+`-----------------------------------------------------------*/
+yydefault:
+  yyn = yydefact[yystate];
+  if (yyn == 0)
+    goto yyerrlab;
+  goto yyreduce;
+
+
+/*-----------------------------.
+| yyreduce -- do a reduction.  |
+`-----------------------------*/
+yyreduce:
+  /* yyn is the number of a rule to reduce with.  */
+  yylen = yyr2[yyn];
+
+  /* If YYLEN is nonzero, implement the default value of the action:
+     '$$ = $1'.
+
+     Otherwise, the following line sets YYVAL to garbage.
+     This behavior is undocumented and Bison
+     users should not rely upon it.  Assigning to YYVAL
+     unconditionally makes the parser a bit smaller, and it avoids a
+     GCC warning that YYVAL may be used uninitialized.  */
+  yyval = yyvsp[1-yylen];
+
+
+  YY_REDUCE_PRINT (yyn);
+  switch (yyn)
+    {
+  case 2: /* expr: optional_conditional  */
+#line 247 "../src/preproc/refer/label.ypp"
+                { parse_result = ((yyvsp[0].expr) ? new analyzed_expr((yyvsp[0].expr)) : 0); }
+#line 1370 "src/preproc/refer/label.cpp"
+    break;
+
+  case 3: /* conditional: alternative  */
+#line 252 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = (yyvsp[0].expr); }
+#line 1376 "src/preproc/refer/label.cpp"
+    break;
+
+  case 4: /* conditional: alternative '?' optional_conditional ':' conditional  */
+#line 254 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = new conditional_expr((yyvsp[-4].expr), (yyvsp[-2].expr), (yyvsp[0].expr)); }
+#line 1382 "src/preproc/refer/label.cpp"
+    break;
+
+  case 5: /* optional_conditional: %empty  */
+#line 259 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = 0; }
+#line 1388 "src/preproc/refer/label.cpp"
+    break;
+
+  case 6: /* optional_conditional: conditional  */
+#line 261 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = (yyvsp[0].expr); }
+#line 1394 "src/preproc/refer/label.cpp"
+    break;
+
+  case 7: /* alternative: list  */
+#line 266 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = (yyvsp[0].expr); }
+#line 1400 "src/preproc/refer/label.cpp"
+    break;
+
+  case 8: /* alternative: alternative '|' list  */
+#line 268 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = new alternative_expr((yyvsp[-2].expr), (yyvsp[0].expr)); }
+#line 1406 "src/preproc/refer/label.cpp"
+    break;
+
+  case 9: /* alternative: alternative '&' list  */
+#line 270 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = new conditional_expr((yyvsp[-2].expr), (yyvsp[0].expr), 0); }
+#line 1412 "src/preproc/refer/label.cpp"
+    break;
+
+  case 10: /* list: substitute  */
+#line 275 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = (yyvsp[0].expr); }
+#line 1418 "src/preproc/refer/label.cpp"
+    break;
+
+  case 11: /* list: list substitute  */
+#line 277 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = new list_expr((yyvsp[-1].expr), (yyvsp[0].expr)); }
+#line 1424 "src/preproc/refer/label.cpp"
+    break;
+
+  case 12: /* substitute: string  */
+#line 282 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = (yyvsp[0].expr); }
+#line 1430 "src/preproc/refer/label.cpp"
+    break;
+
+  case 13: /* substitute: substitute '~' string  */
+#line 284 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = new substitute_expr((yyvsp[-2].expr), (yyvsp[0].expr)); }
+#line 1436 "src/preproc/refer/label.cpp"
+    break;
+
+  case 14: /* string: '@'  */
+#line 289 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = new at_expr; }
+#line 1442 "src/preproc/refer/label.cpp"
+    break;
+
+  case 15: /* string: TOKEN_LITERAL  */
+#line 291 "../src/preproc/refer/label.ypp"
+                {
+		  (yyval.expr) = new literal_expr(literals.contents() + (yyvsp[0].str).start,
+					(yyvsp[0].str).len);
+		}
+#line 1451 "src/preproc/refer/label.cpp"
+    break;
+
+  case 16: /* string: TOKEN_LETTER  */
+#line 296 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = new field_expr((yyvsp[0].num), 0); }
+#line 1457 "src/preproc/refer/label.cpp"
+    break;
+
+  case 17: /* string: TOKEN_LETTER number  */
+#line 298 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = new field_expr((yyvsp[-1].num), (yyvsp[0].num) - 1); }
+#line 1463 "src/preproc/refer/label.cpp"
+    break;
+
+  case 18: /* string: '%' TOKEN_LETTER  */
+#line 300 "../src/preproc/refer/label.ypp"
+                {
+		  switch ((yyvsp[0].num)) {
+		  case 'I':
+		  case 'i':
+		  case 'A':
+		  case 'a':
+		    (yyval.expr) = new format_expr((yyvsp[0].num));
+		    break;
+		  default:
+		    command_error("unrecognized format '%1'", char((yyvsp[0].num)));
+		    (yyval.expr) = new format_expr('a');
+		    break;
+		  }
+		}
+#line 1482 "src/preproc/refer/label.cpp"
+    break;
+
+  case 19: /* string: '%' digits  */
+#line 316 "../src/preproc/refer/label.ypp"
+                {
+		  (yyval.expr) = new format_expr('0', (yyvsp[0].dig).ndigits, (yyvsp[0].dig).val);
+		}
+#line 1490 "src/preproc/refer/label.cpp"
+    break;
+
+  case 20: /* string: string '.' flag TOKEN_LETTER optional_number  */
+#line 320 "../src/preproc/refer/label.ypp"
+                {
+		  switch ((yyvsp[-1].num)) {
+		  case 'l':
+		    (yyval.expr) = new map_expr((yyvsp[-4].expr), lowercase);
+		    break;
+		  case 'u':
+		    (yyval.expr) = new map_expr((yyvsp[-4].expr), uppercase);
+		    break;
+		  case 'c':
+		    (yyval.expr) = new map_expr((yyvsp[-4].expr), capitalize);
+		    break;
+		  case 'r':
+		    (yyval.expr) = new map_expr((yyvsp[-4].expr), reverse_name);
+		    break;
+		  case 'a':
+		    (yyval.expr) = new map_expr((yyvsp[-4].expr), abbreviate_name);
+		    break;
+		  case 'y':
+		    (yyval.expr) = new extractor_expr((yyvsp[-4].expr), find_year, (yyvsp[-2].num));
+		    break;
+		  case 'n':
+		    (yyval.expr) = new extractor_expr((yyvsp[-4].expr), find_last_name, (yyvsp[-2].num));
+		    break;
+		  default:
+		    (yyval.expr) = (yyvsp[-4].expr);
+		    command_error("unknown function '%1'", char((yyvsp[-1].num)));
+		    break;
+		  }
+		}
+#line 1524 "src/preproc/refer/label.cpp"
+    break;
+
+  case 21: /* string: string '+' number  */
+#line 351 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = new truncate_expr((yyvsp[-2].expr), (yyvsp[0].num)); }
+#line 1530 "src/preproc/refer/label.cpp"
+    break;
+
+  case 22: /* string: string '-' number  */
+#line 353 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = new truncate_expr((yyvsp[-2].expr), -(yyvsp[0].num)); }
+#line 1536 "src/preproc/refer/label.cpp"
+    break;
+
+  case 23: /* string: string '*'  */
+#line 355 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = new star_expr((yyvsp[-1].expr)); }
+#line 1542 "src/preproc/refer/label.cpp"
+    break;
+
+  case 24: /* string: '(' optional_conditional ')'  */
+#line 357 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = (yyvsp[-1].expr); }
+#line 1548 "src/preproc/refer/label.cpp"
+    break;
+
+  case 25: /* string: '<' optional_conditional '>'  */
+#line 359 "../src/preproc/refer/label.ypp"
+                { (yyval.expr) = new separator_expr((yyvsp[-1].expr)); }
+#line 1554 "src/preproc/refer/label.cpp"
+    break;
+
+  case 26: /* optional_number: %empty  */
+#line 364 "../src/preproc/refer/label.ypp"
+                { (yyval.num) = -1; }
+#line 1560 "src/preproc/refer/label.cpp"
+    break;
+
+  case 27: /* optional_number: number  */
+#line 366 "../src/preproc/refer/label.ypp"
+                { (yyval.num) = (yyvsp[0].num); }
+#line 1566 "src/preproc/refer/label.cpp"
+    break;
+
+  case 28: /* number: TOKEN_DIGIT  */
+#line 371 "../src/preproc/refer/label.ypp"
+                { (yyval.num) = (yyvsp[0].num); }
+#line 1572 "src/preproc/refer/label.cpp"
+    break;
+
+  case 29: /* number: number TOKEN_DIGIT  */
+#line 373 "../src/preproc/refer/label.ypp"
+                { (yyval.num) = (yyvsp[-1].num)*10 + (yyvsp[0].num); }
+#line 1578 "src/preproc/refer/label.cpp"
+    break;
+
+  case 30: /* digits: TOKEN_DIGIT  */
+#line 378 "../src/preproc/refer/label.ypp"
+                { (yyval.dig).ndigits = 1; (yyval.dig).val = (yyvsp[0].num); }
+#line 1584 "src/preproc/refer/label.cpp"
+    break;
+
+  case 31: /* digits: digits TOKEN_DIGIT  */
+#line 380 "../src/preproc/refer/label.ypp"
+                { (yyval.dig).ndigits = (yyvsp[-1].dig).ndigits + 1; (yyval.dig).val = (yyvsp[-1].dig).val*10 + (yyvsp[0].num); }
+#line 1590 "src/preproc/refer/label.cpp"
+    break;
+
+  case 32: /* flag: %empty  */
+#line 386 "../src/preproc/refer/label.ypp"
+                { (yyval.num) = 0; }
+#line 1596 "src/preproc/refer/label.cpp"
+    break;
+
+  case 33: /* flag: '+'  */
+#line 388 "../src/preproc/refer/label.ypp"
+                { (yyval.num) = 1; }
+#line 1602 "src/preproc/refer/label.cpp"
+    break;
+
+  case 34: /* flag: '-'  */
+#line 390 "../src/preproc/refer/label.ypp"
+                { (yyval.num) = -1; }
+#line 1608 "src/preproc/refer/label.cpp"
+    break;
+
+
+#line 1612 "src/preproc/refer/label.cpp"
+
+      default: break;
+    }
+  /* User semantic actions sometimes alter yychar, and that requires
+     that yytoken be updated with the new translation.  We take the
+     approach of translating immediately before every use of yytoken.
+     One alternative is translating here after every semantic action,
+     but that translation would be missed if the semantic action invokes
+     YYABORT, YYACCEPT, or YYERROR immediately after altering yychar or
+     if it invokes YYBACKUP.  In the case of YYABORT or YYACCEPT, an
+     incorrect destructor might then be invoked immediately.  In the
+     case of YYERROR or YYBACKUP, subsequent parser actions might lead
+     to an incorrect destructor call or verbose syntax error message
+     before the lookahead is translated.  */
+  YY_SYMBOL_PRINT ("-> $$ =", YY_CAST (yysymbol_kind_t, yyr1[yyn]), &yyval, &yyloc);
+
+  YYPOPSTACK (yylen);
+  yylen = 0;
+
+  *++yyvsp = yyval;
+
+  /* Now 'shift' the result of the reduction.  Determine what state
+     that goes to, based on the state we popped back to and the rule
+     number reduced by.  */
+  {
+    const int yylhs = yyr1[yyn] - YYNTOKENS;
+    const int yyi = yypgoto[yylhs] + *yyssp;
+    yystate = (0 <= yyi && yyi <= YYLAST && yycheck[yyi] == *yyssp
+               ? yytable[yyi]
+               : yydefgoto[yylhs]);
+  }
+
+  goto yynewstate;
+
+
+/*--------------------------------------.
+| yyerrlab -- here on detecting error.  |
+`--------------------------------------*/
+yyerrlab:
+  /* Make sure we have latest lookahead translation.  See comments at
+     user semantic actions for why this is necessary.  */
+  yytoken = yychar == YYEMPTY ? YYSYMBOL_YYEMPTY : YYTRANSLATE (yychar);
+  /* If not already recovering from an error, report this error.  */
+  if (!yyerrstatus)
+    {
+      ++yynerrs;
+      yyerror (YY_("syntax error"));
+    }
+
+  if (yyerrstatus == 3)
+    {
+      /* If just tried and failed to reuse lookahead token after an
+         error, discard it.  */
+
+      if (yychar <= YYEOF)
+        {
+          /* Return failure if at end of input.  */
+          if (yychar == YYEOF)
+            YYABORT;
+        }
+      else
+        {
+          yydestruct ("Error: discarding",
+                      yytoken, &yylval);
+          yychar = YYEMPTY;
+        }
+    }
+
+  /* Else will try to reuse lookahead token after shifting the error
+     token.  */
+  goto yyerrlab1;
+
+
+/*---------------------------------------------------.
+| yyerrorlab -- error raised explicitly by YYERROR.  |
+`---------------------------------------------------*/
+yyerrorlab:
+  /* Pacify compilers when the user code never invokes YYERROR and the
+     label yyerrorlab therefore never appears in user code.  */
+  if (0)
+    YYERROR;
+  ++yynerrs;
+
+  /* Do not reclaim the symbols of the rule whose action triggered
+     this YYERROR.  */
+  YYPOPSTACK (yylen);
+  yylen = 0;
+  YY_STACK_PRINT (yyss, yyssp);
+  yystate = *yyssp;
+  goto yyerrlab1;
+
+
+/*-------------------------------------------------------------.
+| yyerrlab1 -- common code for both syntax error and YYERROR.  |
+`-------------------------------------------------------------*/
+yyerrlab1:
+  yyerrstatus = 3;      /* Each real token shifted decrements this.  */
+
+  /* Pop stack until we find a state that shifts the error token.  */
+  for (;;)
+    {
+      yyn = yypact[yystate];
+      if (!yypact_value_is_default (yyn))
+        {
+          yyn += YYSYMBOL_YYerror;
+          if (0 <= yyn && yyn <= YYLAST && yycheck[yyn] == YYSYMBOL_YYerror)
+            {
+              yyn = yytable[yyn];
+              if (0 < yyn)
+                break;
+            }
+        }
+
+      /* Pop the current state because it cannot handle the error token.  */
+      if (yyssp == yyss)
+        YYABORT;
+
+
+      yydestruct ("Error: popping",
+                  YY_ACCESSING_SYMBOL (yystate), yyvsp);
+      YYPOPSTACK (1);
+      yystate = *yyssp;
+      YY_STACK_PRINT (yyss, yyssp);
+    }
+
+  YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+  *++yyvsp = yylval;
+  YY_IGNORE_MAYBE_UNINITIALIZED_END
+
+
+  /* Shift the error token.  */
+  YY_SYMBOL_PRINT ("Shifting", YY_ACCESSING_SYMBOL (yyn), yyvsp, yylsp);
+
+  yystate = yyn;
+  goto yynewstate;
+
+
+/*-------------------------------------.
+| yyacceptlab -- YYACCEPT comes here.  |
+`-------------------------------------*/
+yyacceptlab:
+  yyresult = 0;
+  goto yyreturnlab;
+
+
+/*-----------------------------------.
+| yyabortlab -- YYABORT comes here.  |
+`-----------------------------------*/
+yyabortlab:
+  yyresult = 1;
+  goto yyreturnlab;
+
+
+/*-----------------------------------------------------------.
+| yyexhaustedlab -- YYNOMEM (memory exhaustion) comes here.  |
+`-----------------------------------------------------------*/
+yyexhaustedlab:
+  yyerror (YY_("memory exhausted"));
+  yyresult = 2;
+  goto yyreturnlab;
+
+
+/*----------------------------------------------------------.
+| yyreturnlab -- parsing is finished, clean up and return.  |
+`----------------------------------------------------------*/
+yyreturnlab:
+  if (yychar != YYEMPTY)
+    {
+      /* Make sure we have latest lookahead translation.  See comments at
+         user semantic actions for why this is necessary.  */
+      yytoken = YYTRANSLATE (yychar);
+      yydestruct ("Cleanup: discarding lookahead",
+                  yytoken, &yylval);
+    }
+  /* Do not reclaim the symbols of the rule whose action triggered
+     this YYABORT or YYACCEPT.  */
+  YYPOPSTACK (yylen);
+  YY_STACK_PRINT (yyss, yyssp);
+  while (yyssp != yyss)
+    {
+      yydestruct ("Cleanup: popping",
+                  YY_ACCESSING_SYMBOL (+*yyssp), yyvsp);
+      YYPOPSTACK (1);
+    }
+#ifndef yyoverflow
+  if (yyss != yyssa)
+    YYSTACK_FREE (yyss);
+#endif
+
+  return yyresult;
+}
+
+#line 393 "../src/preproc/refer/label.ypp"
+
+
+/* bison defines const to be empty unless __STDC__ is defined, which it
+isn't under cfront */
+
+#ifdef const
+#undef const
+#endif
+
+const char *spec_ptr;
+const char *spec_end;
+const char *spec_cur;
+
+static char uppercase_array[] = {
+  'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
+  'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
+  'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
+  'Y', 'Z',
+};
+  
+static char lowercase_array[] = {
+  'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h',
+  'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p',
+  'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
+  'y', 'z',
+};
+
+int yylex()
+{
+  while (spec_ptr < spec_end && csspace(*spec_ptr))
+    spec_ptr++;
+  spec_cur = spec_ptr;
+  if (spec_ptr >= spec_end)
+    return 0;
+  unsigned char c = *spec_ptr++;
+  if (csalpha(c)) {
+    yylval.num = c;
+    return TOKEN_LETTER;
+  }
+  if (csdigit(c)) {
+    yylval.num = c - '0';
+    return TOKEN_DIGIT;
+  }
+  if (c == '\'') {
+    yylval.str.start = literals.length();
+    for (; spec_ptr < spec_end; spec_ptr++) {
+      if (*spec_ptr == '\'') {
+	if (++spec_ptr < spec_end && *spec_ptr == '\'')
+	  literals += '\'';
+	else {
+	  yylval.str.len = literals.length() - yylval.str.start;
+	  return TOKEN_LITERAL;
+	}
+      }
+      else
+	literals += *spec_ptr;
+    }
+    yylval.str.len = literals.length() - yylval.str.start;
+    return TOKEN_LITERAL;
+  }
+  return c;
+}
+
+int set_label_spec(const char *label_spec)
+{
+  spec_cur = spec_ptr = label_spec;
+  spec_end = strchr(label_spec, '\0');
+  literals.clear();
+  if (yyparse())
+    return 0;
+  delete parsed_label;
+  parsed_label = parse_result;
+  return 1;
+}
+
+int set_date_label_spec(const char *label_spec)
+{
+  spec_cur = spec_ptr = label_spec;
+  spec_end = strchr(label_spec, '\0');
+  literals.clear();
+  if (yyparse())
+    return 0;
+  delete parsed_date_label;
+  parsed_date_label = parse_result;
+  return 1;
+}
+
+int set_short_label_spec(const char *label_spec)
+{
+  spec_cur = spec_ptr = label_spec;
+  spec_end = strchr(label_spec, '\0');
+  literals.clear();
+  if (yyparse())
+    return 0;
+  delete parsed_short_label;
+  parsed_short_label = parse_result;
+  return 1;
+}
+
+void yyerror(const char *message)
+{
+  if (spec_cur < spec_end)
+    command_error("label specification %1 before '%2'", message, spec_cur);
+  else
+    command_error("label specification %1 at end of string",
+		  message, spec_cur);
+}
+
+void at_expr::evaluate(int tentative, const reference &ref,
+		       string &result, substring_position &)
+{
+  if (tentative)
+    ref.canonicalize_authors(result);
+  else {
+    const char *end, *start = ref.get_authors(&end);
+    if (start)
+      result.append(start, end - start);
+  }
+}
+
+void format_expr::evaluate(int tentative, const reference &ref,
+			   string &result, substring_position &)
+{
+  if (tentative)
+    return;
+  const label_info *lp = ref.get_label_ptr();
+  int num = lp == 0 ? ref.get_number() : lp->count;
+  if (type != '0')
+    result += format_serial(type, num + 1);
+  else {
+    const char *ptr = i_to_a(num + first_number);
+    int pad = width - strlen(ptr);
+    while (--pad >= 0)
+      result += '0';
+    result += ptr;
+  }
+}
+
+static const char *format_serial(char c, int n)
+{
+  assert(n > 0);
+  static char buf[128]; // more than enough.
+  switch (c) {
+  case 'i':
+  case 'I':
+    {
+      char *p = buf;
+      // troff uses z and w to represent 10000 and 5000 in Roman
+      // numerals; I can find no historical basis for this usage
+      const char *s = c == 'i' ? "zwmdclxvi" : "ZWMDCLXVI";
+      if (n >= 40000)
+	return i_to_a(n);
+      while (n >= 10000) {
+	*p++ = s[0];
+	n -= 10000;
+      }
+      for (int i = 1000; i > 0; i /= 10, s += 2) {
+	int m = n/i;
+	n -= m*i;
+	switch (m) {
+	case 3:
+	  *p++ = s[2];
+	  /* falls through */
+	case 2:
+	  *p++ = s[2];
+	  /* falls through */
+	case 1:
+	  *p++ = s[2];
+	  break;
+	case 4:
+	  *p++ = s[2];
+	  *p++ = s[1];
+	  break;
+	case 8:
+	  *p++ = s[1];
+	  *p++ = s[2];
+	  *p++ = s[2];
+	  *p++ = s[2];
+	  break;
+	case 7:
+	  *p++ = s[1];
+	  *p++ = s[2];
+	  *p++ = s[2];
+	  break;
+	case 6:
+	  *p++ = s[1];
+	  *p++ = s[2];
+	  break;
+	case 5:
+	  *p++ = s[1];
+	  break;
+	case 9:
+	  *p++ = s[2];
+	  *p++ = s[0];
+	}
+      }
+      *p = 0;
+      break;
+    }
+  case 'a':
+  case 'A':
+    {
+      char *p = buf;
+      // this is derived from troff/reg.c
+      while (n > 0) {
+	int d = n % 26;
+	if (d == 0)
+	  d = 26;
+	n -= d;
+	n /= 26;
+	*p++ = c == 'a' ? lowercase_array[d - 1] :
+			       uppercase_array[d - 1];
+      }
+      *p-- = 0;
+      // Reverse it.
+      char *q = buf;
+      while (q < p) {
+	char temp = *q;
+	*q = *p;
+	*p = temp;
+	--p;
+	++q;
+      }
+      break;
+    }
+  default:
+    assert(0);
+  }
+  return buf;
+}
+
+void field_expr::evaluate(int, const reference &ref,
+			  string &result, substring_position &)
+{
+  const char *end;
+  const char *start = ref.get_field(name, &end);
+  if (start) {
+    start = nth_field(number, start, &end);
+    if (start)
+      result.append(start, end - start);
+  }
+}
+
+void literal_expr::evaluate(int, const reference &,
+			    string &result, substring_position &)
+{
+  result += s;
+}
+
+analyzed_expr::analyzed_expr(expression *e)
+: unary_expr(e), flags(e ? e->analyze() : 0)
+{
+}
+
+void analyzed_expr::evaluate(int tentative, const reference &ref,
+			     string &result, substring_position &pos)
+{
+  if (expr)
+    expr->evaluate(tentative, ref, result, pos);
+}
+
+void star_expr::evaluate(int tentative, const reference &ref,
+			 string &result, substring_position &pos)
+{
+  const label_info *lp = ref.get_label_ptr();
+  if (!tentative
+      && (lp == 0 || lp->total > 1)
+      && expr)
+    expr->evaluate(tentative, ref, result, pos);
+}
+
+void separator_expr::evaluate(int tentative, const reference &ref,
+			      string &result, substring_position &pos)
+{
+  int start_length = result.length();
+  int is_first = pos.start < 0;
+  if (expr)
+    expr->evaluate(tentative, ref, result, pos);
+  if (is_first) {
+    pos.start = start_length;
+    pos.length = result.length() - start_length;
+  }
+}
+
+void map_expr::evaluate(int tentative, const reference &ref,
+			string &result, substring_position &)
+{
+  if (expr) {
+    string temp;
+    substring_position temp_pos;
+    expr->evaluate(tentative, ref, temp, temp_pos);
+    (*func)(temp.contents(), temp.contents() + temp.length(), result);
+  }
+}
+
+void extractor_expr::evaluate(int tentative, const reference &ref,
+			      string &result, substring_position &)
+{
+  if (expr) {
+    string temp;
+    substring_position temp_pos;
+    expr->evaluate(tentative, ref, temp, temp_pos);
+    const char *end, *start = (*func)(temp.contents(),
+				      temp.contents() + temp.length(),
+				      &end);
+    switch (part) {
+    case BEFORE:
+      if (start)
+	result.append(temp.contents(), start - temp.contents());
+      else
+	result += temp;
+      break;
+    case MATCH:
+      if (start)
+	result.append(start, end - start);
+      break;
+    case AFTER:
+      if (start)
+	result.append(end, temp.contents() + temp.length() - end);
+      break;
+    default:
+      assert(0);
+    }
+  }
+}
+
+static void first_part(int len, const char *ptr, const char *end,
+			  string &result)
+{
+  for (;;) {
+    const char *token_start = ptr;
+    if (!get_token(&ptr, end))
+      break;
+    const token_info *ti = lookup_token(token_start, ptr);
+    int counts = ti->sortify_non_empty(token_start, ptr);
+    if (counts && --len < 0)
+      break;
+    if (counts || ti->is_accent())
+      result.append(token_start, ptr - token_start);
+  }
+}
+
+static void last_part(int len, const char *ptr, const char *end,
+		      string &result)
+{
+  const char *start = ptr;
+  int count = 0;
+  for (;;) {
+    const char *token_start = ptr;
+    if (!get_token(&ptr, end))
+      break;
+    const token_info *ti = lookup_token(token_start, ptr);
+    if (ti->sortify_non_empty(token_start, ptr))
+      count++;
+  }
+  ptr = start;
+  int skip = count - len;
+  if (skip > 0) {
+    for (;;) {
+      const char *token_start = ptr;
+      if (!get_token(&ptr, end))
+	assert(0);
+      const token_info *ti = lookup_token(token_start, ptr);
+      if (ti->sortify_non_empty(token_start, ptr) && --skip < 0) {
+	ptr = token_start;
+	break;
+      }
+    }
+  }
+  first_part(len, ptr, end, result);
+}
+
+void truncate_expr::evaluate(int tentative, const reference &ref,
+			     string &result, substring_position &)
+{
+  if (expr) {
+    string temp;
+    substring_position temp_pos;
+    expr->evaluate(tentative, ref, temp, temp_pos);
+    const char *start = temp.contents();
+    const char *end = start + temp.length();
+    if (n > 0)
+      first_part(n, start, end, result);
+    else if (n < 0)
+      last_part(-n, start, end, result);
+  }
+}
+
+void alternative_expr::evaluate(int tentative, const reference &ref,
+				string &result, substring_position &pos)
+{
+  int start_length = result.length();
+  if (expr1)
+    expr1->evaluate(tentative, ref, result, pos);
+  if (result.length() == start_length && expr2)
+    expr2->evaluate(tentative, ref, result, pos);
+}
+
+void list_expr::evaluate(int tentative, const reference &ref,
+			 string &result, substring_position &pos)
+{
+  if (expr1)
+    expr1->evaluate(tentative, ref, result, pos);
+  if (expr2)
+    expr2->evaluate(tentative, ref, result, pos);
+}
+
+void substitute_expr::evaluate(int tentative, const reference &ref,
+			       string &result, substring_position &pos)
+{
+  int start_length = result.length();
+  if (expr1)
+    expr1->evaluate(tentative, ref, result, pos);
+  if (result.length() > start_length && result[result.length() - 1] == '-') {
+    // ought to see if pos covers the -
+    result.set_length(result.length() - 1);
+    if (expr2)
+      expr2->evaluate(tentative, ref, result, pos);
+  }
+}
+
+void conditional_expr::evaluate(int tentative, const reference &ref,
+				string &result, substring_position &pos)
+{
+  string temp;
+  substring_position temp_pos;
+  if (expr1)
+    expr1->evaluate(tentative, ref, temp, temp_pos);
+  if (temp.length() > 0) {
+    if (expr2)
+      expr2->evaluate(tentative, ref, result, pos);
+  }
+  else {
+    if (expr3)
+      expr3->evaluate(tentative, ref, result, pos);
+  }
+}
+
+void reference::pre_compute_label()
+{
+  if (parsed_label != 0
+      && (parsed_label->analyze() & expression::CONTAINS_VARIABLE)) {
+    label.clear();
+    substring_position temp_pos;
+    parsed_label->evaluate(1, *this, label, temp_pos);
+    label_ptr = lookup_label(label);
+  }
+}
+
+void reference::compute_label()
+{
+  label.clear();
+  if (parsed_label)
+    parsed_label->evaluate(0, *this, label, separator_pos);
+  if (short_label_flag && parsed_short_label)
+    parsed_short_label->evaluate(0, *this, short_label, short_separator_pos);
+  if (date_as_label) {
+    string new_date;
+    if (parsed_date_label) {
+      substring_position temp_pos;
+      parsed_date_label->evaluate(0, *this, new_date, temp_pos);
+    }
+    set_date(new_date);
+  }
+  if (label_ptr)
+    label_ptr->count += 1;
+}
+
+void reference::immediate_compute_label()
+{
+  if (label_ptr)
+    label_ptr->total = 2;	// force use of disambiguator
+  compute_label();
+}
+
+int reference::merge_labels(reference **v, int n, label_type type,
+			    string &result)
+{
+  if (abbreviate_label_ranges)
+    return merge_labels_by_number(v, n, type, result);
+  else
+    return merge_labels_by_parts(v, n, type, result);
+}
+
+int reference::merge_labels_by_number(reference **v, int n, label_type type,
+				      string &result)
+{
+  if (n <= 1)
+    return 0;
+  int num = get_number();
+  // Only merge three or more labels.
+  if (v[0]->get_number() != num + 1
+      || v[1]->get_number() != num + 2)
+    return 0;
+  int i;
+  for (i = 2; i < n; i++)
+    if (v[i]->get_number() != num + i + 1)
+      break;
+  result = get_label(type);
+  result += label_range_indicator;
+  result += v[i - 1]->get_label(type);
+  return i;
+}
+
+const substring_position &reference::get_separator_pos(label_type type) const
+{
+  if (type == SHORT_LABEL && short_label_flag)
+    return short_separator_pos;
+  else
+    return separator_pos;
+}
+
+const string &reference::get_label(label_type type) const
+{
+  if (type == SHORT_LABEL && short_label_flag)
+    return short_label; 
+  else
+    return label;
+}
+
+int reference::merge_labels_by_parts(reference **v, int n, label_type type,
+				     string &result)
+{
+  if (n <= 0)
+    return 0;
+  const string &lb = get_label(type);
+  const substring_position &sp = get_separator_pos(type);
+  if (sp.start < 0
+      || sp.start != v[0]->get_separator_pos(type).start 
+      || memcmp(lb.contents(), v[0]->get_label(type).contents(),
+		sp.start) != 0)
+    return 0;
+  result = lb;
+  int i = 0;
+  do {
+    result += separate_label_second_parts;
+    const substring_position &s = v[i]->get_separator_pos(type);
+    int sep_end_pos = s.start + s.length;
+    result.append(v[i]->get_label(type).contents() + sep_end_pos,
+		  v[i]->get_label(type).length() - sep_end_pos);
+  } while (++i < n
+	   && sp.start == v[i]->get_separator_pos(type).start
+	   && memcmp(lb.contents(), v[i]->get_label(type).contents(),
+		     sp.start) == 0);
+  return i;
+}
+
+string label_pool;
+
+label_info::label_info(const string &s)
+: start(label_pool.length()), length(s.length()), count(0), total(1)
+{
+  label_pool += s;
+}
+
+static label_info **label_table = 0;
+static int label_table_size = 0;
+static int label_table_used = 0;
+
+label_info *lookup_label(const string &label)
+{
+  if (label_table == 0) {
+    label_table = new label_info *[17];
+    label_table_size = 17;
+    for (int i = 0; i < 17; i++)
+      label_table[i] = 0;
+  }
+  unsigned h = hash_string(label.contents(), label.length()) % label_table_size;
+  label_info **ptr;
+  for (ptr = label_table + h;
+       *ptr != 0;
+       (ptr == label_table)
+       ? (ptr = label_table + label_table_size - 1)
+       : ptr--)
+    if ((*ptr)->length == label.length()
+	&& memcmp(label_pool.contents() + (*ptr)->start, label.contents(),
+		  label.length()) == 0) {
+      (*ptr)->total += 1;
+      return *ptr;
+    }
+  label_info *result = *ptr = new label_info(label);
+  if (++label_table_used * 2 > label_table_size) {
+    // Rehash the table.
+    label_info **old_table = label_table;
+    int old_size = label_table_size;
+    label_table_size = next_size(label_table_size);
+    label_table = new label_info *[label_table_size];
+    int i;
+    for (i = 0; i < label_table_size; i++)
+      label_table[i] = 0;
+    for (i = 0; i < old_size; i++)
+      if (old_table[i]) {
+	h = hash_string(label_pool.contents() + old_table[i]->start,
+			old_table[i]->length);
+	label_info **p;
+	for (p = label_table + (h % label_table_size);
+	     *p != 0;
+	     (p == label_table)
+	     ? (p = label_table + label_table_size - 1)
+	     : --p)
+	    ;
+	*p = old_table[i];
+	}
+    delete[] old_table;
+  }
+  return result;
+}
+
+void clear_labels()
+{
+  for (int i = 0; i < label_table_size; i++) {
+    delete label_table[i];
+    label_table[i] = 0;
+  }
+  label_table_used = 0;
+  label_pool.clear();
+}
+
+static void consider_authors(reference **start, reference **end, int i);
+
+void compute_labels(reference **v, int n)
+{
+  if (parsed_label
+      && (parsed_label->analyze() & expression::CONTAINS_AT)
+      && sort_fields.length() >= 2
+      && sort_fields[0] == 'A'
+      && sort_fields[1] == '+')
+    consider_authors(v, v + n, 0);
+  for (int i = 0; i < n; i++)
+    v[i]->compute_label();
+}
+
+
+/* A reference with a list of authors <A0,A1,...,AN> _needs_ author i
+where 0 <= i <= N if there exists a reference with a list of authors
+<B0,B1,...,BM> such that <A0,A1,...,AN> != <B0,B1,...,BM> and M >= i
+and Aj = Bj for 0 <= j < i. In this case if we can't say "A0,
+A1,...,A(i-1) et al" because this would match both <A0,A1,...,AN> and
+<B0,B1,...,BM>.  If a reference needs author i we only have to call
+need_author(j) for some j >= i such that the reference also needs
+author j. */
+
+/* This function handles 2 tasks:
+determine which authors are needed (cannot be elided with et al.);
+determine which authors can have only last names in the labels.
+
+References >= start and < end have the same first i author names.
+Also they're sorted by A+. */
+
+static void consider_authors(reference **start, reference **end, int i)
+{
+  if (start >= end)
+    return;
+  reference **p = start;
+  if (i >= (*p)->get_nauthors()) {
+    for (++p; p < end && i >= (*p)->get_nauthors(); p++)
+      ;
+    if (p < end && i > 0) {
+      // If we have an author list <A B C> and an author list <A B C D>,
+      // then both lists need C.
+      for (reference **q = start; q < end; q++)
+	(*q)->need_author(i - 1);
+    }
+    start = p;
+  }
+  while (p < end) {
+    reference **last_name_start = p;
+    reference **name_start = p;
+    for (++p;
+	 p < end && i < (*p)->get_nauthors()
+	 && same_author_last_name(**last_name_start, **p, i);
+	 p++) {
+      if (!same_author_name(**name_start, **p, i)) {
+	consider_authors(name_start, p, i + 1);
+	name_start = p;
+      }
+    }
+    consider_authors(name_start, p, i + 1);
+    if (last_name_start == name_start) {
+      for (reference **q = last_name_start; q < p; q++)
+	(*q)->set_last_name_unambiguous(i);
+    }
+    // If we have an author list <A B C D> and <A B C E>, then the lists
+    // need author D and E respectively.
+    if (name_start > start || p < end) {
+      for (reference **q = last_name_start; q < p; q++)
+	(*q)->need_author(i);
+    }
+  }
+}
+
+int same_author_last_name(const reference &r1, const reference &r2, int n)
+{
+  const char *ae1;
+  const char *as1 = r1.get_sort_field(0, n, 0, &ae1);
+  const char *ae2;
+  const char *as2 = r2.get_sort_field(0, n, 0, &ae2);
+  if (!as1 && !as2) return 1;	// they are the same
+  if (!as1 || !as2) return 0;
+  return ae1 - as1 == ae2 - as2 && memcmp(as1, as2, ae1 - as1) == 0;
+}
+
+int same_author_name(const reference &r1, const reference &r2, int n)
+{
+  const char *ae1;
+  const char *as1 = r1.get_sort_field(0, n, -1, &ae1);
+  const char *ae2;
+  const char *as2 = r2.get_sort_field(0, n, -1, &ae2);
+  if (!as1 && !as2) return 1;	// they are the same
+  if (!as1 || !as2) return 0;
+  return ae1 - as1 == ae2 - as2 && memcmp(as1, as2, ae1 - as1) == 0;
+}
+
+
+void int_set::set(int i)
+{
+  assert(i >= 0);
+  int bytei = i >> 3;
+  if (bytei >= v.length()) {
+    int old_length = v.length();
+    v.set_length(bytei + 1);
+    for (int j = old_length; j <= bytei; j++)
+      v[j] = 0;
+  }
+  v[bytei] |= 1 << (i & 7);
+}
+
+int int_set::get(int i) const
+{
+  assert(i >= 0);
+  int bytei = i >> 3;
+  return bytei >= v.length() ? 0 : (v[bytei] & (1 << (i & 7))) != 0;
+}
+
+void reference::set_last_name_unambiguous(int i)
+{
+  last_name_unambiguous.set(i);
+}
+
+void reference::need_author(int n)
+{
+  if (n > last_needed_author)
+    last_needed_author = n;
+}
+
+const char *reference::get_authors(const char **end) const
+{
+  if (!computed_authors) {
+    ((reference *)this)->computed_authors = 1;
+    string &result = ((reference *)this)->authors;
+    int na = get_nauthors();
+    result.clear();
+    for (int i = 0; i < na; i++) {
+      if (last_name_unambiguous.get(i)) {
+	const char *e, *start = get_author_last_name(i, &e);
+	assert(start != 0);
+	result.append(start, e - start);
+      }
+      else {
+	const char *e, *start = get_author(i, &e);
+	assert(start != 0);
+	result.append(start, e - start);
+      }
+      if (i == last_needed_author
+	  && et_al.length() > 0
+	  && et_al_min_elide > 0
+	  && last_needed_author + et_al_min_elide < na
+	  && na >= et_al_min_total) {
+	result += et_al;
+	break;
+      }
+      if (i < na - 1) {
+	if (na == 2)
+	  result += join_authors_exactly_two;
+	else if (i < na - 2)
+	  result += join_authors_default;
+	else
+	  result += join_authors_last_two;
+      }
+    }
+  }
+  const char *start = authors.contents();
+  *end = start + authors.length();
+  return start;
+}
+
+int reference::get_nauthors() const
+{
+  if (nauthors < 0) {
+    const char *dummy;
+    int na;
+    for (na = 0; get_author(na, &dummy) != 0; na++)
+      ;
+    ((reference *)this)->nauthors = na;
+  }
+  return nauthors;
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/refer/label.hpp b/src/preproc/refer/label.hpp
new file mode 100644
index 0000000..9f79fd2
--- /dev/null
+++ b/src/preproc/refer/label.hpp
@@ -0,0 +1,98 @@
+/* A Bison parser, made by GNU Bison 3.8.2.  */
+
+/* Bison interface for Yacc-like parsers in C
+
+   Copyright (C) 1984, 1989-1990, 2000-2015, 2018-2021 Free Software Foundation,
+   Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* As a special exception, you may create a larger work that contains
+   part or all of the Bison parser skeleton and distribute that work
+   under terms of your choice, so long as that work isn't itself a
+   parser generator using the skeleton or a modified version thereof
+   as a parser skeleton.  Alternatively, if you modify or redistribute
+   the parser skeleton itself, you may (at your option) remove this
+   special exception, which will cause the skeleton and the resulting
+   Bison output files to be licensed under the GNU General Public
+   License without this special exception.
+
+   This special exception was added by the Free Software Foundation in
+   version 2.2 of Bison.  */
+
+/* DO NOT RELY ON FEATURES THAT ARE NOT DOCUMENTED in the manual,
+   especially those whose name start with YY_ or yy_.  They are
+   private implementation details that can be changed or removed.  */
+
+#ifndef YY_YY_SRC_PREPROC_REFER_LABEL_HPP_INCLUDED
+# define YY_YY_SRC_PREPROC_REFER_LABEL_HPP_INCLUDED
+/* Debug traces.  */
+#ifndef YYDEBUG
+# define YYDEBUG 0
+#endif
+#if YYDEBUG
+extern int yydebug;
+#endif
+
+/* Token kinds.  */
+#ifndef YYTOKENTYPE
+# define YYTOKENTYPE
+  enum yytokentype
+  {
+    YYEMPTY = -2,
+    YYEOF = 0,                     /* "end of file"  */
+    YYerror = 256,                 /* error  */
+    YYUNDEF = 257,                 /* "invalid token"  */
+    TOKEN_LETTER = 258,            /* TOKEN_LETTER  */
+    TOKEN_LITERAL = 259,           /* TOKEN_LITERAL  */
+    TOKEN_DIGIT = 260              /* TOKEN_DIGIT  */
+  };
+  typedef enum yytokentype yytoken_kind_t;
+#endif
+/* Token kinds.  */
+#define YYEMPTY -2
+#define YYEOF 0
+#define YYerror 256
+#define YYUNDEF 257
+#define TOKEN_LETTER 258
+#define TOKEN_LITERAL 259
+#define TOKEN_DIGIT 260
+
+/* Value type.  */
+#if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
+union YYSTYPE
+{
+#line 218 "../src/preproc/refer/label.ypp"
+
+  int num;
+  expression *expr;
+  struct { int ndigits; int val; } dig;
+  struct { int start; int len; } str;
+
+#line 84 "src/preproc/refer/label.hpp"
+
+};
+typedef union YYSTYPE YYSTYPE;
+# define YYSTYPE_IS_TRIVIAL 1
+# define YYSTYPE_IS_DECLARED 1
+#endif
+
+
+extern YYSTYPE yylval;
+
+
+int yyparse (void);
+
+
+#endif /* !YY_YY_SRC_PREPROC_REFER_LABEL_HPP_INCLUDED  */
diff --git a/src/preproc/refer/label.ypp b/src/preproc/refer/label.ypp
new file mode 100644
index 0000000..f5210d5
--- /dev/null
+++ b/src/preproc/refer/label.ypp
@@ -0,0 +1,1195 @@
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+%{
+
+#include "refer.h"
+#include "refid.h"
+#include "ref.h"
+#include "token.h"
+
+int yylex();
+void yyerror(const char *);
+
+static const char *format_serial(char c, int n);
+
+struct label_info {
+  int start;
+  int length;
+  int count;
+  int total;
+  label_info(const string &);
+};
+
+label_info *lookup_label(const string &label);
+
+struct expression {
+  enum {
+    // Does the tentative label depend on the reference?
+    CONTAINS_VARIABLE = 01, 
+    CONTAINS_STAR = 02,
+    CONTAINS_FORMAT = 04,
+    CONTAINS_AT = 010
+  };
+  virtual ~expression() { }
+  virtual void evaluate(int, const reference &, string &,
+			substring_position &) = 0;
+  virtual unsigned analyze() { return 0; }
+};
+
+class at_expr : public expression {
+public:
+  at_expr() { }
+  void evaluate(int, const reference &, string &, substring_position &);
+  unsigned analyze() { return CONTAINS_VARIABLE|CONTAINS_AT; }
+};
+
+class format_expr : public expression {
+  char type;
+  int width;
+  int first_number;
+public:
+  format_expr(char c, int w = 0, int f = 1)
+    : type(c), width(w), first_number(f) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+  unsigned analyze() { return CONTAINS_FORMAT; }
+};
+
+class field_expr : public expression {
+  int number;
+  char name;
+public:
+  field_expr(char nm, int num) : number(num), name(nm) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+  unsigned analyze() { return CONTAINS_VARIABLE; }
+};
+
+class literal_expr : public expression {
+  string s;
+public:
+  literal_expr(const char *ptr, int len) : s(ptr, len) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+};
+
+class unary_expr : public expression {
+protected:
+  expression *expr;
+public:
+  unary_expr(expression *e) : expr(e) { }
+  ~unary_expr() { delete expr; }
+  void evaluate(int, const reference &, string &, substring_position &) = 0;
+  unsigned analyze() { return expr ? expr->analyze() : 0; }
+};
+
+// This caches the analysis of an expression.
+
+class analyzed_expr : public unary_expr {
+  unsigned flags;
+public:
+  analyzed_expr(expression *);
+  void evaluate(int, const reference &, string &, substring_position &);
+  unsigned analyze() { return flags; }
+};
+
+class star_expr : public unary_expr {
+public:
+  star_expr(expression *e) : unary_expr(e) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+  unsigned analyze() {
+    return ((expr ? (expr->analyze() & ~CONTAINS_VARIABLE) : 0)
+	    | CONTAINS_STAR);
+  }
+};
+
+typedef void map_func(const char *, const char *, string &);
+
+class map_expr : public unary_expr {
+  map_func *func;
+public:
+  map_expr(expression *e, map_func *f) : unary_expr(e), func(f) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+};
+  
+typedef const char *extractor_func(const char *, const char *, const char **);
+
+class extractor_expr : public unary_expr {
+  int part;
+  extractor_func *func;
+public:
+  enum { BEFORE = +1, MATCH = 0, AFTER = -1 };
+  extractor_expr(expression *e, extractor_func *f, int pt)
+    : unary_expr(e), part(pt), func(f) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+};
+
+class truncate_expr : public unary_expr {
+  int n;
+public:
+  truncate_expr(expression *e, int i) : unary_expr(e), n(i) { } 
+  void evaluate(int, const reference &, string &, substring_position &);
+};
+
+class separator_expr : public unary_expr {
+public:
+  separator_expr(expression *e) : unary_expr(e) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+};
+
+class binary_expr : public expression {
+protected:
+  expression *expr1;
+  expression *expr2;
+public:
+  binary_expr(expression *e1, expression *e2) : expr1(e1), expr2(e2) { }
+  ~binary_expr() { delete expr1; delete expr2; }
+  void evaluate(int, const reference &, string &, substring_position &) = 0;
+  unsigned analyze() {
+    return (expr1 ? expr1->analyze() : 0) | (expr2 ? expr2->analyze() : 0);
+  }
+};
+
+class alternative_expr : public binary_expr {
+public:
+  alternative_expr(expression *e1, expression *e2) : binary_expr(e1, e2) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+};
+
+class list_expr : public binary_expr {
+public:
+  list_expr(expression *e1, expression *e2) : binary_expr(e1, e2) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+};
+
+class substitute_expr : public binary_expr {
+public:
+  substitute_expr(expression *e1, expression *e2) : binary_expr(e1, e2) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+};
+
+class ternary_expr : public expression {
+protected:
+  expression *expr1;
+  expression *expr2;
+  expression *expr3;
+public:
+  ternary_expr(expression *e1, expression *e2, expression *e3)
+    : expr1(e1), expr2(e2), expr3(e3) { }
+  ~ternary_expr() { delete expr1; delete expr2; delete expr3; }
+  void evaluate(int, const reference &, string &, substring_position &) = 0;
+  unsigned analyze() {
+    return ((expr1 ? expr1->analyze() : 0)
+	    | (expr2 ? expr2->analyze() : 0)
+	    | (expr3 ? expr3->analyze() : 0));
+  }
+};
+
+class conditional_expr : public ternary_expr {
+public:
+  conditional_expr(expression *e1, expression *e2, expression *e3)
+    : ternary_expr(e1, e2, e3) { }
+  void evaluate(int, const reference &, string &, substring_position &);
+};
+
+static expression *parsed_label = 0;
+static expression *parsed_date_label = 0;
+static expression *parsed_short_label = 0;
+
+static expression *parse_result;
+
+string literals;
+
+%}
+
+%union {
+  int num;
+  expression *expr;
+  struct { int ndigits; int val; } dig;
+  struct { int start; int len; } str;
+}
+
+/* uppercase or lowercase letter */
+%token <num> TOKEN_LETTER
+/* literal characters */
+%token <str> TOKEN_LITERAL
+/* digit */
+%token <num> TOKEN_DIGIT
+
+%type <expr> conditional
+%type <expr> alternative
+%type <expr> list
+%type <expr> string
+%type <expr> substitute
+%type <expr> optional_conditional
+%type <num> number
+%type <dig> digits
+%type <num> optional_number
+%type <num> flag
+
+%%
+
+expr:
+	optional_conditional
+		{ parse_result = ($1 ? new analyzed_expr($1) : 0); }
+	;
+
+conditional:
+	alternative
+		{ $$ = $1; }
+	| alternative '?' optional_conditional ':' conditional
+		{ $$ = new conditional_expr($1, $3, $5); }
+	;
+
+optional_conditional:
+	/* empty */
+		{ $$ = 0; }
+	| conditional
+		{ $$ = $1; }
+	;
+
+alternative:
+	list
+		{ $$ = $1; }
+	| alternative '|' list
+		{ $$ = new alternative_expr($1, $3); }
+	| alternative '&' list
+		{ $$ = new conditional_expr($1, $3, 0); }
+	;	
+
+list:
+	substitute
+		{ $$ = $1; }
+	| list substitute
+		{ $$ = new list_expr($1, $2); }
+	;
+
+substitute:
+	string
+		{ $$ = $1; }
+	| substitute '~' string
+		{ $$ = new substitute_expr($1, $3); }
+	;
+
+string:
+	'@'
+		{ $$ = new at_expr; }
+	| TOKEN_LITERAL
+		{
+		  $$ = new literal_expr(literals.contents() + $1.start,
+					$1.len);
+		}
+	| TOKEN_LETTER
+		{ $$ = new field_expr($1, 0); }
+	| TOKEN_LETTER number
+		{ $$ = new field_expr($1, $2 - 1); }
+	| '%' TOKEN_LETTER
+		{
+		  switch ($2) {
+		  case 'I':
+		  case 'i':
+		  case 'A':
+		  case 'a':
+		    $$ = new format_expr($2);
+		    break;
+		  default:
+		    command_error("unrecognized format '%1'", char($2));
+		    $$ = new format_expr('a');
+		    break;
+		  }
+		}
+	
+	| '%' digits
+		{
+		  $$ = new format_expr('0', $2.ndigits, $2.val);
+		}
+	| string '.' flag TOKEN_LETTER optional_number
+		{
+		  switch ($4) {
+		  case 'l':
+		    $$ = new map_expr($1, lowercase);
+		    break;
+		  case 'u':
+		    $$ = new map_expr($1, uppercase);
+		    break;
+		  case 'c':
+		    $$ = new map_expr($1, capitalize);
+		    break;
+		  case 'r':
+		    $$ = new map_expr($1, reverse_name);
+		    break;
+		  case 'a':
+		    $$ = new map_expr($1, abbreviate_name);
+		    break;
+		  case 'y':
+		    $$ = new extractor_expr($1, find_year, $3);
+		    break;
+		  case 'n':
+		    $$ = new extractor_expr($1, find_last_name, $3);
+		    break;
+		  default:
+		    $$ = $1;
+		    command_error("unknown function '%1'", char($4));
+		    break;
+		  }
+		}
+
+	| string '+' number
+		{ $$ = new truncate_expr($1, $3); }
+	| string '-' number
+		{ $$ = new truncate_expr($1, -$3); }
+	| string '*'
+		{ $$ = new star_expr($1); }
+	| '(' optional_conditional ')'
+		{ $$ = $2; }
+	| '<' optional_conditional '>'
+		{ $$ = new separator_expr($2); }
+	;
+
+optional_number:
+	/* empty */
+		{ $$ = -1; }
+	| number
+		{ $$ = $1; }
+	;
+
+number:
+	TOKEN_DIGIT
+		{ $$ = $1; }
+	| number TOKEN_DIGIT
+		{ $$ = $1*10 + $2; }
+	;
+
+digits:
+	TOKEN_DIGIT
+		{ $$.ndigits = 1; $$.val = $1; }
+	| digits TOKEN_DIGIT
+		{ $$.ndigits = $1.ndigits + 1; $$.val = $1.val*10 + $2; }
+	;
+	
+      
+flag:
+	/* empty */
+		{ $$ = 0; }
+	| '+'
+		{ $$ = 1; }
+	| '-'
+		{ $$ = -1; }
+	;
+
+%%
+
+/* bison defines const to be empty unless __STDC__ is defined, which it
+isn't under cfront */
+
+#ifdef const
+#undef const
+#endif
+
+const char *spec_ptr;
+const char *spec_end;
+const char *spec_cur;
+
+static char uppercase_array[] = {
+  'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
+  'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
+  'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
+  'Y', 'Z',
+};
+  
+static char lowercase_array[] = {
+  'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h',
+  'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p',
+  'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
+  'y', 'z',
+};
+
+int yylex()
+{
+  while (spec_ptr < spec_end && csspace(*spec_ptr))
+    spec_ptr++;
+  spec_cur = spec_ptr;
+  if (spec_ptr >= spec_end)
+    return 0;
+  unsigned char c = *spec_ptr++;
+  if (csalpha(c)) {
+    yylval.num = c;
+    return TOKEN_LETTER;
+  }
+  if (csdigit(c)) {
+    yylval.num = c - '0';
+    return TOKEN_DIGIT;
+  }
+  if (c == '\'') {
+    yylval.str.start = literals.length();
+    for (; spec_ptr < spec_end; spec_ptr++) {
+      if (*spec_ptr == '\'') {
+	if (++spec_ptr < spec_end && *spec_ptr == '\'')
+	  literals += '\'';
+	else {
+	  yylval.str.len = literals.length() - yylval.str.start;
+	  return TOKEN_LITERAL;
+	}
+      }
+      else
+	literals += *spec_ptr;
+    }
+    yylval.str.len = literals.length() - yylval.str.start;
+    return TOKEN_LITERAL;
+  }
+  return c;
+}
+
+int set_label_spec(const char *label_spec)
+{
+  spec_cur = spec_ptr = label_spec;
+  spec_end = strchr(label_spec, '\0');
+  literals.clear();
+  if (yyparse())
+    return 0;
+  delete parsed_label;
+  parsed_label = parse_result;
+  return 1;
+}
+
+int set_date_label_spec(const char *label_spec)
+{
+  spec_cur = spec_ptr = label_spec;
+  spec_end = strchr(label_spec, '\0');
+  literals.clear();
+  if (yyparse())
+    return 0;
+  delete parsed_date_label;
+  parsed_date_label = parse_result;
+  return 1;
+}
+
+int set_short_label_spec(const char *label_spec)
+{
+  spec_cur = spec_ptr = label_spec;
+  spec_end = strchr(label_spec, '\0');
+  literals.clear();
+  if (yyparse())
+    return 0;
+  delete parsed_short_label;
+  parsed_short_label = parse_result;
+  return 1;
+}
+
+void yyerror(const char *message)
+{
+  if (spec_cur < spec_end)
+    command_error("label specification %1 before '%2'", message, spec_cur);
+  else
+    command_error("label specification %1 at end of string",
+		  message, spec_cur);
+}
+
+void at_expr::evaluate(int tentative, const reference &ref,
+		       string &result, substring_position &)
+{
+  if (tentative)
+    ref.canonicalize_authors(result);
+  else {
+    const char *end, *start = ref.get_authors(&end);
+    if (start)
+      result.append(start, end - start);
+  }
+}
+
+void format_expr::evaluate(int tentative, const reference &ref,
+			   string &result, substring_position &)
+{
+  if (tentative)
+    return;
+  const label_info *lp = ref.get_label_ptr();
+  int num = lp == 0 ? ref.get_number() : lp->count;
+  if (type != '0')
+    result += format_serial(type, num + 1);
+  else {
+    const char *ptr = i_to_a(num + first_number);
+    int pad = width - strlen(ptr);
+    while (--pad >= 0)
+      result += '0';
+    result += ptr;
+  }
+}
+
+static const char *format_serial(char c, int n)
+{
+  assert(n > 0);
+  static char buf[128]; // more than enough.
+  switch (c) {
+  case 'i':
+  case 'I':
+    {
+      char *p = buf;
+      // troff uses z and w to represent 10000 and 5000 in Roman
+      // numerals; I can find no historical basis for this usage
+      const char *s = c == 'i' ? "zwmdclxvi" : "ZWMDCLXVI";
+      if (n >= 40000)
+	return i_to_a(n);
+      while (n >= 10000) {
+	*p++ = s[0];
+	n -= 10000;
+      }
+      for (int i = 1000; i > 0; i /= 10, s += 2) {
+	int m = n/i;
+	n -= m*i;
+	switch (m) {
+	case 3:
+	  *p++ = s[2];
+	  /* falls through */
+	case 2:
+	  *p++ = s[2];
+	  /* falls through */
+	case 1:
+	  *p++ = s[2];
+	  break;
+	case 4:
+	  *p++ = s[2];
+	  *p++ = s[1];
+	  break;
+	case 8:
+	  *p++ = s[1];
+	  *p++ = s[2];
+	  *p++ = s[2];
+	  *p++ = s[2];
+	  break;
+	case 7:
+	  *p++ = s[1];
+	  *p++ = s[2];
+	  *p++ = s[2];
+	  break;
+	case 6:
+	  *p++ = s[1];
+	  *p++ = s[2];
+	  break;
+	case 5:
+	  *p++ = s[1];
+	  break;
+	case 9:
+	  *p++ = s[2];
+	  *p++ = s[0];
+	}
+      }
+      *p = 0;
+      break;
+    }
+  case 'a':
+  case 'A':
+    {
+      char *p = buf;
+      // this is derived from troff/reg.c
+      while (n > 0) {
+	int d = n % 26;
+	if (d == 0)
+	  d = 26;
+	n -= d;
+	n /= 26;
+	*p++ = c == 'a' ? lowercase_array[d - 1] :
+			       uppercase_array[d - 1];
+      }
+      *p-- = 0;
+      // Reverse it.
+      char *q = buf;
+      while (q < p) {
+	char temp = *q;
+	*q = *p;
+	*p = temp;
+	--p;
+	++q;
+      }
+      break;
+    }
+  default:
+    assert(0);
+  }
+  return buf;
+}
+
+void field_expr::evaluate(int, const reference &ref,
+			  string &result, substring_position &)
+{
+  const char *end;
+  const char *start = ref.get_field(name, &end);
+  if (start) {
+    start = nth_field(number, start, &end);
+    if (start)
+      result.append(start, end - start);
+  }
+}
+
+void literal_expr::evaluate(int, const reference &,
+			    string &result, substring_position &)
+{
+  result += s;
+}
+
+analyzed_expr::analyzed_expr(expression *e)
+: unary_expr(e), flags(e ? e->analyze() : 0)
+{
+}
+
+void analyzed_expr::evaluate(int tentative, const reference &ref,
+			     string &result, substring_position &pos)
+{
+  if (expr)
+    expr->evaluate(tentative, ref, result, pos);
+}
+
+void star_expr::evaluate(int tentative, const reference &ref,
+			 string &result, substring_position &pos)
+{
+  const label_info *lp = ref.get_label_ptr();
+  if (!tentative
+      && (lp == 0 || lp->total > 1)
+      && expr)
+    expr->evaluate(tentative, ref, result, pos);
+}
+
+void separator_expr::evaluate(int tentative, const reference &ref,
+			      string &result, substring_position &pos)
+{
+  int start_length = result.length();
+  int is_first = pos.start < 0;
+  if (expr)
+    expr->evaluate(tentative, ref, result, pos);
+  if (is_first) {
+    pos.start = start_length;
+    pos.length = result.length() - start_length;
+  }
+}
+
+void map_expr::evaluate(int tentative, const reference &ref,
+			string &result, substring_position &)
+{
+  if (expr) {
+    string temp;
+    substring_position temp_pos;
+    expr->evaluate(tentative, ref, temp, temp_pos);
+    (*func)(temp.contents(), temp.contents() + temp.length(), result);
+  }
+}
+
+void extractor_expr::evaluate(int tentative, const reference &ref,
+			      string &result, substring_position &)
+{
+  if (expr) {
+    string temp;
+    substring_position temp_pos;
+    expr->evaluate(tentative, ref, temp, temp_pos);
+    const char *end, *start = (*func)(temp.contents(),
+				      temp.contents() + temp.length(),
+				      &end);
+    switch (part) {
+    case BEFORE:
+      if (start)
+	result.append(temp.contents(), start - temp.contents());
+      else
+	result += temp;
+      break;
+    case MATCH:
+      if (start)
+	result.append(start, end - start);
+      break;
+    case AFTER:
+      if (start)
+	result.append(end, temp.contents() + temp.length() - end);
+      break;
+    default:
+      assert(0);
+    }
+  }
+}
+
+static void first_part(int len, const char *ptr, const char *end,
+			  string &result)
+{
+  for (;;) {
+    const char *token_start = ptr;
+    if (!get_token(&ptr, end))
+      break;
+    const token_info *ti = lookup_token(token_start, ptr);
+    int counts = ti->sortify_non_empty(token_start, ptr);
+    if (counts && --len < 0)
+      break;
+    if (counts || ti->is_accent())
+      result.append(token_start, ptr - token_start);
+  }
+}
+
+static void last_part(int len, const char *ptr, const char *end,
+		      string &result)
+{
+  const char *start = ptr;
+  int count = 0;
+  for (;;) {
+    const char *token_start = ptr;
+    if (!get_token(&ptr, end))
+      break;
+    const token_info *ti = lookup_token(token_start, ptr);
+    if (ti->sortify_non_empty(token_start, ptr))
+      count++;
+  }
+  ptr = start;
+  int skip = count - len;
+  if (skip > 0) {
+    for (;;) {
+      const char *token_start = ptr;
+      if (!get_token(&ptr, end))
+	assert(0);
+      const token_info *ti = lookup_token(token_start, ptr);
+      if (ti->sortify_non_empty(token_start, ptr) && --skip < 0) {
+	ptr = token_start;
+	break;
+      }
+    }
+  }
+  first_part(len, ptr, end, result);
+}
+
+void truncate_expr::evaluate(int tentative, const reference &ref,
+			     string &result, substring_position &)
+{
+  if (expr) {
+    string temp;
+    substring_position temp_pos;
+    expr->evaluate(tentative, ref, temp, temp_pos);
+    const char *start = temp.contents();
+    const char *end = start + temp.length();
+    if (n > 0)
+      first_part(n, start, end, result);
+    else if (n < 0)
+      last_part(-n, start, end, result);
+  }
+}
+
+void alternative_expr::evaluate(int tentative, const reference &ref,
+				string &result, substring_position &pos)
+{
+  int start_length = result.length();
+  if (expr1)
+    expr1->evaluate(tentative, ref, result, pos);
+  if (result.length() == start_length && expr2)
+    expr2->evaluate(tentative, ref, result, pos);
+}
+
+void list_expr::evaluate(int tentative, const reference &ref,
+			 string &result, substring_position &pos)
+{
+  if (expr1)
+    expr1->evaluate(tentative, ref, result, pos);
+  if (expr2)
+    expr2->evaluate(tentative, ref, result, pos);
+}
+
+void substitute_expr::evaluate(int tentative, const reference &ref,
+			       string &result, substring_position &pos)
+{
+  int start_length = result.length();
+  if (expr1)
+    expr1->evaluate(tentative, ref, result, pos);
+  if (result.length() > start_length && result[result.length() - 1] == '-') {
+    // ought to see if pos covers the -
+    result.set_length(result.length() - 1);
+    if (expr2)
+      expr2->evaluate(tentative, ref, result, pos);
+  }
+}
+
+void conditional_expr::evaluate(int tentative, const reference &ref,
+				string &result, substring_position &pos)
+{
+  string temp;
+  substring_position temp_pos;
+  if (expr1)
+    expr1->evaluate(tentative, ref, temp, temp_pos);
+  if (temp.length() > 0) {
+    if (expr2)
+      expr2->evaluate(tentative, ref, result, pos);
+  }
+  else {
+    if (expr3)
+      expr3->evaluate(tentative, ref, result, pos);
+  }
+}
+
+void reference::pre_compute_label()
+{
+  if (parsed_label != 0
+      && (parsed_label->analyze() & expression::CONTAINS_VARIABLE)) {
+    label.clear();
+    substring_position temp_pos;
+    parsed_label->evaluate(1, *this, label, temp_pos);
+    label_ptr = lookup_label(label);
+  }
+}
+
+void reference::compute_label()
+{
+  label.clear();
+  if (parsed_label)
+    parsed_label->evaluate(0, *this, label, separator_pos);
+  if (short_label_flag && parsed_short_label)
+    parsed_short_label->evaluate(0, *this, short_label, short_separator_pos);
+  if (date_as_label) {
+    string new_date;
+    if (parsed_date_label) {
+      substring_position temp_pos;
+      parsed_date_label->evaluate(0, *this, new_date, temp_pos);
+    }
+    set_date(new_date);
+  }
+  if (label_ptr)
+    label_ptr->count += 1;
+}
+
+void reference::immediate_compute_label()
+{
+  if (label_ptr)
+    label_ptr->total = 2;	// force use of disambiguator
+  compute_label();
+}
+
+int reference::merge_labels(reference **v, int n, label_type type,
+			    string &result)
+{
+  if (abbreviate_label_ranges)
+    return merge_labels_by_number(v, n, type, result);
+  else
+    return merge_labels_by_parts(v, n, type, result);
+}
+
+int reference::merge_labels_by_number(reference **v, int n, label_type type,
+				      string &result)
+{
+  if (n <= 1)
+    return 0;
+  int num = get_number();
+  // Only merge three or more labels.
+  if (v[0]->get_number() != num + 1
+      || v[1]->get_number() != num + 2)
+    return 0;
+  int i;
+  for (i = 2; i < n; i++)
+    if (v[i]->get_number() != num + i + 1)
+      break;
+  result = get_label(type);
+  result += label_range_indicator;
+  result += v[i - 1]->get_label(type);
+  return i;
+}
+
+const substring_position &reference::get_separator_pos(label_type type) const
+{
+  if (type == SHORT_LABEL && short_label_flag)
+    return short_separator_pos;
+  else
+    return separator_pos;
+}
+
+const string &reference::get_label(label_type type) const
+{
+  if (type == SHORT_LABEL && short_label_flag)
+    return short_label; 
+  else
+    return label;
+}
+
+int reference::merge_labels_by_parts(reference **v, int n, label_type type,
+				     string &result)
+{
+  if (n <= 0)
+    return 0;
+  const string &lb = get_label(type);
+  const substring_position &sp = get_separator_pos(type);
+  if (sp.start < 0
+      || sp.start != v[0]->get_separator_pos(type).start 
+      || memcmp(lb.contents(), v[0]->get_label(type).contents(),
+		sp.start) != 0)
+    return 0;
+  result = lb;
+  int i = 0;
+  do {
+    result += separate_label_second_parts;
+    const substring_position &s = v[i]->get_separator_pos(type);
+    int sep_end_pos = s.start + s.length;
+    result.append(v[i]->get_label(type).contents() + sep_end_pos,
+		  v[i]->get_label(type).length() - sep_end_pos);
+  } while (++i < n
+	   && sp.start == v[i]->get_separator_pos(type).start
+	   && memcmp(lb.contents(), v[i]->get_label(type).contents(),
+		     sp.start) == 0);
+  return i;
+}
+
+string label_pool;
+
+label_info::label_info(const string &s)
+: start(label_pool.length()), length(s.length()), count(0), total(1)
+{
+  label_pool += s;
+}
+
+static label_info **label_table = 0;
+static int label_table_size = 0;
+static int label_table_used = 0;
+
+label_info *lookup_label(const string &label)
+{
+  if (label_table == 0) {
+    label_table = new label_info *[17];
+    label_table_size = 17;
+    for (int i = 0; i < 17; i++)
+      label_table[i] = 0;
+  }
+  unsigned h = hash_string(label.contents(), label.length()) % label_table_size;
+  label_info **ptr;
+  for (ptr = label_table + h;
+       *ptr != 0;
+       (ptr == label_table)
+       ? (ptr = label_table + label_table_size - 1)
+       : ptr--)
+    if ((*ptr)->length == label.length()
+	&& memcmp(label_pool.contents() + (*ptr)->start, label.contents(),
+		  label.length()) == 0) {
+      (*ptr)->total += 1;
+      return *ptr;
+    }
+  label_info *result = *ptr = new label_info(label);
+  if (++label_table_used * 2 > label_table_size) {
+    // Rehash the table.
+    label_info **old_table = label_table;
+    int old_size = label_table_size;
+    label_table_size = next_size(label_table_size);
+    label_table = new label_info *[label_table_size];
+    int i;
+    for (i = 0; i < label_table_size; i++)
+      label_table[i] = 0;
+    for (i = 0; i < old_size; i++)
+      if (old_table[i]) {
+	h = hash_string(label_pool.contents() + old_table[i]->start,
+			old_table[i]->length);
+	label_info **p;
+	for (p = label_table + (h % label_table_size);
+	     *p != 0;
+	     (p == label_table)
+	     ? (p = label_table + label_table_size - 1)
+	     : --p)
+	    ;
+	*p = old_table[i];
+	}
+    delete[] old_table;
+  }
+  return result;
+}
+
+void clear_labels()
+{
+  for (int i = 0; i < label_table_size; i++) {
+    delete label_table[i];
+    label_table[i] = 0;
+  }
+  label_table_used = 0;
+  label_pool.clear();
+}
+
+static void consider_authors(reference **start, reference **end, int i);
+
+void compute_labels(reference **v, int n)
+{
+  if (parsed_label
+      && (parsed_label->analyze() & expression::CONTAINS_AT)
+      && sort_fields.length() >= 2
+      && sort_fields[0] == 'A'
+      && sort_fields[1] == '+')
+    consider_authors(v, v + n, 0);
+  for (int i = 0; i < n; i++)
+    v[i]->compute_label();
+}
+
+
+/* A reference with a list of authors <A0,A1,...,AN> _needs_ author i
+where 0 <= i <= N if there exists a reference with a list of authors
+<B0,B1,...,BM> such that <A0,A1,...,AN> != <B0,B1,...,BM> and M >= i
+and Aj = Bj for 0 <= j < i. In this case if we can't say "A0,
+A1,...,A(i-1) et al" because this would match both <A0,A1,...,AN> and
+<B0,B1,...,BM>.  If a reference needs author i we only have to call
+need_author(j) for some j >= i such that the reference also needs
+author j. */
+
+/* This function handles 2 tasks:
+determine which authors are needed (cannot be elided with et al.);
+determine which authors can have only last names in the labels.
+
+References >= start and < end have the same first i author names.
+Also they're sorted by A+. */
+
+static void consider_authors(reference **start, reference **end, int i)
+{
+  if (start >= end)
+    return;
+  reference **p = start;
+  if (i >= (*p)->get_nauthors()) {
+    for (++p; p < end && i >= (*p)->get_nauthors(); p++)
+      ;
+    if (p < end && i > 0) {
+      // If we have an author list <A B C> and an author list <A B C D>,
+      // then both lists need C.
+      for (reference **q = start; q < end; q++)
+	(*q)->need_author(i - 1);
+    }
+    start = p;
+  }
+  while (p < end) {
+    reference **last_name_start = p;
+    reference **name_start = p;
+    for (++p;
+	 p < end && i < (*p)->get_nauthors()
+	 && same_author_last_name(**last_name_start, **p, i);
+	 p++) {
+      if (!same_author_name(**name_start, **p, i)) {
+	consider_authors(name_start, p, i + 1);
+	name_start = p;
+      }
+    }
+    consider_authors(name_start, p, i + 1);
+    if (last_name_start == name_start) {
+      for (reference **q = last_name_start; q < p; q++)
+	(*q)->set_last_name_unambiguous(i);
+    }
+    // If we have an author list <A B C D> and <A B C E>, then the lists
+    // need author D and E respectively.
+    if (name_start > start || p < end) {
+      for (reference **q = last_name_start; q < p; q++)
+	(*q)->need_author(i);
+    }
+  }
+}
+
+int same_author_last_name(const reference &r1, const reference &r2, int n)
+{
+  const char *ae1;
+  const char *as1 = r1.get_sort_field(0, n, 0, &ae1);
+  const char *ae2;
+  const char *as2 = r2.get_sort_field(0, n, 0, &ae2);
+  if (!as1 && !as2) return 1;	// they are the same
+  if (!as1 || !as2) return 0;
+  return ae1 - as1 == ae2 - as2 && memcmp(as1, as2, ae1 - as1) == 0;
+}
+
+int same_author_name(const reference &r1, const reference &r2, int n)
+{
+  const char *ae1;
+  const char *as1 = r1.get_sort_field(0, n, -1, &ae1);
+  const char *ae2;
+  const char *as2 = r2.get_sort_field(0, n, -1, &ae2);
+  if (!as1 && !as2) return 1;	// they are the same
+  if (!as1 || !as2) return 0;
+  return ae1 - as1 == ae2 - as2 && memcmp(as1, as2, ae1 - as1) == 0;
+}
+
+
+void int_set::set(int i)
+{
+  assert(i >= 0);
+  int bytei = i >> 3;
+  if (bytei >= v.length()) {
+    int old_length = v.length();
+    v.set_length(bytei + 1);
+    for (int j = old_length; j <= bytei; j++)
+      v[j] = 0;
+  }
+  v[bytei] |= 1 << (i & 7);
+}
+
+int int_set::get(int i) const
+{
+  assert(i >= 0);
+  int bytei = i >> 3;
+  return bytei >= v.length() ? 0 : (v[bytei] & (1 << (i & 7))) != 0;
+}
+
+void reference::set_last_name_unambiguous(int i)
+{
+  last_name_unambiguous.set(i);
+}
+
+void reference::need_author(int n)
+{
+  if (n > last_needed_author)
+    last_needed_author = n;
+}
+
+const char *reference::get_authors(const char **end) const
+{
+  if (!computed_authors) {
+    ((reference *)this)->computed_authors = 1;
+    string &result = ((reference *)this)->authors;
+    int na = get_nauthors();
+    result.clear();
+    for (int i = 0; i < na; i++) {
+      if (last_name_unambiguous.get(i)) {
+	const char *e, *start = get_author_last_name(i, &e);
+	assert(start != 0);
+	result.append(start, e - start);
+      }
+      else {
+	const char *e, *start = get_author(i, &e);
+	assert(start != 0);
+	result.append(start, e - start);
+      }
+      if (i == last_needed_author
+	  && et_al.length() > 0
+	  && et_al_min_elide > 0
+	  && last_needed_author + et_al_min_elide < na
+	  && na >= et_al_min_total) {
+	result += et_al;
+	break;
+      }
+      if (i < na - 1) {
+	if (na == 2)
+	  result += join_authors_exactly_two;
+	else if (i < na - 2)
+	  result += join_authors_default;
+	else
+	  result += join_authors_last_two;
+      }
+    }
+  }
+  const char *start = authors.contents();
+  *end = start + authors.length();
+  return start;
+}
+
+int reference::get_nauthors() const
+{
+  if (nauthors < 0) {
+    const char *dummy;
+    int na;
+    for (na = 0; get_author(na, &dummy) != 0; na++)
+      ;
+    ((reference *)this)->nauthors = na;
+  }
+  return nauthors;
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/refer/ref.cpp b/src/preproc/refer/ref.cpp
new file mode 100644
index 0000000..9e1b5e7
--- /dev/null
+++ b/src/preproc/refer/ref.cpp
@@ -0,0 +1,1161 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+     
+#include "refer.h"
+#include "refid.h"
+#include "ref.h"
+#include "token.h"
+
+static const char *find_day(const char *, const char *, const char **);
+static int find_month(const char *start, const char *end);
+static void abbreviate_names(string &);
+
+#define DEFAULT_ARTICLES "the\000a\000an"
+     
+string articles(DEFAULT_ARTICLES, sizeof(DEFAULT_ARTICLES));
+
+// Multiple occurrences of fields are separated by FIELD_SEPARATOR.
+const char FIELD_SEPARATOR = '\0';
+
+const char MULTI_FIELD_NAMES[] = "AE";
+const char *AUTHOR_FIELDS = "AQ";
+
+enum { OTHER, JOURNAL_ARTICLE, BOOK, ARTICLE_IN_BOOK, TECH_REPORT, BELL_TM };
+
+const char *reference_types[] = {
+  "other",
+  "journal-article",
+  "book",
+  "article-in-book",
+  "tech-report",
+  "bell-tm",
+};
+
+static string temp_fields[256];
+
+reference::reference(const char *start, int len, reference_id *ridp)
+: h(0), merged(0), no(-1), field(0), nfields(0), label_ptr(0),
+  computed_authors(0), last_needed_author(-1), nauthors(-1)
+{
+  int i;
+  for (i = 0; i < 256; i++)
+    field_index[i] = NULL_FIELD_INDEX;
+  if (ridp)
+    rid = *ridp;
+  if (start == 0)
+    return;
+  if (len <= 0)
+    return;
+  const char *end = start + len;
+  const char *ptr = start;
+  assert(*ptr == '%');
+  while (ptr < end) {
+    if (ptr + 1 < end && ptr[1] != '\0'
+	&& ((ptr[1] != '%' && ptr[1] == annotation_field)
+	    || (ptr + 2 < end && ptr[1] == '%' && ptr[2] != '\0'
+		&& discard_fields.search(ptr[2]) < 0))) {
+      if (ptr[1] == '%')
+	ptr++;
+      string &f = temp_fields[(unsigned char)ptr[1]];
+      ptr += 2;
+      while (ptr < end && csspace(*ptr))
+	ptr++;
+      for (;;) {
+	for (;;) {
+	  if (ptr >= end) {
+	    f += '\n';
+	    break;
+	  }
+	  f += *ptr;
+	  if (*ptr++ == '\n')
+	    break;
+	}
+	if (ptr >= end || *ptr == '%')
+	  break;
+      }
+    }
+    else if (ptr + 1 < end && ptr[1] != '\0' && ptr[1] != '%'
+	     && discard_fields.search(ptr[1]) < 0) {
+      string &f = temp_fields[(unsigned char)ptr[1]];
+      if (f.length() > 0) {
+	if (strchr(MULTI_FIELD_NAMES, ptr[1]) != 0)
+	  f += FIELD_SEPARATOR;
+	else
+	  f.clear();
+      }
+      ptr += 2;
+      if (ptr < end) {
+	if (*ptr == ' ')
+	  ptr++;
+	for (;;) {
+	  const char *p = ptr;
+	  while (ptr < end && *ptr != '\n')
+	    ptr++;
+	  // strip trailing white space
+	  const char *q = ptr;
+	  while (q > p && q[-1] != '\n' && csspace(q[-1]))
+	    q--;
+	  while (p < q)
+	    f += *p++;
+	  if (ptr >= end)
+	    break;
+	  ptr++;
+	  if (ptr >= end)
+	    break;
+	  if (*ptr == '%')
+	    break;
+	  f += ' ';
+	}
+      }
+    }
+    else {
+      // skip this field
+      for (;;) {
+	while (ptr < end && *ptr++ != '\n')
+	  ;
+	if (ptr >= end || *ptr == '%')
+	  break;
+      }
+    }
+  }
+  for (i = 0; i < 256; i++)
+    if (temp_fields[i].length() > 0)
+      nfields++;
+  field = new string[nfields];
+  int j = 0;
+  for (i = 0; i < 256; i++)
+    if (temp_fields[i].length() > 0) {
+      field[j].move(temp_fields[i]);
+      if (abbreviate_fields.search(i) >= 0)
+	abbreviate_names(field[j]);
+      field_index[i] = j;
+      j++;
+    }
+}
+
+reference::~reference()
+{
+  if (nfields > 0)
+    delete[] field;
+}
+
+// ref is the inline, this is the database ref
+
+void reference::merge(reference &ref)
+{
+  int i;
+  for (i = 0; i < 256; i++)
+    if (field_index[i] != NULL_FIELD_INDEX)
+      temp_fields[i].move(field[field_index[i]]);
+  for (i = 0; i < 256; i++)
+    if (ref.field_index[i] != NULL_FIELD_INDEX)
+      temp_fields[i].move(ref.field[ref.field_index[i]]);
+  for (i = 0; i < 256; i++)
+    field_index[i] = NULL_FIELD_INDEX;
+  int old_nfields = nfields;
+  nfields = 0;
+  for (i = 0; i < 256; i++)
+    if (temp_fields[i].length() > 0)
+      nfields++;
+  if (nfields != old_nfields) {
+    if (old_nfields > 0)
+      delete[] field;
+    field = new string[nfields];
+  }
+  int j = 0;
+  for (i = 0; i < 256; i++)
+    if (temp_fields[i].length() > 0) {
+      field[j].move(temp_fields[i]);
+      field_index[i] = j;
+      j++;
+    }
+  merged = 1;
+}
+
+void reference::insert_field(unsigned char c, string &s)
+{
+  assert(s.length() > 0);
+  if (field_index[c] != NULL_FIELD_INDEX) {
+    field[field_index[c]].move(s);
+    return;
+  }
+  assert(field_index[c] == NULL_FIELD_INDEX);
+  string *old_field = field;
+  field = new string[nfields + 1];
+  int pos = 0;
+  int i;
+  for (i = 0; i < int(c); i++)
+    if (field_index[i] != NULL_FIELD_INDEX)
+      pos++;
+  for (i = 0; i < pos; i++)
+    field[i].move(old_field[i]);
+  field[pos].move(s);
+  for (i = pos; i < nfields; i++)
+    field[i + 1].move(old_field[i]);
+  if (nfields > 0)
+    delete[] old_field;
+  nfields++;
+  field_index[c] = pos;
+  for (i = c + 1; i < 256; i++)
+    if (field_index[i] != NULL_FIELD_INDEX)
+      field_index[i] += 1;
+}
+
+void reference::delete_field(unsigned char c)
+{
+  if (field_index[c] == NULL_FIELD_INDEX)
+    return;
+  string *old_field = field;
+  field = new string[nfields - 1];
+  int i;
+  for (i = 0; i < int(field_index[c]); i++)
+    field[i].move(old_field[i]);
+  for (i = field_index[c]; i < nfields - 1; i++)
+    field[i].move(old_field[i + 1]);
+  if (nfields > 0)
+    delete[] old_field;
+  nfields--;
+  field_index[c] = NULL_FIELD_INDEX;
+  for (i = c + 1; i < 256; i++)
+    if (field_index[i] != NULL_FIELD_INDEX)
+      field_index[i] -= 1;
+}
+
+void reference::compute_hash_code()
+{
+  if (!rid.is_null())
+    h = rid.hash();
+  else {
+    h = 0;
+    for (int i = 0; i < nfields; i++)
+      if (field[i].length() > 0) {
+	h <<= 4;
+	h ^= hash_string(field[i].contents(), field[i].length());
+      }
+  }
+}
+
+void reference::set_number(int n)
+{
+  no = n;
+}
+
+const char SORT_SEP = '\001';
+const char SORT_SUB_SEP = '\002';
+const char SORT_SUB_SUB_SEP = '\003';
+
+// sep specifies additional word separators
+
+void sortify_words(const char *s, const char *end, const char *sep,
+		   string &result)
+{
+  int non_empty = 0;
+  int need_separator = 0;
+  for (;;) {
+    const char *token_start = s;
+    if (!get_token(&s, end))
+      break;
+    if ((s - token_start == 1
+	 && (*token_start == ' '
+	     || *token_start == '\n'
+	     || (sep && *token_start != '\0'
+		 && strchr(sep, *token_start) != 0)))
+	|| (s - token_start == 2
+	    && token_start[0] == '\\' && token_start[1] == ' ')) {
+      if (non_empty)
+	need_separator = 1;
+    }
+    else {
+      const token_info *ti = lookup_token(token_start, s);
+      if (ti->sortify_non_empty(token_start, s)) {
+	if (need_separator) {
+	  result += ' ';
+	  need_separator = 0;
+	}
+	ti->sortify(token_start, s, result);
+	non_empty = 1;
+      }
+    }
+  }
+}
+
+void sortify_word(const char *s, const char *end, string &result)
+{
+  for (;;) {
+    const char *token_start = s;
+    if (!get_token(&s, end))
+      break;
+    const token_info *ti = lookup_token(token_start, s);
+    ti->sortify(token_start, s, result);
+  }
+}
+
+void sortify_other(const char *s, int len, string &key)
+{
+  sortify_words(s, s + len, 0, key);
+}
+
+void sortify_title(const char *s, int len, string &key)
+{
+  const char *end = s + len;
+  for (; s < end && (*s == ' ' || *s == '\n'); s++) 
+    ;
+  const char *ptr = s;
+  for (;;) {
+    const char *token_start = ptr;
+    if (!get_token(&ptr, end))
+      break;
+    if (ptr - token_start == 1
+	&& (*token_start == ' ' || *token_start == '\n'))
+      break;
+  }
+  if (ptr < end) {
+    unsigned int first_word_len = ptr - s - 1;
+    const char *ae = articles.contents() + articles.length();
+    for (const char *a = articles.contents();
+	 a < ae;
+	 a = strchr(a, '\0') + 1)
+      if (first_word_len == strlen(a)) {
+	unsigned int j;
+	for (j = 0; j < first_word_len; j++)
+	  if (a[j] != cmlower(s[j]))
+	    break;
+	if (j >= first_word_len) {
+	  s = ptr;
+	  for (; s < end && (*s == ' ' || *s == '\n'); s++)
+	    ;
+	  break;
+	}
+      }
+  }
+  sortify_words(s, end, 0, key);
+}
+
+void sortify_name(const char *s, int len, string &key)
+{
+  const char *last_name_end;
+  const char *last_name = find_last_name(s, s + len, &last_name_end);
+  sortify_word(last_name, last_name_end, key);
+  key += SORT_SUB_SUB_SEP;
+  if (last_name > s)
+    sortify_words(s, last_name, ".", key);
+  key += SORT_SUB_SUB_SEP;
+  if (last_name_end < s + len)
+    sortify_words(last_name_end, s + len, ".,", key);
+}
+
+void sortify_date(const char *s, int len, string &key)
+{
+  const char *year_end;
+  const char *year_start = find_year(s, s + len, &year_end);
+  if (!year_start) {
+    // Things without years are often 'forthcoming', so it makes sense
+    // that they sort after things with explicit years.
+    key += 'A';
+    sortify_words(s, s + len, 0, key);
+    return;
+  }
+  int n = year_end - year_start;
+  while (n < 4) {
+    key += '0';
+    n++;
+  }
+  while (year_start < year_end)
+    key += *year_start++;
+  int m = find_month(s, s + len);
+  if (m < 0)
+    return;
+  key += 'A' + m;
+  const char *day_end;
+  const char *day_start = find_day(s, s + len, &day_end);
+  if (!day_start)
+    return;
+  if (day_end - day_start == 1)
+    key += '0';
+  while (day_start < day_end)
+    key += *day_start++;
+}
+
+// SORT_{SUB,SUB_SUB}_SEP can creep in from use of @ in label specification.
+
+void sortify_label(const char *s, int len, string &key)
+{
+  const char *end = s + len;
+  for (;;) {
+    const char *ptr;
+    for (ptr = s;
+	 ptr < end && *ptr != SORT_SUB_SEP && *ptr != SORT_SUB_SUB_SEP;
+	 ptr++)
+      ;
+    if (ptr > s)
+      sortify_words(s, ptr, 0, key);
+    s = ptr;
+    if (s >= end)
+      break;
+    key += *s++;
+  }
+}
+
+void reference::compute_sort_key()
+{
+  if (sort_fields.length() == 0)
+    return;
+  sort_fields += '\0';
+  const char *sf = sort_fields.contents();
+  int first_time = 1;
+  while (*sf != '\0') {
+    if (!first_time)
+      sort_key += SORT_SEP;
+    first_time = 0;
+    char f = *sf++;
+    int n = 1;
+    if (*sf == '+') {
+      n = INT_MAX;
+      sf++;
+    }
+    else if (csdigit(*sf)) {
+      char *ptr;
+      long l = strtol(sf, &ptr, 10);
+      if (l == 0 && ptr == sf)
+	;
+      else {
+	sf = ptr;
+	if (l < 0) {
+	  n = 1;
+	}
+	else {
+	  n = int(l);
+	}
+      }
+    }
+    if (f == '.')
+      sortify_label(label.contents(), label.length(), sort_key);
+    else if (f == AUTHOR_FIELDS[0])
+      sortify_authors(n, sort_key);
+    else
+      sortify_field(f, n, sort_key);
+  }
+  sort_fields.set_length(sort_fields.length() - 1);
+}
+
+void reference::sortify_authors(int n, string &result) const
+{
+  for (const char *p = AUTHOR_FIELDS; *p != '\0'; p++)
+    if (contains_field(*p)) {
+      sortify_field(*p, n, result);
+      return;
+    }
+  sortify_field(AUTHOR_FIELDS[0], n, result);
+}
+
+void reference::canonicalize_authors(string &result) const
+{
+  int len = result.length();
+  sortify_authors(INT_MAX, result);
+  if (result.length() > len)
+    result += SORT_SUB_SEP;
+}
+
+void reference::sortify_field(unsigned char f, int n, string &result) const
+{
+  typedef void (*sortify_t)(const char *, int, string &);
+  sortify_t sortifier = sortify_other;
+  switch (f) {
+  case 'A':
+  case 'E':
+    sortifier = sortify_name;
+    break;
+  case 'D':
+    sortifier = sortify_date;
+    break;
+  case 'B':
+  case 'J':
+  case 'T':
+    sortifier = sortify_title;
+    break;
+  }
+  int fi = field_index[(unsigned char)f];
+  if (fi != NULL_FIELD_INDEX) {
+    string &str = field[fi];
+    const char *start = str.contents();
+    const char *end = start + str.length();
+    for (int i = 0; i < n && start < end; i++) {
+      const char *p = start;
+      while (start < end && *start != FIELD_SEPARATOR)
+	start++;
+      if (i > 0)
+	result += SORT_SUB_SEP;
+      (*sortifier)(p, start - p, result);
+      if (start < end)
+	start++;
+    }
+  }
+}
+
+int compare_reference(const reference &r1, const reference &r2)
+{
+  assert(r1.no >= 0);
+  assert(r2.no >= 0);
+  const char *s1 = r1.sort_key.contents();
+  int n1 = r1.sort_key.length();
+  const char *s2 = r2.sort_key.contents();
+  int n2 = r2.sort_key.length();
+  for (; n1 > 0 && n2 > 0; --n1, --n2, ++s1, ++s2)
+    if (*s1 != *s2)
+      return (int)(unsigned char)*s1 - (int)(unsigned char)*s2;
+  if (n2 > 0)
+    return -1;
+  if (n1 > 0)
+    return 1;
+  return r1.no - r2.no;
+}
+
+int same_reference(const reference &r1, const reference &r2)
+{
+  if (!r1.rid.is_null() && r1.rid == r2.rid)
+    return 1;
+  if (r1.h != r2.h)
+    return 0;
+  if (r1.nfields != r2.nfields)
+    return 0;
+  int i = 0; 
+  for (i = 0; i < 256; i++)
+    if (r1.field_index != r2.field_index)
+      return 0;
+  for (i = 0; i < r1.nfields; i++)
+    if (r1.field[i] != r2.field[i])
+      return 0;
+  return 1;
+}
+
+const char *find_last_name(const char *start, const char *end,
+			   const char **endp)
+{
+  const char *ptr = start;
+  const char *last_word = start;
+  for (;;) {
+    const char *token_start = ptr;
+    if (!get_token(&ptr, end))
+      break;
+    if (ptr - token_start == 1) {
+      if (*token_start == ',') {
+	*endp = token_start;
+	return last_word;
+      }
+      else if (*token_start == ' ' || *token_start == '\n') {
+	if (ptr < end && *ptr != ' ' && *ptr != '\n')
+	  last_word = ptr;
+      }
+    }
+  }
+  *endp = end;
+  return last_word;
+}
+
+void abbreviate_name(const char *ptr, const char *end, string &result)
+{
+  const char *last_name_end;
+  const char *last_name_start = find_last_name(ptr, end, &last_name_end);
+  int need_period = 0;
+  for (;;) {
+    const char *token_start = ptr;
+    if (!get_token(&ptr, last_name_start))
+      break;
+    const token_info *ti = lookup_token(token_start, ptr);
+    if (need_period) {
+      if ((ptr - token_start == 1 && *token_start == ' ')
+	  || (ptr - token_start == 2 && token_start[0] == '\\'
+	      && token_start[1] == ' '))
+	continue;
+      if (ti->is_upper())
+	result += period_before_initial;
+      else
+	result += period_before_other;
+      need_period = 0;
+    }
+    result.append(token_start, ptr - token_start);
+    if (ti->is_upper()) {
+      const char *lower_ptr = ptr;
+      int first_token = 1;
+      for (;;) {
+	token_start = ptr;
+	if (!get_token(&ptr, last_name_start))
+	  break;
+	if ((ptr - token_start == 1 && *token_start == ' ')
+	    || (ptr - token_start == 2 && token_start[0] == '\\'
+		&& token_start[1] == ' '))
+	  break;
+	ti = lookup_token(token_start, ptr);
+	if (ti->is_hyphen()) {
+	  const char *ptr1 = ptr;
+	  if (get_token(&ptr1, last_name_start)) {
+	    ti = lookup_token(ptr, ptr1);
+	    if (ti->is_upper()) {
+	      result += period_before_hyphen;
+	      result.append(token_start, ptr1 - token_start);
+	      ptr = ptr1;
+	    }
+	  }
+	}
+	else if (ti->is_upper()) {
+	  // MacDougal -> MacD.
+	  result.append(lower_ptr, ptr - lower_ptr);
+	  lower_ptr = ptr;
+	  first_token = 1;
+	}
+	else if (first_token && ti->is_accent()) {
+	  result.append(token_start, ptr - token_start);
+	  lower_ptr = ptr;
+	}
+	first_token = 0;
+      }
+      need_period = 1;
+    }
+  }
+  if (need_period)
+    result += period_before_last_name;
+  result.append(last_name_start, end - last_name_start);
+}
+
+static void abbreviate_names(string &result)
+{
+  string str;
+  str.move(result);
+  const char *ptr = str.contents();
+  const char *end = ptr + str.length();
+  while (ptr < end) {
+    const char *name_end = (char *)memchr(ptr, FIELD_SEPARATOR, end - ptr);
+    if (name_end == 0)
+      name_end = end;
+    abbreviate_name(ptr, name_end, result);
+    if (name_end >= end)
+      break;
+    ptr = name_end + 1;
+    result += FIELD_SEPARATOR;
+  }
+}
+
+void reverse_name(const char *ptr, const char *name_end, string &result)
+{
+  const char *last_name_end;
+  const char *last_name_start = find_last_name(ptr, name_end, &last_name_end);
+  result.append(last_name_start, last_name_end - last_name_start);
+  while (last_name_start > ptr
+	 && (last_name_start[-1] == ' ' || last_name_start[-1] == '\n'))
+    last_name_start--;
+  if (last_name_start > ptr) {
+    result += ", ";
+    result.append(ptr, last_name_start - ptr);
+  }
+  if (last_name_end < name_end)
+    result.append(last_name_end, name_end - last_name_end);
+}
+
+void reverse_names(string &result, int n)
+{
+  if (n <= 0)
+    return;
+  string str;
+  str.move(result);
+  const char *ptr = str.contents();
+  const char *end = ptr + str.length();
+  while (ptr < end) {
+    if (--n < 0) {
+      result.append(ptr, end - ptr);
+      break;
+    }
+    const char *name_end = (char *)memchr(ptr, FIELD_SEPARATOR, end - ptr);
+    if (name_end == 0)
+      name_end = end;
+    reverse_name(ptr, name_end, result);
+    if (name_end >= end)
+      break;
+    ptr = name_end + 1;
+    result += FIELD_SEPARATOR;
+  }
+}
+
+// Return number of field separators.
+
+int join_fields(string &f)
+{
+  const char *ptr = f.contents();
+  int len = f.length();
+  int nfield_seps = 0;
+  int j;
+  for (j = 0; j < len; j++)
+    if (ptr[j] == FIELD_SEPARATOR)
+      nfield_seps++;
+  if (nfield_seps == 0)
+    return 0;
+  string temp;
+  int field_seps_left = nfield_seps;
+  for (j = 0; j < len; j++) {
+    if (ptr[j] == FIELD_SEPARATOR) {
+      if (nfield_seps == 1)
+	temp += join_authors_exactly_two;
+      else if (--field_seps_left == 0)
+	temp += join_authors_last_two;
+      else
+	temp += join_authors_default;
+    }
+    else
+      temp += ptr[j];
+  }
+  f = temp;
+  return nfield_seps;
+}
+
+void uppercase(const char *start, const char *end, string &result)
+{
+  for (;;) {
+    const char *token_start = start;
+    if (!get_token(&start, end))
+      break;
+    const token_info *ti = lookup_token(token_start, start);
+    ti->upper_case(token_start, start, result);
+  }
+}
+
+void lowercase(const char *start, const char *end, string &result)
+{
+  for (;;) {
+    const char *token_start = start;
+    if (!get_token(&start, end))
+      break;
+    const token_info *ti = lookup_token(token_start, start);
+    ti->lower_case(token_start, start, result);
+  }
+}
+
+void capitalize(const char *ptr, const char *end, string &result)
+{
+  int in_small_point_size = 0;
+  for (;;) {
+    const char *start = ptr;
+    if (!get_token(&ptr, end))
+      break;
+    const token_info *ti = lookup_token(start, ptr);
+    const char *char_end = ptr;
+    int is_lower = ti->is_lower();
+    if ((is_lower || ti->is_upper()) && get_token(&ptr, end)) {
+      const token_info *ti2 = lookup_token(char_end, ptr);
+      if (!ti2->is_accent())
+	ptr = char_end;
+    }
+    if (is_lower) {
+      if (!in_small_point_size) {
+	result += "\\s-2";
+	in_small_point_size = 1;
+      }
+      ti->upper_case(start, char_end, result);
+      result.append(char_end, ptr - char_end);
+    }
+    else {
+      if (in_small_point_size) {
+	result += "\\s+2";
+	in_small_point_size = 0;
+      }
+      result.append(start, ptr - start);
+    }
+  }
+  if (in_small_point_size)
+    result += "\\s+2";
+}
+
+void capitalize_field(string &str)
+{
+  string temp;
+  capitalize(str.contents(), str.contents() + str.length(), temp);
+  str.move(temp);
+}
+
+int is_terminated(const char *ptr, const char *end)
+{
+  const char *last_token = end;
+  for (;;) {
+    const char *p = ptr;
+    if (!get_token(&ptr, end))
+      break;
+    last_token = p;
+  }
+  return end - last_token == 1
+    && (*last_token == '.' || *last_token == '!' || *last_token == '?');
+}
+
+void reference::output(FILE *fp)
+{
+  fputs(".]-\n", fp);
+  for (int i = 0; i < 256; i++)
+    if (field_index[i] != NULL_FIELD_INDEX && i != annotation_field) {
+      string &f = field[field_index[i]];
+      if (!csdigit(i)) {
+	int j = reverse_fields.search(i);
+	if (j >= 0) {
+	  int n;
+	  int len = reverse_fields.length();
+	  if (++j < len && csdigit(reverse_fields[j])) {
+	    n = reverse_fields[j] - '0';
+	    for (++j; j < len && csdigit(reverse_fields[j]); j++)
+	      // should check for overflow
+	      n = n*10 + reverse_fields[j] - '0';
+	  }
+	  else 
+	    n = INT_MAX;
+	  reverse_names(f, n);
+	}
+      }
+      int is_multiple = join_fields(f) > 0;
+      if (capitalize_fields.search(i) >= 0)
+	capitalize_field(f);
+      if (memchr(f.contents(), '\n', f.length()) == 0) {
+	fprintf(fp, ".ds [%c ", i);
+	if (f[0] == ' ' || f[0] == '\\' || f[0] == '"')
+	  putc('"', fp);
+	put_string(f, fp);
+	putc('\n', fp);
+      }
+      else {
+	fprintf(fp, ".de [%c\n", i);
+	put_string(f, fp);
+	fputs("..\n", fp);
+      }
+      if (i == 'P') {
+	int multiple_pages = 0;
+	const char *s = f.contents();
+	const char *end = f.contents() + f.length();
+	for (;;) {
+	  const char *token_start = s;
+	  if (!get_token(&s, end))
+	    break;
+	  const token_info *ti = lookup_token(token_start, s);
+	  if (ti->is_hyphen() || ti->is_range_sep()) {
+	    multiple_pages = 1;
+	    break;
+	  }
+	}
+	fprintf(fp, ".nr [P %d\n", multiple_pages);
+      }
+      else if (i == 'E')
+	fprintf(fp, ".nr [E %d\n", is_multiple);
+    }
+  for (const char *p = "TAO"; *p; p++) {
+    int fi = field_index[(unsigned char)*p];
+    if (fi != NULL_FIELD_INDEX) {
+      string &f = field[fi];
+      fprintf(fp, ".nr [%c %d\n", *p,
+	      is_terminated(f.contents(), f.contents() + f.length()));
+    }
+  }
+  int t = classify();
+  fprintf(fp, ".][ %d %s\n", t, reference_types[t]);
+  if (annotation_macro.length() > 0 && annotation_field >= 0
+      && field_index[annotation_field] != NULL_FIELD_INDEX) {
+    putc('.', fp);
+    put_string(annotation_macro, fp);
+    putc('\n', fp);
+    put_string(field[field_index[annotation_field]], fp);
+  }
+}
+
+void reference::print_sort_key_comment(FILE *fp)
+{
+  fputs(".\\\"", fp);
+  put_string(sort_key, fp);
+  putc('\n', fp);
+}
+
+const char *find_year(const char *start, const char *end, const char **endp)
+{
+  for (;;) {
+    while (start < end && !csdigit(*start))
+      start++;
+    const char *ptr = start;
+    if (start == end)
+      break;
+    while (ptr < end && csdigit(*ptr))
+      ptr++;
+    if (ptr - start == 4 || ptr - start == 3
+	|| (ptr - start == 2
+	    && (start[0] >= '4' || (start[0] == '3' && start[1] >= '2')))) {
+      *endp = ptr;
+      return start;
+    }
+    start = ptr;
+  }
+  return 0;
+}
+
+static const char *find_day(const char *start, const char *end,
+			    const char **endp)
+{
+  for (;;) {
+    while (start < end && !csdigit(*start))
+      start++;
+    const char *ptr = start;
+    if (start == end)
+      break;
+    while (ptr < end && csdigit(*ptr))
+      ptr++;
+    if ((ptr - start == 1 && start[0] != '0')
+	|| (ptr - start == 2 &&
+	    (start[0] == '1'
+	     || start[0] == '2'
+	     || (start[0] == '3' && start[1] <= '1')
+	     || (start[0] == '0' && start[1] != '0')))) {
+      *endp = ptr;
+      return start;
+    }
+    start = ptr;
+  }
+  return 0;
+}
+
+static int find_month(const char *start, const char *end)
+{
+  static const char *months[] = {
+    "january",
+    "february",
+    "march",
+    "april",
+    "may",
+    "june",
+    "july",
+    "august",
+    "september",
+    "october",
+    "november",
+    "december",
+  };
+  for (;;) {
+    while (start < end && !csalpha(*start))
+      start++;
+    const char *ptr = start;
+    if (start == end)
+      break;
+    while (ptr < end && csalpha(*ptr))
+      ptr++;
+    if (ptr - start >= 3) {
+      for (unsigned int i = 0; i < sizeof(months)/sizeof(months[0]); i++) {
+	const char *q = months[i];
+	const char *p = start;
+	for (; p < ptr; p++, q++)
+	  if (cmlower(*p) != *q)
+	    break;
+	if (p >= ptr)
+	  return i;
+      }
+    }
+    start = ptr;
+  }
+  return -1;
+}
+
+int reference::contains_field(char c) const
+{
+  return field_index[(unsigned char)c] != NULL_FIELD_INDEX;
+}
+
+int reference::classify()
+{
+  if (contains_field('J'))
+    return JOURNAL_ARTICLE;
+  if (contains_field('B'))
+    return ARTICLE_IN_BOOK;
+  if (contains_field('G'))
+    return TECH_REPORT;
+  if (contains_field('R'))
+    return TECH_REPORT;
+  if (contains_field('I'))
+    return BOOK;
+  if (contains_field('M'))
+    return BELL_TM;
+  return OTHER;
+}
+
+const char *reference::get_year(const char **endp) const
+{
+  if (field_index['D'] != NULL_FIELD_INDEX) {
+    string &date = field[field_index['D']];
+    const char *start = date.contents();
+    const char *end = start + date.length();
+    return find_year(start, end, endp);
+  }
+  else
+    return 0;
+}
+
+const char *reference::get_field(unsigned char c, const char **endp) const
+{
+  if (field_index[c] != NULL_FIELD_INDEX) {
+    string &f = field[field_index[c]];
+    const char *start = f.contents();
+    *endp = start + f.length();
+    return start;
+  }
+  else
+    return 0;
+}
+
+const char *reference::get_date(const char **endp) const
+{
+  return get_field('D', endp);
+}
+
+const char *nth_field(int i, const char *start, const char **endp)
+{
+  while (--i >= 0) {
+    start = (char *)memchr(start, FIELD_SEPARATOR, *endp - start);
+    if (!start)
+      return 0;
+    start++;
+  }
+  const char *e = (char *)memchr(start, FIELD_SEPARATOR, *endp - start);
+  if (e)
+    *endp = e;
+  return start;
+}
+
+const char *reference::get_author(int i, const char **endp) const
+{
+  for (const char *f = AUTHOR_FIELDS; *f != '\0'; f++) {
+    const char *start = get_field(*f, endp);
+    if (start) {
+      if (strchr(MULTI_FIELD_NAMES, *f) != 0)
+	return nth_field(i, start, endp);
+      else if (i == 0)
+	return start;
+      else
+	return 0;
+    }
+  }
+  return 0;
+}
+
+const char *reference::get_author_last_name(int i, const char **endp) const
+{
+  for (const char *f = AUTHOR_FIELDS; *f != '\0'; f++) {
+    const char *start = get_field(*f, endp);
+    if (start) {
+      if (strchr(MULTI_FIELD_NAMES, *f) != 0) {
+	start = nth_field(i, start, endp);
+	if (!start)
+	  return 0;
+      }
+      if (*f == 'A')
+	return find_last_name(start, *endp, endp);
+      else
+	return start;
+    }
+  }
+  return 0;
+}
+
+void reference::set_date(string &d)
+{
+  if (d.length() == 0)
+    delete_field('D');
+  else
+    insert_field('D', d);
+}
+
+int same_year(const reference &r1, const reference &r2)
+{
+  const char *ye1;
+  const char *ys1 = r1.get_year(&ye1);
+  const char *ye2;
+  const char *ys2 = r2.get_year(&ye2);
+  if (ys1 == 0) {
+    if (ys2 == 0)
+      return same_date(r1, r2);
+    else
+      return 0;
+  }
+  else if (ys2 == 0)
+    return 0;
+  else if (ye1 - ys1 != ye2 - ys2)
+    return 0;
+  else
+    return memcmp(ys1, ys2, ye1 - ys1) == 0;
+}
+
+int same_date(const reference &r1, const reference &r2)
+{
+  const char *e1;
+  const char *s1 = r1.get_date(&e1);
+  const char *e2;
+  const char *s2 = r2.get_date(&e2);
+  if (s1 == 0)
+    return s2 == 0;
+  else if (s2 == 0)
+    return 0;
+  else if (e1 - s1 != e2 - s2)
+    return 0;
+  else
+    return memcmp(s1, s2, e1 - s1) == 0;
+}
+
+const char *reference::get_sort_field(int i, int si, int ssi,
+				      const char **endp) const
+{
+  const char *start = sort_key.contents();
+  const char *end = start + sort_key.length();
+  if (i < 0) {
+    *endp = end;
+    return start;
+  }
+  while (--i >= 0) {
+    start = (char *)memchr(start, SORT_SEP, end - start);
+    if (!start)
+      return 0;
+    start++;
+  }
+  const char *e = (char *)memchr(start, SORT_SEP, end - start);
+  if (e)
+    end = e;
+  if (si < 0) {
+    *endp = end;
+    return start;
+  }
+  while (--si >= 0) {
+    start = (char *)memchr(start, SORT_SUB_SEP, end - start);
+    if (!start)
+      return 0;
+    start++;
+  }
+  e = (char *)memchr(start, SORT_SUB_SEP, end - start);
+  if (e)
+    end = e;
+  if (ssi < 0) {
+    *endp = end;
+    return start;
+  }
+  while (--ssi >= 0) {
+    start = (char *)memchr(start, SORT_SUB_SUB_SEP, end - start);
+    if (!start)
+      return 0;
+    start++;
+  }
+  e = (char *)memchr(start, SORT_SUB_SUB_SEP, end - start);
+  if (e)
+    end = e;
+  *endp = end;
+  return start;
+}
+
diff --git a/src/preproc/refer/ref.h b/src/preproc/refer/ref.h
new file mode 100644
index 0000000..1205a28
--- /dev/null
+++ b/src/preproc/refer/ref.h
@@ -0,0 +1,127 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+// declarations to avoid friend name injection problems
+int compare_reference(const reference &, const reference &);
+int same_reference(const reference &, const reference &);
+int same_year(const reference &, const reference &);
+int same_date(const reference &, const reference &);
+int same_author_last_name(const reference &, const reference &, int);
+int same_author_name(const reference &, const reference &, int);
+
+struct label_info;
+
+enum label_type { NORMAL_LABEL, SHORT_LABEL };
+const int N_LABEL_TYPES = 2;
+
+struct substring_position {
+  int start;
+  int length;
+  substring_position() : start(-1) { }
+};
+
+class int_set {
+  string v;
+public:
+  int_set() { }
+  void set(int i);
+  int get(int i) const;
+};
+
+class reference {
+private:
+  unsigned h;
+  reference_id rid;
+  int merged;
+  string sort_key;
+  int no;
+  string *field;
+  int nfields;
+  unsigned char field_index[256];
+  enum { NULL_FIELD_INDEX = 255 };
+  string label;
+  substring_position separator_pos;
+  string short_label;
+  substring_position short_separator_pos;
+  label_info *label_ptr;
+  string authors;
+  int computed_authors;
+  int last_needed_author;
+  int nauthors;
+  int_set last_name_unambiguous;
+
+  int contains_field(char) const;
+  void insert_field(unsigned char, string &s);
+  void delete_field(unsigned char);
+  void set_date(string &);
+  const char *get_sort_field(int i, int si, int ssi, const char **endp) const;
+  int merge_labels_by_parts(reference **, int, label_type, string &);
+  int merge_labels_by_number(reference **, int, label_type, string &);
+public:
+  reference(const char * = 0, int = -1, reference_id * = 0);
+  ~reference();
+  void output(FILE *);
+  void print_sort_key_comment(FILE *);
+  void set_number(int);
+  int get_number() const { return no; }
+  unsigned hash() const { return h; }
+  const string &get_label(label_type type) const;
+  const substring_position &get_separator_pos(label_type) const;
+  int is_merged() const { return merged; }
+  void compute_sort_key();
+  void compute_hash_code();
+  void pre_compute_label();
+  void compute_label();
+  void immediate_compute_label();
+  int classify();
+  void merge(reference &);
+  int merge_labels(reference **, int, label_type, string &);
+  int get_nauthors() const;
+  void need_author(int);
+  void set_last_name_unambiguous(int);
+  void sortify_authors(int, string &) const;
+  void canonicalize_authors(string &) const;
+  void sortify_field(unsigned char, int, string &) const;
+  const char *get_author(int, const char **) const;
+  const char *get_author_last_name(int, const char **) const;
+  const char *get_date(const char **) const;
+  const char *get_year(const char **) const;
+  const char *get_field(unsigned char, const char **) const;
+  const label_info *get_label_ptr() const { return label_ptr; }
+  const char *get_authors(const char **) const;
+  // for sorting
+  friend int compare_reference(const reference &r1, const reference &r2);
+  // for merging
+  friend int same_reference(const reference &, const reference &);
+  friend int same_year(const reference &, const reference &);
+  friend int same_date(const reference &, const reference &);
+  friend int same_author_last_name(const reference &, const reference &, int);
+  friend int same_author_name(const reference &, const reference &, int);
+};
+
+const char *find_year(const char *, const char *, const char **);
+const char *find_last_name(const char *, const char *, const char **);
+
+const char *nth_field(int i, const char *start, const char **endp);
+
+void capitalize(const char *ptr, const char *end, string &result);
+void reverse_name(const char *ptr, const char *end, string &result);
+void uppercase(const char *ptr, const char *end, string &result);
+void lowercase(const char *ptr, const char *end, string &result);
+void abbreviate_name(const char *ptr, const char *end, string &result);
diff --git a/src/preproc/refer/refer.1.man b/src/preproc/refer/refer.1.man
new file mode 100644
index 0000000..210afe7
--- /dev/null
+++ b/src/preproc/refer/refer.1.man
@@ -0,0 +1,2020 @@
+.TH @g@refer @MAN1EXT@ "@MDATE@" "groff @VERSION@"
+.SH Name
+@g@refer \- process bibliographic references for
+.I groff
+.
+.
+.\" ====================================================================
+.\" Legal Terms
+.\" ====================================================================
+.\"
+.\" Copyright (C) 1989-2021 Free Software Foundation, Inc.
+.\"
+.\" Permission is granted to make and distribute verbatim copies of this
+.\" manual provided the copyright notice and this permission notice are
+.\" preserved on all copies.
+.\"
+.\" Permission is granted to copy and distribute modified versions of
+.\" this manual under the conditions for verbatim copying, provided that
+.\" the entire resulting derived work is distributed under the terms of
+.\" a permission notice identical to this one.
+.\"
+.\" Permission is granted to copy and distribute translations of this
+.\" manual into another language, under the above conditions for
+.\" modified versions, except that this permission notice may be
+.\" included in translations approved by the Free Software Foundation
+.\" instead of in the original English.
+.
+.
+.\" Save and disable compatibility mode (for, e.g., Solaris 10/11).
+.do nr *groff_refer_1_man_C \n[.cp]
+.cp 0
+.
+.\" Define fallback for groff 1.23's MR macro if the system lacks it.
+.nr do-fallback 0
+.if !\n(.f           .nr do-fallback 1 \" mandoc
+.if  \n(.g .if !d MR .nr do-fallback 1 \" older groff
+.if !\n(.g           .nr do-fallback 1 \" non-groff *roff
+.if \n[do-fallback]  \{\
+.  de MR
+.    ie \\n(.$=1 \
+.      I \%\\$1
+.    el \
+.      IR \%\\$1 (\\$2)\\$3
+.  .
+.\}
+.rr do-fallback
+.
+.
+.\" ====================================================================
+.SH Synopsis
+.\" ====================================================================
+.
+.SY @g@refer
+.RB [ \-bCenPRS ]
+.RB [ \-a\~\c
+.IR n ]
+.RB [ \-B
+.IB field . macro\c
+]
+.RB [ \-c\~\c
+.IR fields ]
+.RB [ \-f\~\c
+.IR n ]
+.RB [ \-i\~\c
+.IR fields ]
+.RB [ \-k\~\c
+.IR field ]
+.RB [ \-l\~\c
+.IR range-expression ]
+.RB [ \-p\~\c
+.IR database-file ]
+.RB [ \-s\~\c
+.IR fields ]
+.RB [ \-t\~\c
+.IR n ]
+.RI [ file\~ .\|.\|.]
+.YS
+.
+.
+.SY @g@refer
+.B \-\-help
+.YS
+.
+.
+.SY @g@refer
+.B \-v
+.
+.SY @g@refer
+.B \-\-version
+.YS
+.
+.
+.\" ====================================================================
+.SH Description
+.\" ====================================================================
+.
+The GNU implementation of
+.I \%refer \" generic
+is part of the
+.MR groff @MAN1EXT@
+document formatting system.
+.
+.I @g@refer
+is a
+.MR @g@troff @MAN1EXT@
+preprocessor that prepares bibilographic citations by looking up
+keywords specified in a
+.MR roff @MAN7EXT@
+input document,
+obviating the need to type such annotations,
+and permitting the citation style in formatted output to be altered
+independently and systematically.
+.
+It copies the contents of each
+.I file
+to the standard output stream,
+except that it interprets lines between
+.B .[
+and
+.B .]\&
+as citations to be translated into
+.I groff
+input,
+and lines between
+.B .R1
+and
+.B .R2
+as instructions regarding how citations are to be processed.
+.
+Normally,
+.I @g@refer
+is not executed directly by the user,
+but invoked by specifying the
+.B \-R
+option to
+.MR groff @MAN1EXT@ .
+.
+If no
+.I file
+operands are given on the command line,
+or if
+.I file
+is
+.RB \[lq] \- \[rq],
+the standard input stream is read.
+.
+.
+.LP
+Each citation specifies a reference.
+.
+The citation can specify a reference that is contained in a
+bibliographic database by giving a set of keywords that only that
+reference contains.
+.
+Alternatively it can specify a reference by supplying a database record
+in the citation.
+.
+A combination of these alternatives is also possible.
+.
+.
+.LP
+For each citation,
+.I @g@refer
+can produce a mark in the text.
+.
+This mark consists of some label which can be separated from the text
+and from other labels in various ways.
+.
+For each reference it also outputs
+.MR groff @MAN7EXT@
+language commands that can be used by a macro package to produce a
+formatted reference for each citation.
+.
+The output of
+.I @g@refer
+must therefore be processed using a suitable macro package,
+such as
+.\" .IR man ,
+.IR me ,
+.IR mm ,
+.IR mom ,
+or
+.IR ms .
+.
+The commands to format a citation's reference can be output immediately
+after the citation,
+or the references may be accumulated,
+and the commands output at some later point.
+.
+If the references are accumulated,
+then multiple citations of the same reference will produce a single
+formatted reference.
+.
+.
+.LP
+The interpretation of lines between
+.B .R1
+and
+.B .R2
+as prepreocessor commands is a feature of GNU
+.IR \%refer . \" GNU
+.
+Documents making use of this feature can still be processed by AT&T
+.I \%refer \" AT&T
+just by adding the lines
+.
+.RS
+.EX
+\&.de R1
+\&.ig R2
+\&..
+.EE
+.RE
+.
+to the beginning of the document.
+.
+This will cause
+.MR @g@troff @MAN1EXT@
+to ignore everything between
+.B .R1
+and
+.BR .R2 .
+.
+The effect of some commands can also be achieved by options.
+.
+These options are supported mainly for compatibility with AT&T
+.IR \%refer . \" AT&T
+.
+It is usually more convenient to use commands.
+.
+.
+.LP
+.I @g@refer
+generates
+.B .lf
+requests so that file names and line numbers in messages produced by
+commands that read
+.I @g@refer
+output will be correct;
+it also interprets lines beginning with
+.B .lf
+so that file names and line numbers in the messages and
+.B .lf
+lines that it produces will be accurate even if the input has been
+preprocessed by a command such as
+.MR @g@soelim @MAN1EXT@ .
+.
+.
+.\" ====================================================================
+.SS "Bibliographic databases"
+.\" ====================================================================
+.
+The bibliographic database is a text file consisting of records
+separated by one or more blank lines.
+.
+Within each record fields start with a
+.B %
+at the beginning of a line.
+.
+Each field has a one character name that immediately follows the
+.BR % .
+It is best to use only upper and lower case letters for the names
+of fields.
+.
+The name of the field should be followed by exactly one space,
+and then by the contents of the field.
+.
+Empty fields are ignored.
+.
+The conventional meaning of each field is as follows:
+.
+.
+.TP
+.B %A
+The name of an author.
+.
+If the name contains a suffix such as \[lq]Jr.\&\[rq],
+it should be separated from the last name by a comma.
+.
+There can be multiple occurrences of the
+.B %A
+field.
+.
+The order is significant.
+.
+It is a good idea always to supply an
+.B %A
+field or a
+.B %Q
+field.
+.
+.
+.TP
+.B %B
+For an article that is part of a book,
+the title of the book.
+.
+.
+.TP
+.B %C
+The place (city) of publication.
+.
+.
+.TP
+.B %D
+The date of publication.
+.
+The year should be specified in full.
+.
+If the month is specified,
+the name rather than the number of the month should be used,
+but only the first three letters are required.
+.
+It is a good idea always to supply a
+.B %D
+field;
+if the date is unknown,
+a value such as
+.B in press
+or
+.B unknown
+can be used.
+.
+.
+.TP
+.B %E
+For an article that is part of a book,
+the name of an editor of the book.
+.
+Where the work has editors and no authors,
+the names of the editors should be given as
+.B %A
+fields and
+.RB \[lq] ,\~(ed.)\& \[rq]
+or
+.RB \[lq] ,\~(eds.)\& \[rq]
+should be appended to the last author.
+.
+.
+.TP
+.B %G
+U.S. government ordering number.
+.
+.
+.TP
+.B %I
+The publisher (issuer).
+.
+.
+.TP
+.B %J
+For an article in a journal,
+the name of the journal.
+.
+.
+.TP
+.B %K
+Keywords to be used for searching.
+.
+.
+.TP
+.B %L
+Label.
+.
+.
+.TP
+.B %N
+Journal issue number.
+.
+.
+.TP
+.B %O
+Other information.
+.
+This is usually printed at the end of the reference.
+.
+.
+.TP
+.B %P
+Page number.
+.
+A range of pages can be specified as
+.IB m \- \c
+.IR n .
+.
+.
+.TP
+.B %Q
+The name of the author,
+if the author is not a person.
+.
+This will only be used if there are no
+.B %A
+fields.
+.
+There can only be one
+.B %Q
+field.
+.
+.
+.TP
+.B %R
+Technical report number.
+.
+.
+.TP
+.B %S
+Series name.
+.
+.
+.TP
+.B %T
+Title.
+.
+For an article in a book or journal,
+this should be the title of the article.
+.
+.
+.TP
+.B %V
+Volume number of the journal or book.
+.
+.
+.TP
+.B %X
+Annotation.
+.
+.
+.LP
+For all fields except
+.B %A
+and
+.BR %E ,
+if there is more than one occurrence of a particular field in a record,
+only the last such field will be used.
+.
+.
+.P
+If accent strings are used,
+they should follow the character to be accented.
+.
+This means that an
+.I ms
+document must call the
+.B .AM
+macro when it initializes.
+.
+Accent strings should not be quoted:
+use one
+.B \e
+rather than two.
+.
+Accent strings are an obsolescent feature of the
+.I me
+and
+.I ms
+macro packages;
+modern documents should use
+.I groff
+special character escape sequences instead;
+see
+.MR groff_char @MAN7EXT@ .
+.
+.
+.\" ====================================================================
+.SS Citations
+.\" ====================================================================
+.
+Citations have a characteristic format.
+.
+.RS
+.EX
+.BI .[ opening-text
+.I flags keywords
+.I fields
+.BI .] closing-text
+.EE
+.RE
+.
+.
+.LP
+The
+.IR opening-text ,
+.IR closing-text ,
+and
+.I flags
+components are optional.
+.
+Only one of the
+.I keywords
+and
+.I fields
+components need be specified.
+.
+.
+.LP
+The
+.I keywords
+component says to search the bibliographic databases for a reference
+that contains all the words in
+.IR keywords .
+.
+It is an error if more than one reference is found.
+.
+.
+.LP
+The
+.I fields
+components specifies additional fields to replace or supplement those
+specified in the reference.
+.
+When references are being accumulated and the
+.I keywords
+component is non-empty,
+then additional fields should be specified only on the first occasion
+that a particular reference is cited,
+and will apply to all citations of that reference.
+.
+.
+.br
+.ne 2v
+.LP
+The
+.I opening-text
+and
+.I closing-text
+components specify strings to be used to bracket the label instead of
+those in the
+.B \%bracket\-label
+command.
+.
+If either of these components is non-empty,
+the strings specified in the
+.B \%bracket\-label
+command will not be used;
+this behavior can be altered using the
+.B [
+and
+.B ]
+flags.
+.
+Leading and trailing spaces are significant for these components.
+.
+.
+.LP
+The
+.I flags
+component is a list of non-alphanumeric characters each of which
+modifies the treatment of this particular citation.
+.
+AT&T
+.I \%refer \" AT&T
+will treat these flags as part of the keywords and so will ignore them
+since they are non-alphanumeric.
+.
+The following flags are currently recognized.
+.
+.
+.TP
+.B #
+Use the label specified by the
+.B \%short\-label
+command,
+instead of that specified by the
+.B \%label
+command.
+.
+If no short label has been specified,
+the normal label will be used.
+.
+Typically the short label is used with author-date labels and consists
+of only the date and possibly a disambiguating letter;
+the
+.RB \[lq] # \[rq]
+is supposed to be suggestive of a numeric type of label.
+.
+.
+.TP
+.B [
+Precede
+.I opening-text
+with the first string specified in the
+.B \%bracket\-label
+command.
+.
+.
+.TP
+.B ]
+Follow
+.I closing-text
+with the second string specified in the
+.B \%bracket\-label
+command.
+.
+.
+.LP
+An advantage of using the
+.B [
+and
+.B ]
+flags rather than including the brackets in
+.I opening-text
+and
+.I closing-text
+is that
+.
+you can change the style of bracket used in the document just by
+changing the
+.B \%bracket\-label
+command.
+.
+Another is that sorting and merging of citations will not necessarily be
+inhibited if the flags are used.
+.
+.
+.LP
+If a label is to be inserted into the text,
+it will be attached to the line preceding the
+.B .[
+line.
+.
+If there is no such line,
+then an extra line will be inserted before the
+.B .[
+line and a warning will be given.
+.
+.
+.LP
+There is no special notation for making a citation to multiple
+references.
+.
+Just use a sequence of citations,
+one for each reference.
+.
+Don't put anything between the citations.
+.
+The labels for all the citations will be attached to the line preceding
+the first citation.
+.
+The labels may also be sorted or merged.
+.
+See the description of the
+.B <>
+label expression,
+and of the
+.B \%sort\-adjacent\-labels
+and
+.B \%abbreviate\-label\-ranges
+commands.
+.
+A label will not be merged if its citation has a non-empty
+.I opening-text
+or
+.IR closing-text .
+.
+However,
+the labels for a citation using the
+.B ]
+flag and without any
+.I closing-text
+immediately followed by a citation using the
+.B [
+flag and without any
+.I opening-text
+may be sorted and merged
+even though the first citation's
+.I opening-text
+or the second citation's
+.I closing-text
+is non-empty.
+.
+(If you wish to prevent this,
+use the dummy character escape sequence
+.B \[rs]&
+as the first citation's
+.IR closing-text .)
+.
+.
+.\" ====================================================================
+.SS Commands
+.\" ====================================================================
+.
+Commands are contained between lines starting with
+.B .R1
+and
+.BR .R2 .
+.
+Recognition of these lines can be prevented by the
+.B \-R
+option.
+.
+When a
+.B .R1
+line is recognized any accumulated references are flushed out.
+.
+Neither
+.B .R1
+nor
+.B .R2
+lines,
+nor anything between them,
+is output.
+.
+.
+.P
+Commands are separated by newlines or semicolons.
+.
+A number sign
+.RB ( # )
+introduces a comment that extends to the end of the line,
+but does not conceal the newline.
+.
+Each command is broken up into words.
+.
+Words are separated by spaces or tabs.
+.
+A word that begins with a (neutral) double quote
+.RB ( \[dq] )
+extends to the next double quote that is not followed by another double
+quote.
+.
+If there is no such double quote,
+the word extends to the end of the line.
+.
+Pairs of double quotes in a word beginning with a double quote collapse
+to one double quote.
+.
+Neither a number sign nor a semicolon is recognized inside double
+quotes.
+.
+A line can be continued by ending it with a backslash
+.RB \[lq] \[rs] \[rq];
+this works everywhere except after a number sign.
+.
+.
+.LP
+.ds n \fR*\fP\"
+Each command
+.I name
+that is marked with \*n has an associated negative command
+.BI no\- name
+that undoes the effect of
+.IR name .
+.
+For example,
+the
+.B no\-sort
+command specifies that references should not be sorted.
+.
+The negative commands take no arguments.
+.
+.
+.LP
+In the following description each argument must be a single word;
+.I field
+is used for a single upper or lower case letter naming a field;
+.I fields
+is used for a sequence of such letters;
+.I m
+and
+.I n
+are used for a non-negative numbers;
+.I string
+is used for an arbitrary string;
+.I file
+is used for the name of a file.
+.
+.
+.TP
+.BI abbreviate\*n\~ fields\~string1\~string2\~string3\~string4
+Abbreviate the first names of
+.IR fields .
+.
+An initial letter will be separated from another initial letter by
+.IR string1 ,
+from the last name by
+.IR string2 ,
+and from anything else
+(such as \[lq]von\[rq] or \[lq]de\[rq])
+by
+.IR string3 .
+.
+These default to a period followed by a space.
+.
+In a hyphenated first name,
+the initial of the first part of the name will be separated from the
+hyphen by
+.IR string4 ;
+this defaults to a period.
+.
+No attempt is made to handle any ambiguities that might
+result from abbreviation.
+.
+Names are abbreviated before sorting and before label construction.
+.
+.
+.TP
+.BI abbreviate\-label\-ranges\*n\~ string
+.
+Three or more adjacent labels that refer to consecutive references
+will be abbreviated to a label consisting of the first label,
+followed by
+.IR string ,
+followed by the last label.
+.
+This is mainly useful with numeric labels.
+.
+If
+.I string
+is omitted,
+it defaults to
+.RB \[lq] \- \[rq].
+.
+.
+.TP
+.B accumulate\*n
+Accumulate references instead of writing out each reference
+as it is encountered.
+.
+Accumulated references will be written out whenever a reference
+of the form
+.
+.RS
+.RS
+.EX
+.B .[
+.B $LIST$
+.B .]
+.EE
+.RE
+.
+is encountered,
+after all input files have been processed,
+and whenever a
+.B .R1
+line is recognized.
+.RE
+.
+.
+.TP
+.BI annotate\*n\~ "field string"
+.I field
+is an annotation;
+print it at the end of the reference as a paragraph preceded by the line
+.
+.RS
+.IP
+.BI . string
+.
+.
+.LP
+If
+.I string
+is omitted,
+it will default to
+.BR AP ;
+if
+.I field
+is also omitted it will default to
+.BR X .
+.
+Only one field can be an annotation.
+.RE
+.
+.
+.TP
+.BI articles\~ string\~\c
+\&.\|.\|.
+Each
+.I string
+is a definite or indefinite article,
+and should be ignored at the beginning of
+.B T
+fields when sorting.
+.
+Initially,
+\[lq]a\[rq],
+\[lq]an\[rq],
+and
+\[lq]the\[rq] are recognized as articles.
+.
+.
+.TP
+.BI bibliography\~ file\~\c
+\&.\|.\|.
+.
+Write out all the references contained in each bibliographic database
+.IR file .
+.
+This command should come last in an
+.BR .R1 / .R2
+block.
+.
+.
+.TP
+.BI bracket\-label\~ "string1 string2 string3"
+In the text,
+bracket each label with
+.I string1
+and
+.IR string2 .
+.
+An occurrence of
+.I string2
+immediately followed by
+.I string1
+will be turned into
+.IR string3 .
+.
+The default behavior is as follows.
+.
+.RS \" RS twice to get inboard of the tagged paragraph indentation.
+.RS
+.EX
+.B bracket\-label \e*([. \e*(.] \[dq], \[dq]
+.EE
+.RE
+.RE
+.
+.
+.TP
+.BI capitalize\~ fields
+Convert
+.I fields
+to caps and small caps.
+.
+.
+.TP
+.B compatible\*n
+Recognize
+.B .R1
+and
+.B .R2
+even when followed by a character other than space or newline.
+.
+.
+.TP
+.BI database\~ file\~\c
+\&.\|.\|.
+Search each bibliographic database
+.IR file .
+.
+For each
+.IR file ,
+if an index
+.RI file @INDEX_SUFFIX@
+created by
+.MR @g@indxbib @MAN1EXT@
+exists,
+then it will be searched instead;
+each index can cover multiple databases.
+.
+.
+.TP
+.BI date\-as\-label\*n\~ string
+.I string
+is a label expression that specifies a string with which to replace the
+.B D
+field after constructing the label.
+.
+See subsection \[lq]Label expressions\[rq] below for a description of
+label expressions.
+.
+This command is useful if you do not want explicit labels in the
+reference list,
+but instead want to handle any necessary disambiguation by qualifying
+the date in some way.
+.
+The label used in the text would typically be some combination of the
+author and date.
+.
+In most cases you should also use the
+.B \%no\-label\-in\-reference
+command.
+.
+For example,
+.
+.RS \" RS twice to get inboard of the tagged paragraph indentation.
+.RS
+.EX
+.B date\-as\-label D.+yD.y%a*D.\-y
+.EE
+.RE
+.
+would attach a disambiguating letter to the year part of the
+.B D
+field in the reference.
+.RE
+.
+.
+.TP
+.B default\-database\*n
+The default database should be searched.
+.
+This is the default behavior,
+so the negative version of this command is more useful.
+.
+.I @g@refer
+determines whether the default database should be searched
+on the first occasion that it needs to do a search.
+.
+Thus a
+.B \%no\-default\-database
+command must be given before then,
+in order to be effective.
+.
+.
+.TP
+.BI discard\*n\~ fields
+When the reference is read,
+.I fields
+should be discarded;
+no string definitions for
+.I fields
+will be output.
+.
+Initially,
+.I fields
+are
+.BR XYZ .
+.
+.
+.TP
+.BI et\-al\*n\~ "string m n"
+Control use of
+.B et al.\&
+in the evaluation of
+.B @
+expressions in label expressions.
+.
+If the number of authors needed to make the author sequence unambiguous
+is
+.I u
+and the total number of authors is
+.I t
+then the last
+.IR t \|\-\| u
+authors will be replaced by
+.I string
+provided that
+.IR t \|\-\| u
+is not less than
+.I m
+and
+.I t
+is not less than
+.IR n .
+.
+The default behavior is as follows.
+.
+.RS \" RS twice to get inboard of the tagged paragraph indentation.
+.RS
+.EX
+.B et\-al \[dq] et al\[dq] 2 3
+.EE
+.RE
+.
+Note the absence of a dot from the end of the abbreviation,
+which is arguably not correct.
+.
+.RI ( "Et al" [.]
+is short for
+.IR "et alli" ,
+as
+.I etc.\&
+is short for
+.IR "et cetera".)
+.RE
+.
+.
+.TP
+.BI include\~ file
+Include
+.I file
+and interpret the contents as commands.
+.
+.
+.TP
+.BI join\-authors\~ "string1 string2 string3"
+Join multiple authors together with
+.IR string s.
+.
+When there are exactly two authors,
+they will be joined with
+.IR string1 .
+.
+When there are more than two authors,
+all but the last two will be joined with
+.IR string2 ,
+and the last two authors will be joined with
+.IR string3 .
+.
+If
+.I string3
+is omitted,
+it will default to
+.IR string1 ;
+if
+.I string2
+is also omitted it will also default to
+.IR string1 .
+.
+For example,
+.
+.RS
+.RS
+.EX
+join\-authors \[dq] and \[dq] \[dq], \[dq] \[dq], and \[dq]
+.EE
+.RE
+.
+will restore the default method for joining authors.
+.RE
+.
+.
+.TP
+.B label\-in\-reference\*n
+When outputting the reference,
+define the string
+.B [F
+to be the reference's label.
+.
+This is the default behavior,
+so the negative version of this command is more useful.
+.
+.
+.TP
+.B label\-in\-text\*n
+For each reference output a label in the text.
+.
+The label will be separated from the surrounding text as described in
+the
+.B \%bracket\-label
+command.
+.
+This is the default behavior,
+so the negative version of this command is more useful.
+.
+.
+.TP
+.BI label\~ string
+.I string
+is a label expression describing how to label each reference.
+.
+.
+.TP
+.BI separate\-label\-second\-parts\~ string
+When merging two-part labels,
+separate the second part of the second label from the first label with
+.IR string .
+.
+See the description of the
+.B <>
+label expression.
+.
+.
+.TP
+.B move\-punctuation\*n
+In the text,
+move any punctuation at the end of line past the label.
+.
+It is usually a good idea to give this command unless you are using
+superscripted numbers as labels.
+.
+.
+.TP
+.BI reverse\*n\~ string
+Reverse the fields whose names
+are in
+.IR string .
+.
+Each field name can be followed by a number which says how many such
+fields should be reversed.
+.
+If no number is given for a field,
+all such fields will be reversed.
+.
+.
+.TP
+.BI search\-ignore\*n\~ fields
+While searching for keys in databases for which no index exists,
+ignore the contents of
+.IR fields .
+.
+Initially,
+fields
+.B XYZ
+are ignored.
+.
+.
+.TP
+.BI search\-truncate\*n\~ n
+Only require the first
+.I n
+characters of keys to be given.
+.
+In effect when searching for a given key words in the database are
+truncated to the maximum of
+.I n
+and the length of the key.
+.
+Initially,
+.I n
+is\~6.
+.
+.
+.TP
+.BI short\-label\*n\~ string
+.I string
+is a label expression that specifies an alternative
+(usually shorter)
+style of label.
+.
+This is used when the
+.B #
+flag is given in the citation.
+.
+When using author-date style labels,
+the identity of the author or authors is sometimes clear from the
+context,
+and so it may be desirable to omit the author or authors from the label.
+.
+The
+.B \%short\-label
+command will typically be used to specify a label containing just
+a date and possibly a disambiguating letter.
+.
+.
+.TP
+.BI sort\*n\~ string
+Sort references according to
+.IR string .
+.
+References will automatically be accumulated.
+.
+.I string
+should be a list of field names,
+each followed by a number,
+indicating how many fields with the name should be used for sorting.
+.
+.RB \[lq] + \[rq]
+can be used to indicate that all the fields with the name should be
+used.
+.
+Also
+.B .\&
+can be used to indicate the references should be sorted using the
+(tentative) label.
+.
+(Subsection \[lq]Label expressions\[rq] below describes the concept of a
+tentative label.)
+.
+.
+.TP
+.B sort\-adjacent\-labels\*n
+Sort labels that are adjacent in the text according to their position
+in the reference list.
+.
+This command should usually be given if the
+.B \%abbreviate\-label\-ranges
+command has been given,
+or if the label expression contains a
+.B <>
+expression.
+.
+This will have no effect unless references are being accumulated.
+.
+.
+.\" ====================================================================
+.SS "Label expressions"
+.\" ====================================================================
+.
+Label expressions can be evaluated both normally and tentatively.
+.
+The result of normal evaluation is used for output.
+.
+The result of tentative evaluation,
+called the
+.IR "tentative label" ,
+is used to gather the information that normal evaluation needs to
+disambiguate the label.
+.
+Label expressions specified by the
+.B \%date\-as\-label
+and
+.B \%short\-label
+commands are not evaluated tentatively.
+.
+Normal and tentative evaluation are the same for all types of expression
+other than
+.BR @ ,
+.BR * ,
+and
+.B %
+expressions.
+.
+The description below applies to normal evaluation,
+except where otherwise specified.
+.
+.
+.TP
+.I field
+.TQ
+.I field\~n
+The
+.IR n -th
+part of
+.IR field .
+.
+If
+.I n
+is omitted,
+it defaults to\~1.
+.
+.
+.TP
+.BI \[aq] string \[aq]
+The characters in
+.I string
+literally.
+.
+.
+.TP
+.B @
+All the authors joined as specified by the
+.B \%join\-authors
+command.
+.
+The whole of each author's name will be used.
+.
+However,
+if the references are sorted by author
+(that is,
+the sort specification starts with
+.RB \[lq] A+ \[rq]),
+then authors' last names will be used instead,
+provided that this does not introduce ambiguity,
+and also an initial subsequence of the authors may be used instead of
+all the authors,
+again provided that this does not introduce ambiguity.
+.
+The use of only the last name for the
+.IR i -th
+author of some reference
+is considered to be ambiguous if
+there is some other reference,
+such that the first
+.IR i \|\-\|1
+authors of the references are the same,
+the
+.IR i -th
+authors are not the same,
+but the
+.IR i -th
+authors last names are the same.
+.
+A proper initial subsequence of the sequence of authors for some
+reference is considered to be ambiguous if there is a reference with
+some other sequence of authors which also has that subsequence as a
+proper initial subsequence.
+.
+When an initial subsequence of authors is used,
+the remaining authors are replaced by the string specified by the
+.B \%et\-al
+command;
+this command may also specify additional requirements that must be
+met before an initial subsequence can be used.
+.
+.B @
+tentatively evaluates to a canonical representation of the authors,
+such that authors that compare equally for sorting purpose will have
+the same representation.
+.
+.
+.TP
+.BI % n
+.TQ
+.B %a
+.TQ
+.B %A
+.TQ
+.B %i
+.TQ
+.B %I
+The serial number of the reference formatted according to the
+character following the
+.BR % .
+The serial number of a reference is\~1 plus the number of earlier
+references with same tentative label as this reference.
+.
+These expressions tentatively evaluate to an empty string.
+.
+.TP
+.IB expr *
+If there is another reference with the same tentative label as this
+reference,
+then
+.IR expr ,
+otherwise an empty string.
+.
+It tentatively evaluates to an empty string.
+.
+.
+.TP
+.IB expr + n
+.TQ
+.IB expr \- n
+The first
+.RB ( + )
+or last
+.RB ( \- )
+.I n
+upper or lower case letters or digits of
+.IR expr .
+.
+.I roff
+special characters
+(such as
+.BR \e(\[aq]a )
+count as a single letter.
+.
+Accent strings are retained but do not count towards the total.
+.
+.
+.TP
+.IB expr .l
+.I expr
+converted to lowercase.
+.
+.
+.TP
+.IB expr .u
+.I expr
+converted to uppercase.
+.
+.
+.TP
+.IB expr .c
+.I expr
+converted to caps and small caps.
+.
+.
+.TP
+.IB expr .r
+.I expr
+reversed so that the last name is first.
+.
+.
+.TP
+.IB expr .a
+.I expr
+with first names abbreviated.
+.
+Fields specified in the
+.B \%abbreviate
+command are abbreviated before any labels are evaluated.
+.
+Thus
+.B .a
+is useful only when you want a field to be abbreviated in a label
+but not in a reference.
+.
+.
+.TP
+.IB expr .y
+The year part of
+.IR expr .
+.
+.
+.TP
+.IB expr .+y
+The part of
+.I expr
+before the year,
+or the whole of
+.I expr
+if it does not contain a year.
+.
+.
+.TP
+.IB expr .\-y
+The part of
+.I expr
+after the year,
+or an empty string if
+.I expr
+does not contain a year.
+.
+.
+.TP
+.IB expr .n
+The last name part of
+.IR expr .
+.
+.
+.TP
+.IB expr1 \[ti] expr2
+.I expr1
+except that if the last character of
+.I expr1
+is
+.B \-
+then it will be replaced by
+.IR expr2 .
+.
+.
+.TP
+.I expr1 expr2
+The concatenation of
+.I expr1
+and
+.IR expr2 .
+.
+.
+.TP
+.IB expr1 | expr2
+If
+.I expr1
+is non-empty then
+.I expr1
+otherwise
+.IR expr2 .
+.
+.
+.TP
+.IB expr1 & expr2
+If
+.I expr1
+is non-empty
+then
+.I expr2
+otherwise an empty string.
+.
+.
+.TP
+.IB expr1 ? expr2 : expr3
+If
+.I expr1
+is non-empty
+then
+.I expr2
+otherwise
+.IR expr3 .
+.
+.
+.TP
+.BI < expr >
+The label is in two parts,
+which are separated by
+.IR expr .
+.
+Two adjacent two-part labels which have the same first part will be
+merged by appending the second part of the second label onto the first
+label separated by the string specified in the
+.B \%separate\-label\-second\-parts
+command
+(initially,
+a comma followed by a space);
+the resulting label will also be a two-part label with the same first
+part as before merging,
+and so additional labels can be merged into it.
+.
+It is permissible for the first part to be empty;
+this may be desirable for expressions used in the
+.B \%short\-label
+command.
+.
+.
+.TP
+.BI ( expr )
+The same as
+.IR expr .
+.
+Used for grouping.
+.
+.
+.LP
+The above expressions are listed in order of precedence
+(highest first);
+.B &
+and
+.B |
+have the same precedence.
+.
+.
+.\" ====================================================================
+.SS "Macro interface"
+.\" ====================================================================
+.
+Each reference starts with a call to the macro
+.BR ]\- .
+.
+The string
+.B [F
+will be defined to be the label for this reference,
+unless the
+.B \%no\-label\-in\-reference
+command has been given.
+.
+There then follows a series of string definitions,
+one for each field:
+string
+.BI [ X
+corresponds to field
+.IR X .
+.
+The register
+.B [P
+is set to\~1 if the
+.B P
+field contains a range of pages.
+.
+The
+.BR [T ,
+.B [A
+and
+.B [O
+registers are set to\~1 according as the
+.BR T ,
+.B A
+and
+.B O
+fields end with any of
+.B .?!\&
+(an end-of-sentence character).
+.
+The
+.B [E
+register will be set to\~1 if the
+.B [E
+string contains more than one name.
+.
+The reference is followed by a call to the
+.B ][
+macro.
+.
+The first argument to this macro gives a number representing
+the type of the reference.
+.
+If a reference contains a
+.B J
+field,
+it will be classified as type\~1,
+otherwise if it contains a
+.B B
+field,
+it will be type\~3,
+otherwise if it contains a
+.B G
+or
+.B R
+field it will be type\~4,
+otherwise if it contains an
+.B I
+field it will be type\~2,
+otherwise it will be type\~0.
+.
+The second argument is a symbolic name for the type:
+.BR other ,
+.BR \%journal\-article ,
+.BR book ,
+.BR \%article\-in\-book ,
+or
+.BR \%tech\-report .
+.
+Groups of references that have been accumulated or are produced by the
+.B \%bibliography
+command are preceded by a call to the
+.B ]<
+macro and followed by a call to the
+.B ]>
+macro.
+.
+.
+.br
+.ne 4v
+.\" ====================================================================
+.SH Options
+.\" ====================================================================
+.
+.B \-\-help
+displays a usage message,
+while
+.B \-v
+and
+.B \-\-version
+show version information;
+all exit afterward.
+.
+.
+.TP
+.B \-R
+Don't recognize lines beginning with
+.BR .R1 / .R2 .
+.
+.
+.P
+Other options are equivalent to
+.I @g@refer
+commands.
+.
+.
+.TP 16n
+.BI \-a\~ n
+.B reverse
+.BI A n
+.
+.
+.TP
+.B \-b
+.B "\%no\-label\-in\-text; \%no\-label\-in\-reference"
+.
+.
+.TP
+.B \-B
+See below.
+.
+.
+.TP
+.BI \-c\~ fields
+.B capitalize
+.I fields
+.
+.
+.TP
+.B \-C
+.B compatible
+.
+.
+.TP
+.B \-e
+.B accumulate
+.
+.
+.TP
+.BI \-f\~ n
+.B \%label
+.BI % n
+.
+.
+.TP
+.BI \-i\~ fields
+.B search\-ignore
+.I fields
+.
+.
+.TP
+.B \-k
+.B \%label
+.B L\[ti]%a
+.
+.
+.TP
+.BI \-k\~ field
+.B \%label
+.IB field \[ti]%a
+.
+.
+.TP
+.B \-l
+.B \%label
+.B A.nD.y%a
+.
+.
+.TP
+.BI \-l\~ m
+.B \%label
+.BI A.n+ m D.y%a
+.
+.
+.TP
+.BI \-l\~, n
+.B \%label
+.BI A.nD.y\- n %a
+.
+.
+.TP
+.BI \-l\~ m , n
+.B \%label
+.BI A.n+ m D.y\- n %a
+.
+.
+.TP
+.B \-n
+.B \%no\-default\-database
+.
+.
+.TP
+.BI \-p\~ db-file
+.B database
+.I db-file
+.
+.
+.TP
+.B \-P
+.B move\-punctuation
+.
+.
+.TP
+.BI \-s\~ spec
+.B sort
+.I spec
+.
+.
+.TP
+.B \-S
+.B \%label \[dq](A.n|Q) \[aq], \[aq] (D.y|D)\[dq]; \
+\%bracket-\%label \[dq]\~(\[dq]\~)\~\[dq];\~\[dq]
+.
+.
+.TP
+.BI \-t\~ n
+.B search\-truncate
+.I n
+.
+.
+.P
+The
+.B B
+option has command equivalents with the addition that the file names
+specified on the command line are processed as if they were arguments to
+the
+.B \%bibliography
+command instead of in the normal way.
+.
+.
+.TP 16n
+.B \-B
+.B "annotate X AP; \%no\-label\-in\-reference"
+.
+.
+.TP
+.BI \-B\~ field . macro
+.B annotate
+.I field
+.IB macro ;
+.B \%no\-label\-in\-reference
+.
+.
+.\" ====================================================================
+.SH Environment
+.\" ====================================================================
+.
+.TP
+.I REFER
+If set,
+overrides the default database.
+.
+.
+.\" ====================================================================
+.SH Files
+.\" ====================================================================
+.
+.TP
+.I @DEFAULT_INDEX@
+Default database.
+.
+.
+.TP
+.RI file @INDEX_SUFFIX@
+Index files.
+.
+.
+.TP
+.I @MACRODIR@/\:refer\:.tmac
+defines macros and strings facilitating integration with macro packages
+that wish to support
+.IR @g@refer .
+.
+.
+.LP
+.I @g@refer
+uses temporary files.
+.
+See the
+.MR groff @MAN1EXT@
+man page for details of where such files are created.
+.
+.
+.\" ====================================================================
+.SH Bugs
+.\" ====================================================================
+.
+In label expressions,
+.B <>
+expressions are ignored inside
+.BI . char
+expressions.
+.
+.
+.\" ====================================================================
+.SH Examples
+.\" ====================================================================
+.
+We can illustrate the operation of
+.I @g@refer
+with a sample bibliographic database containing one entry and a simple
+.I roff
+document to cite that entry.
+.
+.
+.P
+.RS
+.EX
+$ \c
+.B cat > my\-db\-file
+.B %A Daniel P.\[rs]& Friedman
+.B %A Matthias Felleisen
+.B %C Cambridge, Massachusetts
+.B %D 1996
+.B %I The MIT Press
+.B %T The Little Schemer, Fourth Edition
+$ \c
+.B refer -p my\-db\-file
+.B Read the book
+.B .[
+.B friedman
+.B .]
+.B on your summer vacation.
+.I <Control+D>
+\&.lf 1 \-
+Read the book\[rs]*([.1\[rs]*(.]
+\&.ds [F 1
+\&.]\-
+\&.ds [A Daniel P. Friedman and Matthias Felleisen
+\&.ds [C Cambridge, Massachusetts
+\&.ds [D 1996
+\&.ds [I The MIT Press
+\&.ds [T The Little Schemer, Fourth Edition
+\&.nr [T 0
+\&.nr [A 0
+\&.][ 2 book
+\&.lf 5 \-
+on your summer vacation.
+.EE
+.RE
+.
+.
+.P
+The foregoing shows us that
+.I @g@refer
+(a) produces a label \[lq]1\[rq];
+(b) brackets that label with interpolations of the
+.RB \[lq] [. \[rq]
+and
+.RB \[lq] .] \[rq]
+strings;
+(c) calls a macro
+.RB \[lq] ]\- \[rq];
+(d) defines strings and registers containing the label and bibliographic
+data for the reference;
+(e) calls a macro
+.RB \[lq] ][ \[rq];
+and (f) uses the
+.B lf
+request to restore the line numbers of the original input.
+.
+As discussed in subsection \[lq]Macro interface\[rq] above,
+it is up to the document or a macro package to employ and format this
+information usefully.
+.
+Let us see how we might turn
+.MR groff_ms @MAN7EXT@
+to this task.
+.
+.
+.P
+.RS
+.EX
+$ \c
+.B REFER=my\-db\-file groff \-R \-ms
+.B .LP
+.B Read the book
+.B .[
+.B friedman
+.B .]
+.B on your summer vacation.
+.B Commentary is available.\[rs]*{*\[rs]*}
+.B .FS \[rs]*{*\[rs]*}
+.B Space reserved for penetrating insight.
+.B .FE
+.EE
+.RE
+.
+.
+.LP
+.IR ms 's
+automatic footnote numbering mechanism is not aware of
+.IR @g@refer 's
+label numbering,
+so we have manually specified a (superscripted) symbolic footnote for
+our non-bibliographic aside.
+.
+.
+.\" ====================================================================
+.SH "See also"
+.\" ====================================================================
+.
+\[lq]Some Applications of Inverted Indexes on the Unix System\[rq],
+by M.\& E.\& Lesk,
+1978,
+AT&T Bell Laboratories Computing Science Technical Report No.\& 69.
+.
+.
+.LP
+.MR @g@indxbib @MAN1EXT@ ,
+.MR @g@lookbib @MAN1EXT@ ,
+.MR lkbib @MAN1EXT@
+.
+.
+.\" Restore compatibility mode (for, e.g., Solaris 10/11).
+.cp \n[*groff_refer_1_man_C]
+.do rr *groff_refer_1_man_C
+.
+.
+.\" Local Variables:
+.\" fill-column: 72
+.\" mode: nroff
+.\" End:
+.\" vim: set filetype=groff textwidth=72:
diff --git a/src/preproc/refer/refer.am b/src/preproc/refer/refer.am
new file mode 100644
index 0000000..273f334
--- /dev/null
+++ b/src/preproc/refer/refer.am
@@ -0,0 +1,61 @@
+# Copyright (C) 2014-2020 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+prefixexecbin_PROGRAMS += refer
+refer_CPPFLAGS = $(AM_CPPFLAGS) -I $(top_srcdir)/src/preproc/refer
+refer_LDADD = libbib.a libgroff.a $(LIBM) lib/libgnu.a
+refer_SOURCES =  \
+  src/preproc/refer/command.cpp \
+  src/preproc/refer/ref.cpp \
+  src/preproc/refer/refer.cpp \
+  src/preproc/refer/token.cpp \
+  src/preproc/refer/label.ypp \
+  src/preproc/refer/refer.h \
+  src/preproc/refer/ref.h \
+  src/preproc/refer/token.h \
+  src/preproc/refer/command.h
+
+PREFIXMAN1 += src/preproc/refer/refer.1
+EXTRA_DIST += \
+  src/preproc/refer/TODO \
+  src/preproc/refer/refer.1.man
+
+# Since refer_CPPFLAGS was set, all .o files have a 'refer-' prefix.
+src/preproc/refer/refer-command.$(OBJEXT): defs.h
+src/preproc/refer/refer-ref.$(OBJEXT): defs.h
+src/preproc/refer/refer-refer.$(OBJEXT): defs.h
+src/preproc/refer/refer-token.$(OBJEXT): defs.h
+src/preproc/refer/refer-label.$(OBJEXT): defs.h
+
+MAINTAINERCLEANFILES += \
+  src/preproc/refer/label.cpp \
+  src/preproc/refer/label.hpp \
+  src/preproc/refer/label.output
+
+refer_TESTS = \
+  src/preproc/refer/tests/report-correct-line-numbers.sh
+TESTS += $(refer_TESTS)
+EXTRA_DIST += \
+  $(refer_TESTS) \
+  src/preproc/refer/tests/artifacts/62124.bib
+
+
+# Local Variables:
+# fill-column: 72
+# mode: makefile-automake
+# End:
+# vim: set autoindent filetype=automake textwidth=72:
diff --git a/src/preproc/refer/refer.cpp b/src/preproc/refer/refer.cpp
new file mode 100644
index 0000000..a5c291e
--- /dev/null
+++ b/src/preproc/refer/refer.cpp
@@ -0,0 +1,1267 @@
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "refer.h"
+#include "refid.h"
+#include "ref.h"
+#include "token.h"
+#include "search.h"
+#include "command.h"
+
+extern "C" const char *Version_string;
+
+const char PRE_LABEL_MARKER = '\013';
+const char POST_LABEL_MARKER = '\014';
+const char LABEL_MARKER = '\015'; // label_type is added on
+
+#define FORCE_LEFT_BRACKET 04
+#define FORCE_RIGHT_BRACKET 010
+
+static FILE *outfp = stdout;
+
+string capitalize_fields;
+string reverse_fields;
+string abbreviate_fields;
+string period_before_last_name = ". ";
+string period_before_initial = ".";
+string period_before_hyphen = "";
+string period_before_other = ". ";
+string sort_fields;
+int annotation_field = -1;
+string annotation_macro;
+string discard_fields = "XYZ";
+string pre_label = "\\*([.";
+string post_label = "\\*(.]";
+string sep_label = ", ";
+int have_bibliography = 0;
+int accumulate = 0;
+int move_punctuation = 0;
+int abbreviate_label_ranges = 0;
+string label_range_indicator;
+int label_in_text = 1;
+int label_in_reference = 1;
+int date_as_label = 0;
+int sort_adjacent_labels = 0;
+// Join exactly two authors with this.
+string join_authors_exactly_two = " and ";
+// When there are more than two authors join the last two with this.
+string join_authors_last_two = ", and ";
+// Otherwise join authors with this.
+string join_authors_default = ", ";
+string separate_label_second_parts = ", ";
+// Use this string to represent that there are other authors.
+string et_al = " et al";
+// Use et al only if it can replace at least this many authors.
+int et_al_min_elide = 2;
+// Use et al only if the total number of authors is at least this.
+int et_al_min_total = 3;
+
+
+int compatible_flag = 0;
+
+int short_label_flag = 0;
+
+static bool recognize_R1_R2 = true;
+
+search_list database_list;
+int search_default = 1;
+static int default_database_loaded = 0;
+
+static reference **citation = 0;
+static int ncitations = 0;
+static int citation_max = 0;
+
+static reference **reference_hash_table = 0;
+static int hash_table_size;
+static int nreferences = 0;
+
+static int need_syncing = 0;
+string pending_line;
+string pending_lf_lines;
+
+static void output_pending_line();
+static unsigned immediately_handle_reference(const string &);
+static void immediately_output_references();
+static unsigned store_reference(const string &);
+static void divert_to_temporary_file();
+static reference *make_reference(const string &, unsigned *);
+static void usage(FILE *stream);
+static void do_file(const char *);
+static void split_punct(string &line, string &punct);
+static void output_citation_group(reference **v, int n, label_type,
+				  FILE *fp);
+static void possibly_load_default_database();
+
+int main(int argc, char **argv)
+{
+  program_name = argv[0];
+  static char stderr_buf[BUFSIZ];
+  setbuf(stderr, stderr_buf);
+  outfp = stdout;
+  int finished_options = 0;
+  int bib_flag = 0;
+  int done_spec = 0;
+
+  // TODO: Migrate to getopt_long; see, e.g., src/preproc/eqn/main.cpp.
+  for (--argc, ++argv;
+       !finished_options && argc > 0 && argv[0][0] == '-'
+       && argv[0][1] != '\0';
+       argv++, argc--) {
+    const char *opt = argv[0] + 1;
+    while (opt != 0 && *opt != '\0') {
+      switch (*opt) {
+      case 'C':
+	compatible_flag = 1;
+	opt++;
+	break;
+      case 'B':
+	bib_flag = 1;
+	label_in_reference = 0;
+	label_in_text = 0;
+	++opt;
+	if (*opt == '\0') {
+	  annotation_field = 'X';
+	  annotation_macro = "AP";
+	}
+	else if (csalnum(opt[0]) && opt[1] == '.' && opt[2] != '\0') {
+	  annotation_field = opt[0];
+	  annotation_macro = opt + 2;
+	}
+	opt = 0;
+	break;
+      case 'P':
+	move_punctuation = 1;
+	opt++;
+	break;
+      case 'R':
+	recognize_R1_R2 = false;
+	opt++;
+	break;
+      case 'S':
+	// Not a very useful spec.
+	set_label_spec("(A.n|Q)', '(D.y|D)");
+	done_spec = 1;
+	pre_label = " (";
+	post_label = ")";
+	sep_label = "; ";
+	opt++;
+	break;
+      case 'V':
+	do_verify = true;
+	opt++;
+	break;
+      case 'f':
+	{
+	  const char *num = 0;
+	  if (*++opt == '\0') {
+	    if (argc > 1) {
+	      num = *++argv;
+	      --argc;
+	    }
+	    else {
+	      error("'f' option requires an argument");
+	      usage(stderr);
+	      exit(1);
+	    }
+	  }
+	  else {
+	    num = opt;
+	    opt = 0;
+	  }
+	  const char *ptr;
+	  for (ptr = num; *ptr; ptr++)
+	    if (!csdigit(*ptr)) {
+	      error("invalid character '%1' in argument to 'f' option",
+		    *ptr);
+	      break;
+	    }
+	  if (*ptr == '\0') {
+	    string spec;
+	    spec = '%';
+	    spec += num;
+	    spec += '\0';
+	    set_label_spec(spec.contents());
+	    done_spec = 1;
+	  }
+	  break;
+	}
+      case 'b':
+	label_in_text = 0;
+	label_in_reference = 0;
+	opt++;
+	break;
+      case 'e':
+	accumulate = 1;
+	opt++;
+	break;
+      case 'c':
+	capitalize_fields = ++opt;
+	opt = 0;
+	break;
+      case 'k':
+	{
+	  char buf[5];
+	  if (csalpha(*++opt))
+	    buf[0] = *opt++;
+	  else {
+	    if (*opt != '\0')
+	      error("invalid field name '%1' in argument to 'k' option",
+		    *opt++);
+	    buf[0] = 'L';
+	  }
+	  buf[1] = '~';
+	  buf[2] = '%';
+	  buf[3] = 'a';
+	  buf[4] = '\0';
+	  set_label_spec(buf);
+	  done_spec = 1;
+	}
+	break;
+      case 'a':
+	{
+	  const char *ptr;
+	  for (ptr = ++opt; *ptr; ptr++)
+	    if (!csdigit(*ptr)) {
+	      error("'a' option argument must be an integer");
+	      break;
+	    }
+	  if (*ptr == '\0') {
+	    reverse_fields = 'A';
+	    reverse_fields += opt;
+	  }
+	  opt = 0;
+	}
+	break;
+      case 'i':
+	linear_ignore_fields = ++opt;
+	opt = 0;
+	break;
+      case 'l':
+	{
+	  char buf[INT_DIGITS*2 + 11]; // A.n+2D.y-3%a
+	  strcpy(buf, "A.n");
+	  if (*++opt != '\0' && *opt != ',') {
+	    char *ptr;
+	    long n = strtol(opt, &ptr, 10);
+	    if (n == 0 && ptr == opt) {
+	      error("invalid integer '%1' in 'l' option argument", opt);
+	      opt = 0;
+	      break;
+	    }
+	    if (n < 0)
+	      n = 0;
+	    opt = ptr;
+	    sprintf(strchr(buf, '\0'), "+%ld", n);
+	  }
+	  strcat(buf, "D.y");
+	  if (*opt == ',')
+	    opt++;
+	  if (*opt != '\0') {
+	    char *ptr;
+	    long n = strtol(opt, &ptr, 10);
+	    if (n == 0 && ptr == opt) {
+	      error("invalid integer '%1' in 'l' option argument", opt);
+	      opt = 0;
+	      break;
+	    }
+	    if (n < 0)
+	      n = 0;
+	    sprintf(strchr(buf, '\0'), "-%ld", n);
+	    opt = ptr;
+	    if (*opt != '\0')
+	      error("argument to 'l' option not of form 'm,n'");
+	  }
+	  strcat(buf, "%a");
+	  if (!set_label_spec(buf))
+	    assert(0 == "set_label_spec() failed");
+	  done_spec = 1;
+	}
+	break;
+      case 'n':
+	search_default = 0;
+	opt++;
+	break;
+      case 'p':
+	{
+	  const char *filename = 0;
+	  if (*++opt == '\0') {
+	    if (argc > 1) {
+	      filename = *++argv;
+	      argc--;
+	    }
+	    else {
+	      error("option 'p' requires an argument");
+	      usage(stderr);
+	      exit(1);
+	    }
+	  }
+	  else {
+	    filename = opt;
+	    opt = 0;
+	  }
+	  database_list.add_file(filename);
+	}
+	break;
+      case 's':
+	if (*++opt == '\0')
+	  sort_fields = "AD";
+	else {
+	  sort_fields = opt;
+	  opt = 0;
+	}
+	accumulate = 1;
+	break;
+      case 't':
+	{
+	  char *ptr;
+	  long n = strtol(opt, &ptr, 10);
+	  if (n == 0 && ptr == opt) {
+	    error("invalid integer '%1' in 't' option argument", opt);
+	    opt = 0;
+	    break;
+	  }
+	  if (n < 1)
+	    n = 1;
+	  linear_truncate_len = int(n);
+	  opt = ptr;
+	  break;
+	}
+      case '-':
+	if (opt[1] == '\0') {
+	  finished_options = 1;
+	  opt++;
+	  break;
+	}
+	if (strcmp(opt, "-version") == 0) {
+      case 'v':
+	  printf("GNU refer (groff) version %s\n", Version_string);
+	  exit(0);
+	  break;
+	}
+	if (strcmp(opt, "-help") == 0) {
+	  usage(stdout);
+	  exit(0);
+	  break;
+	}
+	// fall through
+      default:
+	error("unrecognized option '%1'", opt);
+	usage(stderr);
+	exit(1);
+	break;
+      }
+    }
+  }
+  if (!done_spec)
+    set_label_spec("%1");
+  if (argc <= 0) {
+    if (bib_flag)
+      do_bib("-");
+    else
+      do_file("-");
+  }
+  else {
+    for (int i = 0; i < argc; i++) {
+      if (bib_flag)
+	do_bib(argv[i]);
+      else
+	do_file(argv[i]);
+    }
+  }
+  if (accumulate)
+    output_references();
+  if (fflush(stdout) < 0)
+    fatal("output error: %1", strerror(errno));
+  return 0;
+}
+
+static void usage(FILE *stream)
+{
+  fprintf(stream,
+"usage: %s [-bCenPRS] [-aN] [-cXYZ] [-fN] [-iXYZ] [-kX] [-lM,N]"
+" [-p db-file] [-sXYZ] [-tN] [-Bl.m] [file ...]\n"
+"usage: %s {-v | --version}\n"
+"usage: %s --help\n",
+	  program_name, program_name, program_name);
+}
+
+static void possibly_load_default_database()
+{
+  if (search_default && !default_database_loaded) {
+    char *filename = getenv("REFER");
+    if (filename)
+      database_list.add_file(filename);
+    else
+      database_list.add_file(DEFAULT_INDEX, 1);
+    default_database_loaded = 1;
+  }
+}
+
+static bool is_list(const string &str)
+{
+  const char *start = str.contents();
+  const char *end = start + str.length();
+  while (end > start && csspace(end[-1]))
+    end--;
+  while (start < end && csspace(*start))
+    start++;
+  return end - start == 6 && memcmp(start, "$LIST$", 6) == 0;
+}
+
+static void do_file(const char *filename)
+{
+  FILE *fp;
+  if (strcmp(filename, "-") == 0) {
+    fp = stdin;
+  }
+  else {
+    errno = 0;
+    fp = fopen(filename, "r");
+    if (fp == 0) {
+      error("can't open '%1': %2", filename, strerror(errno));
+      return;
+    }
+  }
+  string fn(filename);
+  fn += '\0';
+  normalize_for_lf(fn);
+  current_filename = fn.contents();
+  fprintf(outfp, ".lf 1 %s\n", current_filename);
+  current_lineno = 1;
+  string line;
+  for (;;) {
+    line.clear();
+    for (;;) {
+      int c = getc(fp);
+      if (EOF == c) {
+	if (line.length() > 0)
+	  line += '\n';
+	break;
+      }
+      if (is_invalid_input_char(c))
+	error("invalid input character code %1", c);
+      else {
+	line += c;
+	if ('\n' == c)
+	  break;
+      }
+    }
+    int len = line.length();
+    if (len == 0)
+      break;
+    current_lineno++;
+    if (len >= 2 && line[0] == '.' && line[1] == '[') {
+      int start_lineno = current_lineno;
+      bool at_start_of_line = true;
+      string str;
+      string post;
+      string pre(line.contents() + 2, line.length() - 3);
+      for (;;) {
+	int c = getc(fp);
+	if (EOF == c) {
+	  error_with_file_and_line(current_filename, start_lineno,
+				   "missing '.]' line");
+	  break;
+	}
+	if (at_start_of_line)
+	  current_lineno++;
+	if (at_start_of_line && '.' == c) {
+	  int d = getc(fp);
+	  if (d == ']') {
+	    while ((d = getc(fp)) != '\n' && d != EOF) {
+	      if (is_invalid_input_char(d))
+		error("invalid input character code %1", d);
+	      else
+		post += d;
+	    }
+	    break;
+	  }
+	  if (d != EOF)
+	    ungetc(d, fp);
+	}
+	if (is_invalid_input_char(c))
+	  error("invalid input character code %1", c);
+	else
+	  str += c;
+	at_start_of_line = ('\n' == c);
+      }
+      if (is_list(str)) {
+	output_pending_line();
+	if (accumulate)
+	  output_references();
+	else
+	  error("found '$LIST$' but not accumulating references");
+      }
+      else {
+	unsigned flags = (accumulate
+			  ? store_reference(str)
+			  : immediately_handle_reference(str));
+	if (label_in_text) {
+	  if (accumulate && outfp == stdout)
+	    divert_to_temporary_file();
+	  if (pending_line.length() == 0) {
+	    warning("can't attach citation to previous line");
+	  }
+	  else
+	    pending_line.set_length(pending_line.length() - 1);
+	  string punct;
+	  if (move_punctuation)
+	    split_punct(pending_line, punct);
+	  int have_text = pre.length() > 0 || post.length() > 0;
+	  label_type lt = label_type(flags & ~(FORCE_LEFT_BRACKET
+					       |FORCE_RIGHT_BRACKET));
+	  if ((flags & FORCE_LEFT_BRACKET) || !have_text)
+	    pending_line += PRE_LABEL_MARKER;
+	  pending_line += pre;
+	  char lm = LABEL_MARKER + (int)lt;
+	  pending_line += lm;
+	  pending_line += post;
+	  if ((flags & FORCE_RIGHT_BRACKET) || !have_text)
+	    pending_line += POST_LABEL_MARKER;
+	  pending_line += punct;
+	  pending_line += '\n';
+	}
+      }
+      need_syncing = 1;
+    }
+    else if (len >= 4
+	     && '.' == line[0] && 'l' == line[1] && 'f' == line[2]
+	     && (compatible_flag || '\n' == line[3] || ' ' == line[3]))
+    {
+      pending_lf_lines += line;
+      line += '\0';
+      if (interpret_lf_args(line.contents() + 3))
+	current_lineno--;
+    }
+    else if (recognize_R1_R2
+	     && len >= 4
+	     && '.' == line[0] && 'R' == line[1] && '1' == line[2]
+	     && (compatible_flag || '\n' == line[3] || ' ' == line[3]))
+    {
+      line.clear();
+      int start_lineno = current_lineno;
+      bool at_start_of_line = true;
+      for (;;) {
+	int c = getc(fp);
+	if (c != EOF && at_start_of_line)
+	  current_lineno++;
+	if (at_start_of_line && '.' == c) {
+	  c = getc(fp);
+	  if ('R' == c) {
+	    c = getc(fp);
+	    if ('2' == c) {
+	      c = getc(fp);
+	      if (compatible_flag || ' ' == c || '\n' == c || EOF == c)
+	      {
+		while (c != EOF && c != '\n')
+		  c = getc(fp);
+		break;
+	      }
+	      else {
+		line += '.';
+		line += 'R';
+		line += '2';
+	      }
+	    }
+	    else {
+	      line += '.';
+	      line += 'R';
+	    }
+	  }
+	  else
+	    line += '.';
+	}
+	if (EOF == c) {
+	  error_with_file_and_line(current_filename, start_lineno,
+				   "missing '.R2' line");
+	  break;
+	}
+	if (is_invalid_input_char(c))
+	  error_with_file_and_line(current_filename, start_lineno,
+				   "invalid input character code %1",
+				   c);
+	else {
+	  line += c;
+	  at_start_of_line = ('\n' == c);
+	}
+      }
+      output_pending_line();
+      if (accumulate)
+	output_references();
+      else
+	nreferences = 0;
+      process_commands(line, current_filename, start_lineno + 1);
+      need_syncing = 1;
+    }
+    else {
+      output_pending_line();
+      pending_line = line;
+    }
+  }
+  need_syncing = 0;
+  output_pending_line();
+  if (fp != stdin)
+    fclose(fp);
+}
+
+class label_processing_state {
+  enum {
+    NORMAL,
+    PENDING_LABEL,
+    PENDING_LABEL_POST,
+    PENDING_LABEL_POST_PRE,
+    PENDING_POST
+    } state;
+  label_type type;		// type of pending labels
+  int count;			// number of pending labels
+  reference **rptr;		// pointer to next reference
+  int rcount;			// number of references left
+  FILE *fp;
+  int handle_pending(int c);
+public:
+  label_processing_state(reference **, int, FILE *);
+  ~label_processing_state();
+  void process(int c);
+};
+
+static void output_pending_line()
+{
+  if (label_in_text && !accumulate && ncitations > 0) {
+    label_processing_state state(citation, ncitations, outfp);
+    int len = pending_line.length();
+    for (int i = 0; i < len; i++)
+      state.process((unsigned char)(pending_line[i]));
+  }
+  else
+    put_string(pending_line, outfp);
+  pending_line.clear();
+  if (pending_lf_lines.length() > 0) {
+    put_string(pending_lf_lines, outfp);
+    pending_lf_lines.clear();
+  }
+  if (!accumulate)
+    immediately_output_references();
+  if (need_syncing) {
+    fprintf(outfp, ".lf %d %s\n", current_lineno, current_filename);
+    need_syncing = 0;
+  }
+}
+
+static void split_punct(string &line, string &punct)
+{
+  const char *start = line.contents();
+  const char *end = start + line.length();
+  const char *ptr = start;
+  const char *last_token_start = 0;
+  for (;;) {
+    if (ptr >= end)
+      break;
+    last_token_start = ptr;
+    if (*ptr == PRE_LABEL_MARKER || *ptr == POST_LABEL_MARKER
+	|| (*ptr >= LABEL_MARKER
+	    && *ptr < LABEL_MARKER + N_LABEL_TYPES))
+      ptr++;
+    else if (!get_token(&ptr, end))
+      break;
+  }
+  if (last_token_start) {
+    const token_info *ti = lookup_token(last_token_start, end);
+    if (ti->is_punct()) {
+      punct.append(last_token_start, end - last_token_start);
+      line.set_length(last_token_start - start);
+    }
+  }
+}
+
+static void divert_to_temporary_file()
+{
+  outfp = xtmpfile();
+}
+
+static void store_citation(reference *ref)
+{
+  if (ncitations >= citation_max) {
+    if (citation == 0)
+      citation = new reference*[citation_max = 100];
+    else {
+      reference **old_citation = citation;
+      citation_max *= 2;
+      citation = new reference *[citation_max];
+      memcpy(citation, old_citation, ncitations*sizeof(reference *));
+      delete[] old_citation;
+    }
+  }
+  citation[ncitations++] = ref;
+}
+
+static unsigned store_reference(const string &str)
+{
+  if (reference_hash_table == 0) {
+    reference_hash_table = new reference *[17];
+    hash_table_size = 17;
+    for (int i = 0; i < hash_table_size; i++)
+      reference_hash_table[i] = 0;
+  }
+  unsigned flags;
+  reference *ref = make_reference(str, &flags);
+  ref->compute_hash_code();
+  unsigned h = ref->hash();
+  reference **ptr;
+  for (ptr = reference_hash_table + (h % hash_table_size);
+       *ptr != 0;
+       ((ptr == reference_hash_table)
+	? (ptr = reference_hash_table + hash_table_size - 1)
+	: --ptr))
+    if (same_reference(**ptr, *ref))
+      break;
+  if (*ptr != 0) {
+    if (ref->is_merged())
+      warning("fields ignored because reference already used");
+    delete ref;
+    ref = *ptr;
+  }
+  else {
+    *ptr = ref;
+    ref->set_number(nreferences);
+    nreferences++;
+    ref->pre_compute_label();
+    ref->compute_sort_key();
+    if (nreferences*2 >= hash_table_size) {
+      // Rehash it.
+      reference **old_table = reference_hash_table;
+      int old_size = hash_table_size;
+      hash_table_size = next_size(hash_table_size);
+      reference_hash_table = new reference*[hash_table_size];
+      int i;
+      for (i = 0; i < hash_table_size; i++)
+	reference_hash_table[i] = 0;
+      for (i = 0; i < old_size; i++)
+	if (old_table[i]) {
+	  reference **p;
+	  for (p = (reference_hash_table
+		    + (old_table[i]->hash() % hash_table_size));
+	       *p;
+	       ((p == reference_hash_table)
+		? (p = reference_hash_table + hash_table_size - 1)
+		: --p))
+	    ;
+	  *p = old_table[i];
+	}
+      delete[] old_table;
+    }
+  }
+  if (label_in_text)
+    store_citation(ref);
+  return flags;
+}
+
+unsigned immediately_handle_reference(const string &str)
+{
+  unsigned flags;
+  reference *ref = make_reference(str, &flags);
+  ref->set_number(nreferences);
+  if (label_in_text || label_in_reference) {
+    ref->pre_compute_label();
+    ref->immediate_compute_label();
+  }
+  nreferences++;
+  store_citation(ref);
+  return flags;
+}
+
+static void immediately_output_references()
+{
+  for (int i = 0; i < ncitations; i++) {
+    reference *ref = citation[i];
+    if (label_in_reference) {
+      fputs(".ds [F ", outfp);
+      const string &label = ref->get_label(NORMAL_LABEL);
+      if (label.length() > 0
+	  && (label[0] == ' ' || label[0] == '\\' || label[0] == '"'))
+	putc('"', outfp);
+      put_string(label, outfp);
+      putc('\n', outfp);
+    }
+    ref->output(outfp);
+    delete ref;
+  }
+  ncitations = 0;
+}
+
+static void output_citation_group(reference **v, int n, label_type type,
+				  FILE *fp)
+{
+  if (sort_adjacent_labels) {
+    // Do an insertion sort.  Usually n will be very small.
+    for (int i = 1; i < n; i++) {
+      int num = v[i]->get_number();
+      reference *temp = v[i];
+      int j;
+      for (j = i - 1; j >= 0 && v[j]->get_number() > num; j--)
+	v[j + 1] = v[j];
+      v[j + 1] = temp;
+    }
+  }
+  // This messes up if !accumulate.
+  if (accumulate && n > 1) {
+    // remove duplicates
+    int j = 1;
+    for (int i = 1; i < n; i++)
+      if (v[i]->get_label(type) != v[i - 1]->get_label(type))
+	v[j++] = v[i];
+    n = j;
+  }
+  string merged_label;
+  for (int i = 0; i < n; i++) {
+    int nmerged = v[i]->merge_labels(v + i + 1, n - i - 1, type,
+	merged_label);
+    if (nmerged > 0) {
+      put_string(merged_label, fp);
+      i += nmerged;
+    }
+    else
+      put_string(v[i]->get_label(type), fp);
+    if (i < n - 1)
+      put_string(sep_label, fp);
+  }
+}
+
+
+label_processing_state::label_processing_state(reference **p, int n,
+					       FILE *f)
+: state(NORMAL), count(0), rptr(p), rcount(n), fp(f)
+{
+}
+
+label_processing_state::~label_processing_state()
+{
+  int handled = handle_pending(EOF);
+  assert(!handled);
+  assert(rcount == 0);
+}
+
+int label_processing_state::handle_pending(int c)
+{
+  switch (state) {
+  case NORMAL:
+    break;
+  case PENDING_LABEL:
+    if (POST_LABEL_MARKER == c) {
+      state = PENDING_LABEL_POST;
+      return 1;
+    }
+    else {
+      output_citation_group(rptr, count, type, fp);
+      rptr += count ;
+      rcount -= count;
+      state = NORMAL;
+    }
+    break;
+  case PENDING_LABEL_POST:
+    if (PRE_LABEL_MARKER == c) {
+      state = PENDING_LABEL_POST_PRE;
+      return 1;
+    }
+    else {
+      output_citation_group(rptr, count, type, fp);
+      rptr += count;
+      rcount -= count;
+      put_string(post_label, fp);
+      state = NORMAL;
+    }
+    break;
+  case PENDING_LABEL_POST_PRE:
+    if (c >= LABEL_MARKER
+	&& c < LABEL_MARKER + N_LABEL_TYPES
+	&& c - LABEL_MARKER == type) {
+      count += 1;
+      state = PENDING_LABEL;
+      return 1;
+    }
+    else {
+      output_citation_group(rptr, count, type, fp);
+      rptr += count;
+      rcount -= count;
+      put_string(sep_label, fp);
+      state = NORMAL;
+    }
+    break;
+  case PENDING_POST:
+    if (PRE_LABEL_MARKER == c) {
+      put_string(sep_label, fp);
+      state = NORMAL;
+      return 1;
+    }
+    else {
+      put_string(post_label, fp);
+      state = NORMAL;
+    }
+    break;
+  }
+  return 0;
+}
+
+void label_processing_state::process(int c)
+{
+  if (handle_pending(c))
+    return;
+  assert(state == NORMAL);
+  switch (c) {
+  case PRE_LABEL_MARKER:
+    put_string(pre_label, fp);
+    state = NORMAL;
+    break;
+  case POST_LABEL_MARKER:
+    state = PENDING_POST;
+    break;
+  case LABEL_MARKER:
+  case LABEL_MARKER + 1:
+    count = 1;
+    state = PENDING_LABEL;
+    type = label_type(c - LABEL_MARKER);
+    break;
+  default:
+    state = NORMAL;
+    putc(c, fp);
+    break;
+  }
+}
+
+extern "C" {
+
+int rcompare(const void *p1, const void *p2)
+{
+  return compare_reference(**(reference **)p1, **(reference **)p2);
+}
+
+}
+
+void output_references()
+{
+  assert(accumulate);
+  if (!hash_table_size) {
+    if (have_bibliography)
+      error("nothing to reference (probably 'bibliography' before"
+	    " 'sort')");
+    accumulate = 0;
+    nreferences = 0;
+    return;
+  }
+  if (nreferences > 0) {
+    int j = 0;
+    int i;
+    for (i = 0; i < hash_table_size; i++)
+      if (reference_hash_table[i] != 0)
+	reference_hash_table[j++] = reference_hash_table[i];
+    assert(j == nreferences);
+    for (; j < hash_table_size; j++)
+      reference_hash_table[j] = 0;
+    qsort(reference_hash_table, nreferences, sizeof(reference*),
+	  rcompare);
+    for (i = 0; i < nreferences; i++)
+      reference_hash_table[i]->set_number(i);
+    compute_labels(reference_hash_table, nreferences);
+  }
+  if (outfp != stdout) {
+    rewind(outfp);
+    {
+      label_processing_state state(citation, ncitations, stdout);
+      int c;
+      while ((c = getc(outfp)) != EOF)
+	state.process(c);
+    }
+    ncitations = 0;
+    fclose(outfp);
+    outfp = stdout;
+  }
+  if (nreferences > 0) {
+    fputs(".]<\n", outfp);
+    for (int i = 0; i < nreferences; i++) {
+      if (sort_fields.length() > 0)
+	reference_hash_table[i]->print_sort_key_comment(outfp);
+      if (label_in_reference) {
+	fputs(".ds [F ", outfp);
+	const string &label
+	  = reference_hash_table[i]->get_label(NORMAL_LABEL);
+	if (label.length() > 0
+	    && (label[0] == ' ' || label[0] == '\\' || label[0] == '"'))
+	  putc('"', outfp);
+	put_string(label, outfp);
+	putc('\n', outfp);
+      }
+      reference_hash_table[i]->output(outfp);
+      delete reference_hash_table[i];
+      reference_hash_table[i] = 0;
+    }
+    fputs(".]>\n", outfp);
+    nreferences = 0;
+  }
+  clear_labels();
+}
+
+static reference *find_reference(const char *query, int query_len)
+{
+  // This is so that error messages look better.
+  while (query_len > 0 && csspace(query[query_len - 1]))
+    query_len--;
+  string str;
+  for (int i = 0; i < query_len; i++)
+    str += query[i] == '\n' ? ' ' : query[i];
+  str += '\0';
+  possibly_load_default_database();
+  search_list_iterator iter(&database_list, str.contents());
+  reference_id rid;
+  const char *start;
+  int len;
+  if (!iter.next(&start, &len, &rid)) {
+    error("no matches for '%1'", str.contents());
+    return 0;
+  }
+  const char *end = start + len;
+  while (start < end) {
+    if (*start == '%')
+      break;
+    while (start < end && *start++ != '\n')
+      ;
+  }
+  if (start >= end) {
+    error("found a reference for '%1' but it didn't contain any fields",
+	  str.contents());
+    return 0;
+  }
+  reference *result = new reference(start, end - start, &rid);
+  if (iter.next(&start, &len, &rid))
+    warning("multiple matches for '%1'", str.contents());
+  return result;
+}
+
+static reference *make_reference(const string &str, unsigned *flagsp)
+{
+  const char *start = str.contents();
+  const char *end = start + str.length();
+  const char *ptr = start;
+  while (ptr < end) {
+    if (*ptr == '%')
+      break;
+    while (ptr < end && *ptr++ != '\n')
+      ;
+  }
+  *flagsp = 0;
+  for (; start < ptr; start++) {
+    if (*start == '#')
+      *flagsp = (SHORT_LABEL | (*flagsp & (FORCE_RIGHT_BRACKET
+					   | FORCE_LEFT_BRACKET)));
+    else if (*start == '[')
+      *flagsp |= FORCE_LEFT_BRACKET;
+    else if (*start == ']')
+      *flagsp |= FORCE_RIGHT_BRACKET;
+    else if (!csspace(*start))
+      break;
+  }
+  if (start >= end) {
+    error("empty reference");
+    return new reference;
+  }
+  reference *database_ref = 0;
+  if (start < ptr)
+    database_ref = find_reference(start, ptr - start);
+  reference *inline_ref = 0;
+  if (ptr < end)
+    inline_ref = new reference(ptr, end - ptr);
+  if (inline_ref) {
+    if (database_ref) {
+      database_ref->merge(*inline_ref);
+      delete inline_ref;
+      return database_ref;
+    }
+    else
+      return inline_ref;
+  }
+  else if (database_ref)
+    return database_ref;
+  else
+    return new reference;
+}
+
+static void do_ref(const string &str)
+{
+  if (accumulate)
+    (void)store_reference(str);
+  else {
+    (void)immediately_handle_reference(str);
+    immediately_output_references();
+  }
+}
+
+static void trim_blanks(string &str)
+{
+  const char *start = str.contents();
+  const char *end = start + str.length();
+  while (end > start && end[-1] != '\n' && csspace(end[-1]))
+    --end;
+  str.set_length(end - start);
+}
+
+void do_bib(const char *filename)
+{
+  FILE *fp;
+  if (strcmp(filename, "-") == 0)
+    fp = stdin;
+  else {
+    errno = 0;
+    fp = fopen(filename, "r");
+    if (fp == 0) {
+      error("can't open '%1': %2", filename, strerror(errno));
+      return;
+    }
+    current_filename = filename;
+  }
+  current_lineno = 1;
+  enum {
+    START, MIDDLE, BODY, BODY_START, BODY_BLANK, BODY_DOT
+    } state = START;
+  string body;
+  for (;;) {
+    int c = getc(fp);
+    if (EOF == c)
+      break;
+    if (is_invalid_input_char(c)) {
+      error("invalid input character code %1", c);
+      continue;
+    }
+    switch (state) {
+    case START:
+      if ('%' == c) {
+	body = c;
+	state = BODY;
+      }
+      else if (c != '\n')
+	state = MIDDLE;
+      break;
+    case MIDDLE:
+      if ('\n' == c)
+	state = START;
+      break;
+    case BODY:
+      body += c;
+      if ('\n' == c)
+	state = BODY_START;
+      break;
+    case BODY_START:
+      if ('\n' == c) {
+	do_ref(body);
+	state = START;
+      }
+      else if ('.' == c)
+	state = BODY_DOT;
+      else if (csspace(c)) {
+	state = BODY_BLANK;
+	body += c;
+      }
+      else {
+	body += c;
+	state = BODY;
+      }
+      break;
+    case BODY_BLANK:
+      if ('\n' == c) {
+	trim_blanks(body);
+	do_ref(body);
+	state = START;
+      }
+      else if (csspace(c))
+	body += c;
+      else {
+	body += c;
+	state = BODY;
+      }
+      break;
+    case BODY_DOT:
+      if (']' == c) {
+	do_ref(body);
+	state = MIDDLE;
+      }
+      else {
+	body += '.';
+	body += c;
+	state = ('\n' == c) ? BODY_START : BODY;
+      }
+      break;
+    default:
+      assert(0 == "unhandled case while parsing bibliography file");
+    }
+    if ('\n' == c)
+      current_lineno++;
+  }
+  switch (state) {
+  case START:
+  case MIDDLE:
+    break;
+  case BODY:
+    body += '\n';
+    do_ref(body);
+    break;
+  case BODY_DOT:
+  case BODY_START:
+    do_ref(body);
+    break;
+  case BODY_BLANK:
+    trim_blanks(body);
+    do_ref(body);
+    break;
+  }
+  fclose(fp);
+}
+
+// from the Dragon Book
+
+unsigned hash_string(const char *s, int len)
+{
+  const char *end = s + len;
+  unsigned h = 0, g;
+  while (s < end) {
+    h <<= 4;
+    h += *s++;
+    if ((g = h & 0xf0000000) != 0) {
+      h ^= g >> 24;
+      h ^= g;
+    }
+  }
+  return h;
+}
+
+int next_size(int n)
+{
+  static const int table_sizes[] = {
+    101, 503, 1009, 2003, 3001, 4001, 5003, 10007, 20011, 40009,
+    80021, 160001, 500009, 1000003, 2000003, 4000037, 8000009,
+    16000057, 32000011, 64000031, 128000003, 0
+  };
+
+  const int *p;
+  for (p = table_sizes; *p <= n && *p != 0; p++)
+    ;
+  assert(*p != 0);
+  return *p;
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/refer/refer.h b/src/preproc/refer/refer.h
new file mode 100644
index 0000000..3ebff27
--- /dev/null
+++ b/src/preproc/refer/refer.h
@@ -0,0 +1,81 @@
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "lib.h"
+
+#include <stdlib.h>
+#include <errno.h>
+
+#include "errarg.h"
+#include "error.h"
+#include "stringclass.h"
+#include "cset.h"
+#include "cmap.h"
+#include "lf.h"
+
+#include "defs.h"
+
+unsigned hash_string(const char *, int);
+int next_size(int);
+
+extern string capitalize_fields;
+extern string reverse_fields;
+extern string abbreviate_fields;
+extern string period_before_last_name;
+extern string period_before_initial;
+extern string period_before_hyphen;
+extern string period_before_other;
+extern string sort_fields;
+extern int annotation_field;
+extern string annotation_macro;
+extern string discard_fields;
+extern string articles;
+extern int abbreviate_label_ranges;
+extern string label_range_indicator;
+extern int date_as_label;
+extern string join_authors_exactly_two;
+extern string join_authors_last_two;
+extern string join_authors_default;
+extern string separate_label_second_parts;
+extern string et_al;
+extern int et_al_min_elide;
+extern int et_al_min_total;
+
+extern int compatible_flag;
+
+extern int set_label_spec(const char *);
+extern int set_date_label_spec(const char *);
+extern int set_short_label_spec(const char *);
+
+extern int short_label_flag;
+
+void clear_labels();
+void command_error(const char *,
+		   const errarg &arg1 = empty_errarg,
+		   const errarg &arg2 = empty_errarg,
+		   const errarg &arg3 = empty_errarg);
+
+class reference;
+
+void compute_labels(reference **, int);
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/refer/tests/artifacts/62124.bib b/src/preproc/refer/tests/artifacts/62124.bib
new file mode 100644
index 0000000..1093837
--- /dev/null
+++ b/src/preproc/refer/tests/artifacts/62124.bib
@@ -0,0 +1,4 @@
+%A Irritablé, X.
+%T ˆUniversit\*'e de Grenoble. ‰Cours donn\*'es aux Houches.
+%Z ˆMon dieu, Consiel !‰
+%Z NOTE: This file is deliberately not valid UTF-8.  Try Latin-1.
diff --git a/src/preproc/refer/tests/report-correct-line-numbers.sh b/src/preproc/refer/tests/report-correct-line-numbers.sh
new file mode 100755
index 0000000..19cae53
--- /dev/null
+++ b/src/preproc/refer/tests/report-correct-line-numbers.sh
@@ -0,0 +1,136 @@
+#!/bin/sh
+#
+# Copyright (C) 2022 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or (at your
+# option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+refer="${abs_top_builddir:-.}/refer"
+
+fail=
+
+wail () {
+    echo FAILED >&2
+    fail=YES
+}
+
+# Regression-test Savannah #62124.  Ensure correct line numbers in
+# diagnostics on bibliography files.
+
+# Locate directory containing our test artifacts.
+artifact_dir=
+
+for buildroot in . .. ../..
+do
+    d=$buildroot/src/preproc/refer/tests/artifacts
+    if [ -d "$d" ]
+    then
+        artifact_dir=$d
+        break
+    fi
+done
+
+# If we can't find it, we can't test.
+test -z "$artifact_dir" && exit 77 # skip
+
+input=".
+.R1
+bibliography $artifact_dir/62124.bib
+cattywumpus
+.R2
+.
+.R1
+bibliography $artifact_dir/62124.bib
+cattywumpus
+.R2"
+
+# We want standard error _only_.
+output=$(echo "$input" | "$refer" -e -p "$artifact_dir"/62124.bib \
+    2>&1 >/dev/null)
+
+# We should get every complaint about the bibliography twice because it
+# is dumped twice; the line numbers should not change because they're
+# problems with the bibliography file, not the input file.
+
+# We're pattern-matching diagnostic output here, which is a delicate
+# thing to do.  If a test failure occurs, ensure the diagnostic message
+# text hasn't changed before assuming a deeper logic problem.
+
+echo "checking line number of invalid character on bibliography line 1"
+count=$(echo "$output" | grep -c "refer:.*/62124.bib:1:.*code 129")
+test $count -eq 2 || wail
+
+echo "checking line number of first invalid character on bibliography" \
+  "line 2"
+count=$(echo "$output" | grep -c "refer:.*/62124.bib:2:.*code 136")
+test $count -eq 2 || wail
+
+echo "checking line number of second invalid character on" \
+  "bibliography line 2"
+count=$(echo "$output" | grep -c "refer:.*/62124.bib:2:.*code 137")
+test $count -eq 2 || wail
+
+echo "checking line number of first invalid character on" \
+  "bibliography line 3"
+count=$(echo "$output" | grep -c "refer:.*/62124.bib:3:.*code 136")
+test $count -eq 2 || wail
+
+echo "checking line number of second invalid character on" \
+  "bibliography line 3"
+count=$(echo "$output" | grep -c "refer:.*/62124.bib:3:.*code 137")
+test $count -eq 2 || wail
+
+# Problems with the input file should also be accurately located.
+
+echo "checking line number of invalid refer(1) command on input line 4"
+echo "$output"
+echo "$output" | grep -q "refer:.*:4:.*unknown command" || wail
+
+echo "checking line number of invalid refer(1) command on input line 9"
+echo "$output"
+echo "$output" | grep -q "refer:.*:9:.*unknown command" || wail
+
+# Regression-test Savannah #62391.
+
+output=$(printf '\0201\n' | "$refer" 2>&1 >/dev/null)
+
+echo "checking line number of invalid input character on input line 1"
+echo "$output" | grep -q "refer:.*:1:.*invalid input character" \
+  || wail
+
+output=$(printf '.R1\nbogus \0200\n.R2\n' | "$refer" 2>&1 >/dev/null)
+
+echo "checking line number of invalid input character after refer(1)" \
+  "command on input line 2"
+echo "$output" | grep -q "refer:.*:2:.*invalid input character" \
+  || wail
+
+output=$(printf '.R1\ndatabase nonexistent.bib\n.R2\n' | "$refer" 2>&1 \
+  >/dev/null)
+
+echo "checking line number of attempt to load nonexistent database"
+echo "$output" | grep -q "refer:.*:2:.*can't open 'nonexistent\.bib':" \
+  || wail
+
+output=$(printf '.R1\ninclude nonexistent.bib\n.R2\n' | "$refer" 2>&1 \
+  >/dev/null)
+
+echo "checking line number of attempt to load nonexistent inclusion"
+echo "$output" | grep -q "refer:.*:2:.*can't open 'nonexistent\.bib':" \
+  || wail
+test -z "$fail" || exit 1
+
+# vim:set ai et sw=4 ts=4 tw=72:
diff --git a/src/preproc/refer/token.cpp b/src/preproc/refer/token.cpp
new file mode 100644
index 0000000..e643cbd
--- /dev/null
+++ b/src/preproc/refer/token.cpp
@@ -0,0 +1,377 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "refer.h"
+#include "token.h"
+
+#define TOKEN_TABLE_SIZE 1009
+// I believe in Icelandic thorn sorts after z.
+#define THORN_SORT_KEY "{"
+
+struct token_table_entry {
+  const char *tok;
+  token_info ti;
+  token_table_entry();
+};
+
+token_table_entry token_table[TOKEN_TABLE_SIZE];
+int ntokens = 0;
+
+static void skip_name(const char **ptr, const char *end)
+{
+  if (*ptr < end) {
+    switch (*(*ptr)++) {
+    case '(':
+      if (*ptr < end) {
+	*ptr += 1;
+	if (*ptr < end)
+	  *ptr += 1;
+      }
+      break;
+    case '[':
+      while (*ptr < end)
+	if (*(*ptr)++ == ']')
+	  break;
+      break;
+    }
+  }
+}
+
+int get_token(const char **ptr, const char *end)
+{
+  if (*ptr >= end)
+    return 0;
+  char c = *(*ptr)++;
+  if (c == '\\' && *ptr < end) {
+    switch (**ptr) {
+    default:
+      *ptr += 1;
+      break;
+    case '(':
+    case '[':
+      skip_name(ptr, end);
+      break;
+    case '*':
+    case 'f':
+      *ptr += 1;
+      skip_name(ptr, end);
+      break;
+    }
+  }
+  return 1;
+}
+
+token_info::token_info()
+: type(TOKEN_OTHER), sort_key(0), other_case(0)
+{
+}
+
+void token_info::set(token_type t, const char *sk, const char *oc)
+{
+  assert(oc == 0 || t == TOKEN_UPPER || t == TOKEN_LOWER);
+  type = t;
+  sort_key = sk;
+  other_case = oc;
+}
+
+void token_info::sortify(const char *start, const char *end, string &result)
+     const
+{
+  if (sort_key)
+    result += sort_key;
+  else if (type == TOKEN_UPPER || type == TOKEN_LOWER) {
+    for (; start < end; start++)
+      if (csalpha(*start))
+	result += cmlower(*start);
+  }
+}
+
+int token_info::sortify_non_empty(const char *start, const char *end) const
+{
+  if (sort_key)
+    return *sort_key != '\0';
+  if (type != TOKEN_UPPER && type != TOKEN_LOWER)
+    return 0;
+  for (; start < end; start++)
+    if (csalpha(*start))
+      return 1;
+  return 0;
+}
+
+
+void token_info::lower_case(const char *start, const char *end,
+			    string &result) const
+{
+  if (type != TOKEN_UPPER) {
+    while (start < end)
+      result += *start++;
+  }
+  else if (other_case)
+    result += other_case;
+  else {
+    while (start < end)
+      result += cmlower(*start++);
+  }
+}
+
+void token_info::upper_case(const char *start, const char *end,
+			    string &result) const
+{
+  if (type != TOKEN_LOWER) {
+    while (start < end)
+      result += *start++;
+  }
+  else if (other_case)
+    result += other_case;
+  else {
+    while (start < end)
+      result += cmupper(*start++);
+  }
+}
+
+token_table_entry::token_table_entry()
+: tok(0)
+{
+}
+
+static void store_token(const char *tok, token_type typ,
+			const char *sk = 0, const char *oc = 0)
+{
+  unsigned n = hash_string(tok, strlen(tok)) % TOKEN_TABLE_SIZE;
+  for (;;) {
+    if (token_table[n].tok == 0) {
+      if (++ntokens == TOKEN_TABLE_SIZE)
+	assert(0);
+      token_table[n].tok = tok;
+      break;
+    }
+    if (strcmp(tok, token_table[n].tok) == 0)
+      break;
+    if (n == 0)
+      n = TOKEN_TABLE_SIZE - 1;
+    else
+      --n;
+  }
+  token_table[n].ti.set(typ, sk, oc);
+}
+
+
+token_info default_token_info;
+
+const token_info *lookup_token(const char *start, const char *end)
+{
+  unsigned n = hash_string(start, end - start) % TOKEN_TABLE_SIZE;
+  for (;;) {
+    if (token_table[n].tok == 0)
+      break;
+    if (strlen(token_table[n].tok) == size_t(end - start)
+	&& memcmp(token_table[n].tok, start, end - start) == 0)
+      return &(token_table[n].ti);
+    if (n == 0)
+      n = TOKEN_TABLE_SIZE - 1;
+    else
+      --n;
+  }
+  return &default_token_info;
+}
+
+static void init_ascii()
+{
+  const char *p;
+  for (p = "abcdefghijklmnopqrstuvwxyz"; *p; p++) {
+    char buf[2];
+    buf[0] = *p;
+    buf[1] = '\0';
+    store_token(strsave(buf), TOKEN_LOWER);
+    buf[0] = cmupper(buf[0]);
+    store_token(strsave(buf), TOKEN_UPPER);
+  }
+  for (p = "0123456789"; *p; p++) {
+    char buf[2];
+    buf[0] = *p;
+    buf[1] = '\0';
+    const char *s = strsave(buf);
+    store_token(s, TOKEN_OTHER, s);
+  }
+  for (p = ".,:;?!"; *p; p++) {
+    char buf[2];
+    buf[0] = *p;
+    buf[1] = '\0';
+    store_token(strsave(buf), TOKEN_PUNCT);
+  }
+  store_token("-", TOKEN_HYPHEN);
+}
+
+static void store_letter(const char *lower, const char *upper,
+		  const char *sort_key = 0)
+{
+  store_token(lower, TOKEN_LOWER, sort_key, upper);
+  store_token(upper, TOKEN_UPPER, sort_key, lower);
+}
+
+static void init_letter(unsigned char uc_code, unsigned char lc_code,
+		 const char *sort_key)
+{
+  char lbuf[2];
+  lbuf[0] = lc_code;
+  lbuf[1] = 0;
+  char ubuf[2];
+  ubuf[0] = uc_code;
+  ubuf[1] = 0;
+  store_letter(strsave(lbuf), strsave(ubuf), sort_key);
+}
+
+static void init_latin1()
+{
+  init_letter(0xc0, 0xe0, "a");
+  init_letter(0xc1, 0xe1, "a");
+  init_letter(0xc2, 0xe2, "a");
+  init_letter(0xc3, 0xe3, "a");
+  init_letter(0xc4, 0xe4, "a");
+  init_letter(0xc5, 0xe5, "a");
+  init_letter(0xc6, 0xe6, "ae");
+  init_letter(0xc7, 0xe7, "c");
+  init_letter(0xc8, 0xe8, "e");
+  init_letter(0xc9, 0xe9, "e");
+  init_letter(0xca, 0xea, "e");
+  init_letter(0xcb, 0xeb, "e");
+  init_letter(0xcc, 0xec, "i");
+  init_letter(0xcd, 0xed, "i");
+  init_letter(0xce, 0xee, "i");
+  init_letter(0xcf, 0xef, "i");
+
+  init_letter(0xd0, 0xf0, "d");
+  init_letter(0xd1, 0xf1, "n");
+  init_letter(0xd2, 0xf2, "o");
+  init_letter(0xd3, 0xf3, "o");
+  init_letter(0xd4, 0xf4, "o");
+  init_letter(0xd5, 0xf5, "o");
+  init_letter(0xd6, 0xf6, "o");
+  init_letter(0xd8, 0xf8, "o");
+  init_letter(0xd9, 0xf9, "u");
+  init_letter(0xda, 0xfa, "u");
+  init_letter(0xdb, 0xfb, "u");
+  init_letter(0xdc, 0xfc, "u");
+  init_letter(0xdd, 0xfd, "y");
+  init_letter(0xde, 0xfe, THORN_SORT_KEY);
+
+  store_token("\337", TOKEN_LOWER, "ss", "SS");
+  store_token("\377", TOKEN_LOWER, "y", "Y");
+}
+
+static void init_two_char_letter(char l1, char l2, char u1, char u2,
+				 const char *sk = 0)
+{
+  char buf[6];
+  buf[0] = '\\';
+  buf[1] = '(';
+  buf[2] = l1;
+  buf[3] = l2;
+  buf[4] = '\0';
+  const char *p = strsave(buf);
+  buf[2] = u1;
+  buf[3] = u2;
+  store_letter(p, strsave(buf), sk);
+  buf[1] = '[';
+  buf[4] = ']';
+  buf[5] = '\0';
+  p = strsave(buf);
+  buf[2] = l1;
+  buf[3] = l2;
+  store_letter(strsave(buf), p, sk);
+  
+}
+
+static void init_special_chars()
+{
+  const char *p;
+  for (p = "':^`~"; *p; p++)
+    for (const char *q = "aeiouy"; *q; q++) {
+      // Use a variable to work around bug in gcc 2.0
+      char c = cmupper(*q);
+      init_two_char_letter(*p, *q, *p, c);
+    }
+  for (p = "/l/o~n,coeaeij"; *p; p += 2) {
+    // Use variables to work around bug in gcc 2.0
+    char c0 = cmupper(p[0]);
+    char c1 = cmupper(p[1]);
+    init_two_char_letter(p[0], p[1], c0, c1);
+  }
+  init_two_char_letter('v', 's', 'v', 'S', "s");
+  init_two_char_letter('v', 'z', 'v', 'Z', "z");
+  init_two_char_letter('o', 'a', 'o', 'A', "a");
+  init_two_char_letter('T', 'p', 'T', 'P', THORN_SORT_KEY);
+  init_two_char_letter('-', 'd', '-', 'D');
+  
+  store_token("\\(ss", TOKEN_LOWER, 0, "SS");
+  store_token("\\[ss]", TOKEN_LOWER, 0, "SS");
+
+  store_token("\\(Sd", TOKEN_LOWER, "d", "\\(-D");
+  store_token("\\[Sd]", TOKEN_LOWER, "d", "\\[-D]");
+  store_token("\\(hy", TOKEN_HYPHEN);
+  store_token("\\[hy]", TOKEN_HYPHEN);
+  store_token("\\(en", TOKEN_RANGE_SEP);
+  store_token("\\[en]", TOKEN_RANGE_SEP);
+}
+
+static void init_strings()
+{
+  char buf[6];
+  buf[0] = '\\';
+  buf[1] = '*';
+  for (const char *p = "'`^^,:~v_o./;"; *p; p++) {
+    buf[2] = *p;
+    buf[3] = '\0';
+    store_token(strsave(buf), TOKEN_ACCENT);
+    buf[2] = '[';
+    buf[3] = *p;
+    buf[4] = ']';
+    buf[5] = '\0';
+    store_token(strsave(buf), TOKEN_ACCENT);
+  }
+
+  // -ms special letters
+  store_letter("\\*(th", "\\*(Th", THORN_SORT_KEY);
+  store_letter("\\*[th]", "\\*[Th]", THORN_SORT_KEY);
+  store_letter("\\*(d-", "\\*(D-");
+  store_letter("\\*[d-]", "\\*[D-]");
+  store_letter("\\*(ae", "\\*(Ae", "ae");
+  store_letter("\\*[ae]", "\\*[Ae]", "ae");
+  store_letter("\\*(oe", "\\*(Oe", "oe");
+  store_letter("\\*[oe]", "\\*[Oe]", "oe");
+
+  store_token("\\*3", TOKEN_LOWER, "y", "Y");
+  store_token("\\*8", TOKEN_LOWER, "ss", "SS");
+  store_token("\\*q", TOKEN_LOWER, "o", "O");
+}
+
+struct token_initer {
+  token_initer();
+};
+
+static token_initer the_token_initer;
+
+token_initer::token_initer()
+{
+  init_ascii();
+  init_latin1();
+  init_special_chars();
+  init_strings();
+  default_token_info.set(TOKEN_OTHER);
+}
diff --git a/src/preproc/refer/token.h b/src/preproc/refer/token.h
new file mode 100644
index 0000000..9cd688c
--- /dev/null
+++ b/src/preproc/refer/token.h
@@ -0,0 +1,87 @@
+// -*- C++ -*-
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+enum token_type {
+  TOKEN_OTHER,
+  TOKEN_UPPER,
+  TOKEN_LOWER,
+  TOKEN_ACCENT,
+  TOKEN_PUNCT,
+  TOKEN_HYPHEN,
+  TOKEN_RANGE_SEP
+};
+
+class token_info {
+private:
+  token_type type;
+  const char *sort_key;
+  const char *other_case;
+public:
+  token_info();
+  void set(token_type, const char *sk = 0, const char *oc = 0);
+  void lower_case(const char *start, const char *end, string &result) const;
+  void upper_case(const char *start, const char *end, string &result) const;
+  void sortify(const char *start, const char *end, string &result) const;
+  int sortify_non_empty(const char *start, const char *end) const;
+  int is_upper() const;
+  int is_lower() const;
+  int is_accent() const;
+  int is_other() const;
+  int is_punct() const;
+  int is_hyphen() const;
+  int is_range_sep() const;
+};
+
+inline int token_info::is_upper() const
+{
+  return type == TOKEN_UPPER;
+}
+
+inline int token_info::is_lower() const
+{
+  return type == TOKEN_LOWER;
+}
+
+inline int token_info::is_accent() const
+{
+  return type == TOKEN_ACCENT;
+}
+
+inline int token_info::is_other() const
+{
+  return type == TOKEN_OTHER;
+}
+
+inline int token_info::is_punct() const
+{
+  return type == TOKEN_PUNCT;
+}
+
+inline int token_info::is_hyphen() const
+{
+  return type == TOKEN_HYPHEN;
+}
+
+inline int token_info::is_range_sep() const
+{
+  return type == TOKEN_RANGE_SEP;
+}
+
+int get_token(const char **ptr, const char *end);
+const token_info *lookup_token(const char *start, const char *end);
diff --git a/src/preproc/soelim/TODO b/src/preproc/soelim/TODO
new file mode 100644
index 0000000..f2a3924
--- /dev/null
+++ b/src/preproc/soelim/TODO
@@ -0,0 +1 @@
+Understand .pso.
diff --git a/src/preproc/soelim/soelim.1.man b/src/preproc/soelim/soelim.1.man
new file mode 100644
index 0000000..4a1c042
--- /dev/null
+++ b/src/preproc/soelim/soelim.1.man
@@ -0,0 +1,456 @@
+'\" p
+.TH @g@soelim @MAN1EXT@ "@MDATE@" "groff @VERSION@"
+.SH Name
+@g@soelim \- recursively interpolate source requests in
+.I roff
+or other text files
+.
+.
+.\" ====================================================================
+.\" Legal Terms
+.\" ====================================================================
+.\"
+.\" Copyright (C) 1989-2020 Free Software Foundation, Inc.
+.\"
+.\" Permission is granted to make and distribute verbatim copies of this
+.\" manual provided the copyright notice and this permission notice are
+.\" preserved on all copies.
+.\"
+.\" Permission is granted to copy and distribute modified versions of
+.\" this manual under the conditions for verbatim copying, provided that
+.\" the entire resulting derived work is distributed under the terms of
+.\" a permission notice identical to this one.
+.\"
+.\" Permission is granted to copy and distribute translations of this
+.\" manual into another language, under the above conditions for
+.\" modified versions, except that this permission notice may be
+.\" included in translations approved by the Free Software Foundation
+.\" instead of in the original English.
+.
+.
+.\" Save and disable compatibility mode (for, e.g., Solaris 10/11).
+.do nr *groff_soelim_1_man_C \n[.cp]
+.cp 0
+.
+.\" Define fallback for groff 1.23's MR macro if the system lacks it.
+.nr do-fallback 0
+.if !\n(.f           .nr do-fallback 1 \" mandoc
+.if  \n(.g .if !d MR .nr do-fallback 1 \" older groff
+.if !\n(.g           .nr do-fallback 1 \" non-groff *roff
+.if \n[do-fallback]  \{\
+.  de MR
+.    ie \\n(.$=1 \
+.      I \%\\$1
+.    el \
+.      IR \%\\$1 (\\$2)\\$3
+.  .
+.\}
+.rr do-fallback
+.\" Man pages are seldom preprocessed with pic(1).
+.mso pic.tmac
+.
+.
+.\" ====================================================================
+.\" Definitions
+.\" ====================================================================
+.
+.ie t .ds tx T\h'-.1667m'\v'.224m'E\v'-.224m'\h'-.125m'X
+.el   .ds tx TeX
+.
+.
+.\" ====================================================================
+.SH Synopsis
+.\" ====================================================================
+.
+.SY @g@soelim
+.RB [ \-Crt ]
+.RB [ \-I
+.IR dir ]
+.RI [ input-file\~ .\|.\|.]
+.YS
+.
+.
+.SY @g@soelim
+.B \-\-help
+.YS
+.
+.
+.SY @g@soelim
+.B \-v
+.
+.SY @g@soelim
+.B \-\-version
+.YS
+.
+.
+.\" ====================================================================
+.SH Description
+.\" ====================================================================
+.
+GNU
+.I soelim \" GNU
+is a preprocessor for the
+.MR groff @MAN7EXT@
+document formatting system.
+.
+.I @g@soelim
+works as a filter to eliminate source requests in
+.MR roff @MAN7EXT@
+input files;
+that is,
+it replaces lines of the form
+.RB \[lq] .so
+.IR included-file \[rq]
+within each text
+.I input-file
+with the contents of
+.IR included-file ,
+recursively.
+.
+By default,
+it writes
+.B lf
+requests as well to record the name and line number of each
+.I input-file
+and
+.IR included-file ,
+so that any diagnostics produced by later processing can be accurately
+traced to the original input.
+.
+Options allow this information to be suppressed
+.RB ( \-r )
+or supplied in \*[tx] comments instead
+.RB ( \-t ).
+.
+In the absence of
+.I input-file
+arguments,
+.I @g@soelim
+reads the standard input stream.
+.
+Output is written to the standard output stream.
+.
+.
+.PP
+If the name of a
+.I macro-file
+contains a backslash,
+use
+.B \[rs]\[rs]
+or
+.B \[rs]e
+to embed it.
+.
+To embed a space,
+write
+.RB \[lq] \[rs]\~ \[rq]
+(backslash followed by a space).
+.
+Any other escape sequence in
+.IR macro-file ,
+including
+.RB \[lq] \[rs][rs] \[rq],
+prevents
+.I @g@soelim
+from replacing the source request.
+.
+.
+.PP
+The dot must be at the beginning of a line and must be followed by
+.RB \[lq] so \[rq]
+without intervening spaces or tabs for
+.I @g@soelim
+to handle it.
+.
+This convention allows source requests to be \[lq]protected\[rq] from
+processing by
+.IR @g@soelim ,
+for instance as part of macro definitions or
+.RB \[lq] if \[rq]
+requests.
+.
+.
+.PP
+There must also be at least one space between
+.RB \[lq] so \[rq]
+and its
+.I macro-file
+argument.
+.
+The
+.B \-C
+option overrides this requirement.
+.
+.
+.PP
+The foregoing is the limit of
+.IR @g@soelim 's
+understanding of the
+.I roff
+language;
+it does not,
+for example,
+replace the input line
+.
+.RS
+.EX
+\&.if 1 .so otherfile
+.EE
+.RE
+.
+with the contents of
+.IR otherfile .
+.
+With its
+.B \-r
+option,
+therefore,
+.I @g@soelim
+can be used to process text files in general,
+to flatten a tree of input documents.
+.
+.
+.PP
+.I soelim \" generic
+was designed to handle situations where the target of a
+.I roff \" generic
+source request requires a preprocessor such as
+.MR @g@eqn @MAN1EXT@ ,
+.MR @g@pic @MAN1EXT@ ,
+.MR @g@refer @MAN1EXT@ ,
+or
+.MR @g@tbl @MAN1EXT@ .
+.
+The usual processing sequence of
+.MR groff @MAN1EXT@
+is as follows.
+.
+.\" Does this groff installation use a command prefix?  In installed
+.\" pages, this comparison will not look like it needs to be dynamically
+.\" decided.
+.\"
+.\" This is done so that the box sizes (in the pic(1) diagram) and arrow
+.\" alignments (in the text alternative) can remain fixed.
+.if !'@g@'\%' \{\
+In the diagrams below,
+the traditional names for
+.I soelim
+and
+.I troff
+are used;
+on this system,
+the GNU versions are installed as
+.I @g@soelim
+and
+.IR @g@troff .
+.\}
+.
+.
+.PP
+.ie t \{\
+.PS
+.ps 10
+.vs 12
+box invisible width 0.5 height 0.4 "input" "file";
+move to last box .bottom;
+down;
+arrow 0.3;
+box invisible width 0.8 height 0.2 "preprocessor";
+move to last box .right
+right;
+arrow 0.3;
+A: box invisible width 0.35 height 0.2 "troff";
+move to last box .top;
+up;
+move 0.3;
+box invisible width 0.6 height 0.4 "sourced" "file";
+line <- up 0.3 from A.top;
+move to A.right;
+right;
+arrow 0.3;
+box invisible width 0.85 height 0.2 "postprocessor";
+move to last box .bottom;
+down;
+arrow 0.3;
+box invisible width 0.5 height 0.4 "output" "file"
+.ps
+.vs
+.PE
+.\}
+.el \{\
+.EX
+          input        sourced
+          file          file
+            \[bv]             \[bv]
+            \[da]             \[da]
+        preprocessor \[an]\[->] troff \[an]\[->] postprocessor
+                                      \[bv]
+                                      \[da]
+                                   output
+                                    file
+.EE
+.\}
+.PP
+That is,
+files sourced with
+.RB \[lq] so \[rq]
+are normally read
+.I only
+by the formatter,
+.IR @g@troff .
+.
+.I @g@soelim
+is
+.I not
+required for
+.I @g@troff
+to source files.
+.
+.
+.PP
+If a file to be sourced should also be preprocessed,
+it must already be read
+.I before
+the input file passes through the preprocessor.
+.
+.IR @g@soelim ,
+normally invoked via
+.IR groff 's
+.B \-s
+option,
+handles this.
+.
+.
+.PP
+.ie t \{\
+.PS
+.ps 10
+.vs 12
+box invisible width 0.5 height 0.4 "input" "file";
+move to last box .bottom;
+down;
+arrow 0.3;
+A: box invisible width 0.5 height 0.2 "soelim";
+line <- 0.3;
+box invisible width 0.5 height 0.4 "sourced" "file";
+move to A.right;
+right;
+arrow 0.3;
+box invisible width 0.8 height 0.2 "preprocessor";
+arrow 0.3;
+box invisible width 0.35 height 0.2 "troff";
+arrow 0.3
+box invisible width 0.85 height 0.2 "postprocessor";
+move to last box .bottom;
+down;
+arrow 0.3;
+box invisible width 0.5 height 0.4 "output" "file"
+.ps
+.vs
+.PE
+.\}
+.el \{\
+.EX
+          input
+          file
+            \[bv]
+            \[da]
+          soelim \[an]\[->] preprocessor \[an]\[->] troff \[an]\[->] \
+postprocessor
+            \[ua]                                     \[bv]
+            \[bv]                                     \[da]
+         sourced                               output
+          file                                  file
+.EE
+.\}
+.
+.
+.\" ====================================================================
+.SH Options
+.\" ====================================================================
+.
+.B \-\-help
+displays a usage message,
+while
+.B \-v
+and
+.B \-\-version
+show version information;
+all exit afterward.
+.
+.
+.TP
+.B \-C
+Recognize an input line starting with
+.B .so
+even if a character other than a space or newline follows.
+.
+.TP
+.BI \-I\~ dir
+Search the directory
+.I dir
+path for
+.I input-
+and
+.I included-files.
+.
+.B \-I
+may be specified more than once;
+each
+.I dir
+is searched in the given order.
+.
+To search the current working directory before others,
+add
+.RB \[lq] "\-I .\&" \[rq]
+at the desired place;
+it is otherwise searched last.
+.
+.
+.TP
+.B \-r
+Write files \[lq]raw\[rq];
+do not add
+.B lf
+requests.
+.
+.
+.TP
+.B \-t
+Emit \*[tx] comment lines starting with
+.RB \[lq] % \[rq]
+indicating the current file and line number,
+rather than
+.B lf
+requests for the same purpose.
+.
+.
+.PP
+If both
+.B \-r
+and
+.B \-t
+are given,
+the last one specified controls.
+.
+.
+.\" ====================================================================
+.SH "See also"
+.\" ====================================================================
+.
+.MR groff @MAN1EXT@
+.
+.
+.\" Clean up.
+.rm tx
+.
+.\" Restore compatibility mode (for, e.g., Solaris 10/11).
+.cp \n[*groff_soelim_1_man_C]
+.do rr *groff_soelim_1_man_C
+.
+.
+.\" Local Variables:
+.\" fill-column: 72
+.\" mode: nroff
+.\" End:
+.\" vim: set filetype=groff textwidth=72:
diff --git a/src/preproc/soelim/soelim.am b/src/preproc/soelim/soelim.am
new file mode 100644
index 0000000..1aa7941
--- /dev/null
+++ b/src/preproc/soelim/soelim.am
@@ -0,0 +1,31 @@
+# Copyright (C) 2014-2020 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+prefixexecbin_PROGRAMS += soelim
+soelim_LDADD = libgroff.a $(LIBM) lib/libgnu.a
+soelim_SOURCES = src/preproc/soelim/soelim.cpp
+PREFIXMAN1 += src/preproc/soelim/soelim.1
+EXTRA_DIST += \
+  src/preproc/soelim/TODO \
+  src/preproc/soelim/soelim.1.man
+
+
+# Local Variables:
+# fill-column: 72
+# mode: makefile-automake
+# End:
+# vim: set autoindent filetype=automake textwidth=72:
diff --git a/src/preproc/soelim/soelim.cpp b/src/preproc/soelim/soelim.cpp
new file mode 100644
index 0000000..bafc5cd
--- /dev/null
+++ b/src/preproc/soelim/soelim.cpp
@@ -0,0 +1,315 @@
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "lib.h"
+
+#include <assert.h>
+#include <ctype.h>
+#include <errno.h>
+#include <stdlib.h>
+
+#include "errarg.h"
+#include "error.h"
+#include "stringclass.h"
+#include "nonposix.h"
+#include "searchpath.h"
+#include "lf.h"
+
+// The include search path initially contains only the current directory.
+static search_path include_search_path(0, 0, 0, 1);
+
+int compatible_flag = 0;
+int raw_flag = 0;
+int tex_flag = 0;
+
+extern "C" const char *Version_string;
+
+int do_file(const char *);
+
+
+void usage(FILE *stream)
+{
+  fprintf(stream, "usage: %s [-Crt] [-I dir] [file ...]\n"
+	  "usage: %s {-v | --version}\n"
+	  "usage: %s --help\n",
+	  program_name, program_name, program_name);
+}
+
+int main(int argc, char **argv)
+{
+  program_name = argv[0];
+  int opt;
+  static const struct option long_options[] = {
+    { "help", no_argument, 0, CHAR_MAX + 1 },
+    { "version", no_argument, 0, 'v' },
+    { NULL, 0, 0, 0 }
+  };
+  while ((opt = getopt_long(argc, argv, "CI:rtv", long_options, NULL)) != EOF)
+    switch (opt) {
+    case 'v':
+      printf("GNU soelim (groff) version %s\n", Version_string);
+      exit(0);
+      break;
+    case 'C':
+      compatible_flag = 1;
+      break;
+    case 'I':
+      include_search_path.command_line_dir(optarg);
+      break;
+    case 'r':
+      raw_flag = 1;
+      break;
+    case 't':
+      tex_flag = 1;
+      break;
+    case CHAR_MAX + 1: // --help
+      usage(stdout);
+      exit(0);
+      break;
+    case '?':
+      usage(stderr);
+      exit(1);
+      break;
+    default:
+      assert(0);
+    }
+  int nbad = 0;
+  if (optind >= argc)
+    nbad += !do_file("-");
+  else
+    for (int i = optind; i < argc; i++)
+      nbad += !do_file(argv[i]);
+  if (ferror(stdout) || fflush(stdout) < 0)
+    fatal("output error");
+  return nbad != 0;
+}
+
+void set_location()
+{
+  if (!raw_flag) {
+    if (!tex_flag)
+      printf(".lf %d %s\n", current_lineno, current_filename);
+    else
+      printf("%% file %s, line %d\n", current_filename, current_lineno);
+  }
+}
+
+void do_so(const char *line)
+{
+  const char *p = line;
+  while (*p == ' ')
+    p++;
+  string filename;
+  int success = 1;
+  for (const char *q = p;
+       success && *q != '\0' && *q != '\n' && *q != ' ';
+       q++)
+    if (*q == '\\') {
+      switch (*++q) {
+      case 'e':
+      case '\\':
+	filename += '\\';
+	break;
+      case ' ':
+	filename += ' ';
+	break;
+      default:
+	success = 0;
+	break;
+      }
+    }
+    else
+      filename += char(*q);
+  if (success && filename.length() > 0) {
+    filename += '\0';
+    const char *fn = current_filename;
+    int ln = current_lineno;
+    current_lineno--;
+    if (do_file(filename.contents())) {
+      current_filename = fn;
+      current_lineno = ln;
+      set_location();
+      return;
+    }
+    current_lineno++;
+  }
+  fputs(".so", stdout);
+  fputs(line, stdout);
+}
+
+int do_file(const char *filename)
+{
+  char *file_name_in_path = 0;
+  FILE *fp = include_search_path.open_file_cautious(filename,
+						    &file_name_in_path);
+  int err = errno;
+  string whole_filename(file_name_in_path ? file_name_in_path : filename);
+  whole_filename += '\0';
+  free(file_name_in_path);
+  if (fp == 0) {
+    error("can't open '%1': %2", whole_filename.contents(), strerror(err));
+    return 0;
+  }
+  normalize_for_lf(whole_filename);
+  current_filename = whole_filename.contents();
+  current_lineno = 1;
+  set_location();
+  enum { START, MIDDLE, HAD_DOT, HAD_s, HAD_so, HAD_l, HAD_lf } state = START;
+  for (;;) {
+    int c = getc(fp);
+    if (c == EOF)
+      break;
+    switch (state) {
+    case START:
+      if (c == '.')
+	state = HAD_DOT;
+      else {
+	putchar(c);
+	if (c == '\n') {
+	  current_lineno++;
+	  state = START;
+	}
+	else
+	  state = MIDDLE;
+      }
+      break;
+    case MIDDLE:
+      putchar(c);
+      if (c == '\n') {
+	current_lineno++;
+	state = START;
+      }
+      break;
+    case HAD_DOT:
+      if (c == 's')
+	state = HAD_s;
+      else if (c == 'l')
+	state = HAD_l;
+      else {
+	putchar('.');
+	putchar(c);
+	if (c == '\n') {
+	  current_lineno++;
+	  state = START;
+	}
+	else
+	  state = MIDDLE;
+      }
+      break;
+    case HAD_s:
+      if (c == 'o')
+	state = HAD_so;
+      else  {
+	putchar('.');
+	putchar('s');
+	putchar(c);
+	if (c == '\n') {
+	  current_lineno++;
+	  state = START;
+	}
+	else
+	  state = MIDDLE;
+      }
+      break;
+    case HAD_so:
+      if (c == ' ' || c == '\n' || compatible_flag) {
+	string line;
+	for (; c != EOF && c != '\n'; c = getc(fp))
+	  line += c;
+	current_lineno++;
+	line += '\n';
+	line += '\0';
+	do_so(line.contents());
+	state = START;
+      }
+      else {
+	fputs(".so", stdout);
+	putchar(c);
+	state = MIDDLE;
+      }
+      break;
+    case HAD_l:
+      if (c == 'f')
+	state = HAD_lf;
+      else {
+	putchar('.');
+	putchar('l');
+	putchar(c);
+	if (c == '\n') {
+	  current_lineno++;
+	  state = START;
+	}
+	else
+	  state = MIDDLE;
+      }
+      break;
+    case HAD_lf:
+      if (c == ' ' || c == '\n' || compatible_flag) {
+	string line;
+	for (; c != EOF && c != '\n'; c = getc(fp))
+	  line += c;
+	current_lineno++;
+	line += '\n';
+	line += '\0';
+	interpret_lf_args(line.contents());
+	printf(".lf%s", line.contents());
+	state = START;
+      }
+      else {
+	fputs(".lf", stdout);
+	putchar(c);
+	state = MIDDLE;
+      }
+      break;
+    default:
+      assert(0);
+    }
+  }
+  switch (state) {
+  case HAD_DOT:
+    fputs(".\n", stdout);
+    break;
+  case HAD_l:
+    fputs(".l\n", stdout);
+    break;
+  case HAD_s:
+    fputs(".s\n", stdout);
+    break;
+  case HAD_lf:
+    fputs(".lf\n", stdout);
+    break;
+  case HAD_so:
+    fputs(".so\n", stdout);
+    break;
+  case MIDDLE:
+    putc('\n', stdout);
+    break;
+  case START:
+    break;
+  }
+  if (fp != stdin)
+    fclose(fp);
+  current_filename = 0;
+  return 1;
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/tbl/main.cpp b/src/preproc/tbl/main.cpp
new file mode 100644
index 0000000..db105c2
--- /dev/null
+++ b/src/preproc/tbl/main.cpp
@@ -0,0 +1,1692 @@
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "table.h"
+
+#define MAX_POINT_SIZE 99
+#define MAX_VERTICAL_SPACING 72
+
+extern "C" const char *Version_string;
+
+int compatible_flag = 0;
+
+class table_input {
+  FILE *fp;
+  enum { START, MIDDLE,
+	 REREAD_T, REREAD_TE, REREAD_E,
+	 LEADER_1, LEADER_2, LEADER_3, LEADER_4,
+	 END, ERROR } state;
+  string unget_stack;
+public:
+  table_input(FILE *);
+  int get();
+  int ended() { return unget_stack.empty() && state == END; }
+  void unget(char);
+};
+
+table_input::table_input(FILE *p)
+: fp(p), state(START)
+{
+}
+
+void table_input::unget(char c)
+{
+  assert(c != '\0');
+  unget_stack += c;
+  if (c == '\n')
+    current_lineno--;
+}
+
+int table_input::get()
+{
+  int len = unget_stack.length();
+  if (len != 0) {
+    unsigned char c = unget_stack[len - 1];
+    unget_stack.set_length(len - 1);
+    if (c == '\n')
+      current_lineno++;
+    return c;
+  }
+  int c;
+  for (;;) {
+    switch (state) {
+    case START:
+      if ((c = getc(fp)) == '.') {
+	if ((c = getc(fp)) == 'T') {
+	  if ((c = getc(fp)) == 'E') {
+	    if (compatible_flag) {
+	      state = END;
+	      return EOF;
+	    }
+	    else {
+	      c = getc(fp);
+	      if (c != EOF)
+		ungetc(c, fp);
+	      if (c == EOF || c == ' ' || c == '\n') {
+		state = END;
+		return EOF;
+	      }
+	      state = REREAD_TE;
+	      return '.';
+	    }
+	  }
+	  else {
+	    if (c != EOF)
+	      ungetc(c, fp);
+	    state = REREAD_T;
+	    return '.';
+	  }
+	}
+	else {
+	  if (c != EOF)
+	    ungetc(c, fp);
+	  state = MIDDLE;
+	  return '.';
+	}
+      }
+      else if (c == EOF) {
+	state = ERROR;
+	return EOF;
+      }
+      else {
+	if (c == '\n')
+	  current_lineno++;
+	else {
+	  state = MIDDLE;
+	  if (c == '\0') {
+	    error("invalid input character code 0");
+	    break;
+	  }
+	}
+	return c;
+      }
+      break;
+    case MIDDLE:
+      // handle line continuation and uninterpreted leader character
+      if ((c = getc(fp)) == '\\') {
+	c = getc(fp);
+	if (c == '\n') {
+	  current_lineno++;
+	  c = getc(fp);
+	}
+	else if (c == 'a' && compatible_flag) {
+	  state = LEADER_1;
+	  return '\\';
+	}
+	else {
+	  if (c != EOF)
+	    ungetc(c, fp);
+	  c = '\\';
+	}
+      }
+      if (c == EOF) {
+	state = ERROR;
+	return EOF;
+      }
+      else {
+	if (c == '\n') {
+	  state = START;
+	  current_lineno++;
+	}
+	else if (c == '\0') {
+	  error("invalid input character code 0");
+	  break;
+	}
+	return c;
+      }
+    case REREAD_T:
+      state = MIDDLE;
+      return 'T';
+    case REREAD_TE:
+      state = REREAD_E;
+      return 'T';
+    case REREAD_E:
+      state = MIDDLE;
+      return 'E';
+    case LEADER_1:
+      state = LEADER_2;
+      return '*';
+    case LEADER_2:
+      state = LEADER_3;
+      return '(';
+    case LEADER_3:
+      state = LEADER_4;
+      return PREFIX_CHAR;
+    case LEADER_4:
+      state = MIDDLE;
+      return LEADER_CHAR;
+    case END:
+    case ERROR:
+      return EOF;
+    }
+  }
+}
+
+void process_input_file(FILE *);
+void process_table(table_input &in);
+
+void process_input_file(FILE *fp)
+{
+  enum { START, MIDDLE, HAD_DOT, HAD_T, HAD_TS, HAD_l, HAD_lf } state;
+  state = START;
+  int c;
+  while ((c = getc(fp)) != EOF)
+    switch (state) {
+    case START:
+      if (c == '.')
+	state = HAD_DOT;
+      else {
+	if (c == '\n')
+	  current_lineno++;
+	else
+	  state = MIDDLE;
+	putchar(c);
+      }
+      break;
+    case MIDDLE:
+      if (c == '\n') {
+	current_lineno++;
+	state = START;
+      }
+      putchar(c);
+      break;
+    case HAD_DOT:
+      if (c == 'T')
+	state = HAD_T;
+      else if (c == 'l')
+	state = HAD_l;
+      else {
+	putchar('.');
+	putchar(c);
+	if (c == '\n') {
+	  current_lineno++;
+	  state = START;
+	}
+	else
+	  state = MIDDLE;
+      }
+      break;
+    case HAD_T:
+      if (c == 'S')
+	state = HAD_TS;
+      else {
+	putchar('.');
+	putchar('T');
+	putchar(c);
+	if (c == '\n') {
+ 	  current_lineno++;
+	  state = START;
+	}
+	else
+	  state = MIDDLE;
+      }
+      break;
+    case HAD_TS:
+      if (c == ' ' || c == '\n' || compatible_flag) {
+	putchar('.');
+	putchar('T');
+	putchar('S');
+	while (c != '\n') {
+	  if (c == EOF) {
+	    error("end of file at beginning of table");
+	    return;
+	  }
+	  putchar(c);
+	  c = getc(fp);
+	}
+	putchar('\n');
+	current_lineno++;
+	{
+	  table_input input(fp);
+	  process_table(input);
+	  set_troff_location(current_filename, current_lineno);
+	  if (input.ended()) {
+	    fputs(".TE", stdout);
+	    while ((c = getc(fp)) != '\n') {
+	      if (c == EOF) {
+		putchar('\n');
+		return;
+	      }
+	      putchar(c);
+	    }
+	    putchar('\n');
+	    current_lineno++;
+	  }
+	}
+	state = START;
+      }
+      else {
+	fputs(".TS", stdout);
+	putchar(c);
+	state = MIDDLE;
+      }
+      break;
+    case HAD_l:
+      if (c == 'f')
+	state = HAD_lf;
+      else {
+	putchar('.');
+	putchar('l');
+	putchar(c);
+	if (c == '\n') {
+ 	  current_lineno++;
+	  state = START;
+	}
+	else
+	  state = MIDDLE;
+      }
+      break;
+    case HAD_lf:
+      if (c == ' ' || c == '\n' || compatible_flag) {
+	string line;
+	while (c != EOF) {
+	  line += c;
+	  if (c == '\n') {
+	    current_lineno++;
+	    break;
+	  }
+	  c = getc(fp);
+	}
+	line += '\0';
+	interpret_lf_args(line.contents());
+	printf(".lf%s", line.contents());
+	state = START;
+      }
+      else {
+	fputs(".lf", stdout);
+	putchar(c);
+	state = MIDDLE;
+      }
+      break;
+    default:
+      assert(0 == "invalid `state` in switch");
+    }
+  switch(state) {
+  case START:
+    break;
+  case MIDDLE:
+    putchar('\n');
+    break;
+  case HAD_DOT:
+    fputs(".\n", stdout);
+    break;
+  case HAD_l:
+    fputs(".l\n", stdout);
+    break;
+  case HAD_T:
+    fputs(".T\n", stdout);
+    break;
+  case HAD_lf:
+    fputs(".lf\n", stdout);
+    break;
+  case HAD_TS:
+    fputs(".TS\n", stdout);
+    break;
+  }
+  if (fp != stdin)
+    fclose(fp);
+}
+
+struct options {
+  unsigned flags;
+  int linesize;
+  char delim[2];
+  char tab_char;
+  char decimal_point_char;
+
+  options();
+};
+
+options::options()
+: flags(0), linesize(0), tab_char('\t'), decimal_point_char('.')
+{
+  delim[0] = delim[1] = '\0';
+}
+
+// Return non-zero if p and q are the same ignoring case.
+
+int strieq(const char *p, const char *q)
+{
+  for (; cmlower(*p) == cmlower(*q); p++, q++)
+    if (*p == '\0')
+      return 1;
+  return 0;
+}
+
+// Handle region options.  Return a null pointer if we should give up on
+// this table.
+options *process_options(table_input &in)
+{
+  options *opt = new options;
+  string line;
+  int level = 0;
+  for (;;) {
+    int c = in.get();
+    if (c == EOF) {
+      int i = line.length();
+      while (--i >= 0)
+	in.unget(line[i]);
+      return opt;
+    }
+    if (c == '\n') {
+      in.unget(c);
+      int i = line.length();
+      while (--i >= 0)
+	in.unget(line[i]);
+      return opt;
+    }
+    else if (c == '(')
+      level++;
+    else if (c == ')')
+      level--;
+    else if (c == ';' && 0 == level) {
+      line += '\0';
+      break;
+    }
+    line += c;
+  }
+  if (line.empty())
+    return opt;
+  char *p = &line[0];
+  for (;;) {
+    while (!csalpha(*p) && *p != '\0')
+      p++;
+    if (*p == '\0')
+      break;
+    char *q = p;
+    while (csalpha(*q))
+      q++;
+    char *arg = 0;
+    if (*q != '(' && *q != '\0')
+      *q++ = '\0';
+    while (csspace(*q))
+      q++;
+    if (*q == '(') {
+      *q++ = '\0';
+      arg = q;
+      while (*q != ')' && *q != '\0')
+	q++;
+      if (*q == '\0')
+	error("'%1' region option argument missing closing parenthesis",
+	      arg);
+      else
+	*q++ = '\0';
+    }
+    if (*p == '\0') {
+      if (arg)
+	error("'%1' region option argument cannot be empty", arg);
+    }
+    else if (strieq(p, "tab")) {
+      if (!arg)
+	error("'tab' region option requires argument in parentheses");
+      else {
+	if (arg[0] == '\0' || arg[1] != '\0')
+	  error("'tab' region option argument must be a single"
+		" character");
+	else
+	  opt->tab_char = arg[0];
+      }
+    }
+    else if (strieq(p, "linesize")) {
+      if (!arg)
+	error("'linesize' region option requires argument in"
+	      " parentheses");
+      else {
+	if (sscanf(arg, "%d", &opt->linesize) != 1)
+	  error("invalid argument to 'linesize' region option: '%1'",
+		arg);
+	else if (opt->linesize <= 0) {
+	  error("'linesize' region option argument must be positive");
+	  opt->linesize = 0;
+	}
+      }
+    }
+    else if (strieq(p, "delim")) {
+      if (!arg)
+	error("'delim' region option requires argument in parentheses");
+      else if (arg[0] == '\0' || arg[1] == '\0' || arg[2] != '\0')
+	error("argument to 'delim' option must be two characters");
+      else {
+	opt->delim[0] = arg[0];
+	opt->delim[1] = arg[1];
+      }
+    }
+    else if (strieq(p, "center") || strieq(p, "centre")) {
+      if (arg)
+	error("'center' region option does not take an argument");
+      opt->flags |= table::CENTER;
+    }
+    else if (strieq(p, "expand")) {
+      if (arg)
+	error("'expand' region option does not take an argument");
+      opt->flags |= table::EXPAND;
+      opt->flags |= table::GAP_EXPAND;
+    }
+    else if (strieq(p, "box") || strieq(p, "frame")) {
+      if (arg)
+	error("'box' region option does not take an argument");
+      opt->flags |= table::BOX;
+    }
+    else if (strieq(p, "doublebox") || strieq(p, "doubleframe")) {
+      if (arg)
+	error("'doublebox' region option does not take an argument");
+      opt->flags |= table::DOUBLEBOX;
+    }
+    else if (strieq(p, "allbox")) {
+      if (arg)
+	error("'allbox' region option does not take an argument");
+      opt->flags |= table::ALLBOX;
+    }
+    else if (strieq(p, "nokeep")) {
+      if (arg)
+	error("'nokeep' region option does not take an argument");
+      opt->flags |= table::NOKEEP;
+    }
+    else if (strieq(p, "nospaces")) {
+      if (arg)
+	error("'nospaces' region option does not take an argument");
+      opt->flags |= table::NOSPACES;
+    }
+    else if (strieq(p, "nowarn")) {
+      if (arg)
+	error("'nowarn' region option does not take an argument");
+      opt->flags |= table::NOWARN;
+    }
+    else if (strieq(p, "decimalpoint")) {
+      if (!arg)
+	error("'decimalpoint' region option requires argument in"
+	      " parentheses");
+      else {
+	if (arg[0] == '\0' || arg[1] != '\0')
+	  error("'decimalpoint' region option argument must be a single"
+		" character");
+	else
+	  opt->decimal_point_char = arg[0];
+      }
+    }
+    else if (strieq(p, "experimental")) {
+      opt->flags |= table::EXPERIMENTAL;
+    }
+    else {
+      error("unrecognized region option '%1'", p);
+      // delete opt;
+      // return 0;
+    }
+    p = q;
+  }
+  return opt;
+}
+
+entry_modifier::entry_modifier()
+: vertical_alignment(CENTER), zero_width(0), stagger(0)
+{
+  vertical_spacing.inc = vertical_spacing.val = 0;
+  point_size.inc = point_size.val = 0;
+}
+
+entry_modifier::~entry_modifier()
+{
+}
+
+entry_format::entry_format() : type(FORMAT_LEFT)
+{
+}
+
+entry_format::entry_format(format_type t) : type(t)
+{
+}
+
+void entry_format::debug_print() const
+{
+  switch (type) {
+  case FORMAT_LEFT:
+    putc('l', stderr);
+    break;
+  case FORMAT_CENTER:
+    putc('c', stderr);
+    break;
+  case FORMAT_RIGHT:
+    putc('r', stderr);
+    break;
+  case FORMAT_NUMERIC:
+    putc('n', stderr);
+    break;
+  case FORMAT_ALPHABETIC:
+    putc('a', stderr);
+    break;
+  case FORMAT_SPAN:
+    putc('s', stderr);
+    break;
+  case FORMAT_VSPAN:
+    putc('^', stderr);
+    break;
+  case FORMAT_HLINE:
+    putc('_', stderr);
+    break;
+  case FORMAT_DOUBLE_HLINE:
+    putc('=', stderr);
+    break;
+  default:
+    assert(0 == "invalid column classifier in switch");
+    break;
+  }
+  if (point_size.val != 0) {
+    putc('p', stderr);
+    if (point_size.inc > 0)
+      putc('+', stderr);
+    else if (point_size.inc < 0)
+      putc('-', stderr);
+    fprintf(stderr, "%d ", point_size.val);
+  }
+  if (vertical_spacing.val != 0) {
+    putc('v', stderr);
+    if (vertical_spacing.inc > 0)
+      putc('+', stderr);
+    else if (vertical_spacing.inc < 0)
+      putc('-', stderr);
+    fprintf(stderr, "%d ", vertical_spacing.val);
+  }
+  if (!font.empty()) {
+    putc('f', stderr);
+    put_string(font, stderr);
+    putc(' ', stderr);
+  }
+  if (!macro.empty()) {
+    putc('m', stderr);
+    put_string(macro, stderr);
+    putc(' ', stderr);
+  }
+  switch (vertical_alignment) {
+  case entry_modifier::CENTER:
+    break;
+  case entry_modifier::TOP:
+    putc('t', stderr);
+    break;
+  case entry_modifier::BOTTOM:
+    putc('d', stderr);
+    break;
+  }
+  if (zero_width)
+    putc('z', stderr);
+  if (stagger)
+    putc('u', stderr);
+}
+
+struct format {
+  int nrows;
+  int ncolumns;
+  int *separation;
+  string *width;
+  char *equal;
+  char *expand;
+  entry_format **entry;
+  char **vline;
+
+  format(int nr, int nc);
+  ~format();
+  void add_rows(int n);
+};
+
+format::format(int nr, int nc) : nrows(nr), ncolumns(nc)
+{
+  int i;
+  separation = ncolumns > 1 ? new int[ncolumns - 1] : 0;
+  for (i = 0; i < ncolumns-1; i++)
+    separation[i] = -1;
+  width = new string[ncolumns];
+  equal = new char[ncolumns];
+  expand = new char[ncolumns];
+  for (i = 0; i < ncolumns; i++) {
+    equal[i] = 0;
+    expand[i] = 0;
+  }
+  entry = new entry_format *[nrows];
+  for (i = 0; i < nrows; i++)
+    entry[i] = new entry_format[ncolumns];
+  vline = new char*[nrows];
+  for (i = 0; i < nrows; i++) {
+    vline[i] = new char[ncolumns+1];
+    for (int j = 0; j < ncolumns+1; j++)
+      vline[i][j] = 0;
+  }
+}
+
+void format::add_rows(int n)
+{
+  int i;
+  char **old_vline = vline;
+  vline = new char*[nrows + n];
+  for (i = 0; i < nrows; i++)
+    vline[i] = old_vline[i];
+  delete[] old_vline;
+  for (i = 0; i < n; i++) {
+    vline[nrows + i] = new char[ncolumns + 1];
+    for (int j = 0; j < ncolumns + 1; j++)
+      vline[nrows + i][j] = 0;
+  }
+  entry_format **old_entry = entry;
+  entry = new entry_format *[nrows + n];
+  for (i = 0; i < nrows; i++)
+    entry[i] = old_entry[i];
+  delete[] old_entry;
+  for (i = 0; i < n; i++)
+    entry[nrows + i] = new entry_format[ncolumns];
+  nrows += n;
+}
+
+format::~format()
+{
+  delete[] separation;
+  delete[] width;
+  delete[] equal;
+  delete[] expand;
+  for (int i = 0; i < nrows; i++) {
+    delete[] vline[i];
+    delete[] entry[i];
+  }
+  delete[] vline;
+  delete[] entry;
+}
+
+struct input_entry_format : public entry_format {
+  input_entry_format *next;
+  string width;
+  int separation;
+  int vline;
+  int vline_count;
+  bool is_last_column;
+  bool is_equal_width;
+  int expand;
+  input_entry_format(format_type, input_entry_format * = 0);
+  ~input_entry_format();
+  void debug_print();
+};
+
+input_entry_format::input_entry_format(format_type t, input_entry_format *p)
+: entry_format(t), next(p)
+{
+  separation = -1;
+  is_last_column = false;
+  vline = 0;
+  vline_count = 0;
+  is_equal_width = false;
+  expand = 0;
+}
+
+input_entry_format::~input_entry_format()
+{
+}
+
+void free_input_entry_format_list(input_entry_format *list)
+{
+  while (list) {
+    input_entry_format *tem = list;
+    list = list->next;
+    delete tem;
+  }
+}
+
+void input_entry_format::debug_print()
+{
+  int i;
+  for (i = 0; i < vline_count; i++)
+    putc('|', stderr);
+  entry_format::debug_print();
+  if (!width.empty()) {
+    putc('w', stderr);
+    putc('(', stderr);
+    put_string(width, stderr);
+    putc(')', stderr);
+  }
+  if (is_equal_width)
+    putc('e', stderr);
+  if (expand)
+    putc('x', stderr);
+  if (separation >= 0)
+    fprintf(stderr, "%d", separation); 
+  for (i = 0; i < vline; i++)
+    putc('|', stderr);
+  if (is_last_column)
+    putc(',', stderr);
+}
+
+// Interpret a table format specification, like "CC,LR.".  Return null
+// pointer if we should give up on this table.  If this is a
+// continuation format line, `current_format` will be the current format
+// line.
+format *process_format(table_input &in, options *opt,
+		       format *current_format = 0)
+{
+  input_entry_format *list = 0 /* nullptr */;
+  bool have_expand = false;
+  bool is_first_row = true;
+  int c = in.get();
+  for (;;) {
+    int vline_count = 0;
+    bool got_format = false;
+    bool got_period = false;
+    format_type t = FORMAT_LEFT;
+    for (;;) {
+      if (c == EOF) {
+	error("end of input while processing table format"
+	      " specification");
+	free_input_entry_format_list(list);
+	list = 0 /* nullptr */;
+	return 0 /* nullptr */;
+      }
+      switch (c) {
+      case 'n':
+      case 'N':
+	t = FORMAT_NUMERIC;
+	got_format = true;
+	break;
+      case 'a':
+      case 'A':
+	got_format = true;
+	t = FORMAT_ALPHABETIC;
+	break;
+      case 'c':
+      case 'C':
+	got_format = true;
+	t = FORMAT_CENTER;
+	break;
+      case 'l':
+      case 'L':
+	got_format = true;
+	t = FORMAT_LEFT;
+	break;
+      case 'r':
+      case 'R':
+	got_format = true;
+	t = FORMAT_RIGHT;
+	break;
+      case 's':
+      case 'S':
+	got_format = true;
+	t = FORMAT_SPAN;
+	break;
+      case '^':
+	got_format = true;
+	t = FORMAT_VSPAN;
+	break;
+      case '_':
+      case '-':			// tbl also accepts this
+	got_format = true;
+	t = FORMAT_HLINE;
+	if (is_first_row)
+	  opt->flags |= table::HAS_TOP_HLINE;
+	break;
+      case '=':
+	got_format = true;
+	t = FORMAT_DOUBLE_HLINE;
+	break;
+      case '.':
+	got_period = true;
+	break;
+      case '|':
+	// leading vertical line in row
+	opt->flags |= table::HAS_TOP_VLINE;
+	vline_count++;
+	// list->vline_count is updated later
+	break;
+      case ' ':
+      case '\t':
+      case '\n':
+	break;
+      default:
+	if (c == opt->tab_char)
+	  break;
+	error("invalid column classifier '%1'", char(c));
+	free_input_entry_format_list(list);
+	list = 0 /* nullptr */;
+	return 0 /* nullptr */;
+      }
+      if (got_period)
+	break;
+      c = in.get();
+      if (got_format)
+	break;
+    }
+    if (got_period)
+      break;
+    list = new input_entry_format(t, list);
+    if (vline_count > 2) {
+      vline_count = 2;
+      error("more than 2 vertical lines at beginning of row description");
+    }
+    list->vline_count = vline_count;
+    // Now handle modifiers.
+    vline_count = 0;
+    bool is_valid_modifier_sequence = true;
+    do {
+      switch (c) {
+      case '0':
+      case '1':
+      case '2':
+      case '3':
+      case '4':
+      case '5':
+      case '6':
+      case '7':
+      case '8':
+      case '9':
+	{
+	  int w = 0;
+	  do {
+	    w = w*10 + (c - '0');
+	    c = in.get();
+	  } while (c != EOF && csdigit(c));
+	  list->separation = w;
+	}
+	break;
+      case 'B':
+      case 'b':
+	c = in.get();
+	list->font = "B";
+	break;
+      case 'd':
+      case 'D':
+	c = in.get();
+	list->vertical_alignment = entry_modifier::BOTTOM;
+	break;
+      case 'e':
+      case 'E':
+	c = in.get();
+	list->is_equal_width = true;
+	// 'e' and 'x' are mutually exclusive
+	list->expand = 0;
+	break;
+      case 'f':
+      case 'F':
+	do {
+	  c = in.get();
+	} while (c == ' ' || c == '\t');
+	if (c == EOF) {
+	  error("'f' column modifier missing font name or mounting"
+		" position");
+	  break;
+	}
+	if (c == '(') {
+	  for (;;) {
+	    c = in.get();
+	    if (c == EOF || c == ' ' || c == '\t') {
+	      error("'f' column modifier missing closing parenthesis");
+	      break;
+	    }
+	    if (c == ')') {
+	      c = in.get();
+	      break;
+	    }
+	    list->font += char(c);
+	  }
+	}
+	else {
+	  list->font = c;
+	  char cc = c;
+	  c = in.get();
+	  if (!csdigit(cc)
+	      && c != EOF && c != ' ' && c != '\t' && c != '.' && c != '\n') {
+	    list->font += char(c);
+	    c = in.get();
+	  }
+	}
+	break;
+      case 'I':
+      case 'i':
+	c = in.get();
+	list->font = "I";
+	break;
+      case 'm':
+      case 'M':
+	do {
+	  c = in.get();
+	} while (c == ' ' || c == '\t');
+	if (c == EOF) {
+	  error("'m' column modifier missing macro name");
+	  break;
+	}
+	if (c == '(') {
+	  for (;;) {
+	    c = in.get();
+	    if (c == EOF || c == ' ' || c == '\t') {
+	      error("'m' column modifier missing closing parenthesis");
+	      break;
+	    }
+	    if (c == ')') {
+	      c = in.get();
+	      break;
+	    }
+	    list->macro += char(c);
+	  }
+	}
+	else {
+	  list->macro = c;
+	  char cc = c;
+	  c = in.get();
+	  if (!csdigit(cc)
+	      && c != EOF && c != ' ' && c != '\t' && c != '.' && c != '\n') {
+	    list->macro += char(c);
+	    c = in.get();
+	  }
+	}
+	break;
+      case 'p':
+      case 'P':
+	{
+	  inc_number &ps = list->point_size;
+	  ps.val = 0;
+	  ps.inc = 0;
+	  c = in.get();
+	  if (c == '+' || c == '-') {
+	    ps.inc = (c == '+' ? 1 : -1);
+	    c = in.get();
+	  }
+	  if (c == EOF || !csdigit(c)) {
+	    warning("'p' column modifier must be followed by"
+		    " (optionally signed) integer; ignoring");
+	    ps.inc = 0;
+	  }
+	  else {
+	    do {
+	      ps.val *= 10;
+	      ps.val += c - '0';
+	      c = in.get();
+	    } while (c != EOF && csdigit(c));
+	  }
+	  if (ps.val > MAX_POINT_SIZE || ps.val < -MAX_POINT_SIZE) {
+	    warning("'p' column modifier argument magnitude of %1"
+		    " points out of range (> %2); ignoring", ps.val,
+		    MAX_POINT_SIZE);
+	    ps.val = 0;
+	    ps.inc = 0;
+	  }
+	  break;
+	}
+      case 't':
+      case 'T':
+	c = in.get();
+	list->vertical_alignment = entry_modifier::TOP;
+	break;
+      case 'u':
+      case 'U':
+	c = in.get();
+	list->stagger = 1;
+	break;
+      case 'v':
+      case 'V':
+	{
+	  inc_number &vs = list->vertical_spacing;
+	  vs.val = 0;
+	  vs.inc = 0;
+	  c = in.get();
+	  if (c == '+' || c == '-') {
+	    vs.inc = (c == '+' ? 1 : -1);
+	    c = in.get();
+	  }
+	  if (c == EOF || !csdigit(c)) {
+	    warning("'v' column modifier must be followed by"
+		    " (optionally signed) integer; ignoring");
+	    vs.inc = 0;
+	  }
+	  else {
+	    do {
+	      vs.val *= 10;
+	      vs.val += c - '0';
+	      c = in.get();
+	    } while (c != EOF && csdigit(c));
+	  }
+	  if (vs.val > MAX_VERTICAL_SPACING
+	      || vs.val < -MAX_VERTICAL_SPACING) {
+	    warning("'v' column modifier argument magnitude of %1"
+		    " points out of range (> %2); ignoring", vs.val,
+		    MAX_VERTICAL_SPACING);
+	    vs.val = 0;
+	    vs.inc = 0;
+	  }
+	  break;
+	}
+      case 'w':
+      case 'W':
+	c = in.get();
+	while (c == ' ' || c == '\t')
+	  c = in.get();
+	if (c == '(') {
+	  list->width = "";
+	  c = in.get();
+	  while (c != ')') {
+	    if (c == EOF || c == '\n') {
+	      error("'w' column modifier missing closing parenthesis");
+	      free_input_entry_format_list(list);
+	      list = 0 /* nullptr */;
+	      return 0 /* nullptr */;
+	    }
+	    list->width += c;
+	    c = in.get();
+	  }
+	  c = in.get();
+	}
+	else {
+	  if (c == '+' || c == '-') {
+	    list->width = char(c);
+	    c = in.get();
+	  }
+	  else
+	    list->width = "";
+	  if (c == EOF || !csdigit(c))
+	    error("invalid argument to 'w' modifier");
+	  else {
+	    do {
+	      list->width += char(c);
+	      c = in.get();
+	    } while (c != EOF && csdigit(c));
+	  }
+	}
+	// 'w' and 'x' are mutually exclusive
+	list->expand = 0;
+	break;
+      case 'x':
+      case 'X':
+	c = in.get();
+	list->expand = 1;
+	// 'x' and 'e' are mutually exclusive
+	list->is_equal_width = false;
+	// 'x' and 'w' are mutually exclusive
+	list->width = "";
+	break;
+      case 'z':
+      case 'Z':
+	c = in.get();
+	list->zero_width = 1;
+	break;
+      case '|':
+	if (is_first_row)
+	  opt->flags |= table::HAS_TOP_VLINE;
+	c = in.get();
+	vline_count++;
+	break;
+      case ' ':
+      case '\t':
+	c = in.get();
+	break;
+      default:
+	if (c == opt->tab_char)
+	  c = in.get();
+	else
+	  is_valid_modifier_sequence = false;
+	break;
+      }
+    } while (is_valid_modifier_sequence);
+    if (vline_count > 2) {
+      vline_count = 2;
+      error("more than 2 vertical lines after column descriptor");
+    }
+    list->vline += vline_count;
+    if (c == '\n' || c == ',') {
+      vline_count = 0;
+      is_first_row = false;
+      c = in.get();
+      list->is_last_column = true;
+    }
+  }
+  if (c == '.') {
+    do {
+      c = in.get();
+    } while (c == ' ' || c == '\t');
+    if (c != '\n') {
+      error("'.' is not the last character of the table format");
+      free_input_entry_format_list(list);
+      list = 0 /* nullptr */;
+      return 0 /* nullptr */;
+    }
+  }
+  if (!list) {
+    error("table format specification is empty");
+    free_input_entry_format_list(list);
+    list = 0 /* nullptr */;
+    return 0 /* nullptr */;
+  }
+  list->is_last_column = true;
+  // now reverse the list so that the first row is at the beginning
+  input_entry_format *rev = 0;
+  while (list != 0) {
+    input_entry_format *tem = list->next;
+    list->next = rev;
+    rev = list;
+    list = tem;
+  }
+  list = rev;
+  input_entry_format *tem;
+
+#if 0
+  for (tem = list; tem; tem = tem->next)
+    tem->debug_print();
+  putc('\n', stderr);
+#endif
+  // compute number of columns and rows
+  int ncolumns = 0;
+  int nrows = 0;
+  int col = 0;
+  for (tem = list; tem; tem = tem->next) {
+    if (tem->is_last_column) {
+      if (col >= ncolumns)
+	ncolumns = col + 1;
+      col = 0;
+      nrows++;
+    }
+    else
+      col++;
+  }
+  int row;
+  format *f;
+  if (current_format) {
+    if (ncolumns > current_format->ncolumns) {
+      error("cannot increase the number of columns in a continued format");
+      free_input_entry_format_list(list);
+      list = 0 /* nullptr */;
+      return 0 /* nullptr */;
+    }
+    f = current_format;
+    row = f->nrows;
+    f->add_rows(nrows);
+  }
+  else {
+    f = new format(nrows, ncolumns);
+    row = 0;
+  }
+  col = 0;
+  for (tem = list; tem; tem = tem->next) {
+    f->entry[row][col] = *tem;
+    if (col < ncolumns - 1) {
+      // use the greatest separation
+      if (tem->separation > f->separation[col]) {
+	if (current_format)
+	  error("cannot change column separation in continued format");
+	else
+	  f->separation[col] = tem->separation;
+      }
+    }
+    else if (tem->separation >= 0)
+      error("column separation specified for last column");
+    if (tem->is_equal_width && !f->equal[col]) {
+      if (current_format)
+	error("cannot change which columns are equal in continued format");
+      else
+	f->equal[col] = 1;
+    }
+    if (tem->expand && !f->expand[col]) {
+      if (current_format)
+	error("cannot change which columns are expanded in continued format");
+      else {
+	f->expand[col] = 1;
+	have_expand = true;
+      }
+    }
+    if (!tem->width.empty()) {
+      // use the last width
+      if (!f->width[col].empty() && f->width[col] != tem->width)
+	error("multiple widths for column %1", col + 1);
+      f->width[col] = tem->width;
+    }
+    if (tem->vline_count)
+      f->vline[row][col] = tem->vline_count;
+    f->vline[row][col + 1] = tem->vline;
+    if (tem->is_last_column) {
+      row++;
+      col = 0;
+    }
+    else
+      col++;
+  }
+  free_input_entry_format_list(list);
+  list = 0 /* nullptr */;
+  for (col = 0; col < ncolumns; col++) {
+    entry_format *e = f->entry[f->nrows - 1] + col;
+    if (e->type != FORMAT_HLINE
+	&& e->type != FORMAT_DOUBLE_HLINE
+	&& e->type != FORMAT_SPAN)
+      break;
+  }
+  if (col >= ncolumns) {
+    error("last row of format is all lines");
+    delete f;
+    return 0 /* nullptr */;
+  }
+  if (have_expand && (opt->flags & table::EXPAND)) {
+    error("'x' column modifier encountered; ignoring region option"
+	  " 'expand'");
+    opt->flags &= ~table::EXPAND;
+  }
+  return f;
+}
+
+table *process_data(table_input &in, format *f, options *opt)
+{
+  char tab_char = opt->tab_char;
+  int ncolumns = f->ncolumns;
+  int current_row = 0;
+  int format_index = 0;
+  bool give_up = false;
+  enum { DATA_INPUT_LINE, TROFF_INPUT_LINE, SINGLE_HLINE, DOUBLE_HLINE } type;
+  table *tbl = new table(ncolumns, opt->flags, opt->linesize,
+			 opt->decimal_point_char);
+  if (opt->delim[0] != '\0')
+    tbl->set_delim(opt->delim[0], opt->delim[1]);
+  for (;;) {
+    // first determine what type of line this is
+    int c = in.get();
+    if (c == EOF)
+      break;
+    if (c == '.') {
+      int d = in.get();
+      if (d != EOF && csdigit(d)) {
+	in.unget(d);
+	type = DATA_INPUT_LINE;
+      }
+      else {
+	in.unget(d);
+	type = TROFF_INPUT_LINE;
+      }
+    }
+    else if (c == '_' || c == '=') {
+      int d = in.get();
+      if (d == '\n') {
+	if (c == '_')
+	  type = SINGLE_HLINE;
+	else
+	  type = DOUBLE_HLINE;
+	if (0 == current_row)
+	  tbl->flags |= table::HAS_TOP_HLINE;
+      }
+      else {
+	in.unget(d);
+	type = DATA_INPUT_LINE;
+      }
+    }
+    else {
+      type = DATA_INPUT_LINE;
+    }
+    switch (type) {
+    case DATA_INPUT_LINE:
+      {
+	string input_entry;
+	if (format_index >= f->nrows)
+	  format_index = f->nrows - 1;
+	// A format row that is all lines doesn't use up a data line.
+	while (format_index < f->nrows - 1) {
+	  int cnt;
+	  for (cnt = 0; cnt < ncolumns; cnt++) {
+	    entry_format *e = f->entry[format_index] + cnt;
+	    if (e->type != FORMAT_HLINE
+		&& e->type != FORMAT_DOUBLE_HLINE
+		// Unfortunately tbl treats a span as needing data.
+		// && e->type != FORMAT_SPAN
+		)
+	      break;
+	  }
+	  if (cnt < ncolumns)
+	    break;
+	  for (cnt = 0; cnt < ncolumns; cnt++)
+	    tbl->add_entry(current_row, cnt, input_entry,
+			   f->entry[format_index] + cnt, current_filename,
+			   current_lineno);
+	  tbl->add_vlines(current_row, f->vline[format_index]);
+	  format_index++;
+	  current_row++;
+	}
+	entry_format *line_format = f->entry[format_index];
+	int col = 0;
+	bool seen_row_comment = false;
+	for (;;) {
+	  if (c == tab_char || c == '\n') {
+	    int ln = current_lineno;
+	    if (c == '\n')
+	      --ln;
+	    if ((opt->flags & table::NOSPACES))
+	      input_entry.remove_spaces();
+	    while (col < ncolumns
+		   && line_format[col].type == FORMAT_SPAN) {
+	      tbl->add_entry(current_row, col, "", &line_format[col],
+			     current_filename, ln);
+	      col++;
+	    }
+	    if (c == '\n' && input_entry.length() == 2
+		&& input_entry[0] == 'T' && input_entry[1] == '{') {
+	      input_entry = "";
+	      ln++;
+	      enum {
+		START, MIDDLE, GOT_T, GOT_RIGHT_BRACE, GOT_DOT,
+		GOT_l, GOT_lf, END
+	      } state = START;
+	      while (state != END) {
+		c = in.get();
+		if (c == EOF)
+		  break;
+		switch (state) {
+		case START:
+		  if (c == 'T')
+		    state = GOT_T;
+		  else if (c == '.')
+		    state = GOT_DOT;
+		  else {
+		    input_entry += c;
+		    if (c != '\n')
+		      state = MIDDLE;
+		  }
+		  break;
+		case GOT_T:
+		  if (c == '}')
+		    state = GOT_RIGHT_BRACE;
+		  else {
+		    input_entry += 'T';
+		    input_entry += c;
+		    state = c == '\n' ? START : MIDDLE;
+		  }
+		  break;
+		case GOT_DOT:
+		  if (c == 'l')
+		    state = GOT_l;
+		  else {
+		    input_entry += '.';
+		    input_entry += c;
+		    state = c == '\n' ? START : MIDDLE;
+		  }
+		  break;
+		case GOT_l:
+		  if (c == 'f')
+		    state = GOT_lf;
+		  else {
+		    input_entry += ".l";
+		    input_entry += c;
+		    state = c == '\n' ? START : MIDDLE;
+		  }
+		  break;
+		case GOT_lf:
+		  if (c == ' ' || c == '\n' || compatible_flag) {
+		    string args;
+		    input_entry += ".lf";
+		    while (c != EOF) {
+		      args += c;
+		      if (c == '\n')
+			break;
+		      c = in.get();
+		    }
+		    args += '\0';
+		    interpret_lf_args(args.contents());
+		    // remove the '\0'
+		    args.set_length(args.length() - 1);
+		    input_entry += args;
+		    state = START;
+		  }
+		  else {
+		    input_entry += ".lf";
+		    input_entry += c;
+		    state = MIDDLE;
+		  }
+		  break;
+		case GOT_RIGHT_BRACE:
+		  if ((opt->flags & table::NOSPACES)) {
+		    while (c == ' ')
+		      c = in.get();
+		    if (c == EOF)
+		      break;
+		  }
+		  if (c == '\n' || c == tab_char)
+		    state = END;
+		  else {
+		    input_entry += 'T';
+		    input_entry += '}';
+		    input_entry += c;
+		    state = MIDDLE;
+		  }
+		  break;
+		case MIDDLE:
+		  if (c == '\n')
+		    state = START;
+		  input_entry += c;
+		  break;
+		case END:
+		default:
+		  assert(0 == "invalid `state` in switch");
+		}
+	      }
+	      if (c == EOF) {
+		error("end of data in middle of text block");
+		give_up = true;
+		break;
+	      }
+	    }
+	    if (col >= ncolumns) {
+	      if (!input_entry.empty()) {
+		if (input_entry.length() >= 2
+		    && input_entry[0] == '\\'
+		    && input_entry[1] == '"')
+		  seen_row_comment = true;
+		else if (!seen_row_comment) {
+		  if (c == '\n')
+		    in.unget(c);
+		  input_entry += '\0';
+		  error("excess table entry '%1' discarded",
+			input_entry.contents());
+		  if (c == '\n')
+		    (void)in.get();
+		}
+	      }
+	    }
+	    else
+	      tbl->add_entry(current_row, col, input_entry,
+			     &line_format[col], current_filename, ln);
+	    col++;
+	    if (c == '\n')
+	      break;
+	    input_entry = "";
+	  }
+	  else
+	    input_entry += c;
+	  c = in.get();
+	  if (c == EOF)
+	    break;
+	}
+	if (give_up)
+	  break;
+	input_entry = "";
+	for (; col < ncolumns; col++)
+	  tbl->add_entry(current_row, col, input_entry, &line_format[col],
+			 current_filename, current_lineno - 1);
+	tbl->add_vlines(current_row, f->vline[format_index]);
+	current_row++;
+	format_index++;
+      }
+      break;
+    case TROFF_INPUT_LINE:
+      {
+	string line;
+	int ln = current_lineno;
+	for (;;) {
+	  line += c;
+	  if (c == '\n')
+	    break;
+	  c = in.get();
+	  if (c == EOF) {
+	    break;
+	  }
+	}
+	tbl->add_text_line(current_row, line, current_filename, ln);
+	if (line.length() >= 4 
+	    && line[0] == '.' && line[1] == 'T' && line[2] == '&') {
+	  format *newf = process_format(in, opt, f);
+	  if (newf == 0)
+	    give_up = true;
+	  else
+	    f = newf;
+	}
+	if (line.length() >= 3
+	    && line[0] == '.' && line[1] == 'l' && line[2] == 'f') {
+	  line += '\0';
+	  interpret_lf_args(line.contents() + 3);
+	}
+      }
+      break;
+    case SINGLE_HLINE:
+      tbl->add_single_hline(current_row);
+      break;
+    case DOUBLE_HLINE:
+      tbl->add_double_hline(current_row);
+      break;
+    default:
+      assert(0 == "invalid `type` in switch");
+    }
+    if (give_up)
+      break;
+  }
+  if (!give_up && current_row == 0) {
+    error("no real data");
+    give_up = true;
+  }
+  if (give_up) {
+    delete tbl;
+    return 0;
+  }
+  // Do this here rather than at the beginning in case continued formats
+  // change it.
+  int i;
+  for (i = 0; i < ncolumns - 1; i++)
+    if (f->separation[i] >= 0)
+      tbl->set_column_separation(i, f->separation[i]);
+  for (i = 0; i < ncolumns; i++)
+    if (!f->width[i].empty())
+      tbl->set_minimum_width(i, f->width[i]);
+  for (i = 0; i < ncolumns; i++)
+    if (f->equal[i])
+      tbl->set_equal_column(i);
+  for (i = 0; i < ncolumns; i++)
+    if (f->expand[i])
+      tbl->set_expand_column(i);
+  return tbl;
+}
+
+void process_table(table_input &in)
+{
+  options *opt = 0 /* nullptr */;
+  format *fmt = 0 /* nullptr */;
+  table *tbl = 0 /* nullptr */;
+  if ((opt = process_options(in)) != 0 /* nullptr */
+      && (fmt = process_format(in, opt)) != 0 /* nullptr */
+      && (tbl = process_data(in, fmt, opt)) != 0 /* nullptr */) {
+    tbl->print();
+    delete tbl;
+  }
+  else {
+    error("giving up on this table region");
+    while (in.get() != EOF)
+      ;
+  }
+  delete opt;
+  delete fmt;
+  if (!in.ended())
+    error("premature end of file");
+}
+
+static void usage(FILE *stream)
+{
+  fprintf(stream,
+"usage: %s [-C] [file ...]\n"
+"usage: %s {-v | --version}\n"
+"usage: %s --help\n",
+	 program_name, program_name, program_name);
+}
+
+int main(int argc, char **argv)
+{
+  program_name = argv[0];
+  static char stderr_buf[BUFSIZ];
+  setbuf(stderr, stderr_buf);
+  int opt;
+  static const struct option long_options[] = {
+    { "help", no_argument, 0, CHAR_MAX + 1 },
+    { "version", no_argument, 0, 'v' },
+    { NULL, 0, 0, 0 }
+  };
+  while ((opt = getopt_long(argc, argv, "vC", long_options, NULL))
+         != EOF)
+    switch (opt) {
+    case 'C':
+      compatible_flag = 1;
+      break;
+    case 'v':
+      {
+	printf("GNU tbl (groff) version %s\n", Version_string);
+	exit(EXIT_SUCCESS);
+	break;
+      }
+    case CHAR_MAX + 1: // --help
+      usage(stdout);
+      exit(EXIT_SUCCESS);
+      break;
+    case '?':
+      usage(stderr);
+      exit(EXIT_FAILURE);
+      break;
+    default:
+      assert(0 == "unhandled getopt_long return value");
+    }
+  printf(".if !\\n(.g .ab GNU tbl requires groff extensions; aborting\n"
+	 ".do if !dTS .ds TS\n"
+	 ".do if !dT& .ds T&\n"
+	 ".do if !dTE .ds TE\n");
+  if (argc > optind) {
+    for (int i = optind; i < argc; i++) 
+      if (argv[i][0] == '-' && argv[i][1] == '\0') {
+	current_filename = "-";
+	current_lineno = 1;
+	printf(".lf 1 -\n");
+	process_input_file(stdin);
+      }
+      else {
+	errno = 0;
+	FILE *fp = fopen(argv[i], "r");
+	if (fp == 0) {
+	  current_filename = 0 /* nullptr */;
+	  fatal("can't open '%1': %2", argv[i], strerror(errno));
+	}
+	else {
+	  current_lineno = 1;
+	  string fn(argv[i]);
+	  fn += '\0';
+	  normalize_for_lf(fn);
+	  current_filename = fn.contents();
+	  printf(".lf 1 %s\n", current_filename);
+	  process_input_file(fp);
+	}
+      }
+  }
+  else {
+    current_filename = "-";
+    current_lineno = 1;
+    printf(".lf 1 -\n");
+    process_input_file(stdin);
+  }
+  if (ferror(stdout) || fflush(stdout) < 0)
+    fatal("output error");
+  return 0;
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/tbl/table.cpp b/src/preproc/tbl/table.cpp
new file mode 100644
index 0000000..c391c90
--- /dev/null
+++ b/src/preproc/tbl/table.cpp
@@ -0,0 +1,3161 @@
+/* Copyright (C) 1989-2023 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "table.h"
+
+#define BAR_HEIGHT ".25m"
+#define DOUBLE_LINE_SEP "2p"
+#define HALF_DOUBLE_LINE_SEP "1p"
+#define LINE_SEP "2p"
+#define BODY_DEPTH ".25m"
+
+const int DEFAULT_COLUMN_SEPARATION = 3;
+
+#define DELIMITER_CHAR "\\[tbl]"
+#define SEPARATION_FACTOR_REG PREFIX "sep"
+#define LEFTOVER_FACTOR_REG PREFIX "leftover"
+#define BOTTOM_REG PREFIX "bot"
+#define RESET_MACRO_NAME PREFIX "init"
+#define LINESIZE_REG PREFIX "lps"
+#define TOP_REG PREFIX "top"
+#define CURRENT_ROW_REG PREFIX "crow"
+#define LAST_PASSED_ROW_REG PREFIX "passed"
+#define TRANSPARENT_STRING_NAME PREFIX "trans"
+#define QUOTE_STRING_NAME PREFIX "quote"
+#define SECTION_DIVERSION_NAME PREFIX "section"
+#define SECTION_DIVERSION_FLAG_REG PREFIX "sflag"
+#define SAVED_VERTICAL_POS_REG PREFIX "vert"
+#define NEED_BOTTOM_RULE_REG PREFIX "brule"
+#define USE_KEEPS_REG PREFIX "usekeeps"
+#define KEEP_MACRO_NAME PREFIX "keep"
+#define RELEASE_MACRO_NAME PREFIX "release"
+#define SAVED_FONT_REG PREFIX "fnt"
+#define SAVED_SIZE_REG PREFIX "sz"
+#define SAVED_FILL_REG PREFIX "fll"
+#define SAVED_INDENT_REG PREFIX "ind"
+#define SAVED_CENTER_REG PREFIX "cent"
+#define SAVED_TABS_NAME PREFIX "tabs"
+#define SAVED_INTER_WORD_SPACE_SIZE PREFIX "ss"
+#define SAVED_INTER_SENTENCE_SPACE_SIZE PREFIX "sss"
+#define TABLE_DIVERSION_NAME PREFIX "table"
+#define TABLE_DIVERSION_FLAG_REG PREFIX "tflag"
+#define TABLE_KEEP_MACRO_NAME PREFIX "tkeep"
+#define TABLE_RELEASE_MACRO_NAME PREFIX "trelease"
+#define NEEDED_REG PREFIX "needed"
+#define REPEATED_MARK_MACRO PREFIX "rmk"
+#define REPEATED_VPT_MACRO PREFIX "rvpt"
+#define SUPPRESS_BOTTOM_REG PREFIX "supbot"
+#define SAVED_DN_REG PREFIX "dn"
+#define SAVED_HYPHENATION_MODE_REG PREFIX "hyphmode"
+#define SAVED_HYPHENATION_LANG_NAME PREFIX "hyphlang"
+#define SAVED_HYPHENATION_MAX_LINES_REG PREFIX "hyphmaxlines"
+#define SAVED_HYPHENATION_MARGIN_REG PREFIX "hyphmargin"
+#define SAVED_HYPHENATION_SPACE_REG PREFIX "hyphspace"
+#define SAVED_NUMBERING_LINENO PREFIX "linenumber"
+#define SAVED_NUMBERING_SUPPRESSION_COUNT PREFIX "linenumbersuppresscnt"
+#define STARTING_PAGE_REG PREFIX "starting-page"
+#define IS_BOXED_REG PREFIX "is-boxed"
+#define PREVIOUS_PAGE_REG PREFIX "previous-page"
+
+// this must be one character
+#define COMPATIBLE_REG PREFIX "c"
+
+// for use with `ig` requests embedded inside macro definitions
+#define NOP_NAME PREFIX "nop"
+
+#define AVAILABLE_WIDTH_REG PREFIX "available-width"
+#define EXPAND_REG PREFIX "expansion-amount"
+
+#define LEADER_REG PREFIX LEADER
+
+#define BLOCK_WIDTH_PREFIX PREFIX "tbw"
+#define BLOCK_DIVERSION_PREFIX PREFIX "tbd"
+#define BLOCK_HEIGHT_PREFIX PREFIX "tbh"
+#define SPAN_WIDTH_PREFIX PREFIX "w"
+#define SPAN_LEFT_NUMERIC_WIDTH_PREFIX PREFIX "lnw"
+#define SPAN_RIGHT_NUMERIC_WIDTH_PREFIX PREFIX "rnw"
+#define SPAN_ALPHABETIC_WIDTH_PREFIX PREFIX "aw"
+#define COLUMN_SEPARATION_PREFIX PREFIX "cs"
+#define ROW_START_PREFIX PREFIX "rs"
+#define COLUMN_START_PREFIX PREFIX "cl"
+#define COLUMN_END_PREFIX PREFIX "ce"
+#define COLUMN_DIVIDE_PREFIX PREFIX "cd"
+#define ROW_TOP_PREFIX PREFIX "rt"
+
+string block_width_reg(int, int);
+string block_diversion_name(int, int);
+string block_height_reg(int, int);
+string span_width_reg(int, int);
+string span_left_numeric_width_reg(int, int);
+string span_right_numeric_width_reg(int, int);
+string span_alphabetic_width_reg(int, int);
+string column_separation_reg(int);
+string row_start_reg(int);
+string column_start_reg(int);
+string column_end_reg(int);
+string column_divide_reg(int);
+string row_top_reg(int);
+
+void set_inline_modifier(const entry_modifier *);
+void restore_inline_modifier(const entry_modifier *);
+void set_modifier(const entry_modifier *);
+int find_decimal_point(const char *, char, const char *);
+
+string an_empty_string;
+int location_force_filename = 0;
+
+void printfs(const char *,
+	     const string &arg1 = an_empty_string,
+	     const string &arg2 = an_empty_string,
+	     const string &arg3 = an_empty_string,
+	     const string &arg4 = an_empty_string,
+	     const string &arg5 = an_empty_string);
+
+void prints(const string &);
+
+inline void prints(char c)
+{
+  putchar(c);
+}
+
+inline void prints(const char *s)
+{
+  fputs(s, stdout);
+}
+
+void prints(const string &s)
+{
+  if (!s.empty())
+    fwrite(s.contents(), 1, s.length(), stdout);
+}
+
+struct horizontal_span {
+  horizontal_span *next;
+  int start_col;
+  int end_col;
+  horizontal_span(int, int, horizontal_span *);
+};
+
+class single_line_entry;
+class double_line_entry;
+class simple_entry;
+
+class table_entry {
+friend class table;
+  table_entry *next;
+  int input_lineno;
+  const char *input_filename;
+protected:
+  int start_row;
+  int end_row;
+  int start_col;
+  int end_col;
+  const table *parent;
+  const entry_modifier *mod;
+public:
+  void set_location();
+  table_entry(const table *, const entry_modifier *);
+  virtual ~table_entry();
+  virtual int divert(int, const string *, int *, int);
+  virtual void do_width();
+  virtual void do_depth();
+  virtual void print() = 0;
+  virtual void position_vertically() = 0;
+  virtual single_line_entry *to_single_line_entry();
+  virtual double_line_entry *to_double_line_entry();
+  virtual simple_entry *to_simple_entry();
+  virtual int line_type();
+  virtual void note_double_vrule_on_right(int);
+  virtual void note_double_vrule_on_left(int);
+};
+
+class simple_entry : public table_entry {
+public:
+  simple_entry(const table *, const entry_modifier *);
+  void print();
+  void position_vertically();
+  simple_entry *to_simple_entry();
+  virtual void add_tab();
+  virtual void simple_print(int);
+};
+
+class empty_entry : public simple_entry {
+public:
+  empty_entry(const table *, const entry_modifier *);
+  int line_type();
+};
+
+class text_entry : public simple_entry {
+protected:
+  char *contents;
+  void print_contents();
+public:
+  text_entry(const table *, const entry_modifier *, char *);
+  ~text_entry();
+};
+
+void text_entry::print_contents()
+{
+  set_inline_modifier(mod);
+  prints(contents);
+  restore_inline_modifier(mod);
+}
+
+class repeated_char_entry : public text_entry {
+public:
+  repeated_char_entry(const table *, const entry_modifier *, char *);
+  void simple_print(int);
+};
+
+class simple_text_entry : public text_entry {
+public:
+  simple_text_entry(const table *, const entry_modifier *, char *);
+  void do_width();
+};
+
+class left_text_entry : public simple_text_entry {
+public:
+  left_text_entry(const table *, const entry_modifier *, char *);
+  void simple_print(int);
+  void add_tab();
+};
+
+class right_text_entry : public simple_text_entry {
+public:
+  right_text_entry(const table *, const entry_modifier *, char *);
+  void simple_print(int);
+  void add_tab();
+};
+
+class center_text_entry : public simple_text_entry {
+public:
+  center_text_entry(const table *, const entry_modifier *, char *);
+  void simple_print(int);
+  void add_tab();
+};
+
+class numeric_text_entry : public text_entry {
+  int dot_pos;
+public:
+  numeric_text_entry(const table *, const entry_modifier *, char *, int);
+  void do_width();
+  void simple_print(int);
+};
+
+class alphabetic_text_entry : public text_entry {
+public:
+  alphabetic_text_entry(const table *, const entry_modifier *, char *);
+  void do_width();
+  void simple_print(int);
+  void add_tab();
+};
+
+class line_entry : public simple_entry {
+protected:
+  char double_vrule_on_right;
+  char double_vrule_on_left;
+public:
+  line_entry(const table *, const entry_modifier *);
+  void note_double_vrule_on_right(int);
+  void note_double_vrule_on_left(int);
+  void simple_print(int) = 0;
+};
+
+class single_line_entry : public line_entry {
+public:
+  single_line_entry(const table *, const entry_modifier *);
+  void simple_print(int);
+  single_line_entry *to_single_line_entry();
+  int line_type();
+};
+
+class double_line_entry : public line_entry {
+public:
+  double_line_entry(const table *, const entry_modifier *);
+  void simple_print(int);
+  double_line_entry *to_double_line_entry();
+  int line_type();
+};
+
+class short_line_entry : public simple_entry {
+public:
+  short_line_entry(const table *, const entry_modifier *);
+  void simple_print(int);
+  int line_type();
+};
+
+class short_double_line_entry : public simple_entry {
+public:
+  short_double_line_entry(const table *, const entry_modifier *);
+  void simple_print(int);
+  int line_type();
+};
+
+class block_entry : public table_entry {
+  char *contents;
+protected:
+  void do_divert(int, int, const string *, int *, int);
+public:
+  block_entry(const table *, const entry_modifier *, char *);
+  ~block_entry();
+  int divert(int, const string *, int *, int);
+  void do_depth();
+  void position_vertically();
+  void print() = 0;
+};
+
+class left_block_entry : public block_entry {
+public:
+  left_block_entry(const table *, const entry_modifier *, char *);
+  void print();
+};
+
+class right_block_entry : public block_entry {
+public:
+  right_block_entry(const table *, const entry_modifier *, char *);
+  void print();
+};
+
+class center_block_entry : public block_entry {
+public:
+  center_block_entry(const table *, const entry_modifier *, char *);
+  void print();
+};
+
+class alphabetic_block_entry : public block_entry {
+public:
+  alphabetic_block_entry(const table *, const entry_modifier *, char *);
+  void print();
+  int divert(int, const string *, int *, int);
+};
+
+table_entry::table_entry(const table *p, const entry_modifier *m)
+: next(0), input_lineno(-1), input_filename(0),
+  start_row(-1), end_row(-1), start_col(-1), end_col(-1), parent(p), mod(m)
+{
+}
+
+table_entry::~table_entry()
+{
+}
+
+int table_entry::divert(int, const string *, int *, int)
+{
+  return 0;
+}
+
+void table_entry::do_width()
+{
+}
+
+single_line_entry *table_entry::to_single_line_entry()
+{
+  return 0;
+}
+
+double_line_entry *table_entry::to_double_line_entry()
+{
+  return 0;
+}
+
+simple_entry *table_entry::to_simple_entry()
+{
+  return 0;
+}
+
+void table_entry::do_depth()
+{
+}
+
+void table_entry::set_location()
+{
+  set_troff_location(input_filename, input_lineno);
+}
+
+int table_entry::line_type()
+{
+  return -1;
+}
+
+void table_entry::note_double_vrule_on_right(int)
+{
+}
+
+void table_entry::note_double_vrule_on_left(int)
+{
+}
+
+simple_entry::simple_entry(const table *p, const entry_modifier *m)
+: table_entry(p, m)
+{
+}
+
+void simple_entry::add_tab()
+{
+  // do nothing
+}
+
+void simple_entry::simple_print(int)
+{
+  // do nothing
+}
+
+void simple_entry::position_vertically()
+{
+  if (start_row != end_row)
+    switch (mod->vertical_alignment) {
+    case entry_modifier::TOP:
+      printfs(".sp |\\n[%1]u\n", row_start_reg(start_row));
+      break;
+    case entry_modifier::CENTER:
+      // Perform the motion in two stages so that the center is rounded
+      // vertically upwards even if net vertical motion is upwards.
+      printfs(".sp |\\n[%1]u\n", row_start_reg(start_row));
+      printfs(".sp \\n[" BOTTOM_REG "]u-\\n[%1]u-1v/2u\n",
+	      row_start_reg(start_row));
+      break;
+    case entry_modifier::BOTTOM:
+      printfs(".sp |\\n[%1]u+\\n[" BOTTOM_REG "]u-\\n[%1]u-1v\n",
+	      row_start_reg(start_row));
+      break;
+    default:
+      assert(0 == "simple entry vertical position modifier not TOP,"
+		  " CENTER, or BOTTOM");
+    }
+}
+
+void simple_entry::print()
+{
+  prints(".ta");
+  add_tab();
+  prints('\n');
+  set_location();
+  prints("\\&");
+  simple_print(0);
+  prints('\n');
+}
+
+simple_entry *simple_entry::to_simple_entry()
+{
+  return this;
+}
+
+empty_entry::empty_entry(const table *p, const entry_modifier *m)
+: simple_entry(p, m)
+{
+}
+
+int empty_entry::line_type()
+{
+  return 0;
+}
+
+text_entry::text_entry(const table *p, const entry_modifier *m, char *s)
+: simple_entry(p, m), contents(s)
+{
+}
+
+text_entry::~text_entry()
+{
+  free(contents);
+}
+
+repeated_char_entry::repeated_char_entry(const table *p,
+					 const entry_modifier *m, char *s)
+: text_entry(p, m, s)
+{
+}
+
+void repeated_char_entry::simple_print(int)
+{
+  printfs("\\h'|\\n[%1]u'", column_start_reg(start_col));
+  set_inline_modifier(mod);
+  printfs("\\l" DELIMITER_CHAR "\\n[%1]u\\&",
+	  span_width_reg(start_col, end_col));
+  prints(contents);
+  prints(DELIMITER_CHAR);
+  restore_inline_modifier(mod);
+}
+
+simple_text_entry::simple_text_entry(const table *p,
+				     const entry_modifier *m, char *s)
+: text_entry(p, m, s)
+{
+}
+
+void simple_text_entry::do_width()
+{
+  set_location();
+  printfs(".nr %1 \\n[%1]>?\\w" DELIMITER_CHAR,
+	  span_width_reg(start_col, end_col));
+  print_contents();
+  prints(DELIMITER_CHAR "\n");
+}
+
+left_text_entry::left_text_entry(const table *p,
+				 const entry_modifier *m, char *s)
+: simple_text_entry(p, m, s)
+{
+}
+
+void left_text_entry::simple_print(int)
+{
+  printfs("\\h'|\\n[%1]u'", column_start_reg(start_col));
+  print_contents();
+}
+
+// The only point of this is to make '\a' "work" as in Unix tbl.  Grrr.
+
+void left_text_entry::add_tab()
+{
+  printfs(" \\n[%1]u", column_end_reg(end_col));
+}
+
+right_text_entry::right_text_entry(const table *p,
+				   const entry_modifier *m, char *s)
+: simple_text_entry(p, m, s)
+{
+}
+
+void right_text_entry::simple_print(int)
+{
+  printfs("\\h'|\\n[%1]u'", column_start_reg(start_col));
+  prints("\002\003");
+  print_contents();
+  prints("\002");
+}
+
+void right_text_entry::add_tab()
+{
+  printfs(" \\n[%1]u", column_end_reg(end_col));
+}
+
+center_text_entry::center_text_entry(const table *p,
+				     const entry_modifier *m, char *s)
+: simple_text_entry(p, m, s)
+{
+}
+
+void center_text_entry::simple_print(int)
+{
+  printfs("\\h'|\\n[%1]u'", column_start_reg(start_col));
+  prints("\002\003");
+  print_contents();
+  prints("\003\002");
+}
+
+void center_text_entry::add_tab()
+{
+  printfs(" \\n[%1]u", column_end_reg(end_col));
+}
+
+numeric_text_entry::numeric_text_entry(const table *p,
+				       const entry_modifier *m,
+				       char *s, int pos)
+: text_entry(p, m, s), dot_pos(pos)
+{
+}
+
+void numeric_text_entry::do_width()
+{
+  if (dot_pos != 0) {
+    set_location();
+    printfs(".nr %1 0\\w" DELIMITER_CHAR,
+	    block_width_reg(start_row, start_col));
+    set_inline_modifier(mod);
+    for (int i = 0; i < dot_pos; i++)
+      prints(contents[i]);
+    restore_inline_modifier(mod);
+    prints(DELIMITER_CHAR "\n");
+    printfs(".nr %1 \\n[%1]>?\\n[%2]\n",
+	    span_left_numeric_width_reg(start_col, end_col),
+	    block_width_reg(start_row, start_col));
+  }
+  else
+    printfs(".nr %1 0\n", block_width_reg(start_row, start_col));
+  if (contents[dot_pos] != '\0') {
+    set_location();
+    printfs(".nr %1 \\n[%1]>?\\w" DELIMITER_CHAR,
+	    span_right_numeric_width_reg(start_col, end_col));
+    set_inline_modifier(mod);
+    prints(contents + dot_pos);
+    restore_inline_modifier(mod);
+    prints(DELIMITER_CHAR "\n");
+  }
+}
+
+void numeric_text_entry::simple_print(int)
+{
+  printfs("\\h'|(\\n[%1]u-\\n[%2]u-\\n[%3]u/2u+\\n[%2]u+\\n[%4]u-\\n[%5]u)'",
+	  span_width_reg(start_col, end_col),
+	  span_left_numeric_width_reg(start_col, end_col),
+	  span_right_numeric_width_reg(start_col, end_col),
+	  column_start_reg(start_col),
+	  block_width_reg(start_row, start_col));
+  print_contents();
+}
+
+alphabetic_text_entry::alphabetic_text_entry(const table *p,
+					     const entry_modifier *m,
+					     char *s)
+: text_entry(p, m, s)
+{
+}
+
+void alphabetic_text_entry::do_width()
+{
+  set_location();
+  printfs(".nr %1 \\n[%1]>?\\w" DELIMITER_CHAR,
+	  span_alphabetic_width_reg(start_col, end_col));
+  print_contents();
+  prints(DELIMITER_CHAR "\n");
+}
+
+void alphabetic_text_entry::simple_print(int)
+{
+  printfs("\\h'|\\n[%1]u'", column_start_reg(start_col));
+  printfs("\\h'\\n[%1]u-\\n[%2]u/2u'",
+	  span_width_reg(start_col, end_col),
+	  span_alphabetic_width_reg(start_col, end_col));
+  print_contents();
+}
+
+// The only point of this is to make '\a' "work" as in Unix tbl.  Grrr.
+
+void alphabetic_text_entry::add_tab()
+{
+  printfs(" \\n[%1]u", column_end_reg(end_col));
+}
+
+block_entry::block_entry(const table *p, const entry_modifier *m, char *s)
+: table_entry(p, m), contents(s)
+{
+}
+
+block_entry::~block_entry()
+{
+  delete[] contents;
+}
+
+void block_entry::position_vertically()
+{
+  if (start_row != end_row)
+    switch(mod->vertical_alignment) {
+    case entry_modifier::TOP:
+      printfs(".sp |\\n[%1]u\n", row_start_reg(start_row));
+      break;
+    case entry_modifier::CENTER:
+      // Perform the motion in two stages so that the center is rounded
+      // vertically upwards even if net vertical motion is upwards.
+      printfs(".sp |\\n[%1]u\n", row_start_reg(start_row));
+      printfs(".sp \\n[" BOTTOM_REG "]u-\\n[%1]u-\\n[%2]u/2u\n",
+	      row_start_reg(start_row),
+	      block_height_reg(start_row, start_col));
+      break;
+    case entry_modifier::BOTTOM:
+      printfs(".sp |\\n[%1]u+\\n[" BOTTOM_REG "]u-\\n[%1]u-\\n[%2]u\n",
+	      row_start_reg(start_row),
+	      block_height_reg(start_row, start_col));
+      break;
+    default:
+      assert(0 == "block entry vertical position modifier not TOP,"
+		  " CENTER, or BOTTOM");
+    }
+  if (mod->stagger)
+    prints(".sp -.5v\n");
+}
+
+int block_entry::divert(int ncols, const string *mw, int *sep, int do_expand)
+{
+  do_divert(0, ncols, mw, sep, do_expand);
+  return 1;
+}
+
+void block_entry::do_divert(int alphabetic, int ncols, const string *mw,
+			    int *sep, int do_expand)
+{
+  int i;
+  for (i = start_col; i <= end_col; i++)
+    if (parent->expand[i])
+      break;
+  if (i > end_col) {
+    if (do_expand)
+      return;
+  }
+  else {
+    if (!do_expand)
+      return;
+  }
+  printfs(".di %1\n", block_diversion_name(start_row, start_col));
+  prints(".if \\n[" SAVED_FILL_REG "] .fi\n"
+	 ".in 0\n");
+  prints(".ll ");
+  for (i = start_col; i <= end_col; i++)
+    if (mw[i].empty() && !parent->expand[i])
+      break;
+  if (i > end_col) {
+    // Every column spanned by this entry has a minimum width.
+    for (int j = start_col; j <= end_col; j++) {
+      if (j > start_col) {
+	if (sep)
+	  printfs("+%1n", as_string(sep[j - 1]));
+	prints('+');
+      }
+      if (parent->expand[j])
+	prints("\\n[" EXPAND_REG "]u");
+      else
+	printfs("(n;%1)", mw[j]);
+    }
+    printfs(">?\\n[%1]u", span_width_reg(start_col, end_col));
+  }
+  else
+    // Assign each column with a block entry 1/(n+1) of the line
+    // width, where n is the column count.
+    printfs("(u;\\n[%1]>?(\\n[.l]*%2/%3))",
+	    span_width_reg(start_col, end_col),
+	    as_string(end_col - start_col + 1),
+	    as_string(ncols + 1));
+  if (alphabetic)
+    prints("-2n");
+  prints("\n");
+  prints(".ss \\n[" SAVED_INTER_WORD_SPACE_SIZE "]"
+      " \\n[" SAVED_INTER_SENTENCE_SPACE_SIZE "]\n");
+  prints(".cp \\n(" COMPATIBLE_REG "\n");
+  set_modifier(mod);
+  set_location();
+  prints(contents);
+  prints(".br\n.di\n.cp 0\n");
+  if (!mod->zero_width) {
+    if (alphabetic) {
+      printfs(".nr %1 \\n[%1]>?(\\n[dl]+2n)\n",
+	      span_width_reg(start_col, end_col));
+      printfs(".nr %1 \\n[%1]>?\\n[dl]\n",
+	      span_alphabetic_width_reg(start_col, end_col));
+    }
+    else
+      printfs(".nr %1 \\n[%1]>?\\n[dl]\n",
+	      span_width_reg(start_col, end_col));
+  }
+  printfs(".nr %1 \\n[dn]\n", block_height_reg(start_row, start_col));
+  printfs(".nr %1 \\n[dl]\n", block_width_reg(start_row, start_col));
+  prints("." RESET_MACRO_NAME "\n"
+	 ".in \\n[" SAVED_INDENT_REG "]u\n"
+	 ".nf\n");
+  // the block might have contained .lf commands
+  location_force_filename = 1;
+}
+
+void block_entry::do_depth()
+{
+  printfs(".nr " BOTTOM_REG " \\n[" BOTTOM_REG "]>?(\\n[%1]+\\n[%2])\n",
+	  row_start_reg(start_row),
+	  block_height_reg(start_row, start_col));
+}
+
+left_block_entry::left_block_entry(const table *p,
+				   const entry_modifier *m, char *s)
+: block_entry(p, m, s)
+{
+}
+
+void left_block_entry::print()
+{
+  printfs(".in +\\n[%1]u\n", column_start_reg(start_col));
+  printfs(".%1\n", block_diversion_name(start_row, start_col));
+  prints(".in\n");
+}
+
+right_block_entry::right_block_entry(const table *p,
+				     const entry_modifier *m, char *s)
+: block_entry(p, m, s)
+{
+}
+
+void right_block_entry::print()
+{
+  printfs(".in +\\n[%1]u+\\n[%2]u-\\n[%3]u\n",
+	  column_start_reg(start_col),
+	  span_width_reg(start_col, end_col),
+	  block_width_reg(start_row, start_col));
+  printfs(".%1\n", block_diversion_name(start_row, start_col));
+  prints(".in\n");
+}
+
+center_block_entry::center_block_entry(const table *p,
+				       const entry_modifier *m, char *s)
+: block_entry(p, m, s)
+{
+}
+
+void center_block_entry::print()
+{
+  printfs(".in +\\n[%1]u+(\\n[%2]u-\\n[%3]u/2u)\n",
+	  column_start_reg(start_col),
+	  span_width_reg(start_col, end_col),
+	  block_width_reg(start_row, start_col));
+  printfs(".%1\n", block_diversion_name(start_row, start_col));
+  prints(".in\n");
+}
+
+alphabetic_block_entry::alphabetic_block_entry(const table *p,
+					       const entry_modifier *m,
+					       char *s)
+: block_entry(p, m, s)
+{
+}
+
+int alphabetic_block_entry::divert(int ncols, const string *mw, int *sep,
+				   int do_expand)
+{
+  do_divert(1, ncols, mw, sep, do_expand);
+  return 1;
+}
+
+void alphabetic_block_entry::print()
+{
+  printfs(".in +\\n[%1]u+(\\n[%2]u-\\n[%3]u/2u)\n",
+	  column_start_reg(start_col),
+	  span_width_reg(start_col, end_col),
+	  span_alphabetic_width_reg(start_col, end_col));
+  printfs(".%1\n", block_diversion_name(start_row, start_col));
+  prints(".in\n");
+}
+
+line_entry::line_entry(const table *p, const entry_modifier *m)
+: simple_entry(p, m), double_vrule_on_right(0), double_vrule_on_left(0)
+{
+}
+
+void line_entry::note_double_vrule_on_right(int is_corner)
+{
+  double_vrule_on_right = is_corner ? 1 : 2;
+}
+
+void line_entry::note_double_vrule_on_left(int is_corner)
+{
+  double_vrule_on_left = is_corner ? 1 : 2;
+}
+
+single_line_entry::single_line_entry(const table *p, const entry_modifier *m)
+: line_entry(p, m)
+{
+}
+
+int single_line_entry::line_type()
+{
+  return 1;
+}
+
+void single_line_entry::simple_print(int dont_move)
+{
+  printfs("\\h'|\\n[%1]u",
+	  column_divide_reg(start_col));
+  if (double_vrule_on_left) {
+    prints(double_vrule_on_left == 1 ? "-" : "+");
+    prints(HALF_DOUBLE_LINE_SEP);
+  }
+  prints("'");
+  if (!dont_move)
+    prints("\\v'-" BAR_HEIGHT "'");
+  printfs("\\s[\\n[" LINESIZE_REG "]]" "\\D'l |\\n[%1]u",
+	  column_divide_reg(end_col+1));
+  if (double_vrule_on_right) {
+    prints(double_vrule_on_left == 1 ? "+" : "-");
+    prints(HALF_DOUBLE_LINE_SEP);
+  }
+  prints("0'\\s0");
+  if (!dont_move)
+    prints("\\v'" BAR_HEIGHT "'");
+}
+
+single_line_entry *single_line_entry::to_single_line_entry()
+{
+  return this;
+}
+
+double_line_entry::double_line_entry(const table *p,
+				     const entry_modifier *m)
+: line_entry(p, m)
+{
+}
+
+int double_line_entry::line_type()
+{
+  return 2;
+}
+
+void double_line_entry::simple_print(int dont_move)
+{
+  if (!dont_move)
+    prints("\\v'-" BAR_HEIGHT "'");
+  printfs("\\h'|\\n[%1]u",
+	  column_divide_reg(start_col));
+  if (double_vrule_on_left) {
+    prints(double_vrule_on_left == 1 ? "-" : "+");
+    prints(HALF_DOUBLE_LINE_SEP);
+  }
+  prints("'");
+  printfs("\\v'-" HALF_DOUBLE_LINE_SEP "'"
+	  "\\s[\\n[" LINESIZE_REG "]]"
+	  "\\D'l |\\n[%1]u",
+	  column_divide_reg(end_col+1));
+  if (double_vrule_on_right)
+    prints("-" HALF_DOUBLE_LINE_SEP);
+  prints(" 0'");
+  printfs("\\v'" DOUBLE_LINE_SEP "'"
+	  "\\D'l |\\n[%1]u",
+	  column_divide_reg(start_col));
+  if (double_vrule_on_right) {
+    prints(double_vrule_on_left == 1 ? "+" : "-");
+    prints(HALF_DOUBLE_LINE_SEP);
+  }
+  prints(" 0'");
+  prints("\\s0"
+	 "\\v'-" HALF_DOUBLE_LINE_SEP "'");
+  if (!dont_move)
+    prints("\\v'" BAR_HEIGHT "'");
+}
+
+double_line_entry *double_line_entry::to_double_line_entry()
+{
+  return this;
+}
+
+short_line_entry::short_line_entry(const table *p, const entry_modifier *m)
+: simple_entry(p, m)
+{
+}
+
+int short_line_entry::line_type()
+{
+  return 1;
+}
+
+void short_line_entry::simple_print(int dont_move)
+{
+  if (mod->stagger)
+    prints("\\v'-.5v'");
+  if (!dont_move)
+    prints("\\v'-" BAR_HEIGHT "'");
+  printfs("\\h'|\\n[%1]u'", column_start_reg(start_col));
+  printfs("\\s[\\n[" LINESIZE_REG "]]"
+	  "\\D'l \\n[%1]u 0'"
+	  "\\s0",
+	  span_width_reg(start_col, end_col));
+  if (!dont_move)
+    prints("\\v'" BAR_HEIGHT "'");
+  if (mod->stagger)
+    prints("\\v'.5v'");
+}
+
+short_double_line_entry::short_double_line_entry(const table *p,
+						 const entry_modifier *m)
+: simple_entry(p, m)
+{
+}
+
+int short_double_line_entry::line_type()
+{
+  return 2;
+}
+
+void short_double_line_entry::simple_print(int dont_move)
+{
+  if (mod->stagger)
+    prints("\\v'-.5v'");
+  if (!dont_move)
+    prints("\\v'-" BAR_HEIGHT "'");
+  printfs("\\h'|\\n[%2]u'"
+	  "\\v'-" HALF_DOUBLE_LINE_SEP "'"
+	  "\\s[\\n[" LINESIZE_REG "]]"
+	  "\\D'l \\n[%1]u 0'"
+	  "\\v'" DOUBLE_LINE_SEP "'"
+	  "\\D'l |\\n[%2]u 0'"
+	  "\\s0"
+	  "\\v'-" HALF_DOUBLE_LINE_SEP "'",
+	  span_width_reg(start_col, end_col),
+	  column_start_reg(start_col));
+  if (!dont_move)
+    prints("\\v'" BAR_HEIGHT "'");
+  if (mod->stagger)
+    prints("\\v'.5v'");
+}
+
+void set_modifier(const entry_modifier *m)
+{
+  if (!m->font.empty())
+    printfs(".ft %1\n", m->font);
+  if (m->point_size.val != 0) {
+    prints(".ps ");
+    if (m->point_size.inc > 0)
+      prints('+');
+    else if (m->point_size.inc < 0)
+      prints('-');
+    printfs("%1\n", as_string(m->point_size.val));
+  }
+  if (m->vertical_spacing.val != 0) {
+    prints(".vs ");
+    if (m->vertical_spacing.inc > 0)
+      prints('+');
+    else if (m->vertical_spacing.inc < 0)
+      prints('-');
+    printfs("%1\n", as_string(m->vertical_spacing.val));
+  }
+  if (!m->macro.empty())
+    printfs(".%1\n", m->macro);
+}
+
+void set_inline_modifier(const entry_modifier *m)
+{
+  if (!m->font.empty())
+    printfs("\\f[%1]", m->font);
+  if (m->point_size.val != 0) {
+    prints("\\s[");
+    if (m->point_size.inc > 0)
+      prints('+');
+    else if (m->point_size.inc < 0)
+      prints('-');
+    printfs("%1]", as_string(m->point_size.val));
+  }
+  if (m->stagger)
+    prints("\\v'-.5v'");
+}
+
+void restore_inline_modifier(const entry_modifier *m)
+{
+  if (!m->font.empty())
+    prints("\\f[\\n[" SAVED_FONT_REG "]]");
+  if (m->point_size.val != 0)
+    prints("\\s[\\n[" SAVED_SIZE_REG "]]");
+  if (m->stagger)
+    prints("\\v'.5v'");
+}
+
+struct stuff {
+  stuff *next;
+  int row;			// occurs before row 'row'
+  char printed;			// has it been printed?
+
+  stuff(int);
+  virtual void print(table *) = 0;
+  virtual ~stuff();
+  virtual int is_single_line() { return 0; };
+  virtual int is_double_line() { return 0; };
+};
+
+stuff::stuff(int r) : next(0), row(r), printed(0)
+{
+}
+
+stuff::~stuff()
+{
+}
+
+struct text_stuff : public stuff {
+  string contents;
+  const char *filename;
+  int lineno;
+
+  text_stuff(const string &, int, const char *, int);
+  ~text_stuff();
+  void print(table *);
+};
+
+text_stuff::text_stuff(const string &s, int r, const char *fn, int ln)
+: stuff(r), contents(s), filename(fn), lineno(ln)
+{
+}
+
+text_stuff::~text_stuff()
+{
+}
+
+void text_stuff::print(table *)
+{
+  printed = 1;
+  prints(".cp \\n(" COMPATIBLE_REG "\n");
+  set_troff_location(filename, lineno);
+  prints(contents);
+  prints(".cp 0\n");
+  location_force_filename = 1;	// it might have been a .lf command
+}
+
+struct single_hline_stuff : public stuff {
+  single_hline_stuff(int);
+  void print(table *);
+  int is_single_line();
+};
+
+single_hline_stuff::single_hline_stuff(int r) : stuff(r)
+{
+}
+
+void single_hline_stuff::print(table *tbl)
+{
+  printed = 1;
+  tbl->print_single_hline(row);
+}
+
+int single_hline_stuff::is_single_line()
+{
+  return 1;
+}
+
+struct double_hline_stuff : stuff {
+  double_hline_stuff(int);
+  void print(table *);
+  int is_double_line();
+};
+
+double_hline_stuff::double_hline_stuff(int r) : stuff(r)
+{
+}
+
+void double_hline_stuff::print(table *tbl)
+{
+  printed = 1;
+  tbl->print_double_hline(row);
+}
+
+int double_hline_stuff::is_double_line()
+{
+  return 1;
+}
+
+struct vertical_rule {
+  vertical_rule *next;
+  int start_row;
+  int end_row;
+  int col;
+  char is_double;
+  string top_adjust;
+  string bot_adjust;
+
+  vertical_rule(int, int, int, int, vertical_rule *);
+  ~vertical_rule();
+  void contribute_to_bottom_macro(table *);
+  void print();
+};
+
+vertical_rule::vertical_rule(int sr, int er, int c, int dbl,
+			     vertical_rule *p)
+: next(p), start_row(sr), end_row(er), col(c), is_double(dbl)
+{
+}
+
+vertical_rule::~vertical_rule()
+{
+}
+
+void vertical_rule::contribute_to_bottom_macro(table *tbl)
+{
+  printfs(".if \\n[" CURRENT_ROW_REG "]>=%1",
+	  as_string(start_row));
+  if (end_row != tbl->get_nrows() - 1)
+    printfs("&(\\n[" CURRENT_ROW_REG "]<%1)",
+	    as_string(end_row));
+  prints(" \\{\\\n");
+  printfs(".  if %1<=\\n[" LAST_PASSED_ROW_REG "] .nr %2 \\n[#T]\n",
+	  as_string(start_row),
+	  row_top_reg(start_row));
+  const char *offset_table[3];
+  if (is_double) {
+    offset_table[0] = "-" HALF_DOUBLE_LINE_SEP;
+    offset_table[1] = "+" HALF_DOUBLE_LINE_SEP;
+    offset_table[2] = 0;
+  }
+  else {
+    offset_table[0] = "";
+    offset_table[1] = 0;
+  }
+  for (const char **offsetp = offset_table; *offsetp; offsetp++) {
+    prints(".  sp -1\n"
+	   "\\v'" BODY_DEPTH);
+    if (!bot_adjust.empty())
+      printfs("+%1", bot_adjust);
+    prints("'");
+    printfs("\\h'\\n[%1]u%3'\\s[\\n[" LINESIZE_REG "]]\\D'l 0 |\\n[%2]u-1v",
+	    column_divide_reg(col),
+	    row_top_reg(start_row),
+	    *offsetp);
+    if (!bot_adjust.empty())
+      printfs("-(%1)", bot_adjust);
+    // don't perform the top adjustment if the top is actually #T
+    if (!top_adjust.empty())
+      printfs("+((%1)*(%2>\\n[" LAST_PASSED_ROW_REG "]))",
+	      top_adjust,
+	      as_string(start_row));
+    prints("'\\s0\n");
+  }
+  prints(".\\}\n");
+}
+
+void vertical_rule::print()
+{
+  printfs("\\*[" TRANSPARENT_STRING_NAME "]"
+	  ".if %1<=\\*[" QUOTE_STRING_NAME "]\\n[" LAST_PASSED_ROW_REG "] "
+	  ".nr %2 \\*[" QUOTE_STRING_NAME "]\\n[#T]\n",
+	  as_string(start_row),
+	  row_top_reg(start_row));
+  const char *offset_table[3];
+  if (is_double) {
+    offset_table[0] = "-" HALF_DOUBLE_LINE_SEP;
+    offset_table[1] = "+" HALF_DOUBLE_LINE_SEP;
+    offset_table[2] = 0;
+  }
+  else {
+    offset_table[0] = "";
+    offset_table[1] = 0;
+  }
+  for (const char **offsetp = offset_table; *offsetp; offsetp++) {
+    prints("\\*[" TRANSPARENT_STRING_NAME "].sp -1\n"
+	   "\\*[" TRANSPARENT_STRING_NAME "]\\v'" BODY_DEPTH);
+    if (!bot_adjust.empty())
+      printfs("+%1", bot_adjust);
+    prints("'");
+    printfs("\\h'\\n[%1]u%3'"
+	    "\\s[\\n[" LINESIZE_REG "]]"
+	    "\\D'l 0 |\\*[" QUOTE_STRING_NAME "]\\n[%2]u-1v",
+	    column_divide_reg(col),
+	    row_top_reg(start_row),
+	    *offsetp);
+    if (!bot_adjust.empty())
+      printfs("-(%1)", bot_adjust);
+    // don't perform the top adjustment if the top is actually #T
+    if (!top_adjust.empty())
+      printfs("+((%1)*(%2>\\*[" QUOTE_STRING_NAME "]\\n["
+	      LAST_PASSED_ROW_REG "]))",
+	      top_adjust,
+	      as_string(start_row));
+    prints("'"
+	   "\\s0\n");
+  }
+}
+
+table::table(int nc, unsigned f, int ls, char dpc)
+: nrows(0), ncolumns(nc), linesize(ls), decimal_point_char(dpc),
+  vrule_list(0), stuff_list(0), span_list(0),
+  entry_list(0), entry_list_tailp(&entry_list), entry(0),
+  vline(0), row_is_all_lines(0), left_separation(0),
+  right_separation(0), total_separation(0), allocated_rows(0), flags(f)
+{
+  minimum_width = new string[ncolumns];
+  column_separation = ncolumns > 1 ? new int[ncolumns - 1] : 0;
+  equal = new char[ncolumns];
+  expand = new char[ncolumns];
+  int i;
+  for (i = 0; i < ncolumns; i++) {
+    equal[i] = 0;
+    expand[i] = 0;
+  }
+  for (i = 0; i < ncolumns - 1; i++)
+    column_separation[i] = DEFAULT_COLUMN_SEPARATION;
+  delim[0] = delim[1] = '\0';
+}
+
+table::~table()
+{
+  for (int i = 0; i < nrows; i++) {
+    delete[] entry[i];
+    delete[] vline[i];
+  }
+  delete[] entry;
+  delete[] vline;
+  while (entry_list) {
+    table_entry *tem = entry_list;
+    entry_list = entry_list->next;
+    delete tem;
+  }
+  delete[] minimum_width;
+  delete[] column_separation;
+  delete[] equal;
+  delete[] expand;
+  while (stuff_list) {
+    stuff *tem = stuff_list;
+    stuff_list = stuff_list->next;
+    delete tem;
+  }
+  while (vrule_list) {
+    vertical_rule *tem = vrule_list;
+    vrule_list = vrule_list->next;
+    delete tem;
+  }
+  delete[] row_is_all_lines;
+  while (span_list) {
+    horizontal_span *tem = span_list;
+    span_list = span_list->next;
+    delete tem;
+  }
+}
+
+void table::set_delim(char c1, char c2)
+{
+  delim[0] = c1;
+  delim[1] = c2;
+}
+
+void table::set_minimum_width(int c, const string &w)
+{
+  assert(c >= 0 && c < ncolumns);
+  minimum_width[c] = w;
+}
+
+void table::set_column_separation(int c, int n)
+{
+  assert(c >= 0 && c < ncolumns - 1);
+  column_separation[c] = n;
+}
+
+void table::set_equal_column(int c)
+{
+  assert(c >= 0 && c < ncolumns);
+  equal[c] = 1;
+}
+
+void table::set_expand_column(int c)
+{
+  assert(c >= 0 && c < ncolumns);
+  expand[c] = 1;
+}
+
+void table::add_stuff(stuff *p)
+{
+  stuff **pp;
+  for (pp = &stuff_list; *pp; pp = &(*pp)->next)
+    ;
+  *pp = p;
+}
+
+void table::add_text_line(int r, const string &s, const char *filename,
+			  int lineno)
+{
+  add_stuff(new text_stuff(s, r, filename, lineno));
+}
+
+void table::add_single_hline(int r)
+{
+  add_stuff(new single_hline_stuff(r));
+}
+
+void table::add_double_hline(int r)
+{
+  add_stuff(new double_hline_stuff(r));
+}
+
+void table::allocate(int r)
+{
+  if (r >= nrows) {
+    typedef table_entry **PPtable_entry; // work around g++ 1.36.1 bug
+    if (r >= allocated_rows) {
+      if (allocated_rows == 0) {
+	allocated_rows = 16;
+	if (allocated_rows <= r)
+	  allocated_rows = r + 1;
+	entry = new PPtable_entry[allocated_rows];
+	vline = new char*[allocated_rows];
+      }
+      else {
+	table_entry ***old_entry = entry;
+	int old_allocated_rows = allocated_rows;
+	allocated_rows *= 2;
+	if (allocated_rows <= r)
+	  allocated_rows = r + 1;
+	entry = new PPtable_entry[allocated_rows];
+	memcpy(entry, old_entry, sizeof(table_entry**)*old_allocated_rows);
+	delete[] old_entry;
+	char **old_vline = vline;
+	vline = new char*[allocated_rows];
+	memcpy(vline, old_vline, sizeof(char*)*old_allocated_rows);
+	delete[] old_vline;
+      }
+    }
+    assert(allocated_rows > r);
+    while (nrows <= r) {
+      entry[nrows] = new table_entry*[ncolumns];
+      int i;
+      for (i = 0; i < ncolumns; i++)
+	entry[nrows][i] = 0;
+      vline[nrows] = new char[ncolumns+1];
+      for (i = 0; i < ncolumns+1; i++)
+	vline[nrows][i] = 0;
+      nrows++;
+    }
+  }
+}
+
+void table::do_hspan(int r, int c)
+{
+  assert(r >= 0 && c >= 0 && r < nrows && c < ncolumns);
+  if (c == 0) {
+    error("first column cannot be horizontally spanned");
+    return;
+  }
+  table_entry *e = entry[r][c];
+  if (e) {
+    assert(e->start_row <= r && r <= e->end_row
+	   && e->start_col <= c && c <= e->end_col
+	   && e->end_row - e->start_row > 0
+	   && e->end_col - e->start_col > 0);
+    return;
+  }
+  e = entry[r][c-1];
+  // e can be 0 if we had an empty entry or an error
+  if (e == 0)
+    return;
+  if (e->start_row != r) {
+    /*
+      l l
+      ^ s */
+    error("impossible horizontal span at row %1, column %2", r + 1,
+	  c + 1);
+  }
+  else {
+    e->end_col = c;
+    entry[r][c] = e;
+  }
+}
+
+void table::do_vspan(int r, int c)
+{
+  assert(r >= 0 && c >= 0 && r < nrows && c < ncolumns);
+  if (0 == r) {
+    error("first row cannot be vertically spanned");
+    return;
+  }
+  table_entry *e = entry[r][c];
+  if (e) {
+    assert(e->start_row <= r);
+    assert(r <= e->end_row);
+    assert(e->start_col <= c);
+    assert(c <= e->end_col);
+    assert((e->end_row - e->start_row) > 0);
+    assert((e->end_col - e->start_col) > 0);
+    return;
+  }
+  e = entry[r-1][c];
+  // e can be a null pointer if we had an empty entry or an error
+  if (0 == e)
+    return;
+  if (e->start_col != c) {
+    /* l s
+       l ^ */
+    error("impossible vertical span at row %1, column %2", r + 1,
+	  c + 1);
+  }
+  else {
+    for (int i = c; i <= e->end_col; i++) {
+      assert(entry[r][i] == 0);
+      entry[r][i] = e;
+    }
+    e->end_row = r;
+  }
+}
+
+int find_decimal_point(const char *s, char decimal_point_char,
+		       const char *delim)
+{
+  if (s == 0 || *s == '\0')
+    return -1;
+  const char *p;
+  int in_delim = 0;		// is p within eqn delimiters?
+  // tbl recognises \& even within eqn delimiters; I don't
+  for (p = s; *p; p++)
+    if (in_delim) {
+      if (*p == delim[1])
+	in_delim = 0;
+    }
+    else if (*p == delim[0])
+      in_delim = 1;
+    else if (p[0] == '\\' && p[1] == '&')
+      return p - s;
+  int possible_pos = -1;
+  in_delim = 0;
+  for (p = s; *p; p++)
+    if (in_delim) {
+      if (*p == delim[1])
+	in_delim = 0;
+    }
+    else if (*p == delim[0])
+      in_delim = 1;
+    else if (p[0] == decimal_point_char && csdigit(p[1]))
+      possible_pos = p - s;
+  if (possible_pos >= 0)
+    return possible_pos;
+  in_delim = 0;
+  for (p = s; *p; p++)
+    if (in_delim) {
+      if (*p == delim[1])
+	in_delim = 0;
+    }
+    else if (*p == delim[0])
+      in_delim = 1;
+    else if (csdigit(*p))
+      possible_pos = p + 1 - s;
+  return possible_pos;
+}
+
+void table::add_entry(int r, int c, const string &str,
+		      const entry_format *f, const char *fn, int ln)
+{
+  allocate(r);
+  table_entry *e = 0;
+  char *s = str.extract();
+  if (str.search('\n') >= 0) {
+    bool was_changed = false;
+    for (int i = 0; s[i] != '\0'; i++)
+      if ((i > 0) && (s[(i - 1)] == '\\') && (s[i] == 'R')) {
+	s[i] = '&';
+	was_changed = true;
+      }
+    if (was_changed)
+      error_with_file_and_line(fn, ln, "repeating a glyph with '\\R'"
+			       " is not allowed in a text block");
+  }
+  if (str == "\\_") {
+    e = new short_line_entry(this, f);
+  }
+  else if (str == "\\=") {
+    e = new short_double_line_entry(this, f);
+  }
+  else if (str == "_") {
+    single_line_entry *lefte;
+    if (c > 0 && entry[r][c-1] != 0 &&
+	(lefte = entry[r][c-1]->to_single_line_entry()) != 0
+	&& lefte->start_row == r
+	&& lefte->mod->stagger == f->stagger) {
+      lefte->end_col = c;
+      entry[r][c] = lefte;
+    }
+    else
+      e = new single_line_entry(this, f);
+  }
+  else if (str == "=") {
+    double_line_entry *lefte;
+    if (c > 0 && entry[r][c-1] != 0 &&
+	(lefte = entry[r][c-1]->to_double_line_entry()) != 0
+	&& lefte->start_row == r
+	&& lefte->mod->stagger == f->stagger) {
+      lefte->end_col = c;
+      entry[r][c] = lefte;
+    }
+    else
+      e = new double_line_entry(this, f);
+  }
+  else if (str == "\\^") {
+    if (r == 0) {
+      error("first row cannot contain a vertical span entry '\\^'");
+      e = new empty_entry(this, f);
+    }
+    else
+      do_vspan(r, c);
+  }
+  else {
+    int is_block = str.search('\n') >= 0;
+    switch (f->type) {
+    case FORMAT_SPAN:
+      assert(str.empty());
+      do_hspan(r, c);
+      break;
+    case FORMAT_LEFT:
+      if (!str.empty()) {
+	if (is_block)
+	  e = new left_block_entry(this, f, s);
+	else
+	  e = new left_text_entry(this, f, s);
+      }
+      else
+	e = new empty_entry(this, f);
+      break;
+    case FORMAT_CENTER:
+      if (!str.empty()) {
+	if (is_block)
+	  e = new center_block_entry(this, f, s);
+	else
+	  e = new center_text_entry(this, f, s);
+      }
+      else
+	e = new empty_entry(this, f);
+      break;
+    case FORMAT_RIGHT:
+      if (!str.empty()) {
+	if (is_block)
+	  e = new right_block_entry(this, f, s);
+	else
+	  e = new right_text_entry(this, f, s);
+      }
+      else
+	e = new empty_entry(this, f);
+      break;
+    case FORMAT_NUMERIC:
+      if (!str.empty()) {
+	if (is_block) {
+	  error_with_file_and_line(fn, ln, "can't have numeric text block");
+	  e = new left_block_entry(this, f, s);
+	}
+	else {
+	  int pos = find_decimal_point(s, decimal_point_char, delim);
+	  if (pos < 0)
+	    e = new center_text_entry(this, f, s);
+	  else
+	    e = new numeric_text_entry(this, f, s, pos);
+	}
+      }
+      else
+	e = new empty_entry(this, f);
+      break;
+    case FORMAT_ALPHABETIC:
+      if (!str.empty()) {
+	if (is_block)
+	  e = new alphabetic_block_entry(this, f, s);
+	else
+	  e = new alphabetic_text_entry(this, f, s);
+      }
+      else
+	e = new empty_entry(this, f);
+      break;
+    case FORMAT_VSPAN:
+      do_vspan(r, c);
+      break;
+    case FORMAT_HLINE:
+      if ((str.length() != 0) && (str != "\\&"))
+	error_with_file_and_line(fn, ln,
+				 "ignoring non-empty data entry using"
+				 " '_' column classifier");
+      e = new single_line_entry(this, f);
+      break;
+    case FORMAT_DOUBLE_HLINE:
+      if ((str.length() != 0) && (str != "\\&"))
+	error_with_file_and_line(fn, ln,
+				 "ignoring non-empty data entry using"
+				 " '=' column classifier");
+      e = new double_line_entry(this, f);
+      break;
+    default:
+      assert(0 == "table column format not in FORMAT_{SPAN,LEFT,CENTER,"
+		  "RIGHT,NUMERIC,ALPHABETIC,VSPAN,HLINE,DOUBLE_HLINE}");
+    }
+  }
+  if (e) {
+    table_entry *preve = entry[r][c];
+    if (preve) {
+      /* c s
+         ^ l */
+      error_with_file_and_line(fn, ln, "row %1, column %2 already"
+				       " spanned",
+			       r + 1, c + 1);
+      delete e;
+    }
+    else {
+      e->input_lineno = ln;
+      e->input_filename = fn;
+      e->start_row = e->end_row = r;
+      e->start_col = e->end_col = c;
+      *entry_list_tailp = e;
+      entry_list_tailp = &e->next;
+      entry[r][c] = e;
+    }
+  }
+}
+
+// add vertical lines for row r
+
+void table::add_vlines(int r, const char *v)
+{
+  allocate(r);
+  bool lwarned = false;
+  bool twarned = false;
+  for (int i = 0; i < ncolumns+1; i++) {
+    assert(v[i] < 3);
+    if (v[i] && (flags & (BOX | ALLBOX | DOUBLEBOX)) && (i == 0)
+	&& (!lwarned)) {
+      error("ignoring vertical line at leading edge of boxed table");
+      lwarned = true;
+    }
+    else if (v[i] && (flags & (BOX | ALLBOX | DOUBLEBOX))
+	     && (i == ncolumns) && (!twarned)) {
+      error("ignoring vertical line at trailing edge of boxed table");
+      twarned = true;
+    }
+    else
+      vline[r][i] = v[i];
+  }
+}
+
+void table::check()
+{
+  table_entry *p = entry_list;
+  int i, j;
+  while (p) {
+    for (i = p->start_row; i <= p->end_row; i++)
+      for (j = p->start_col; j <= p->end_col; j++)
+	assert(entry[i][j] == p);
+    p = p->next;
+  }
+}
+
+void table::print()
+{
+  location_force_filename = 1;
+  check();
+  init_output();
+  determine_row_type();
+  compute_widths();
+  if (!(flags & CENTER))
+    prints(".if \\n[" SAVED_CENTER_REG "] \\{\\\n");
+  prints(".  in +(u;\\n[.l]-\\n[.i]-\\n[TW]/2>?-\\n[.i])\n"
+	 ".  nr " SAVED_INDENT_REG " \\n[.i]\n");
+  if (!(flags & CENTER))
+    prints(".\\}\n");
+  build_vrule_list();
+  define_bottom_macro();
+  do_top();
+  for (int i = 0; i < nrows; i++)
+    do_row(i);
+  do_bottom();
+}
+
+void table::determine_row_type()
+{
+  row_is_all_lines = new char[nrows];
+  for (int i = 0; i < nrows; i++) {
+    bool had_single = false;
+    bool had_double = false;
+    bool had_non_line = false;
+    for (int c = 0; c < ncolumns; c++) {
+      table_entry *e = entry[i][c];
+      if (e != 0) {
+	if (e->start_row == e->end_row) {
+	  int t = e->line_type();
+	  switch (t) {
+	  case -1:
+	    had_non_line = true;
+	    break;
+	  case 0:
+	    // empty
+	    break;
+	  case 1:
+	    had_single = true;
+	    break;
+	  case 2:
+	    had_double = true;
+	    break;
+	  default:
+	    assert(0 == "table entry line type not in {-1, 0, 1, 2}");
+	  }
+	  if (had_non_line)
+	    break;
+	}
+	c = e->end_col;
+      }
+    }
+    if (had_non_line)
+      row_is_all_lines[i] = 0;
+    else if (had_double)
+      row_is_all_lines[i] = 2;
+    else if (had_single)
+      row_is_all_lines[i] = 1;
+    else
+      row_is_all_lines[i] = 0;
+  }
+}
+
+int table::count_expand_columns()
+{
+  int count = 0;
+  for (int i = 0; i < ncolumns; i++)
+    if (expand[i])
+      count++;
+  return count;
+}
+
+void table::init_output()
+{
+  prints(".\\\" initialize output\n");
+  prints(".nr " COMPATIBLE_REG " \\n(.C\n"
+	 ".cp 0\n");
+  if (linesize > 0)
+    printfs(".nr " LINESIZE_REG " %1\n", as_string(linesize));
+  else
+    prints(".nr " LINESIZE_REG " \\n[.s]\n");
+  if (!(flags & CENTER))
+    prints(".nr " SAVED_CENTER_REG " \\n[.ce]\n");
+  if (compatible_flag)
+    prints(".ds " LEADER_REG " \\a\n");
+  if (!(flags & NOKEEP))
+    prints(".if !r " USE_KEEPS_REG " .nr " USE_KEEPS_REG " 1\n");
+  prints(".de " RESET_MACRO_NAME "\n"
+	 ".  ft \\n[.f]\n"
+	 ".  ps \\n[.s]\n"
+	 ".  vs \\n[.v]u\n"
+	 ".  in \\n[.i]u\n"
+	 ".  ll \\n[.l]u\n"
+	 ".  ls \\n[.L]\n"
+	 ".  hy \\\\n[" SAVED_HYPHENATION_MODE_REG "]\n"
+	 ".  hla \\\\*[" SAVED_HYPHENATION_LANG_NAME "]\n"
+	 ".  hlm \\\\n[" SAVED_HYPHENATION_MAX_LINES_REG "]\n"
+	 ".  hym \\\\n[" SAVED_HYPHENATION_MARGIN_REG "]\n"
+	 ".  hys \\\\n[" SAVED_HYPHENATION_SPACE_REG "]\n"
+	 ".  ad \\n[.j]\n"
+	 ".  ie \\n[.u] .fi\n"
+	 ".  el .nf\n"
+	 ".  ce \\n[.ce]\n"
+	 ".  ta \\\\*[" SAVED_TABS_NAME "]\n"
+	 ".  ss \\\\n[" SAVED_INTER_WORD_SPACE_SIZE "]"
+	 " \\\\n[" SAVED_INTER_SENTENCE_SPACE_SIZE "]\n"
+	 "..\n"
+	 ".nr " SAVED_INDENT_REG " \\n[.i]\n"
+	 ".nr " SAVED_FONT_REG " \\n[.f]\n"
+	 ".nr " SAVED_SIZE_REG " \\n[.s]\n"
+	 ".nr " SAVED_FILL_REG " \\n[.u]\n"
+	 ".ds " SAVED_TABS_NAME " \\n[.tabs]\n"
+	 ".nr " SAVED_INTER_WORD_SPACE_SIZE " \\n[.ss]\n"
+	 ".nr " SAVED_INTER_SENTENCE_SPACE_SIZE " \\n[.sss]\n"
+	 ".nr " SAVED_HYPHENATION_MODE_REG " \\n[.hy]\n"
+	 ".ds " SAVED_HYPHENATION_LANG_NAME " \\n[.hla]\n"
+	 ".nr " SAVED_HYPHENATION_MAX_LINES_REG " (\\n[.hlm])\n"
+	 ".nr " SAVED_HYPHENATION_MARGIN_REG " \\n[.hym]\n"
+	 ".nr " SAVED_HYPHENATION_SPACE_REG " \\n[.hys]\n"
+	 ".nr T. 0\n"
+	 ".nr " CURRENT_ROW_REG " 0-1\n"
+	 ".nr " LAST_PASSED_ROW_REG " 0-1\n"
+	 ".nr " SECTION_DIVERSION_FLAG_REG " 0\n"
+	 ".ds " TRANSPARENT_STRING_NAME "\n"
+	 ".ds " QUOTE_STRING_NAME "\n"
+	 ".nr " NEED_BOTTOM_RULE_REG " 1\n"
+	 ".nr " SUPPRESS_BOTTOM_REG " 0\n"
+	 ".eo\n"
+	 ".de " REPEATED_MARK_MACRO "\n"
+	 ".  mk \\$1\n"
+	 ".  if !'\\n(.z'' \\!." REPEATED_MARK_MACRO " \"\\$1\"\n"
+	 "..\n"
+	 ".de " REPEATED_VPT_MACRO "\n"
+	 ".  vpt \\$1\n"
+	 ".  if !'\\n(.z'' \\!." REPEATED_VPT_MACRO " \"\\$1\"\n"
+	 "..\n");
+  if (!(flags & NOKEEP)) {
+    prints(".de " KEEP_MACRO_NAME "\n"
+	   ".  if '\\n[.z]'' \\{\\\n"
+	   ".    ds " QUOTE_STRING_NAME " \\\\\n"
+	   ".    ds " TRANSPARENT_STRING_NAME " \\!\n"
+	   ".    di " SECTION_DIVERSION_NAME "\n"
+	   ".    nr " SECTION_DIVERSION_FLAG_REG " 1\n"
+	   ".    in 0\n"
+	   ".  \\}\n"
+	   "..\n"
+	   // Protect '#' in macro name from being interpreted by eqn.
+	   ".ig\n"
+	   ".EQ\n"
+	   "delim off\n"
+	   ".EN\n"
+	   "..\n"
+	   ".de " RELEASE_MACRO_NAME "\n"
+	   ".  if \\n[" SECTION_DIVERSION_FLAG_REG "] \\{\\\n"
+	   ".    di\n"
+	   ".    in \\n[" SAVED_INDENT_REG "]u\n"
+	   ".    nr " SAVED_DN_REG " \\n[dn]\n"
+	   ".    ds " QUOTE_STRING_NAME "\n"
+	   ".    ds " TRANSPARENT_STRING_NAME "\n"
+	   ".    nr " SECTION_DIVERSION_FLAG_REG " 0\n"
+	   ".    if \\n[.t]<=\\n[dn] \\{\\\n"
+	   ".      nr T. 1\n"
+	   ".      T#\n"
+	   ".      nr " SUPPRESS_BOTTOM_REG " 1\n"
+	   ".      sp \\n[.t]u\n"
+	   ".      nr " SUPPRESS_BOTTOM_REG " 0\n"
+	   ".      mk #T\n"
+	   ".    \\}\n");
+    if (!(flags & NOWARN)) {
+      prints(".    if \\n[.t]<=\\n[" SAVED_DN_REG "] \\{\\\n");
+      // eqn(1) delimiters have already been switched off.
+      entry_list->set_location();
+      // Since we turn off traps, troff won't go into an infinite loop
+      // when we output the table row; it will just flow off the bottom
+      // of the page.
+      prints(".      tmc \\n[.F]:\\n[.c]: warning:\n"
+	     ".      tm1 \" table row does not fit on page \\n%\n");
+      prints(".    \\}\n");
+    }
+    prints(".    nf\n"
+	   ".    ls 1\n"
+	   ".    " SECTION_DIVERSION_NAME "\n"
+	   ".    ls\n"
+	   ".    rm " SECTION_DIVERSION_NAME "\n"
+	   ".  \\}\n"
+	   "..\n"
+	   ".ig\n"
+	   ".EQ\n"
+	   "delim on\n"
+	   ".EN\n"
+	   "..\n"
+	   ".nr " TABLE_DIVERSION_FLAG_REG " 0\n"
+	   ".de " TABLE_KEEP_MACRO_NAME "\n"
+	   ".  if '\\n[.z]'' \\{\\\n"
+	   ".    di " TABLE_DIVERSION_NAME "\n"
+	   ".    nr " TABLE_DIVERSION_FLAG_REG " 1\n"
+	   ".  \\}\n"
+	   "..\n"
+	   ".de " TABLE_RELEASE_MACRO_NAME "\n"
+	   ".  if \\n[" TABLE_DIVERSION_FLAG_REG "] \\{\\\n"
+	   ".    br\n"
+	   ".    di\n"
+	   ".    nr " SAVED_DN_REG " \\n[dn]\n"
+	   ".    ne \\n[dn]u+\\n[.V]u\n"
+	   ".    ie \\n[.t]<=\\n[" SAVED_DN_REG "] \\{\\\n");
+    // Protect characters in diagnostic message (especially :, [, ])
+    // from being interpreted by eqn.
+    prints(".      ds " NOP_NAME " \\\" empty\n");
+    prints(".      ig " NOP_NAME "\n"
+	   ".EQ\n"
+	   "delim off\n"
+	   ".EN\n"
+	   ".      " NOP_NAME "\n");
+    entry_list->set_location();
+    prints(".      nr " PREVIOUS_PAGE_REG " (\\n% - 1)\n"
+	   ".      tmc \\n[.F]:\\n[.c]: error:\n"
+	   ".      tmc \" boxed table does not fit on page"
+	   " \\n[" PREVIOUS_PAGE_REG "];\n"
+	   ".      tm1 \" use .TS H/.TH with a supporting macro package"
+	   "\n"
+	   ".      rr " PREVIOUS_PAGE_REG "\n");
+    prints(".      ig " NOP_NAME "\n"
+	   ".EQ\n"
+	   "delim on\n"
+	   ".EN\n"
+	   ".      " NOP_NAME "\n");
+    prints(".    \\}\n"
+	   ".  el \\{\\\n"
+	   ".    in 0\n"
+	   ".    ls 1\n"
+	   ".    nf\n"
+	   ".    " TABLE_DIVERSION_NAME "\n"
+	   ".  \\}\n"
+	   ".  rm " TABLE_DIVERSION_NAME "\n"
+	   ".  \\}\n"
+	   "..\n");
+  }
+  prints(".ec\n"
+	 ".ce 0\n");
+  prints(".nr " SAVED_NUMBERING_LINENO " \\n[ln]\n"
+	 ".nr ln 0\n"
+	 ".nr " SAVED_NUMBERING_SUPPRESSION_COUNT " \\n[.nn]\n"
+	 ".nn 2147483647\n"); // 2^31-1; inelegant but effective
+  prints(".nf\n");
+}
+
+string block_width_reg(int r, int c)
+{
+  static char name[sizeof(BLOCK_WIDTH_PREFIX)+INT_DIGITS+1+INT_DIGITS];
+  sprintf(name, BLOCK_WIDTH_PREFIX "%d,%d", r, c);
+  return string(name);
+}
+
+string block_diversion_name(int r, int c)
+{
+  static char name[sizeof(BLOCK_DIVERSION_PREFIX)+INT_DIGITS+1+INT_DIGITS];
+  sprintf(name, BLOCK_DIVERSION_PREFIX "%d,%d", r, c);
+  return string(name);
+}
+
+string block_height_reg(int r, int c)
+{
+  static char name[sizeof(BLOCK_HEIGHT_PREFIX)+INT_DIGITS+1+INT_DIGITS];
+  sprintf(name, BLOCK_HEIGHT_PREFIX "%d,%d", r, c);
+  return string(name);
+}
+
+string span_width_reg(int start_col, int end_col)
+{
+  static char name[sizeof(SPAN_WIDTH_PREFIX)+INT_DIGITS+1+INT_DIGITS];
+  sprintf(name, SPAN_WIDTH_PREFIX "%d", start_col);
+  if (end_col != start_col)
+    sprintf(strchr(name, '\0'), ",%d", end_col);
+  return string(name);
+}
+
+string span_left_numeric_width_reg(int start_col, int end_col)
+{
+  static char name[sizeof(SPAN_LEFT_NUMERIC_WIDTH_PREFIX)+INT_DIGITS+1+INT_DIGITS];
+  sprintf(name, SPAN_LEFT_NUMERIC_WIDTH_PREFIX "%d", start_col);
+  if (end_col != start_col)
+    sprintf(strchr(name, '\0'), ",%d", end_col);
+  return string(name);
+}
+
+string span_right_numeric_width_reg(int start_col, int end_col)
+{
+  static char name[sizeof(SPAN_RIGHT_NUMERIC_WIDTH_PREFIX)+INT_DIGITS+1+INT_DIGITS];
+  sprintf(name, SPAN_RIGHT_NUMERIC_WIDTH_PREFIX "%d", start_col);
+  if (end_col != start_col)
+    sprintf(strchr(name, '\0'), ",%d", end_col);
+  return string(name);
+}
+
+string span_alphabetic_width_reg(int start_col, int end_col)
+{
+  static char name[sizeof(SPAN_ALPHABETIC_WIDTH_PREFIX)+INT_DIGITS+1+INT_DIGITS];
+  sprintf(name, SPAN_ALPHABETIC_WIDTH_PREFIX "%d", start_col);
+  if (end_col != start_col)
+    sprintf(strchr(name, '\0'), ",%d", end_col);
+  return string(name);
+}
+
+string column_separation_reg(int col)
+{
+  static char name[sizeof(COLUMN_SEPARATION_PREFIX)+INT_DIGITS];
+  sprintf(name, COLUMN_SEPARATION_PREFIX "%d", col);
+  return string(name);
+}
+
+string row_start_reg(int row)
+{
+  static char name[sizeof(ROW_START_PREFIX)+INT_DIGITS];
+  sprintf(name, ROW_START_PREFIX "%d", row);
+  return string(name);
+}
+
+string column_start_reg(int col)
+{
+  static char name[sizeof(COLUMN_START_PREFIX)+INT_DIGITS];
+  sprintf(name, COLUMN_START_PREFIX "%d", col);
+  return string(name);
+}
+
+string column_end_reg(int col)
+{
+  static char name[sizeof(COLUMN_END_PREFIX)+INT_DIGITS];
+  sprintf(name, COLUMN_END_PREFIX "%d", col);
+  return string(name);
+}
+
+string column_divide_reg(int col)
+{
+  static char name[sizeof(COLUMN_DIVIDE_PREFIX)+INT_DIGITS];
+  sprintf(name, COLUMN_DIVIDE_PREFIX "%d", col);
+  return string(name);
+}
+
+string row_top_reg(int row)
+{
+  static char name[sizeof(ROW_TOP_PREFIX)+INT_DIGITS];
+  sprintf(name, ROW_TOP_PREFIX "%d", row);
+  return string(name);
+}
+
+void init_span_reg(int start_col, int end_col)
+{
+  printfs(".nr %1 \\n(.H\n.nr %2 0\n.nr %3 0\n.nr %4 0\n",
+	  span_width_reg(start_col, end_col),
+	  span_alphabetic_width_reg(start_col, end_col),
+	  span_left_numeric_width_reg(start_col, end_col),
+	  span_right_numeric_width_reg(start_col, end_col));
+}
+
+void compute_span_width(int start_col, int end_col)
+{
+  printfs(".nr %1 \\n[%1]>?(\\n[%2]+\\n[%3])\n"
+	  ".if \\n[%4] .nr %1 \\n[%1]>?(\\n[%4]+2n)\n",
+	  span_width_reg(start_col, end_col),
+	  span_left_numeric_width_reg(start_col, end_col),
+	  span_right_numeric_width_reg(start_col, end_col),
+	  span_alphabetic_width_reg(start_col, end_col));
+}
+
+// Increase the widths of columns so that the width of any spanning
+// entry is not greater than the sum of the widths of the columns that
+// it spans.  Ensure that the widths of columns remain equal.
+
+void table::divide_span(int start_col, int end_col)
+{
+  assert(end_col > start_col);
+  printfs(".nr " NEEDED_REG " \\n[%1]-(\\n[%2]",
+	  span_width_reg(start_col, end_col),
+	  span_width_reg(start_col, start_col));
+  int i;
+  for (i = start_col + 1; i <= end_col; i++) {
+    // The column separation may shrink with the expand option.
+    if (!(flags & EXPAND))
+      printfs("+%1n", as_string(column_separation[i - 1]));
+    printfs("+\\n[%1]", span_width_reg(i, i));
+  }
+  prints(")\n");
+  printfs(".nr " NEEDED_REG " \\n[" NEEDED_REG "]/%1\n",
+	  as_string(end_col - start_col + 1));
+  prints(".if \\n[" NEEDED_REG "] \\{\\\n");
+  for (i = start_col; i <= end_col; i++)
+    printfs(".  nr %1 +\\n[" NEEDED_REG "]\n",
+	    span_width_reg(i, i));
+  int equal_flag = 0;
+  for (i = start_col; i <= end_col && !equal_flag; i++)
+    if (equal[i] || expand[i])
+      equal_flag = 1;
+  if (equal_flag) {
+    for (i = 0; i < ncolumns; i++)
+      if (i < start_col || i > end_col)
+	printfs(".  nr %1 +\\n[" NEEDED_REG "]\n",
+	    span_width_reg(i, i));
+  }
+  prints(".\\}\n");
+}
+
+void table::sum_columns(int start_col, int end_col, int do_expand)
+{
+  assert(end_col > start_col);
+  int i;
+  for (i = start_col; i <= end_col; i++)
+    if (expand[i])
+      break;
+  if (i > end_col) {
+    if (do_expand)
+      return;
+  }
+  else {
+    if (!do_expand)
+      return;
+  }
+  printfs(".nr %1 \\n[%2]",
+	  span_width_reg(start_col, end_col),
+	  span_width_reg(start_col, start_col));
+  for (i = start_col + 1; i <= end_col; i++)
+    printfs("+(%1*\\n[" SEPARATION_FACTOR_REG "])+\\n[%2]",
+	    as_string(column_separation[i - 1]),
+	    span_width_reg(i, i));
+  prints('\n');
+}
+
+horizontal_span::horizontal_span(int sc, int ec, horizontal_span *p)
+: next(p), start_col(sc), end_col(ec)
+{
+}
+
+void table::build_span_list()
+{
+  span_list = 0;
+  table_entry *p = entry_list;
+  while (p) {
+    if (p->end_col != p->start_col) {
+      horizontal_span *q;
+      for (q = span_list; q; q = q->next)
+	if (q->start_col == p->start_col
+	    && q->end_col == p->end_col)
+	  break;
+      if (!q)
+	span_list = new horizontal_span(p->start_col, p->end_col, span_list);
+    }
+    p = p->next;
+  }
+  // Now sort span_list primarily by order of end_row, and secondarily
+  // by reverse order of start_row. This ensures that if we divide
+  // spans using the order in span_list, we will get reasonable results.
+  horizontal_span *unsorted = span_list;
+  span_list = 0;
+  while (unsorted) {
+    horizontal_span **pp;
+    for (pp = &span_list; *pp; pp = &(*pp)->next)
+      if (unsorted->end_col < (*pp)->end_col
+	  || (unsorted->end_col == (*pp)->end_col
+	      && (unsorted->start_col > (*pp)->start_col)))
+	break;
+    horizontal_span *tem = unsorted->next;
+    unsorted->next = *pp;
+    *pp = unsorted;
+    unsorted = tem;
+  }
+}
+
+void table::compute_overall_width()
+{
+  prints(".\\\" compute overall width\n");
+  if (!(flags & GAP_EXPAND)) {
+    if (left_separation)
+      printfs(".if n .ll -%1n\n", as_string(left_separation));
+    if (right_separation)
+      printfs(".if n .ll -%1n\n", as_string(right_separation));
+  }
+  // Compute the amount of horizontal space available for expansion,
+  // measuring every column _including_ those eligible for expansion.
+  // This is the minimum required to set the table without compression.
+  prints(".nr " EXPAND_REG " 0\n");
+  prints(".nr " AVAILABLE_WIDTH_REG " \\n[.l]-\\n[.i]");
+  for (int i = 0; i < ncolumns; i++)
+    printfs("-\\n[%1]", span_width_reg(i, i));
+  if (total_separation)
+    printfs("-%1n", as_string(total_separation));
+  prints("\n");
+  // If the "expand" region option was given, a different warning will
+  // be issued later (if "nowarn" was not also specified).
+  if ((!(flags & NOWARN)) && (!(flags & EXPAND))) {
+    prints(".if \\n[" AVAILABLE_WIDTH_REG "]<0 \\{\\\n");
+    // Protect characters in diagnostic message (especially :, [, ])
+    // from being interpreted by eqn.
+    prints(".  ig\n"
+	   ".EQ\n"
+	   "delim off\n"
+	   ".EN\n"
+	   ".  .\n");
+    entry_list->set_location();
+    prints(".  tmc \\n[.F]:\\n[.c]: warning:\n"
+	   ".  tm1 \" table wider than line length minus indentation"
+	   "\n");
+    prints(".  ig\n"
+	   ".EQ\n"
+	   "delim on\n"
+	   ".EN\n"
+	   ".  .\n");
+    prints(".  nr " AVAILABLE_WIDTH_REG " 0\n");
+    prints(".\\}\n");
+  }
+  // Now do a similar computation, this time omitting columns that
+  // _aren't_ undergoing expansion.  The difference is the amount of
+  // space we have to distribute among the expanded columns.
+  bool do_expansion = false;
+  for (int i = 0; i < ncolumns; i++)
+    if (expand[i]) {
+      do_expansion = true;
+      break;
+    }
+  if (do_expansion) {
+    prints(".if \\n[" AVAILABLE_WIDTH_REG "] \\\n");
+    prints(".  nr " EXPAND_REG " \\n[.l]-\\n[.i]");
+    for (int i = 0; i < ncolumns; i++)
+      if (!expand[i])
+	printfs("-\\n[%1]", span_width_reg(i, i));
+    if (total_separation)
+      printfs("-%1n", as_string(total_separation));
+    prints("\n");
+    int colcount = count_expand_columns();
+    if (colcount > 1)
+      printfs(".nr " EXPAND_REG " \\n[" EXPAND_REG "]/%1\n",
+	      as_string(colcount));
+    for (int i = 0; i < ncolumns; i++)
+      if (expand[i])
+	printfs(".nr %1 \\n[%1]>?\\n[" EXPAND_REG "]\n",
+		span_width_reg(i, i));
+  }
+}
+
+void table::compute_total_separation()
+{
+  if (flags & (ALLBOX | BOX | DOUBLEBOX))
+    left_separation = right_separation = 1;
+  else {
+    for (int r = 0; r < nrows; r++) {
+      if (vline[r][0] > 0)
+	left_separation = 1;
+      if (vline[r][ncolumns] > 0)
+	right_separation = 1;
+    }
+  }
+  total_separation = left_separation + right_separation;
+  for (int c = 0; c < ncolumns - 1; c++)
+    total_separation += column_separation[c];
+}
+
+void table::compute_separation_factor()
+{
+  prints(".\\\" compute column separation factor\n");
+  // Don't let the separation factor be negative.
+  prints(".nr " SEPARATION_FACTOR_REG " \\n[.l]-\\n[.i]");
+  for (int i = 0; i < ncolumns; i++)
+    printfs("-\\n[%1]", span_width_reg(i, i));
+  printfs("/%1\n", as_string(total_separation));
+  // Store the remainder for use in compute_column_positions().
+  if (flags & GAP_EXPAND) {
+    prints(".if n \\\n");
+    prints(".  nr " LEFTOVER_FACTOR_REG " \\n[.l]-\\n[.i]");
+    for (int i = 0; i < ncolumns; i++)
+      printfs("-\\n[%1]", span_width_reg(i, i));
+    printfs("%%%1\n", as_string(total_separation));
+  }
+  prints(".ie \\n[" SEPARATION_FACTOR_REG "]<=0 \\{\\\n");
+  if (!(flags & NOWARN)) {
+    // Protect characters in diagnostic message (especially :, [, ])
+    // from being interpreted by eqn.
+    prints(".ig\n"
+	   ".EQ\n"
+	   "delim off\n"
+	   ".EN\n"
+	   "..\n");
+    entry_list->set_location();
+    prints(".tmc \\n[.F]:\\n[.c]: warning:\n"
+	   ".tm1 \" table column separation reduced to zero\n"
+	   ".nr " SEPARATION_FACTOR_REG " 0\n");
+  }
+  prints(".\\}\n"
+	 ".el .if \\n[" SEPARATION_FACTOR_REG "]<1n \\{\\\n");
+  if (!(flags & NOWARN)) {
+    entry_list->set_location();
+    prints(".tmc \\n[.F]:\\n[.c]: warning:\n"
+	   ".tm1 \" table column separation reduced to fit line"
+	   " length\n");
+    prints(".ig\n"
+	   ".EQ\n"
+	   "delim on\n"
+	   ".EN\n"
+	   "..\n");
+  }
+  prints(".\\}\n");
+}
+
+void table::compute_column_positions()
+{
+  prints(".\\\" compute column positions\n");
+  printfs(".nr %1 0\n", column_divide_reg(0));
+  printfs(".nr %1 %2n\n", column_start_reg(0),
+	  as_string(left_separation));
+  // In nroff mode, compensate for width of vertical rule.
+  if (left_separation)
+    printfs(".if n .nr %1 +1n\n", column_start_reg(0));
+  int i;
+  for (i = 1;; i++) {
+    printfs(".nr %1 \\n[%2]+\\n[%3]\n",
+	    column_end_reg(i-1),
+	    column_start_reg(i-1),
+	    span_width_reg(i-1, i-1));
+    if (i >= ncolumns)
+      break;
+    printfs(".nr %1 \\n[%2]+(%3*\\n[" SEPARATION_FACTOR_REG "])\n",
+	    column_start_reg(i),
+	    column_end_reg(i-1),
+	    as_string(column_separation[i-1]));
+    // If we have leftover expansion room in a table using the "expand"
+    // region option, put it prior to the last column so that the table
+    // looks as if expanded to the available line length.
+    if ((ncolumns > 2) && (flags & GAP_EXPAND) && (i == (ncolumns - 1)))
+      printfs(".if n .if \\n[" LEFTOVER_FACTOR_REG "] .nr %1 +(1n>?\\n["
+	      LEFTOVER_FACTOR_REG "])\n",
+	      column_start_reg(i));
+    printfs(".nr %1 \\n[%2]+\\n[%3]/2\n",
+	    column_divide_reg(i),
+	    column_end_reg(i-1),
+	    column_start_reg(i));
+  }
+  printfs(".nr %1 \\n[%2]+%3n\n",
+	  column_divide_reg(ncolumns),
+	  column_end_reg(i-1),
+	  as_string(right_separation));
+  printfs(".nr TW \\n[%1]\n",
+	  column_divide_reg(ncolumns));
+  if (flags & DOUBLEBOX) {
+    printfs(".nr %1 +" DOUBLE_LINE_SEP "\n", column_divide_reg(0));
+    printfs(".nr %1 -" DOUBLE_LINE_SEP "\n", column_divide_reg(ncolumns));
+  }
+}
+
+void table::make_columns_equal()
+{
+  int first = -1;		// index of first equal column
+  int i;
+  for (i = 0; i < ncolumns; i++)
+    if (equal[i]) {
+      if (first < 0) {
+	printfs(".nr %1 \\n[%1]", span_width_reg(i, i));
+	first = i;
+      }
+      else
+	printfs(">?\\n[%1]", span_width_reg(i, i));
+    }
+  if (first >= 0) {
+    prints('\n');
+    for (i = first + 1; i < ncolumns; i++)
+      if (equal[i])
+	printfs(".nr %1 \\n[%2]\n",
+		span_width_reg(i, i),
+		span_width_reg(first, first));
+  }
+}
+
+void table::compute_widths()
+{
+  prints(".\\\" compute column widths\n");
+  build_span_list();
+  int i;
+  horizontal_span *p;
+  // These values get refined later.
+  prints(".nr " SEPARATION_FACTOR_REG " 1n\n");
+  for (i = 0; i < ncolumns; i++) {
+    init_span_reg(i, i);
+    if (!minimum_width[i].empty())
+      printfs(".nr %1 (n;%2)\n", span_width_reg(i, i), minimum_width[i]);
+  }
+  for (p = span_list; p; p = p->next)
+    init_span_reg(p->start_col, p->end_col);
+  // Compute all field widths except for blocks.
+  table_entry *q;
+  for (q = entry_list; q; q = q->next)
+    if (!q->mod->zero_width)
+      q->do_width();
+  // Compute all span widths, not handling blocks yet.
+  for (i = 0; i < ncolumns; i++)
+    compute_span_width(i, i);
+  for (p = span_list; p; p = p->next)
+    compute_span_width(p->start_col, p->end_col);
+  // Making columns equal normally increases the width of some columns.
+  make_columns_equal();
+  // Note that divide_span keeps equal width columns equal.
+  // This function might increase the width of some columns, too.
+  for (p = span_list; p; p = p->next)
+    divide_span(p->start_col, p->end_col);
+  compute_total_separation();
+  for (p = span_list; p; p = p->next)
+    sum_columns(p->start_col, p->end_col, 0);
+  // Now handle unexpanded blocks.
+  bool had_spanning_block = false;
+  bool had_equal_block = false;
+  for (q = entry_list; q; q = q->next)
+    if (q->divert(ncolumns, minimum_width,
+		  (flags & EXPAND) ? column_separation : 0, 0)) {
+      if (q->end_col > q->start_col)
+	had_spanning_block = true;
+      for (i = q->start_col; i <= q->end_col && !had_equal_block; i++)
+	if (equal[i])
+	  had_equal_block = true;
+    }
+  // Adjust widths.
+  if (had_equal_block)
+    make_columns_equal();
+  if (had_spanning_block)
+    for (p = span_list; p; p = p->next)
+      divide_span(p->start_col, p->end_col);
+  compute_overall_width();
+  if ((flags & EXPAND) && total_separation != 0) {
+    compute_separation_factor();
+    for (p = span_list; p; p = p->next)
+      sum_columns(p->start_col, p->end_col, 0);
+  }
+  else {
+    // Handle expanded blocks.
+    for (p = span_list; p; p = p->next)
+      sum_columns(p->start_col, p->end_col, 1);
+    for (q = entry_list; q; q = q->next)
+      if (q->divert(ncolumns, minimum_width, 0, 1)) {
+	if (q->end_col > q->start_col)
+	  had_spanning_block = true;
+      }
+    // Adjust widths again.
+    if (had_spanning_block)
+      for (p = span_list; p; p = p->next)
+	divide_span(p->start_col, p->end_col);
+  }
+  compute_column_positions();
+}
+
+void table::print_single_hline(int r)
+{
+  prints(".vs " LINE_SEP ">?\\n[.V]u\n"
+	 ".ls 1\n"
+	 "\\v'" BODY_DEPTH "'"
+	 "\\s[\\n[" LINESIZE_REG "]]");
+  if (r > nrows - 1)
+    prints("\\D'l |\\n[TW]u 0'");
+  else {
+    int start_col = 0;
+    for (;;) {
+      while (start_col < ncolumns
+	     && entry[r][start_col] != 0
+	     && entry[r][start_col]->start_row != r)
+	start_col++;
+      int end_col;
+      for (end_col = start_col;
+	   end_col < ncolumns
+	   && (entry[r][end_col] == 0
+	       || entry[r][end_col]->start_row == r);
+	   end_col++)
+	;
+      if (end_col <= start_col)
+	break;
+      printfs("\\h'|\\n[%1]u",
+	      column_divide_reg(start_col));
+      if ((r > 0 && vline[r-1][start_col] == 2)
+	  || (r < nrows && vline[r][start_col] == 2))
+	prints("-" HALF_DOUBLE_LINE_SEP);
+      prints("'");
+      printfs("\\D'l |\\n[%1]u",
+	      column_divide_reg(end_col));
+      if ((r > 0 && vline[r-1][end_col] == 2)
+	  || (r < nrows && vline[r][end_col] == 2))
+	prints("+" HALF_DOUBLE_LINE_SEP);
+      prints(" 0'");
+      start_col = end_col;
+    }
+  }
+  prints("\\s0\n");
+  prints(".ls\n"
+	 ".vs\n");
+}
+
+void table::print_double_hline(int r)
+{
+  prints(".vs " LINE_SEP "+" DOUBLE_LINE_SEP
+	 ">?\\n[.V]u\n"
+	 ".ls 1\n"
+	 "\\v'" BODY_DEPTH "'"
+	 "\\s[\\n[" LINESIZE_REG "]]");
+  if (r > nrows - 1)
+    prints("\\v'-" DOUBLE_LINE_SEP "'"
+	   "\\D'l |\\n[TW]u 0'"
+	   "\\v'" DOUBLE_LINE_SEP "'"
+	   "\\h'|0'"
+	   "\\D'l |\\n[TW]u 0'");
+  else {
+    int start_col = 0;
+    for (;;) {
+      while (start_col < ncolumns
+	     && entry[r][start_col] != 0
+	     && entry[r][start_col]->start_row != r)
+	start_col++;
+      int end_col;
+      for (end_col = start_col;
+	   end_col < ncolumns
+	   && (entry[r][end_col] == 0
+	       || entry[r][end_col]->start_row == r);
+	   end_col++)
+	;
+      if (end_col <= start_col)
+	break;
+      const char *left_adjust = 0;
+      if ((r > 0 && vline[r-1][start_col] == 2)
+	  || (r < nrows && vline[r][start_col] == 2))
+	left_adjust = "-" HALF_DOUBLE_LINE_SEP;
+      const char *right_adjust = 0;
+      if ((r > 0 && vline[r-1][end_col] == 2)
+	  || (r < nrows && vline[r][end_col] == 2))
+	right_adjust = "+" HALF_DOUBLE_LINE_SEP;
+      printfs("\\v'-" DOUBLE_LINE_SEP "'"
+	      "\\h'|\\n[%1]u",
+	      column_divide_reg(start_col));
+      if (left_adjust)
+	prints(left_adjust);
+      prints("'");
+      printfs("\\D'l |\\n[%1]u",
+	      column_divide_reg(end_col));
+      if (right_adjust)
+	prints(right_adjust);
+      prints(" 0'");
+      printfs("\\v'" DOUBLE_LINE_SEP "'"
+	      "\\h'|\\n[%1]u",
+	      column_divide_reg(start_col));
+      if (left_adjust)
+	prints(left_adjust);
+      prints("'");
+      printfs("\\D'l |\\n[%1]u",
+	      column_divide_reg(end_col));
+      if (right_adjust)
+	prints(right_adjust);
+      prints(" 0'");
+      start_col = end_col;
+    }
+  }
+  prints("\\s0\n"
+	 ".ls\n"
+	 ".vs\n");
+}
+
+void table::compute_vrule_top_adjust(int start_row, int col, string &result)
+{
+  if (row_is_all_lines[start_row] && start_row < nrows - 1) {
+    if (row_is_all_lines[start_row] == 2)
+      result = LINE_SEP ">?\\n[.V]u" "+" DOUBLE_LINE_SEP;
+    else
+      result = LINE_SEP ">?\\n[.V]u";
+    start_row++;
+  }
+  else {
+    result = "";
+    if (start_row == 0)
+      return;
+    for (stuff *p = stuff_list; p && p->row <= start_row; p = p->next)
+      if (p->row == start_row
+	  && (p->is_single_line() || p->is_double_line()))
+	return;
+  }
+  int left = 0;
+  if (col > 0) {
+    table_entry *e = entry[start_row-1][col-1];
+    if (e && e->start_row == e->end_row) {
+      if (e->to_double_line_entry() != 0)
+	left = 2;
+      else if (e->to_single_line_entry() != 0)
+	left = 1;
+    }
+  }
+  int right = 0;
+  if (col < ncolumns) {
+    table_entry *e = entry[start_row-1][col];
+    if (e && e->start_row == e->end_row) {
+      if (e->to_double_line_entry() != 0)
+	right = 2;
+      else if (e->to_single_line_entry() != 0)
+	right = 1;
+    }
+  }
+  if (row_is_all_lines[start_row-1] == 0) {
+    if (left > 0 || right > 0) {
+      result += "-" BODY_DEPTH "-" BAR_HEIGHT;
+      if ((left == 2 && right != 2) || (right == 2 && left != 2))
+	result += "-" HALF_DOUBLE_LINE_SEP;
+      else if (left == 2 && right == 2)
+	result += "+" HALF_DOUBLE_LINE_SEP;
+    }
+  }
+  else if (row_is_all_lines[start_row-1] == 2) {
+    if ((left == 2 && right != 2) || (right == 2 && left != 2))
+      result += "-" DOUBLE_LINE_SEP;
+    else if (left == 1 || right == 1)
+      result += "-" HALF_DOUBLE_LINE_SEP;
+  }
+}
+
+void table::compute_vrule_bot_adjust(int end_row, int col, string &result)
+{
+  if (row_is_all_lines[end_row] && end_row > 0) {
+    end_row--;
+    result = "";
+  }
+  else {
+    stuff *p;
+    for (p = stuff_list; p && p->row < end_row + 1; p = p->next)
+      ;
+    if (p && p->row == end_row + 1 && p->is_double_line()) {
+      result = "-" DOUBLE_LINE_SEP;
+      return;
+    }
+    if ((p != 0 && p->row == end_row + 1)
+	|| end_row == nrows - 1) {
+      result = "";
+      return;
+    }
+    if (row_is_all_lines[end_row+1] == 1)
+      result = LINE_SEP;
+    else if (row_is_all_lines[end_row+1] == 2)
+      result = LINE_SEP "+" DOUBLE_LINE_SEP;
+    else
+      result = "";
+  }
+  int left = 0;
+  if (col > 0) {
+    table_entry *e = entry[end_row+1][col-1];
+    if (e && e->start_row == e->end_row) {
+      if (e->to_double_line_entry() != 0)
+	left = 2;
+      else if (e->to_single_line_entry() != 0)
+	left = 1;
+    }
+  }
+  int right = 0;
+  if (col < ncolumns) {
+    table_entry *e = entry[end_row+1][col];
+    if (e && e->start_row == e->end_row) {
+      if (e->to_double_line_entry() != 0)
+	right = 2;
+      else if (e->to_single_line_entry() != 0)
+	right = 1;
+    }
+  }
+  if (row_is_all_lines[end_row+1] == 0) {
+    if (left > 0 || right > 0) {
+      result = "1v-" BODY_DEPTH "-" BAR_HEIGHT;
+      if ((left == 2 && right != 2) || (right == 2 && left != 2))
+	result += "+" HALF_DOUBLE_LINE_SEP;
+      else if (left == 2 && right == 2)
+	result += "-" HALF_DOUBLE_LINE_SEP;
+    }
+  }
+  else if (row_is_all_lines[end_row+1] == 2) {
+    if (left == 2 && right == 2)
+      result += "-" DOUBLE_LINE_SEP;
+    else if (left != 2 && right != 2 && (left == 1 || right == 1))
+      result += "-" HALF_DOUBLE_LINE_SEP;
+  }
+}
+
+void table::add_vertical_rule(int start_row, int end_row,
+			      int col, int is_double)
+{
+  vrule_list = new vertical_rule(start_row, end_row, col, is_double,
+				 vrule_list);
+  compute_vrule_top_adjust(start_row, col, vrule_list->top_adjust);
+  compute_vrule_bot_adjust(end_row, col, vrule_list->bot_adjust);
+}
+
+void table::build_vrule_list()
+{
+  int col;
+  if (flags & ALLBOX) {
+    for (col = 1; col < ncolumns; col++) {
+      int start_row = 0;
+      for (;;) {
+	while (start_row < nrows && vline_spanned(start_row, col))
+	  start_row++;
+	if (start_row >= nrows)
+	  break;
+	int end_row = start_row;
+	while (end_row < nrows && !vline_spanned(end_row, col))
+	  end_row++;
+	end_row--;
+	add_vertical_rule(start_row, end_row, col, 0);
+	start_row = end_row + 1;
+      }
+    }
+  }
+  if (flags & (BOX | ALLBOX | DOUBLEBOX)) {
+    add_vertical_rule(0, nrows - 1, 0, 0);
+    add_vertical_rule(0, nrows - 1, ncolumns, 0);
+  }
+  for (int end_row = 0; end_row < nrows; end_row++)
+    for (col = 0; col < ncolumns+1; col++)
+      if (vline[end_row][col] > 0
+	  && !vline_spanned(end_row, col)
+	  && (end_row == nrows - 1
+	      || vline[end_row+1][col] != vline[end_row][col]
+	      || vline_spanned(end_row+1, col))) {
+	int start_row;
+	for (start_row = end_row - 1;
+	     start_row >= 0
+	     && vline[start_row][col] == vline[end_row][col]
+	     && !vline_spanned(start_row, col);
+	     start_row--)
+	  ;
+	start_row++;
+	add_vertical_rule(start_row, end_row, col, vline[end_row][col] > 1);
+      }
+  for (vertical_rule *p = vrule_list; p; p = p->next)
+    if (p->is_double)
+      for (int r = p->start_row; r <= p->end_row; r++) {
+	if (p->col > 0 && entry[r][p->col-1] != 0
+	    && entry[r][p->col-1]->end_col == p->col-1) {
+	  int is_corner = r == p->start_row || r == p->end_row;
+	  entry[r][p->col-1]->note_double_vrule_on_right(is_corner);
+	}
+	if (p->col < ncolumns && entry[r][p->col] != 0
+	    && entry[r][p->col]->start_col == p->col) {
+	  int is_corner = r == p->start_row || r == p->end_row;
+	  entry[r][p->col]->note_double_vrule_on_left(is_corner);
+	}
+      }
+}
+
+void table::define_bottom_macro()
+{
+  prints(".\\\" define bottom macro\n");
+  prints(".eo\n"
+	 // protect # in macro name against eqn
+	 ".ig\n"
+	 ".EQ\n"
+	 "delim off\n"
+	 ".EN\n"
+	 "..\n"
+	 ".de T#\n"
+	 ".  if !\\n[" SUPPRESS_BOTTOM_REG "] \\{\\\n"
+	 ".    " REPEATED_VPT_MACRO " 0\n"
+	 ".    mk " SAVED_VERTICAL_POS_REG "\n");
+  if (flags & (BOX | ALLBOX | DOUBLEBOX)) {
+    prints(".    if \\n[T.]&\\n[" NEED_BOTTOM_RULE_REG "] \\{\\\n");
+    print_single_hline(0);
+    prints(".    \\}\n");
+  }
+  prints(".    ls 1\n");
+  for (vertical_rule *p = vrule_list; p; p = p->next)
+    p->contribute_to_bottom_macro(this);
+  if (flags & DOUBLEBOX)
+    prints(".  if \\n[T.] \\{\\\n"
+	   ".    vs " DOUBLE_LINE_SEP ">?\\n[.V]u\n"
+	   "\\v'" BODY_DEPTH "'\\s[\\n[" LINESIZE_REG "]]"
+	   "\\D'l \\n[TW]u 0'\\s0\n"
+	   ".    vs\n"
+	   ".  \\}\n"
+	   ".  if \\n[" LAST_PASSED_ROW_REG "]>=0 "
+	   ".nr " TOP_REG " \\n[#T]-" DOUBLE_LINE_SEP "\n"
+	   ".  sp -1\n"
+	   "\\v'" BODY_DEPTH "'\\s[\\n[" LINESIZE_REG "]]"
+	   "\\D'l 0 |\\n[" TOP_REG "]u-1v'\\s0\n"
+	   ".  sp -1\n"
+	   "\\v'" BODY_DEPTH "'\\h'|\\n[TW]u'\\s[\\n[" LINESIZE_REG "]]"
+	   "\\D'l 0 |\\n[" TOP_REG "]u-1v'\\s0\n");
+  prints(".    ls\n");
+  prints(".    nr " LAST_PASSED_ROW_REG " \\n[" CURRENT_ROW_REG "]\n"
+	 ".    sp |\\n[" SAVED_VERTICAL_POS_REG "]u\n"
+	 ".    " REPEATED_VPT_MACRO " 1\n");
+  if ((flags & NOKEEP) && (flags & (BOX | DOUBLEBOX | ALLBOX)))
+    prints(".    if (\\n% > \\n[" STARTING_PAGE_REG "]) \\{\\\n"
+	   ".      tmc \\n[.F]:\\n[.c]: warning:\n"
+	   ".      tmc \" boxed, unkept table does not fit on page\n"
+	   ".      tm1 \" \\n[" STARTING_PAGE_REG "]\n"
+	   ".    \\}\n");
+  prints(".  \\}\n"
+	 "..\n"
+	 ".ig\n"
+	 ".EQ\n"
+	 "delim on\n"
+	 ".EN\n"
+	 "..\n"
+	 ".ec\n");
+}
+
+// is the vertical line before column c in row r horizontally spanned?
+
+int table::vline_spanned(int r, int c)
+{
+  assert(r >= 0 && r < nrows && c >= 0 && c < ncolumns + 1);
+  return (c != 0 && c != ncolumns && entry[r][c] != 0
+	  && entry[r][c]->start_col != c
+	  // horizontally spanning lines don't count
+	  && entry[r][c]->to_double_line_entry() == 0
+	  && entry[r][c]->to_single_line_entry() == 0);
+}
+
+int table::row_begins_section(int r)
+{
+  assert(r >= 0 && r < nrows);
+  for (int i = 0; i < ncolumns; i++)
+    if (entry[r][i] && entry[r][i]->start_row != r)
+      return 0;
+  return 1;
+}
+
+int table::row_ends_section(int r)
+{
+  assert(r >= 0 && r < nrows);
+  for (int i = 0; i < ncolumns; i++)
+    if (entry[r][i] && entry[r][i]->end_row != r)
+      return 0;
+  return 1;
+}
+
+void table::do_row(int r)
+{
+  printfs(".\\\" do row %1\n", i_to_a(r));
+  if (!(flags & NOKEEP) && row_begins_section(r))
+    prints(".if \\n[" USE_KEEPS_REG "] ." KEEP_MACRO_NAME "\n");
+  bool had_line = false;
+  stuff *p;
+  for (p = stuff_list; p && p->row < r; p = p->next)
+    ;
+  for (stuff *p1 = p; p1 && p1->row == r; p1 = p1->next)
+    if (!p1->printed && (p1->is_single_line() || p1->is_double_line())) {
+      had_line = true;
+      break;
+    }
+  if (!had_line && !row_is_all_lines[r])
+    printfs("." REPEATED_MARK_MACRO " %1\n", row_top_reg(r));
+  had_line = false;
+  for (; p && p->row == r; p = p->next)
+    if (!p->printed) {
+      p->print(this);
+      if (!had_line && (p->is_single_line() || p->is_double_line())) {
+	printfs("." REPEATED_MARK_MACRO " %1\n", row_top_reg(r));
+	had_line = true;
+      }
+    }
+  // change the row *after* printing the stuff list (which might contain .TH)
+  printfs("\\*[" TRANSPARENT_STRING_NAME "].nr " CURRENT_ROW_REG " %1\n",
+	  as_string(r));
+  if (!had_line && row_is_all_lines[r])
+    printfs("." REPEATED_MARK_MACRO " %1\n", row_top_reg(r));
+  // we might have had a .TH, for example,  since we last tried
+  if (!(flags & NOKEEP) && row_begins_section(r))
+    prints(".if \\n[" USE_KEEPS_REG "] ." KEEP_MACRO_NAME "\n");
+  printfs(".mk %1\n", row_start_reg(r));
+  prints(".mk " BOTTOM_REG "\n"
+	 "." REPEATED_VPT_MACRO " 0\n");
+  int c;
+  int row_is_blank = 1;
+  int first_start_row = r;
+  for (c = 0; c < ncolumns; c++) {
+    table_entry *e = entry[r][c];
+    if (e) {
+      if (e->end_row == r) {
+	e->do_depth();
+	if (e->start_row < first_start_row)
+	  first_start_row = e->start_row;
+	row_is_blank = 0;
+      }
+      c = e->end_col;
+    }
+  }
+  if (row_is_blank)
+    prints(".nr " BOTTOM_REG " +1v\n");
+  if (row_is_all_lines[r]) {
+    prints(".vs " LINE_SEP);
+    if (row_is_all_lines[r] == 2)
+      prints("+" DOUBLE_LINE_SEP);
+    prints(">?\\n[.V]u\n.ls 1\n");
+    prints("\\&");
+    prints("\\v'" BODY_DEPTH);
+    if (row_is_all_lines[r] == 2)
+      prints("-" HALF_DOUBLE_LINE_SEP);
+    prints("'");
+    for (c = 0; c < ncolumns; c++) {
+      table_entry *e = entry[r][c];
+      if (e) {
+	if (e->end_row == e->start_row)
+	  e->to_simple_entry()->simple_print(1);
+	c = e->end_col;
+      }
+    }
+    prints("\n");
+    prints(".ls\n"
+	   ".vs\n");
+    prints(".nr " BOTTOM_REG " \\n[" BOTTOM_REG "]>?\\n[.d]\n");
+    printfs(".sp |\\n[%1]u\n", row_start_reg(r));
+  }
+  for (int i = row_is_all_lines[r] ? r - 1 : r;
+       i >= first_start_row;
+       i--) {
+    simple_entry *first = 0;
+    for (c = 0; c < ncolumns; c++) {
+      table_entry *e = entry[r][c];
+      if (e) {
+	if (e->end_row == r && e->start_row == i) {
+	  simple_entry *simple = e->to_simple_entry();
+	  if (simple) {
+	    if (!first) {
+	      prints(".ta");
+	      first = simple;
+	    }
+	    simple->add_tab();
+	  }
+	}
+	c = e->end_col;
+      }
+    }
+    if (first) {
+      prints('\n');
+      first->position_vertically();
+      first->set_location();
+      prints("\\&");
+      first->simple_print(0);
+      for (c = first->end_col + 1; c < ncolumns; c++) {
+	table_entry *e = entry[r][c];
+	if (e) {
+	  if (e->end_row == r && e->start_row == i) {
+	    simple_entry *simple = e->to_simple_entry();
+	    if (simple) {
+	      if (e->end_row != e->start_row) {
+		prints('\n');
+		simple->position_vertically();
+		prints("\\&");
+	      }
+	      simple->simple_print(0);
+	    }
+	  }
+	  c = e->end_col;
+	}
+      }
+      prints('\n');
+      prints(".nr " BOTTOM_REG " \\n[" BOTTOM_REG "]>?\\n[.d]\n");
+      printfs(".sp |\\n[%1]u\n", row_start_reg(r));
+    }
+  }
+  for (c = 0; c < ncolumns; c++) {
+    table_entry *e = entry[r][c];
+    if (e) {
+      if (e->end_row == r && e->to_simple_entry() == 0) {
+	e->position_vertically();
+	e->print();
+	prints(".nr " BOTTOM_REG " \\n[" BOTTOM_REG "]>?\\n[.d]\n");
+	printfs(".sp |\\n[%1]u\n", row_start_reg(r));
+      }
+      c = e->end_col;
+    }
+  }
+  prints("." REPEATED_VPT_MACRO " 1\n"
+	 ".sp |\\n[" BOTTOM_REG "]u\n"
+	 "\\*[" TRANSPARENT_STRING_NAME "].nr " NEED_BOTTOM_RULE_REG " 1\n");
+  if (r != nrows - 1 && (flags & ALLBOX)) {
+    print_single_hline(r + 1);
+    prints("\\*[" TRANSPARENT_STRING_NAME "].nr " NEED_BOTTOM_RULE_REG " 0\n");
+  }
+  if (r != nrows - 1) {
+    if (p && p->row == r + 1
+	&& (p->is_single_line() || p->is_double_line())) {
+      p->print(this);
+      prints("\\*[" TRANSPARENT_STRING_NAME "].nr " NEED_BOTTOM_RULE_REG
+	     " 0\n");
+    }
+    int printed_one = 0;
+    for (vertical_rule *vr = vrule_list; vr; vr = vr->next)
+      if (vr->end_row == r) {
+	if (!printed_one) {
+	  prints("." REPEATED_VPT_MACRO " 0\n");
+	  printed_one = 1;
+	}
+	vr->print();
+      }
+    if (printed_one)
+      prints("." REPEATED_VPT_MACRO " 1\n");
+    if (!(flags & NOKEEP) && row_ends_section(r))
+      prints(".if \\n[" USE_KEEPS_REG "] ." RELEASE_MACRO_NAME "\n");
+  }
+}
+
+void table::do_top()
+{
+  prints(".\\\" do top\n");
+  prints(".ss \\n[" SAVED_INTER_WORD_SPACE_SIZE "]\n");
+  prints(".fc \002\003\n");
+  if (flags & (BOX | DOUBLEBOX | ALLBOX))
+    prints(".nr " IS_BOXED_REG " 1\n");
+  else
+    prints(".nr " IS_BOXED_REG " 0\n");
+  if (!(flags & NOKEEP) && (flags & (BOX | DOUBLEBOX | ALLBOX)))
+    prints("." TABLE_KEEP_MACRO_NAME "\n");
+  if (flags & DOUBLEBOX) {
+    prints(".ls 1\n"
+	   ".vs " LINE_SEP ">?\\n[.V]u\n"
+	   "\\v'" BODY_DEPTH "'\\s[\\n[" LINESIZE_REG "]]\\D'l \\n[TW]u 0'\\s0\n"
+	   ".vs\n"
+	   "." REPEATED_MARK_MACRO " " TOP_REG "\n"
+	   ".vs " DOUBLE_LINE_SEP ">?\\n[.V]u\n");
+    printfs("\\v'" BODY_DEPTH "'"
+	    "\\s[\\n[" LINESIZE_REG "]]"
+	    "\\h'\\n[%1]u'"
+	    "\\D'l |\\n[%2]u 0'"
+	    "\\s0"
+	    "\n",
+	    column_divide_reg(0),
+	    column_divide_reg(ncolumns));
+    prints(".ls\n"
+	   ".vs\n");
+  }
+  else if (flags & (ALLBOX | BOX))
+    print_single_hline(0);
+  // On terminal devices, a vertical rule on the first row of the table
+  // will stick out 1v above it if it the table is unboxed or lacks a
+  // horizontal rule on the first row.  This is necessary for grotty's
+  // rule intersection detection.  We must make room for it so that the
+  // vertical rule is not drawn above the top of the page.
+  else if ((flags & HAS_TOP_VLINE) && !(flags & HAS_TOP_HLINE))
+    prints(".if n .sp\n");
+  prints(".nr " STARTING_PAGE_REG " \\n%\n");
+  //printfs(".mk %1\n", row_top_reg(0));
+}
+
+void table::do_bottom()
+{
+  prints(".\\\" do bottom\n");
+  // print stuff after last row
+  for (stuff *p = stuff_list; p; p = p->next)
+    if (p->row > nrows - 1)
+      p->print(this);
+  if (!(flags & NOKEEP))
+    prints(".if \\n[" USE_KEEPS_REG "] ." RELEASE_MACRO_NAME "\n");
+  printfs(".mk %1\n", row_top_reg(nrows));
+  prints(".nr " NEED_BOTTOM_RULE_REG " 1\n"
+	 ".nr T. 1\n"
+	 // protect # in macro name against eqn
+	 ".ig\n"
+	 ".EQ\n"
+	 "delim off\n"
+	 ".EN\n"
+	 "..\n"
+	 ".T#\n"
+	 ".ig\n"
+	 ".EQ\n"
+	 "delim on\n"
+	 ".EN\n"
+	 "..\n");
+  if (!(flags & NOKEEP) && (flags & (BOX | DOUBLEBOX | ALLBOX)))
+    prints("." TABLE_RELEASE_MACRO_NAME "\n");
+  if (flags & DOUBLEBOX)
+    prints(".sp " DOUBLE_LINE_SEP "\n");
+  // Horizontal box lines take up an entire row on nroff devices (maybe
+  // a half-row if we ever support [emulators of] devices like the
+  // Teletype Model 37 with half-line motions).
+  if (flags & (BOX | DOUBLEBOX | ALLBOX))
+    prints(".if n .sp\n");
+  // Space again for the doublebox option, until we can draw that more
+  // attractively; see Savannah #43637.
+  if (flags & DOUBLEBOX)
+    prints(".if n .sp\n");
+  prints("." RESET_MACRO_NAME "\n"
+	 ".nn \\n[" SAVED_NUMBERING_SUPPRESSION_COUNT "]\n"
+	 ".ie \\n[" SAVED_NUMBERING_LINENO "] "
+	 ".nm \\n[" SAVED_NUMBERING_LINENO "]\n"
+	 ".el .nm\n"
+	 ".fc\n"
+	 ".cp \\n(" COMPATIBLE_REG "\n");
+}
+
+int table::get_nrows()
+{
+  return nrows;
+}
+
+const char *last_filename = 0;
+
+void set_troff_location(const char *fn, int ln)
+{
+  if (!location_force_filename && last_filename != 0
+      && strcmp(fn, last_filename) == 0)
+    printfs(".lf %1\n", as_string(ln));
+  else {
+    string filename(fn);
+    filename += '\0';
+    normalize_for_lf(filename);
+    printfs(".lf %1 %2\n", as_string(ln), filename.contents());
+    last_filename = fn;
+    location_force_filename = 0;
+  }
+}
+
+void printfs(const char *s, const string &arg1, const string &arg2,
+	     const string &arg3, const string &arg4, const string &arg5)
+{
+  if (s) {
+    char c;
+    while ((c = *s++) != '\0') {
+      if (c == '%') {
+	switch (*s++) {
+	case '1':
+	  prints(arg1);
+	  break;
+	case '2':
+	  prints(arg2);
+	  break;
+	case '3':
+	  prints(arg3);
+	  break;
+	case '4':
+	  prints(arg4);
+	  break;
+	case '5':
+	  prints(arg5);
+	  break;
+	case '6':
+	case '7':
+	case '8':
+	case '9':
+	  break;
+	case '%':
+	  prints('%');
+	  break;
+	default:
+	  assert(0 == "printfs format character not in [1-9%]");
+	}
+      }
+      else
+	prints(c);
+    }
+  }
+}
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/tbl/table.h b/src/preproc/tbl/table.h
new file mode 100644
index 0000000..62346fa
--- /dev/null
+++ b/src/preproc/tbl/table.h
@@ -0,0 +1,179 @@
+/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
+     Written by James Clark (jjc@jclark.com)
+
+This file is part of groff.
+
+groff is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+groff is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include "lib.h"
+
+#include <stdlib.h>
+#include <ctype.h>
+#include <errno.h>
+
+#include "cset.h"
+#include "cmap.h"
+#include "stringclass.h"
+#include "errarg.h"
+#include "error.h"
+#include "lf.h"
+
+// PREFIX and PREFIX_CHAR must be the same.
+#define PREFIX "3"
+#define PREFIX_CHAR '3'
+
+// LEADER and LEADER_CHAR must be the same.
+#define LEADER "a"
+#define LEADER_CHAR 'a'
+
+struct inc_number {
+  short inc;
+  short val;
+};
+
+struct entry_modifier {
+  inc_number point_size;
+  inc_number vertical_spacing;
+  string font;
+  string macro;
+  enum { CENTER, TOP, BOTTOM } vertical_alignment;
+  char zero_width;
+  char stagger;
+
+  entry_modifier();
+  ~entry_modifier();
+};
+
+enum format_type {
+  FORMAT_LEFT, 
+  FORMAT_CENTER, 
+  FORMAT_RIGHT, 
+  FORMAT_NUMERIC,
+  FORMAT_ALPHABETIC,
+  FORMAT_SPAN, 
+  FORMAT_VSPAN,
+  FORMAT_HLINE,
+  FORMAT_DOUBLE_HLINE
+};
+
+struct entry_format : public entry_modifier {
+  format_type type;
+
+  entry_format(format_type);
+  entry_format();
+  void debug_print() const;
+};
+
+class table_entry;
+struct horizontal_span;
+struct stuff;
+struct vertical_rule;
+
+class table {
+  int nrows;
+  int ncolumns;
+  int linesize;
+  char delim[2];
+  char decimal_point_char;
+  vertical_rule *vrule_list;
+  stuff *stuff_list;
+  horizontal_span *span_list;
+  table_entry *entry_list;
+  table_entry **entry_list_tailp;
+  table_entry ***entry;
+  char **vline;
+  char *row_is_all_lines;
+  string *minimum_width;
+  int *column_separation;
+  char *equal;
+  int left_separation; // from a vertical rule or box border, in ens
+  int right_separation; // from a vertical rule or box border, in ens
+  int total_separation;
+  int allocated_rows;
+  void build_span_list();
+  void compute_overall_width();
+  void do_hspan(int r, int c);
+  void do_vspan(int r, int c);
+  void allocate(int r);
+  void compute_widths();
+  void divide_span(int, int);
+  void sum_columns(int, int, int);
+  void compute_total_separation();
+  void compute_separation_factor();
+  void compute_column_positions();
+  void do_row(int);
+  void init_output();
+  void add_stuff(stuff *);
+  void do_top();
+  void do_bottom();
+  void do_vertical_rules();
+  void build_vrule_list();
+  void add_vertical_rule(int, int, int, int);
+  void define_bottom_macro();
+  int vline_spanned(int r, int c);
+  int row_begins_section(int);
+  int row_ends_section(int);
+  void make_columns_equal();
+  void compute_vrule_top_adjust(int, int, string &);
+  void compute_vrule_bot_adjust(int, int, string &);
+  void determine_row_type();
+  int count_expand_columns();
+public:
+  unsigned flags;
+  enum {
+    CENTER        = 0x00000001,
+    EXPAND        = 0x00000002,
+    BOX           = 0x00000004,
+    ALLBOX        = 0x00000008,
+    DOUBLEBOX     = 0x00000010,
+    NOKEEP        = 0x00000020,
+    NOSPACES      = 0x00000040,
+    NOWARN        = 0x00000080,
+    // The next few properties help manage nroff mode output.
+    HAS_TOP_VLINE = 0x00000100,
+    HAS_TOP_HLINE = 0x00000200,
+    GAP_EXPAND    = 0x00000400,
+    EXPERIMENTAL  = 0x80000000 // undocumented
+    };
+  char *expand;
+  table(int nc, unsigned flags, int linesize, char decimal_point_char);
+  ~table();
+
+  void add_text_line(int r, const string &, const char *, int);
+  void add_single_hline(int r);
+  void add_double_hline(int r);
+  void add_entry(int r, int c, const string &, const entry_format *,
+		 const char *, int lineno);
+  void add_vlines(int r, const char *);
+  void check();
+  void print();
+  void set_minimum_width(int c, const string &w);
+  void set_column_separation(int c, int n);
+  void set_equal_column(int c);
+  void set_expand_column(int c);
+  void set_delim(char c1, char c2);
+  void print_single_hline(int r);
+  void print_double_hline(int r);
+  int get_nrows();
+};
+
+void set_troff_location(const char *, int);
+
+extern int compatible_flag;
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
diff --git a/src/preproc/tbl/tbl.1.man b/src/preproc/tbl/tbl.1.man
new file mode 100644
index 0000000..4c9a98a
--- /dev/null
+++ b/src/preproc/tbl/tbl.1.man
@@ -0,0 +1,2018 @@
+'\" t
+.TH @g@tbl @MAN1EXT@ "@MDATE@" "groff @VERSION@"
+.SH Name
+@g@tbl \- prepare tables for
+.I groff
+documents
+.
+.
+.\" ====================================================================
+.\" Legal Terms
+.\" ====================================================================
+.\"
+.\" Copyright (C) 1989-2023 Free Software Foundation, Inc.
+.\"
+.\" Permission is granted to make and distribute verbatim copies of this
+.\" manual provided the copyright notice and this permission notice are
+.\" preserved on all copies.
+.\"
+.\" Permission is granted to copy and distribute modified versions of
+.\" this manual under the conditions for verbatim copying, provided that
+.\" the entire resulting derived work is distributed under the terms of
+.\" a permission notice identical to this one.
+.\"
+.\" Permission is granted to copy and distribute translations of this
+.\" manual into another language, under the above conditions for
+.\" modified versions, except that this permission notice may be
+.\" included in translations approved by the Free Software Foundation
+.\" instead of in the original English.
+.
+.
+.\" Save and disable compatibility mode (for, e.g., Solaris 10/11).
+.do nr *groff_tbl_1_man_C \n[.cp]
+.cp 0
+.
+.\" Define fallback for groff 1.23's MR macro if the system lacks it.
+.nr do-fallback 0
+.if !\n(.f           .nr do-fallback 1 \" mandoc
+.if  \n(.g .if !d MR .nr do-fallback 1 \" older groff
+.if !\n(.g           .nr do-fallback 1 \" non-groff *roff
+.if \n[do-fallback]  \{\
+.  de MR
+.    ie \\n(.$=1 \
+.      I \%\\$1
+.    el \
+.      IR \%\\$1 (\\$2)\\$3
+.  .
+.\}
+.rr do-fallback
+.
+.
+.\" ====================================================================
+.SH Synopsis
+.\" ====================================================================
+.
+.SY @g@tbl
+.RB [ \-C ]
+.RI [ file\~ .\|.\|.]
+.YS
+.
+.
+.SY @g@tbl
+.B \-\-help
+.YS
+.
+.
+.SY @g@tbl
+.B \-v
+.
+.SY @g@tbl
+.B \-\-version
+.YS
+.
+.
+.\" ====================================================================
+.SH Description
+.\" ====================================================================
+.
+The GNU implementation of
+.I tbl \" generic
+is part of the
+.MR groff @MAN1EXT@
+document formatting system.
+.
+.I @g@tbl
+is a
+.MR @g@troff @MAN1EXT@
+preprocessor that translates descriptions of tables embedded in
+.MR roff @MAN7EXT@
+input files into the language understood by
+.IR @g@troff .
+.
+It copies the contents of each
+.I file
+to the standard output stream,
+except that lines between
+.B .TS
+and
+.B .TE
+are interpreted as table descriptions.
+.
+While GNU
+.IR tbl 's \" GNU
+input syntax is highly compatible with AT&T
+.IR tbl , \" AT&T
+the output GNU
+.I tbl \" GNU
+produces cannot be processed by AT&T
+.IR troff ; \" AT&T
+GNU
+.I troff \" GNU
+(or a
+.I troff \" generic
+implementing any GNU extensions employed)
+must be used.
+.
+Normally,
+.I @g@tbl
+is not executed directly by the user,
+but invoked by specifying the
+.B \-t
+option to
+.MR groff @MAN1EXT@ .
+.
+If no
+.I file
+operands are given on the command line,
+or if
+.I file
+is
+.RB \[lq] \- \[rq],
+.I @g@tbl
+reads the standard input stream.
+.
+.
+.\" ====================================================================
+.SS Overview
+.\" ====================================================================
+.
+.I @g@tbl
+expects to find table descriptions between input lines that begin with
+.B .TS
+(table start)
+and
+.B .TE
+(table end).
+.
+Each such
+.I table region
+encloses one or more table descriptions.
+.
+Within a table region,
+table descriptions beyond the first must each be preceded
+by an input line beginning with
+.BR .T& .
+.
+This mechanism does not start a new table region;
+all table descriptions are treated as part of their
+.BR .TS / .TE
+enclosure,
+even if they are boxed or have column headings that repeat on subsequent
+pages
+(see below).
+.
+.
+.P
+(Experienced
+.I roff
+users should observe that
+.I @g@tbl
+is not a
+.I roff
+language interpreter:
+the default control character must be used,
+and no spaces or tabs are permitted between the control character and
+the macro name.
+.
+These
+.I @g@tbl
+input tokens remain as-is in the output,
+where they become ordinary macro calls.
+.
+Macro packages often define
+.BR TS ,
+.BR T& ,
+and
+.B TE
+macros to handle issues of table placement on the page.
+.
+.I @g@tbl
+produces
+.I groff
+code to define these macros as empty if their definitions do not exist
+when the formatter encounters a table region.)
+.
+.
+.P
+Each table region may begin with
+.I region options,
+and must contain one or more
+.I table definitions;
+each table definition contains a
+.I format specification
+followed by one or more input lines (rows) of
+.I entries.
+.
+These entries comprise the
+.I table data.
+.
+.
+.
+.\" ====================================================================
+.SS "Region options"
+.\" ====================================================================
+.
+The line immediately following the
+.B .TS
+token may specify region options,
+keywords that influence the interpretation or rendering of the region as
+a whole or all table entries within it indiscriminately.
+.
+They must be separated by commas,
+spaces,
+or tabs.
+.
+Those that require a parenthesized argument permit spaces and tabs
+between the option's name and the opening parenthesis.
+.
+Options accumulate and cannot be unset within a region once declared;
+if an option that takes a parameter is repeated,
+the last occurrence controls.
+.
+If present,
+the set of region options must be terminated with a semicolon
+.RB ( ; ).
+.
+.
+.P
+Any of the
+.BR allbox ,
+.BR box ,
+.BR doublebox ,
+.BR frame ,
+and
+.B doubleframe
+region options makes a table \[lq]boxed\[rq] for the purpose of later
+discussion.
+.
+.
+.TP
+.B allbox
+Enclose each table entry in a box;
+implies
+.BR box .
+.
+.
+.TP
+.B box
+Enclose the entire table region in a box.
+.
+As a GNU extension,
+the alternative option name
+.B frame
+is also recognized.
+.
+.
+.TP
+.B center
+Center the table region with respect to the current indentation and line
+length;
+the default is to left-align it.
+.
+As a GNU extension,
+the alternative option name
+.B centre
+is also recognized.
+.
+.
+.TP
+.BI decimalpoint( c )
+Recognize character
+.I c
+as the decimal separator in columns using the
+.B N
+(numeric) classifier
+(see subsection \[lq]Column classifiers\[rq] below).
+.
+This is a GNU extension.
+.
+.
+.TP
+.BI delim( xy )
+Recognize characters
+.I x
+.RI and\~ y
+as start and end delimiters,
+respectively,
+for
+.MR @g@eqn @MAN1EXT@
+input,
+and ignore input between them.
+.
+.I x
+.RI and\~ y
+need not be distinct.
+.
+.
+.TP
+.B doublebox
+Enclose the entire table region in a double box;
+implies
+.BR box .
+.
+As a GNU extension,
+the alternative option name
+.B \%doubleframe
+is also recognized.
+.
+.
+.TP
+.B expand
+Spread the table horizontally to fill the available space
+(line length minus indentation)
+by increasing column separation.
+.
+Ordinarily,
+a table is made only as wide as necessary to accommodate the widths of
+its entries and its column separations
+(whether specified or default).
+.
+When
+.B expand
+applies to a table that exceeds the available horizontal space,
+column separation is reduced as far as necessary
+(even to zero).
+.
+.I @g@tbl
+produces
+.I groff
+input that issues a diagnostic if such compression occurs.
+.
+The column modifier
+.B x
+(see below)
+overrides this option.
+.
+.
+.TP
+.BI linesize( n )
+Draw lines or rules
+(e.g.,
+from
+.BR box )
+with a thickness of
+.IR n \~points.
+.
+The default is the current type size when the region begins.
+.
+This option is ignored on terminal devices.
+.
+.
+.TP
+.B nokeep
+Don't use
+.I roff
+diversions to manage page breaks.
+.
+Normally,
+.I @g@tbl
+employs them to avoid breaking a page within a table row.
+.
+This usage can sometimes interact badly with macro packages' own use of
+diversions\[em]when footnotes,
+for example,
+are employed.
+.
+This is a GNU extension.
+.
+.
+.TP
+.B nospaces
+Ignore leading and trailing spaces in table entries.
+.
+This is a GNU extension.
+.
+.
+.TP
+.B nowarn
+Suppress diagnostic messages produced at document formatting time when
+the line or page lengths are inadequate to contain a table row.
+.
+This is a GNU extension.
+.
+.
+.\" TODO: How about "right"?  (and "left" for symmetry)
+.TP
+.BI tab( c )
+Use the character
+.I c
+instead of a tab to separate entries in a row of table data.
+.
+.
+.\" ====================================================================
+.SS "Table format specification"
+.\" ====================================================================
+.
+The table format specification is mandatory:
+it determines the number of columns in the table and directs how the
+entries within it are to be typeset.
+.
+The format specification is a series of column
+.I descriptors.
+.
+Each descriptor encodes a
+.I classifier
+followed by zero or more
+.I modifiers.
+.
+Classifiers are letters
+(recognized case-insensitively)
+or punctuation symbols;
+modifiers consist of or begin with letters or numerals.
+.
+Spaces,
+tabs,
+newlines,
+and commas separate descriptors.
+.
+Newlines and commas are special;
+they apply the descriptors following them to a subsequent row of the
+table.
+.
+(This enables column headings to be centered or emboldened while the
+table entries for the data are not,
+for instance.)
+.
+We term the resulting group of column descriptors a
+.I row definition.
+.
+Within a row definition,
+separation between column descriptors
+(by spaces or tabs)
+is often optional;
+only some modifiers,
+described below,
+make separation necessary.
+.
+.
+.P
+Each column descriptor begins with a mandatory
+.I classifier,
+a character that selects from one of several arrangements.
+.
+Some determine the positioning of table entries within a rectangular
+cell:
+centered,
+left-aligned,
+numeric
+(aligned to a configurable decimal separator),
+and so on.
+.
+Others perform special operations like drawing lines or spanning entries
+from adjacent cells in the table.
+.
+Except for
+.RB \[lq] | \[rq],
+any classifier can be followed by one or more
+.I modifiers;
+some of these accept an argument,
+which in GNU
+.I tbl \" GNU
+can be parenthesized.
+.\" AT&T tbl allowed parentheses only after 'w'.
+.\" TODO: Accept parentheses after 'p' and 'v'.
+.
+Modifiers select fonts,
+set the type size,
+.\"define the column width,
+.\"adjust inter-column spacing, \" slack text for window/orphan control
+and perform other tasks described below.
+.
+.
+.P
+The format specification can occupy multiple input lines,
+but must conclude with a dot
+.RB \[lq] .\& \[rq]
+followed by a newline.
+.
+Each row definition is applied in turn to one row of the table.
+.
+The last row definition is applied to rows of table data in excess of
+the row definitions.
+.
+.
+.P
+For clarity in this document's examples,
+we shall write classifiers in uppercase and modifiers in lowercase.
+.
+Thus,
+.RB \[lq] CbCb,LR.\& \[rq]
+defines two rows of two columns.
+.
+The first row's entries are centered and boldfaced;
+the second and any further rows' first and second columns are left- and
+right-aligned,
+respectively.
+.
+.\" slack text for window/orphan control
+.\"If more rows of entries are added to the table data,
+.\"they reuse the row definition
+.\".RB \[lq] LR \[rq].
+.
+.
+.P
+The row definition with the most column descriptors determines the
+number of columns in the table;
+any row definition with fewer is implicitly extended on the right-hand
+side with
+.B L
+classifiers as many times as necessary to make the table rectangular.
+.
+.
+.\" ====================================================================
+.SS "Column classifiers"
+.\" ====================================================================
+.
+The
+.BR L ,
+.BR R ,
+and
+.B C
+classifiers are the easiest to understand and use.
+.
+.
+.TP
+.BR A ,\~ a
+Center longest entry in this column,
+left-align remaining entries in the column with respect to the centered
+entry,
+then indent all entries by one en.
+.
+Such \[lq]alphabetic\[rq] entries
+(hence the name of the classifier)
+can be used in the same column as
+.BR L -classified
+entries,
+as in
+.RB \[lq] LL,AR.\& \[rq].
+.
+The
+.B A
+entries are often termed \[lq]sub-columns\[rq] due to their indentation.
+.
+.
+.TP
+.BR C ,\~ c
+Center entry within the column.
+.
+.
+.TP
+.BR L ,\~ l
+Left-align entry within the column.
+.
+.
+.TP
+.BR N ,\~ n
+Numerically align entry in the column.
+.
+.I @g@tbl
+aligns columns of numbers vertically at the units place.
+.
+If multiple decimal separators are adjacent to a digit,
+it uses the rightmost one for vertical alignment.
+.
+If there is no decimal separator,
+the rightmost digit is used for vertical alignment;
+otherwise,
+.I @g@tbl
+centers the entry within the column.
+.
+The
+.I roff
+dummy character
+.B \[rs]&
+in an entry marks the glyph preceding it
+(if any)
+as the units place;
+if multiple instances occur in the data,
+the leftmost is used for alignment.
+.
+.
+.IP
+If
+.BR N -classified
+entries share a column with
+.B L
+or
+.BR R \~entries,
+.I @g@tbl
+centers the widest
+.BR N \~entry
+with respect to the widest
+.B L
+or
+.BR R \~entry,
+preserving the alignment of
+.BR N \~entries
+with respect to each other.
+.
+.
+.IP
+The appearance of
+.I @g@eqn
+equations
+within
+.BR N -classified
+columns
+can be troublesome due to the foregoing textual scan for a decimal
+separator.
+.
+Use the
+.B \%delim
+region option to make
+.I @g@tbl
+ignore the data within
+.I eqn
+delimiters for that purpose.
+.
+.
+.TP
+.BR R ,\~ r
+Right-align entry within the column.
+.
+.
+.TP
+.BR S ,\~ s
+Span previous entry on the left into this column.
+.
+.
+.TP
+.B \[ha]
+Span entry in the same column from the previous row into this row.
+.
+.
+.TP
+.BR _ ,\~ \-
+Replace table entry with a horizontal rule.
+.
+An empty table entry is expected to correspond to this classifier;
+if data are found there,
+.I @g@tbl
+issues a diagnostic message.
+.
+.
+.TP
+.B =
+Replace table entry with a double horizontal rule.
+.
+An empty table entry is expected to correspond to this classifier;
+if data are found there,
+.I @g@tbl
+issues a diagnostic message.
+.
+.
+.TP
+.B |
+Place a vertical rule (line) on the corresponding row of the table
+(if two of these are adjacent,
+a double vertical rule).
+.
+This classifier does not contribute to the column count and no table
+entries correspond to it.
+.
+A
+.B |
+to the left of the first column descriptor or to the right of the last
+one produces a vertical rule at the edge of the table;
+these are redundant
+(and ignored)
+in boxed tables.
+.
+.
+.P
+To change the table format within a
+.I @g@tbl
+region,
+use the
+.B .T&
+token at the start of a line.
+.
+It is followed by a format specification and table data,
+but
+.I not
+region options.
+.
+The quantity of columns in a new table format thus introduced cannot
+increase relative to the previous table format;
+in that case,
+you must end the table region and start another.
+.
+If that will not serve because the region uses box options or the
+columns align in an undesirable manner,
+you must design the initial table format specification to include the
+maximum quantity of columns required,
+and use the
+.B S
+horizontal spanning classifier where necessary to achieve the desired
+columnar alignment.
+.
+.
+.P
+Attempting to horizontally span in the first column or vertically span
+on the first row is an error.
+.
+Non-rectangular span areas are also not supported.
+.
+.
+.\" ====================================================================
+.SS "Column modifiers"
+.\" ====================================================================
+.
+Any number of modifiers can follow a column classifier.
+.
+Arguments to modifiers,
+where accepted,
+are case-sensitive.
+.
+If the same modifier is applied to a column specifier more than once,
+or if conflicting modifiers are applied,
+only the last occurrence has effect.
+.
+The
+.RB modifier\~ x
+is mutually exclusive with
+.B e
+.RB and\~ w ,
+but
+.B e
+is not mutually exclusive
+.RB with\~ w ;
+if these are used in combination,
+.BR x \~unsets
+both
+.B e
+.RB and\~ w ,
+while either
+.B e
+or
+.B w
+.RB overrides\~ x .
+.
+.
+.br
+.ne 4v \" Keep next two tagged paragraphs together.
+.TP
+.BR b ,\~ B
+Typeset entry in boldface,
+abbreviating
+.BR f(B) .
+.
+.
+.TP
+.BR d ,\~ D
+Align a vertically spanned table entry to the bottom
+(\[lq]down\[rq]),
+instead of the center,
+of its range.
+.
+This is a GNU extension.
+.
+.
+.TP
+.BR e ,\~ E
+Equalize the widths of columns with this modifier.
+.
+The column with the largest width controls.
+.
+This modifier sets the default line length used in a text block.
+.
+.
+.TP
+.BR f ,\~ F
+Select the typeface for the table entry.
+.
+This modifier must be followed by a font or style name
+(one or two characters not starting with a digit),
+font mounting position
+(a single digit),
+or a name or mounting position of any length in parentheses.
+.
+The last form is a GNU extension.
+.
+(The parameter corresponds to that accepted by the
+.I troff \" generic
+.B ft
+request.)
+.
+A one-character argument not in parentheses must be separated by one or
+more spaces or tabs from what follows.
+.
+.
+.TP
+.BR i ,\~ I
+Typeset entry in an oblique or italic face,
+abbreviating
+.BR f(I) .
+.
+.
+.TP
+.BR m ,\~ M
+Call a
+.I groff
+macro before typesetting a text block
+(see subsection \[lq]Text blocks\[rq] below).
+.
+This is a GNU extension.
+.
+This modifier must be followed by a macro name of one or two characters
+or a name of any length in parentheses.
+.
+A one-character macro name not in parentheses must be separated by one
+or more spaces or tabs from what follows.
+.
+The named macro must be defined before the table region containing this
+column modifier is encountered.
+.
+The macro should contain only simple
+.I groff
+requests to change text formatting,
+like adjustment or hyphenation.
+.
+The macro is called
+.I after
+the column modifiers
+.BR b ,
+.BR f ,
+.BR i ,
+.BR p ,
+and
+.B v
+take effect;
+it can thus override other column modifiers.
+.
+.
+.TP
+.BR p ,\~ P
+Set the type size for the table entry.
+.
+This modifier must be followed by an
+.RI integer\~ n
+with an optional leading sign.
+.
+If unsigned,
+the type size is set to
+.IR n \~scaled
+points.
+.
+Otherwise,
+the type size is incremented or decremented per the sign by
+.IR n \~scaled
+points.
+.
+The use of a signed multi-digit number is a GNU extension.
+.
+(The parameter corresponds to that accepted by the
+.I troff \" generic
+.B ps
+request.)
+.
+If a type size modifier is followed by a column separation modifier
+(see below),
+they must be separated by at least one space or tab.
+.\" TODO: Allow parentheses so scaling units and fractional values can
+.\" be used?
+.
+.
+.TP
+.BR t ,\~ T
+Align a vertically spanned table entry to the top,
+instead of the center,
+of its range.
+.
+.
+.TP
+.BR u ,\~ U
+Move the column up one half-line,
+\[lq]staggering\[rq] the rows.
+.
+This is a GNU extension.
+.
+.
+.TP
+.BR v ,\~ V
+Set the vertical spacing to be used in a text block.
+.
+This modifier must be followed by an
+.RI integer\~ n
+with an optional leading sign.
+.
+If unsigned,
+the vertical spacing is set to
+.IR n\~ points.
+.
+Otherwise,
+the vertical spacing is incremented or decremented per the sign by
+.IR n\~ points.
+.
+The use of a signed multi-digit number is a GNU extension.
+.
+(This parameter corresponds to that accepted by the
+.I troff \" generic
+.B vs
+request.)
+.
+If a vertical spacing modifier is followed by a column separation
+modifier
+(see below),
+they must be separated by at least one space or tab.
+.\" TODO: Allow parentheses so scaling units and fractional values can
+.\" be used?
+.
+.
+.TP
+.BR w ,\~ W
+Set the column's minimum width.
+.
+This modifier must be followed by a number,
+which is either a unitless integer,
+or a
+.I roff
+horizontal measurement in parentheses.
+.
+Parentheses are required if the width is to be followed immediately by
+an explicit column separation
+(alternatively,
+follow the width with one or more spaces or tabs).
+.
+If no unit is specified,
+ens are assumed.
+.
+This modifier sets the default line length used in a text block.
+.
+.
+.TP
+.BR x ,\~ X
+Expand the column.
+.
+After computing the column widths,
+distribute any remaining line length evenly over all columns bearing
+this modifier.
+.
+Applying the
+.BR x \~modifier
+to more than one column is a GNU extension.
+.\" 'x' wasn't documented at all in Lesk 1979.
+.
+This modifier sets the default line length used in a text block.
+.
+.
+.TP
+.BR z ,\~ Z
+Ignore the table entries corresponding to this column for width
+calculation purposes;
+that is,
+compute the column's width using only the information in its descriptor.
+.
+.
+.TP
+.I n
+A numeric suffix on a column descriptor sets the separation distance
+(in ens)
+from the succeeding column;
+the default separation is
+.BR 3n .
+.
+This separation is
+proportionally multiplied if the
+.B expand
+region option is in effect;
+in the case of tables wider than the output line length,
+this separation might be zero.
+.
+A negative separation cannot be specified.
+.
+A separation amount after the last column in a row is nonsensical and
+provokes a diagnostic from
+.IR @g@tbl .
+.
+.
+.\" ====================================================================
+.SS "Table data"
+.\" ====================================================================
+.
+The table data come after the format specification.
+.
+Each input line corresponds to a table row,
+except that a backslash at the end of a line of table data continues an
+entry on the next input line.
+.
+(Text blocks,
+discussed below,
+also spread table entries across multiple input lines.)
+.
+Table entries within a row are separated in the input by a tab character
+by default;
+see the
+.B tab
+region option above.
+.
+Excess entries in a row of table data
+(those that have no corresponding column descriptor,
+not even an implicit one arising from rectangularization of the table)
+are discarded with a diagnostic message.
+.
+.I roff
+control lines are accepted between rows of table data and within text
+blocks.
+.
+If you wish to visibly mark an empty table entry in the document source,
+populate it with the
+.B \[rs]&
+.I roff
+dummy character.
+.
+The table data are interrupted by a line consisting of the
+.B .T&
+input token,
+and conclude with the line
+.BR .TE .
+.
+.
+.P
+Ordinarily,
+a table entry is typeset rigidly.
+.
+It is not filled,
+broken,
+hyphenated,
+adjusted,
+or populated with additional inter-sentence space.
+.
+.I @g@tbl
+instructs the formatter to measure each table entry as it occurs in the
+input,
+updating the width required by its corresponding column.
+.
+If the
+.B z
+modifier applies to the column,
+this measurement is ignored;
+if
+.B w
+applies and its argument is larger than this width,
+that argument is used instead.
+.
+In contrast to conventional
+.I roff
+input
+(within a paragraph,
+say),
+changes to text formatting,
+such as font selection or vertical spacing,
+do not persist between entries.
+.
+.
+.P
+Several forms of table entry are interpreted specially.
+.
+.
+.IP \[bu] 2n
+If a table row contains only an underscore or equals sign
+.RB ( _
+or
+.BR = ),
+a single or double horizontal rule (line),
+respectively,
+is drawn across the table at that point.
+.
+.
+.IP \[bu] 2n
+A table entry containing only
+.B _
+or
+.B =
+on an otherwise populated row is replaced by a single or double
+horizontal rule,
+respectively,
+joining its
+neighbors.
+.
+.
+.IP \[bu] 2n
+Prefixing a lone underscore or equals sign with a backslash also has
+meaning.
+.
+If a table entry consists only of
+.B \[rs]_
+or
+.B \[rs]=
+on an otherwise populated row,
+it is replaced by a single or double horizontal rule,
+respectively,
+that does
+.I not
+(quite) join its neighbors.
+.
+.
+.IP \[bu]
+A table entry consisting of
+.BI \[rs]R x\c
+,
+where
+.IR x \~is
+any
+.I roff
+ordinary or special character,
+is replaced by enough repetitions of the glyph corresponding
+.RI to\~ x
+to fill the column,
+albeit without joining its neighbors.
+.\" TODO: Bad things happen if there's garbage in the entry after 'x',
+.\" which can be a *roff special character escape sequence, so
+.\" validation is not trivial.
+.
+.
+.IP \[bu]
+On any row but the first,
+a table entry of
+.B \[rs]\[ha]
+causes the entry above it to span down into the current one.
+.
+.
+.P
+On occasion,
+these special tokens may be required as literal table data.
+.
+To use either
+.B _
+or
+.B =
+literally and alone in an entry,
+prefix or suffix it with the
+.I roff
+dummy character
+.BR \[rs]& .
+.
+To express
+.BR \[rs]_ ,
+.BR \[rs]= ,
+or
+.BR \[rs]R ,
+use a
+.I roff
+escape sequence to interpolate the backslash
+.RB ( \[rs]e
+or
+.BR \[rs][rs] ).
+.
+A reliable way to emplace the
+.B \[rs]\[ha]
+glyph sequence within a table entry is to use a pair of
+.I groff
+special character escape sequences
+.RB ( \[rs][rs]\[rs][ha] ).
+.
+.
+.P
+Rows of table entries can be interleaved with
+.I groff
+control lines;
+these do not count as table data.
+.
+On such lines the default control character
+.RB ( .\& )
+must be used
+(and not changed);
+the no-break control character is not recognized.
+.
+To start the first table entry in a row with a dot,
+precede it with the
+.I roff
+dummy character
+.BR \[rs]& .
+.
+.
+.\" ====================================================================
+.SS "Text blocks"
+.\" ====================================================================
+.
+An ordinary table entry's contents can make a column,
+and therefore the table,
+excessively wide;
+the table then exceeds the line length of the page,
+and becomes ugly or is exposed to truncation by the output device.
+.
+When a table entry requires more conventional typesetting,
+breaking across more than one output line
+(and thereby increasing the height of its row),
+it can be placed within a
+.I text block.
+.
+.
+.P
+.I @g@tbl
+interprets a table entry beginning with
+.RB \[lq] T{ \[rq]
+at the end of an input line not as table data,
+but as a token starting a text block.
+.
+Similarly,
+.RB \[lq] T} \[rq]
+at the start of an input line ends a text block;
+it must also end the table entry.
+.
+Text block tokens can share an input line with other table data
+(preceding
+.B T{
+and following
+.BR T} ).
+.
+Input lines between these tokens are formatted in a diversion by
+.IR troff . \" generic
+.
+Text blocks cannot be nested.
+.
+Multiple text blocks can occur in a table row.
+.
+.
+.P
+Text blocks are formatted as was the text prior to the table,
+modified by applicable column descriptors.
+.
+Specifically,
+the classifiers
+.BR A ,
+.BR C ,
+.BR L ,
+.BR N ,
+.BR R ,
+and
+.B S
+determine a text block's
+.I alignment
+within its cell,
+but not its
+.I adjustment.
+.
+Add
+.B na
+or
+.B ad
+requests to the beginning of a text block to alter its adjustment
+distinctly from other text in the document.
+.
+As with other table entries,
+when a text block ends,
+any alterations to formatting parameters are discarded.
+.
+They do not affect subsequent table entries,
+not even other text blocks.
+.
+.
+.P
+.ne 2v
+If
+.B w
+or
+.B x
+modifiers are not specified for
+.I all
+columns of a text block's span,
+the default length of the text block
+(more precisely,
+the line length used to process the text block diversion)
+is computed as
+.IR L \[tmu] C /( N +1),
+.\" ...and rounded to the horizontal motion quantum of the output device
+where
+.I L
+is the current line length,
+.I C
+the number of columns spanned by the text block,
+and
+.I N
+the number of columns in the table.
+.
+If necessary,
+you can also control a text block's width by including an
+.B ll
+(line length)
+request in it prior to any text to be formatted.
+.
+Because a diversion is used to format the text block,
+its height and width are subsequently available in the registers
+.B dn
+and
+.BR dl ,
+respectively.
+.
+.
+.\" ====================================================================
+.SS \f[I]roff\f[] interface
+.\" ====================================================================
+.
+The register
+.B TW
+stores the width of the table region in basic units;
+it can't be used within the region itself,
+but is defined before the
+.B .TE
+token is output so that a
+.I groff
+macro named
+.B TE
+can make use of it.
+.
+.B T.\&
+is a Boolean-valued register indicating whether the bottom of the table
+is being processed.
+.
+The
+.B #T
+register marks the top of the table.
+.
+Avoid using these names for any other purpose.
+.
+.
+.P
+.I @g@tbl
+also defines a macro
+.B T#
+to produce the bottom and side lines of a boxed table.
+.
+While
+.I @g@tbl
+itself arranges for the output to include a call of this macro at the
+end of such a table,
+it can also be used by macro packages to create boxes for multi-page
+tables by calling it from a page footer macro that is itself called by
+a trap planted near the bottom of the page.
+.
+See section \[lq]Limitations\[rq] below for more on multi-page tables.
+.
+.
+.P
+GNU
+.I tbl \" GNU
+.\" AT&T tbl used all kinds of registers; many began with "3".
+internally employs register,
+string,
+macro,
+and diversion names beginning with the
+.RB numeral\~ 3 .
+.
+A document to be preprocessed with GNU
+.I tbl \" GNU
+should not use any such identifiers.
+.\" XXX: Why are they not named starting with "gtbl*" or something?  GNU
+.\" tbl turns AT&T troff compatibility mode off anyway.
+.
+.
+.\" ====================================================================
+.SS "Interaction with \f[I]@g@eqn\f[]"
+.\" ====================================================================
+.
+.I @g@tbl
+should always be called before
+.MR @g@eqn @MAN1EXT@ .
+.
+(\c
+.MR groff @MAN1EXT@
+automatically arranges preprocessors in the correct order.)
+.
+Don't call the
+.B EQ
+and
+.B EN
+macros within tables;
+instead,
+set up delimiters in your
+.I eqn \" generic
+input and use the
+.B \%delim
+region option so that
+.I @g@tbl
+will recognize them.
+.
+.
+.br
+.ne 5v \" Keep enough space for heading, intro sentence, and first item.
+.\" ====================================================================
+.SS "GNU \f[I]tbl\f[] enhancements"
+.\" ====================================================================
+.
+In addition to extensions noted above,
+GNU
+.I tbl \" GNU
+removes constraints endured by users of AT&T
+.IR tbl .\" AT&T
+.
+.
+.IP \[bu] 2n
+Region options can be specified in any lettercase.
+.
+.
+.IP \[bu]
+There is no limit on the number of columns in a table,
+regardless of their classification,
+nor any limit on the number of text blocks.
+.
+.
+.IP \[bu]
+All table rows are considered when deciding column widths,
+not just those occurring in the first 200 input lines of a region.
+.
+Similarly,
+table continuation
+.RB ( .T& )
+tokens are recognized outside a region's first 200 input lines.
+.
+.
+.IP \[bu]
+Numeric and alphabetic entries may appear in the same column.
+.
+.
+.IP \[bu]
+Numeric and alphabetic entries may span horizontally.
+.
+.
+.\" ====================================================================
+.SS "Using GNU \f[I]tbl\f[] within macros"
+.\" ====================================================================
+.
+You can embed a table region inside a macro definition.
+.
+However,
+since
+.I @g@tbl
+writes its own macro definitions at the beginning of each table region,
+it is necessary to call end macros instead of ending macro definitions
+with
+.RB \[lq] ..\& \[rq].
+.\" XXX: Why don't we fix that by ending all of tbl's own macro
+.\" definitions with a call to a macro in its own reserved name space?
+.
+Additionally,
+the escape character must be disabled. \" XXX: Why?
+.
+.
+.P
+Not all
+.I @g@tbl
+features can be exercised from such macros because
+.I @g@tbl
+is a
+.I roff
+preprocessor:
+it sees the input earlier than
+.I @g@troff
+does.
+.
+For example,
+vertically aligning decimal separators fails if the numbers containing
+them occur as macro or string parameters;
+the alignment is performed by
+.I @g@tbl
+itself,
+which sees only
+.BR \[rs]$1 ,
+.BR \[rs]$2 ,
+and so on,
+and therefore can't recognize a decimal separator that only appears
+later when
+.I @g@troff
+interpolates a macro or string definition.
+.
+.
+.\" XXX: The following is a general caveat about preprocessors; move it.
+.P
+Using
+.I @g@tbl
+macros within conditional input
+(that is,
+contingent upon an
+.BR if ,
+.BR ie ,
+.BR el ,
+or
+.B while
+request)
+can result in misleading line numbers in subsequent diagnostics.
+.
+.I @g@tbl
+unconditionally injects its output into the source document,
+but the conditional branch containing it may not be taken,
+and if it is not,
+the
+.B lf
+requests that
+.I @g@tbl
+injects to restore the source line number cannot take effect.
+.
+Consider copying the input line counter register
+.B c.\&
+and restoring its value at a convenient location after applicable
+arithmetic.
+.
+.
+.br
+.ne 5v
+.\" ====================================================================
+.SH Options
+.\" ====================================================================
+.
+.B \-\-help
+displays a usage message,
+while
+.B \-v
+and
+.B \-\-version
+show version information;
+all exit afterward.
+.
+.
+.TP
+.B \-C
+Enable AT&T compatibility mode:
+recognize
+.B .TS
+and
+.B .TE
+even when followed by a character other than space or newline.
+.
+Furthermore,
+interpret the uninterpreted leader escape sequence
+.BR \[rs]a .
+.
+.
+.\" ====================================================================
+.SH Limitations
+.\" ====================================================================
+.
+Multi-page tables,
+if boxed and/or if you want their column headings repeated after page
+breaks,
+require support at the time the document is formatted.
+.
+A convention for such support has arisen in macro packages such as
+.IR ms ,
+.IR mm ,
+and
+.IR me .
+.
+To use it,
+follow the
+.B .TS
+token with a space and then
+.RB \[lq] H \[rq];
+this will be interpreted by the formatter
+as a
+.B TS
+macro call with an
+.B H
+argument.
+.
+Then,
+within the table data,
+call the
+.B TH
+macro;
+this informs the macro package where the headings end.
+.
+If your table has no such heading rows,
+or you do not desire their repetition,
+call
+.B TH
+immediately after the table format specification.
+.
+If a multi-page table is boxed or has repeating column headings,
+do not enclose it with keep/release macros,
+or divert it in any other way.
+.
+Further,
+the
+.B bp
+request will not cause a page break in a
+.RB \[lq] "TS H" \[rq]
+table.
+.
+Define a macro to wrap
+.BR bp :
+invoke it normally if there is no current diversion.
+.
+Otherwise,
+pass the macro call to the enclosing diversion using the transparent
+line escape sequence
+.BR \[rs]!\& ;
+this will \[lq]bubble up\[rq] the page break to the output device.
+.
+See section \[lq]Examples\[rq] below for a demonstration.
+.
+.
+.P
+Double horizontal rules are not supported by
+.MR grotty @MAN1EXT@ ;
+single rules are used instead.
+.
+.I \%grotty
+also ignores half-line motions,
+so the
+.B u
+column modifier has no effect.
+.
+On terminal devices
+.RI (\[lq] nroff\~ mode\[rq]),
+horizontal rules and box borders occupy a full vee of space;
+this amount is doubled for
+.B doublebox
+tables.
+.
+Tables using these features thus require more vertical space in
+.I nroff
+mode than in
+.I troff
+mode:
+write
+.B ne
+requests accordingly.
+.
+Vertical rules between columns are drawn in the space between columns in
+.I nroff
+mode;
+using double vertical rules and/or reducing the column separation below
+the default can make them ugly or overstrike them with table data.
+.
+.
+.P
+A text block within a table must be able to fit on one page.
+.
+.
+.P
+Using
+.B \[rs]a
+to put leaders in table entries does not work
+in GNU
+.IR tbl , \" GNU
+except in compatibility mode.
+.
+This is correct behavior:
+.B \[rs]a
+is an
+.I uninterpreted
+leader.
+.
+You can still use the
+.I roff
+leader character (Control+A) or define a string to use
+.B \[rs]a
+as it was designed:
+to be interpreted only in copy mode.
+.
+.
+.RS
+.P
+.EX
+\&.ds a \[rs]a
+\&.TS
+\&box center tab(;);
+\&Lw(2i)0 L.
+\&Population\[rs]*a;6,327,119
+\&.TE
+.EE
+.RE
+.
+.
+.\" We use a real leader to avoid defining a string in a man page.
+.P
+.TS
+box center tab(;);
+Lw(2i)0 L.
+Population
;6,327,119
+.TE
+.
+.
+.P
+A leading and/or trailing
+.B |
+in a format specification,
+such as
+.RB \[lq] |LCR|.\& \[rq],
+produces an en space between the vertical rules and the content of the
+adjacent columns.
+.
+If no such space is desired
+(so that the rule abuts the content),
+you can introduce \[lq]dummy\[rq] columns with zero separation and empty
+corresponding table entries before and/or after.
+.
+.
+.RS
+.P
+.EX
+\&.TS
+\&center tab(#);
+\&R0|L C R0|L.
+_
+\&#levulose#glucose#dextrose#
+_
+\&.TE
+.EE
+.RE
+.
+.
+.P
+These dummy columns have zero width and are therefore invisible;
+unfortunately they usually don't work as intended on terminal devices.
+.
+.
+.if t \{\
+.TS
+center tab(#);
+R0|L C R0|L.
+_
+#levulose#glucose#dextrose#
+_
+.TE
+.\}
+.
+.
+.\" ====================================================================
+.SH Examples
+.\" ====================================================================
+.
+It can be easier to acquire the language of
+.I tbl \" generic
+through examples than formal description,
+especially at first.
+.
+.
+.\" Note: This example is nearly at the column limit (78n) for nroff
+.\" output.  Recast with care.
+.RS
+.P
+.EX
+\&.TS
+box center tab(#);
+Cb Cb
+L L.
+Ability#Application
+Strength#crushes a tomato
+Dexterity#dodges a thrown tomato
+Constitution#eats a month-old tomato without becoming ill
+Intelligence#knows that a tomato is a fruit
+Wisdom#chooses \[rs]f[I]not\[rs]f[] to put tomato in a fruit salad
+Charisma#sells obligate carnivores tomato-based fruit salads
+\&.TE
+.EE
+.RE
+.
+.
+.P
+.TS
+box center tab(#);
+Cb Cb
+L L.
+Ability#Application
+Strength#crushes a tomato
+Dexterity#dodges a thrown tomato
+Constitution#eats a month-old tomato without becoming ill
+Intelligence#knows that a tomato is a fruit
+Wisdom#chooses \f[I]not\f[] to put tomato in a fruit salad
+Charisma#sells obligate carnivores tomato-based fruit salads
+.TE
+.
+.
+.P
+The
+.B A
+and
+.B N
+column classifiers can be easier to grasp in visual rendering than in
+description.
+.
+.
+.RS
+.P
+.EX
+\&.TS
+center tab(;);
+CbS,LN,AN.
+Daily energy intake (in MJ)
+Macronutrients
+\&.\[rs]" assume 3 significant figures of precision
+Carbohydrates;4.5
+Fats;2.25
+Protein;3
+\&.T&
+LN,AN.
+Mineral
+Pu\-239;14.6
+_
+\&.T&
+LN.
+Total;\[rs][ti]24.4
+\&.TE
+.EE
+.RE
+.
+.
+.RS
+.P
+.TS
+center tab(;);
+CbS,LN,AN.
+Daily energy intake (in MJ)
+.\" assume 3 significant figures of precision
+Macronutrients
+Carbohydrates;4.5
+Fats;2.25
+Protein;3
+.T&
+LN,AN.
+Mineral
+Pu-239;14.6
+_
+.T&
+LN.
+Total;\[ti]24.4
+.TE
+.RE
+.
+.
+.br
+.ne 12v
+.P
+Next,
+we'll lightly adapt a compact presentation of spanning,
+vertical alignment,
+and zero-width column modifiers from the
+.I mandoc
+reference for its
+.I tbl \" generic
+interpreter.
+.
+It rewards close study.
+.
+.
+.RS
+.P
+.EX
+\&.TS
+box center tab(:);
+Lz  S | Rt
+Ld| Cb| \[ha]
+\[ha] | Rz  S.
+left:r
+l:center:
+:right
+\&.TE
+.EE
+.RE
+.
+.
+.RS
+.P
+.TS
+box center tab(:);
+Lz  S | Rt
+Ld| Cb| ^
+^ | Rz  S.
+left:r
+l:center:
+:right
+.TE
+.RE
+.
+.
+.P
+.ne 2v
+Row staggering is not visually achievable on terminal devices,
+but a table using it can remain comprehensible nonetheless.
+.
+.
+.RS
+.P
+.EX
+\&.TS
+center tab(|);
+Cf(BI) Cf(BI) Cf(B), C C Cu.
+n|n\[rs]f[B]\[rs][tmu]\[rs]f[]n|difference
+1|1
+2|4|3
+3|9|5
+4|16|7
+5|25|9
+6|36|11
+\&.TE
+.EE
+.RE
+.
+.
+.RS
+.P
+.TS
+center tab(|);
+Cf(BI) Cf(BI) Cf(B), C C Cu.
+n|n\f[B]\[tmu]\f[]n|difference
+1|1
+2|4|3
+3|9|5
+4|16|7
+5|25|9
+6|36|11
+.TE
+.RE
+.
+.
+.P
+Some
+.I @g@tbl
+features cannot be illustrated in the limited environment of a portable
+man page.
+.
+.
+.\" TODO: Find a better example than this.
+.\".P
+.\"As noted above,
+.\"we can embed a table region in a
+.\".I groff
+.\"macro definition.
+.\".
+.\".IR @g@tbl ,
+.\"however,
+.\"cannot know what will result from any macro argument interpolations,
+.\"so we might confine such interpolations to one column of the table and
+.\"apply the
+.\".B x
+.\"modifier to it.
+.\".
+.\".
+.\".RS
+.\".P
+.\".EX
+.\"\&.de END
+.\"\&..
+.\"\&.eo
+.\"\&.de MYTABLE END
+.\"\&.TS
+.\"\&allbox tab(;);
+.\"\&C Lx.
+.\"\&This is table \[rs]$1.;\[rs]$2
+.\"\&.TE
+.\"\&.END
+.\"\&.ec
+.\"\&.MYTABLE 1 alpha
+.\"\&.MYTABLE 2 beta
+.\"\&.MYTABLE 3 "gamma delta"
+.\".EE
+.\".RE
+.\"
+.\"
+.P
+We can define a macro outside of a
+.I tbl \" generic
+region that we can call from within it to cause a page break inside a
+multi-page boxed table.
+.
+You can choose a different name;
+be sure to change both occurrences of \[lq]BP\[rq].
+.
+.
+.RS
+.P
+.ne 4v
+.EX
+\&.de BP
+\&.\&  ie \[aq]\[rs]\[rs]n(.z\[aq]\[aq] \&.bp \[rs]\[rs]$1
+\&.\&  el \[rs]!.BP \[rs]\[rs]$1
+\&..
+.EE
+.RE
+.
+.
+.\" ====================================================================
+.SH "See also"
+.\" ====================================================================
+.
+\[lq]Tbl\[em]A Program to Format Tables\[rq],
+by M.\& E.\& Lesk,
+1976
+(revised 16 January 1979),
+AT&T Bell Laboratories Computing Science Technical Report No.\& 49.
+.
+.
+.P
+The spanning example above was taken from
+.UR https://man.openbsd.org/tbl.7
+.IR mandoc 's
+man page for its
+.I tbl \" mandoc
+implementation
+.UE .
+.
+.
+.P
+.MR groff @MAN1EXT@ ,
+.MR @g@troff @MAN1EXT@
+.
+.
+.\" Restore compatibility mode (for, e.g., Solaris 10/11).
+.cp \n[*groff_tbl_1_man_C]
+.do rr *groff_tbl_1_man_C
+.
+.
+.\" Local Variables:
+.\" fill-column: 72
+.\" mode: nroff
+.\" End:
+.\" vim: set filetype=groff textwidth=72:
diff --git a/src/preproc/tbl/tbl.am b/src/preproc/tbl/tbl.am
new file mode 100644
index 0000000..d4b0edb
--- /dev/null
+++ b/src/preproc/tbl/tbl.am
@@ -0,0 +1,54 @@
+# Copyright (C) 2014-2020 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+prefixexecbin_PROGRAMS += tbl
+tbl_LDADD = libgroff.a $(LIBM) lib/libgnu.a
+tbl_SOURCES = \
+  src/preproc/tbl/main.cpp \
+  src/preproc/tbl/table.cpp \
+  src/preproc/tbl/table.h
+PREFIXMAN1 += src/preproc/tbl/tbl.1
+EXTRA_DIST += src/preproc/tbl/tbl.1.man
+
+tbl_TESTS = \
+  src/preproc/tbl/tests/boxes-and-vertical-rules.sh \
+  src/preproc/tbl/tests/check-horizontal-line-length.sh \
+  src/preproc/tbl/tests/check-line-intersections.sh \
+  src/preproc/tbl/tests/check-vertical-line-length.sh \
+  src/preproc/tbl/tests/cooperate-with-nm-request.sh \
+  src/preproc/tbl/tests/count-continued-input-lines.sh \
+  src/preproc/tbl/tests/do-not-overdraw-page-top-in-nroff-mode.sh \
+  src/preproc/tbl/tests/do-not-overlap-bottom-border-in-nroff.sh \
+  src/preproc/tbl/tests/do-not-segv-on-invalid-vertical-span-entry.sh \
+  src/preproc/tbl/tests/do-not-segv-when-backslash-R-in-text-block.sh \
+  src/preproc/tbl/tests/expand-region-option-works.sh \
+  src/preproc/tbl/tests/format-time-diagnostics-work.sh \
+  src/preproc/tbl/tests/save-and-restore-hyphenation-parameters.sh \
+  src/preproc/tbl/tests/save-and-restore-inter-sentence-space.sh \
+  src/preproc/tbl/tests/save-and-restore-line-numbering.sh \
+  src/preproc/tbl/tests/save-and-restore-tab-stops.sh \
+  src/preproc/tbl/tests/warn-on-long-boxed-unkept-table.sh \
+  src/preproc/tbl/tests/x-column-modifier-works.sh
+TESTS += $(tbl_TESTS)
+EXTRA_DIST += $(tbl_TESTS)
+
+
+# Local Variables:
+# fill-column: 72
+# mode: makefile-automake
+# End:
+# vim: set autoindent filetype=automake textwidth=72:
diff --git a/src/preproc/tbl/tests/boxes-and-vertical-rules.sh b/src/preproc/tbl/tests/boxes-and-vertical-rules.sh
new file mode 100755
index 0000000..0471188
--- /dev/null
+++ b/src/preproc/tbl/tests/boxes-and-vertical-rules.sh
@@ -0,0 +1,174 @@
+#!/bin/sh
+#
+# Copyright (C) 2023 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+groff="${abs_top_builddir:-.}/test-groff"
+
+fail=
+
+wail () {
+    echo ...FAILED >&2
+    fail=YES
+}
+
+# Test behavior of unexpanded tables using boxes and/or vertical rules.
+
+# Case 1: "naked" table
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+tab(@);
+L L L L L.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking unboxed table without vertical rules" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+# 3 spaces between table entries
+echo "$output" | sed -n '2p' \
+    | grep -qx 'abcdef   abcdef   abcdef   abcdef   abcdef' || wail
+
+# Case 2: left-hand vertical rule
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+tab(@);
+| L L L L L.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking unboxed table with left-hand rule" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+# 3 spaces between table entries
+echo "$output" | sed -n '3p' \
+    | grep -qx '| abcdef   abcdef   abcdef   abcdef   abcdef' || wail
+
+# Case 3: right-hand vertical rule
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+tab(@);
+L L L L L |.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking unboxed table with right-hand rule" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+# 3 spaces between table entries
+echo "$output" | sed -n '3p' \
+    | grep -qx 'abcdef   abcdef   abcdef   abcdef   abcdef |' || wail
+
+# Case 4: vertical rule on both ends
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+tab(@);
+| L L L L L |.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking unboxed table with both rules" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+# 3 spaces between table entries
+echo "$output" | sed -n '3p' \
+    | grep -qx '| abcdef   abcdef   abcdef   abcdef   abcdef |' || wail
+
+# Case 5: vertical rule on both ends and interior rule
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+tab(@);
+| L L L | L L |.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking unboxed table with both edge and interior rules" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+# 3 spaces between table entries
+echo "$output" | sed -n '3p' \
+    | grep -qx '| abcdef   abcdef   abcdef | abcdef   abcdef |' || wail
+
+# Case 6: boxed table
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+box tab(@);
+L L L L L.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking boxed table without interior rules" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+# 3 spaces between table entries
+echo "$output" | sed -n '3p' \
+    | grep -qx '| abcdef   abcdef   abcdef   abcdef   abcdef |' || wail
+
+# Case 7: boxed table with interior vertical rule
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+box tab(@);
+L L L | L L.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking boxed table with interior rules" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+# 3 spaces between table entries
+echo "$output" | sed -n '3p' \
+    | grep -qx '| abcdef   abcdef   abcdef | abcdef   abcdef |' || wail
+
+test -z "$fail"
+
+# vim:set ai et sw=4 ts=4 tw=72:
diff --git a/src/preproc/tbl/tests/check-horizontal-line-length.sh b/src/preproc/tbl/tests/check-horizontal-line-length.sh
new file mode 100755
index 0000000..3d5e2a2
--- /dev/null
+++ b/src/preproc/tbl/tests/check-horizontal-line-length.sh
@@ -0,0 +1,78 @@
+#!/bin/sh
+#
+# Copyright (C) 2022 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+groff="${abs_top_builddir:-.}/test-groff"
+fail=
+
+wail () {
+    echo "...FAILED" >&2
+    echo "$output"
+    fail=yes
+}
+
+# GNU tbl draws horizontal lines 1n wider than they need to be on nroff
+# devices to enable them to cross a vertical line on the right-hand
+# side.
+
+input='.ll 10n
+.TS
+L.
+_
+1234567890
+.TE
+.pl \n(nlu
+'
+
+echo "checking length of plain horizontal rule" >&2
+output=$(printf "%s" "$input" | "$groff" -Tascii -t)
+echo "$output" | grep -Eqx -- '-{11}' || wail
+
+input='.ll 12n
+.TS
+| L |.
+_
+1234567890
+_
+.TE
+.pl \n(nlu
+'
+
+echo "checking intersection of vertical and horizontal rules" >&2
+output=$(printf "%s" "$input" | "$groff" -Tascii -t)
+echo "$output" | sed -n '1p' | grep -Eqx '\+-{12}\+' || wail
+echo "$output" | sed -n '3p' | grep -Eqx '\+-{12}\+' || wail
+
+input='.ll 12n
+.TS
+box;
+L.
+1234567890
+.TE
+.pl \n(nlu
+'
+
+echo "checking width of boxed table" >&2
+output=$(printf "%s" "$input" | "$groff" -Tascii -t)
+echo "$output" | sed -n '1p' | grep -Eqx '\+-{12}\+' || wail
+echo "$output" | sed -n '3p' | grep -Eqx '\+-{12}\+' || wail
+
+test -z "$fail"
+
+# vim:set ai et sw=4 ts=4 tw=72:
diff --git a/src/preproc/tbl/tests/check-line-intersections.sh b/src/preproc/tbl/tests/check-line-intersections.sh
new file mode 100755
index 0000000..2012beb
--- /dev/null
+++ b/src/preproc/tbl/tests/check-line-intersections.sh
@@ -0,0 +1,52 @@
+#!/bin/sh
+#
+# Copyright (C) 2022 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+groff="${abs_top_builddir:-.}/test-groff"
+fail=
+
+wail () {
+    echo "...FAILED" >&2
+    echo "$output"
+    fail=yes
+}
+
+input='.TS
+allbox tab(@);
+L L L.
+a@b@c
+d@e@f
+g@h@i
+.TE
+'
+
+output=$(printf "%s" "$input" | "$groff" -Tascii -t)
+echo "$output"
+
+for l in 1 3 5 7
+do
+    echo "checking intersections on line $l"
+    echo "$output" | sed -n ${l}p | grep -Fqx '+---+---+---+' || wail
+done
+
+# TODO: Check `-Tutf8` output for correct crossing glyph identities.
+
+test -z "$fail"
+
+# vim:set ai et sw=4 ts=4 tw=72:
diff --git a/src/preproc/tbl/tests/check-vertical-line-length.sh b/src/preproc/tbl/tests/check-vertical-line-length.sh
new file mode 100755
index 0000000..1aafd09
--- /dev/null
+++ b/src/preproc/tbl/tests/check-vertical-line-length.sh
@@ -0,0 +1,49 @@
+#!/bin/sh
+#
+# Copyright (C) 2022 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+groff="${abs_top_builddir:-.}/test-groff"
+fail=
+
+wail () {
+    echo "...FAILED" >&2
+    echo "$output"
+    fail=yes
+}
+
+# GNU tbl draws vertical lines 1v taller than they need to be on nroff
+# devices to enable them to cross a potential horizontal line in the
+# table.
+
+input='.ll 12n
+.TS
+| L |.
+_
+1234567890
+.TE
+.pl \n(nlu
+'
+
+echo "checking length of plain vertical rule" >&2
+output=$(printf "%s" "$input" | "$groff" -Tascii -t)
+echo "$output" | sed -n '2p' | grep -Fqx -- '| 1234567890 |' || wail
+
+test -z "$fail"
+
+# vim:set ai et sw=4 ts=4 tw=72:
diff --git a/src/preproc/tbl/tests/cooperate-with-nm-request.sh b/src/preproc/tbl/tests/cooperate-with-nm-request.sh
new file mode 100755
index 0000000..cfbd750
--- /dev/null
+++ b/src/preproc/tbl/tests/cooperate-with-nm-request.sh
@@ -0,0 +1,47 @@
+#!/bin/sh
+#
+# Copyright (C) 2021 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+groff="${abs_top_builddir:-.}/test-groff"
+
+set -e
+
+# Regression-test Savannah #59812.
+#
+# A nonzero value of \n[ln] should not cause spurious numbering of table
+# rows.
+
+DOC='\
+.nf
+foo
+.nm 1
+bar
+.nm
+baz
+.TS
+l.
+qux
+.TE
+'
+
+OUTPUT=$(printf "%s" "$DOC" | "$groff" -Tascii -t)
+
+echo "$OUTPUT" | grep -Fqx qux
+
+# vim:set ai noet sw=4 ts=4 tw=72:
diff --git a/src/preproc/tbl/tests/count-continued-input-lines.sh b/src/preproc/tbl/tests/count-continued-input-lines.sh
new file mode 100755
index 0000000..4682788
--- /dev/null
+++ b/src/preproc/tbl/tests/count-continued-input-lines.sh
@@ -0,0 +1,43 @@
+#!/bin/sh
+#
+# Copyright (C) 2022 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+groff="${abs_top_builddir:-.}/test-groff"
+
+set -e
+
+# Regression-test Savannah #62191.
+#
+# Line continuation in a row of table data should not make the input
+# line counter inaccurate.
+
+input='.this-is-line-1
+.TS
+L.
+foo\
+bar\
+baz\
+qux
+.TE
+.this-is-line-9'
+
+output=$(printf "%s\n" "$input" | "$groff" -Tascii -t -ww -z 2>&1)
+echo "$output" | grep -q '^troff.*:9:.*this-is-line-9'
+
+# vim:set ai et sw=4 ts=4 tw=72:
diff --git a/src/preproc/tbl/tests/do-not-overdraw-page-top-in-nroff-mode.sh b/src/preproc/tbl/tests/do-not-overdraw-page-top-in-nroff-mode.sh
new file mode 100755
index 0000000..c4698f1
--- /dev/null
+++ b/src/preproc/tbl/tests/do-not-overdraw-page-top-in-nroff-mode.sh
@@ -0,0 +1,225 @@
+#!/bin/sh
+#
+# Copyright (C) 2022-2023 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+groff="${abs_top_builddir:-.}/test-groff"
+grotty="${abs_top_builddir:-.}/grotty"
+
+fail=
+
+wail () {
+    echo ...FAILED >&2
+    fail=YES
+}
+
+# Regression-test Savannah #63449.
+#
+# In nroff mode, a table at the top of the page (i.e., one starting at
+# the first possible output line, with no vertical margin) that has
+# vertical rules should not overdraw the page top and provoke a warning
+# from grotty about "character(s) above [the] first line [being]
+# discarded".
+
+# Case 1: No horizontal rules; vertical rule at leading column.
+input='.TS
+| L.
+foo
+.TE'
+
+tmp=$(printf "%s\n" "$input" | "$groff" -t -Z -Tascii -P-cbou)
+output=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>/dev/null)
+error=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>&1 >/dev/null)
+echo "$output"
+
+echo "checking that no diagnostic messages are produced by grotty (1)"
+echo "$error" | grep -q 'grotty:' && wail
+
+echo "checking that a lone vertical rule starts the first output line"
+echo "$output" | sed -n '1p' | grep -Fqx '|' || wail
+
+# Case 2: No horizontal rules; vertical rule between columns.
+input='.TS
+tab(@);
+L | L.
+foo@bar
+.TE'
+
+tmp=$(printf "%s\n" "$input" | "$groff" -t -Z -Tascii -P-cbou)
+output=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>/dev/null)
+error=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>&1 >/dev/null)
+echo "$output"
+
+echo "checking that no diagnostic messages are produced by grotty (2)"
+echo "$error" | grep -q 'grotty:' && wail
+
+echo "checking that a lone vertical rule ends the first output line"
+echo "$output" | sed -n '1p' | grep -Eqx ' +\|' || wail
+
+# Case 3: No horizontal rules; vertical rule at trailing column.
+input='.TS
+L |.
+foo
+.TE'
+
+tmp=$(printf "%s\n" "$input" | "$groff" -t -Z -Tascii -P-cbou)
+output=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>/dev/null)
+error=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>&1 >/dev/null)
+echo "$output"
+
+echo "checking that no diagnostic messages are produced by grotty (3)"
+echo "$error" | grep -q 'grotty:' && wail
+
+echo "checking that a lone vertical rule ends the first output line"
+echo "$output" | sed -n '1p' | grep -Eqx ' +\|' || wail
+
+# Case 4: Vertical rule with horizontal rule in row description.
+input='.TS
+_
+L |.
+foo
+.TE'
+
+tmp=$(printf "%s\n" "$input" | "$groff" -t -Z -Tascii -P-cbou)
+output=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>/dev/null)
+error=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>&1 >/dev/null)
+echo "$output"
+
+echo "checking that no diagnostic messages are produced by grotty (4)"
+echo "$error" | grep -q 'grotty:' && wail
+
+echo "checking that intersection is placed on the first output line"
+echo "$output" | sed -n '1p' | grep -q '+' || wail
+
+# Case 5: Vertical rule with horizontal rule as first table datum.
+input='.TS
+L |.
+_
+foo
+.TE'
+
+tmp=$(printf "%s\n" "$input" | "$groff" -t -Z -Tascii -P-cbou)
+output=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>/dev/null)
+error=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>&1 >/dev/null)
+echo "$output"
+
+echo "checking that no diagnostic messages are produced by grotty (5)"
+echo "$error" | grep -q 'grotty:' && wail
+
+echo "checking that intersection is placed on the first output line"
+echo "$output" | sed -n '1p' | grep -q '+' || wail
+
+# Case 6: Horizontal rule as non-first row description with vertical
+# rule.
+input='.TS
+L,_,L |.
+foo
+bar
+.TE'
+
+tmp=$(printf "%s\n" "$input" | "$groff" -t -Z -Tascii -P-cbou)
+output=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>/dev/null)
+error=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>&1 >/dev/null)
+echo "$output"
+
+echo "checking that no diagnostic messages are produced by grotty (6)"
+echo "$error" | grep -q 'grotty:' && wail
+
+echo "checking that table data begin on first output line"
+echo "$output" | sed -n '1p' | grep -q 'foo' || wail
+
+# Also ensure that no collateral damage arises in related cases.
+
+# Case 7: Horizontal rule as first table datum with no vertical rule.
+input='.TS
+L.
+_
+foo
+.TE'
+
+tmp=$(printf "%s\n" "$input" | "$groff" -t -Z -Tascii -P-cbou)
+output=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>/dev/null)
+error=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>&1 >/dev/null)
+echo "$output"
+
+echo "checking that no diagnostic messages are produced by grotty (7)"
+echo "$error" | grep -q 'grotty:' && wail
+
+echo "checking that horizontal rule is placed on the first output line"
+echo "$output" | sed -n '1p' | grep -q '^---' || wail
+
+# Case 8: Horizontal rule as last table datum with no vertical rule.
+input='.TS
+L.
+foo
+_
+.TE
+.ec @
+.pl @n(nlu'
+
+tmp=$(printf "%s\n" "$input" | "$groff" -t -Z -Tascii -P-cbou)
+output=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>/dev/null)
+error=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>&1 >/dev/null)
+echo "$output"
+
+echo "checking that no diagnostic messages are produced by grotty (8)"
+echo "$error" | grep -q 'grotty:' && wail
+
+echo "checking that horizontal rule is placed on the last output line"
+echo "$output" | sed -n '$p' | grep -q '^---' || wail
+
+# Case 9: Horizontal rule in row description with no vertical rule.
+input='.TS
+_
+L.
+foo
+.TE'
+
+tmp=$(printf "%s\n" "$input" | "$groff" -t -Z -Tascii -P-cbou)
+output=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>/dev/null)
+error=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>&1 >/dev/null)
+echo "$output"
+
+echo "checking that no diagnostic messages are produced by grotty (9)"
+echo "$error" | grep -q 'grotty:' && wail
+
+echo "checking that intersection is placed on the first output line"
+echo "$output" | sed -n '1p' | grep -q '^---' || wail
+
+# Case 10: Horizontal rule as non-first row description with no vertical
+# rule.
+input='.TS
+L,_,L.
+foo
+bar
+.TE'
+
+tmp=$(printf "%s\n" "$input" | "$groff" -t -Z -Tascii -P-cbou)
+output=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>/dev/null)
+error=$(printf "%s" "$tmp" | "$grotty" -F ./font 2>&1 >/dev/null)
+echo "$output"
+
+echo "checking that no diagnostic messages are produced by grotty (10)"
+echo "$error" | grep -q 'grotty:' && wail
+
+echo "checking that table data begin on first output line"
+echo "$output" | sed -n '1p' | grep -q 'foo' || wail
+
+test -z "$fail"
+
+# vim:set ai et sw=4 ts=4 tw=72:
diff --git a/src/preproc/tbl/tests/do-not-overlap-bottom-border-in-nroff.sh b/src/preproc/tbl/tests/do-not-overlap-bottom-border-in-nroff.sh
new file mode 100755
index 0000000..4f63eed
--- /dev/null
+++ b/src/preproc/tbl/tests/do-not-overlap-bottom-border-in-nroff.sh
@@ -0,0 +1,62 @@
+#!/bin/sh
+#
+# Copyright (C) 2022 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+groff="${abs_top_builddir:-.}/test-groff"
+
+fail=
+
+wail () {
+    echo "...FAILED" >&2
+    fail=yes
+}
+
+# Regression-test Savannah #49390.
+
+input='foo
+.TS
+box;
+L.
+bar
+.TE
+baz
+.pl \n(nlu
+'
+
+echo "checking for post-table text non-overlap of (single) box border"
+output=$(printf "%s" "$input" | "$groff" -t -Tascii)
+echo "$output" | grep -q baz || wail
+
+input='foo
+.TS
+doublebox;
+L.
+bar
+.TE
+baz
+.pl \n(nlu
+'
+
+echo "checking for post-table text non-overlap of double box border"
+output=$(printf "%s" "$input" | "$groff" -t -Tascii)
+echo "$output" | grep -q baz || wail
+
+test -z "$fail"
+
+# vim:set ai et sw=4 ts=4 tw=72:
diff --git a/src/preproc/tbl/tests/do-not-segv-on-invalid-vertical-span-entry.sh b/src/preproc/tbl/tests/do-not-segv-on-invalid-vertical-span-entry.sh
new file mode 100755
index 0000000..1d672ec
--- /dev/null
+++ b/src/preproc/tbl/tests/do-not-segv-on-invalid-vertical-span-entry.sh
@@ -0,0 +1,41 @@
+#!/bin/sh
+#
+# Copyright (C) 2021 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+tbl="${abs_top_builddir:-.}/tbl"
+
+# Regression-test Savannah #61417.
+#
+# Don't segfault because we tried to span down from an invalid span that
+# tbl neglected to replace with an empty table entry.
+
+test -f core && exit 77 # skip
+
+input=$(cat <<EOF
+.TS
+l.
+\^
+\^
+.TE
+EOF
+)
+output=$(printf "%s" "$input" | "$tbl")
+! test -f core
+
+# vim:set ai noet sw=4 ts=4 tw=72:
diff --git a/src/preproc/tbl/tests/do-not-segv-when-backslash-R-in-text-block.sh b/src/preproc/tbl/tests/do-not-segv-when-backslash-R-in-text-block.sh
new file mode 100755
index 0000000..30bd9f6
--- /dev/null
+++ b/src/preproc/tbl/tests/do-not-segv-when-backslash-R-in-text-block.sh
@@ -0,0 +1,75 @@
+#!/bin/sh
+#
+# Copyright (C) 2022 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+groff="${abs_top_builddir:-.}/test-groff"
+
+fail=
+
+wail () {
+    echo "...FAILED" >&2
+    fail=yes
+}
+
+# Regression-test Savannah #62366.
+#
+# Do not SEGV when a text block begins with a repeating glyph token, and
+# do not malformat the output if it ends with one.
+
+test -f core && exit 77 # skip
+
+input='.TS
+L.
+T{
+\Ra
+T}
+.TE
+.TS
+L.
+T{
+foo
+\Ra
+T}
+.TE
+.TS
+L.
+T{
+foo
+\Ra
+bar
+T}
+.TE'
+
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii -P-cbou)
+
+echo "checking that tbl doesn't segfault" >&2
+test -f core && wail
+
+echo "checking text block starting with repeating glyph" >&2
+echo "$output" | sed -n 1p | grep -qx 'a' || wail
+
+echo "checking text block ending with repeating glyph" >&2
+echo "$output" | sed -n 2p | grep -qx 'foo a' || wail
+
+echo "checking text block containing repeating glyph" >&2
+echo "$output" | sed -n 3p | grep -qx 'foo a bar' || wail
+
+test -z "$fail"
+
+# vim:set ai et sw=4 ts=4 tw=72:
diff --git a/src/preproc/tbl/tests/expand-region-option-works.sh b/src/preproc/tbl/tests/expand-region-option-works.sh
new file mode 100755
index 0000000..97da39d
--- /dev/null
+++ b/src/preproc/tbl/tests/expand-region-option-works.sh
@@ -0,0 +1,173 @@
+#!/bin/sh
+#
+# Copyright (C) 2023 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+groff="${abs_top_builddir:-.}/test-groff"
+
+fail=
+
+wail () {
+    echo ...FAILED >&2
+    fail=YES
+}
+
+# Ensure that the "expand" region option expands to the line length.
+
+# Case 1: "naked" table
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+expand tab(@);
+L L L L L.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking unboxed table without vertical rules" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+echo "$output" | sed -n '2p' \
+    | grep -Eqx '(abcdef {8,9}){4}abcdef' || wail
+
+# Case 2: left-hand vertical rule
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+expand tab(@);
+| L L L L L.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking unboxed table with left-hand rule" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+echo "$output" | sed -n '3p' \
+    | grep -Eqx '\| abcdef {8}abcdef {7}abcdef {8}abcdef {9}abcdef' \
+    || wail
+
+# Case 3: right-hand vertical rule
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+expand tab(@);
+L L L L L |.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking unboxed table with right-hand rule" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+echo "$output" | sed -n '3p' \
+    | grep -Eqx 'abcdef {8}abcdef {7}abcdef {8}abcdef {9}abcdef \|' \
+    || wail
+
+# Case 4: vertical rule on both ends
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+expand tab(@);
+| L L L L L |.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking unboxed table with both rules" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+echo "$output" | sed -n '3p' \
+    | grep -Eqx '\| abcdef {7}abcdef {7}abcdef {8}abcdef {8}abcdef \|' \
+    || wail
+
+# Case 5: vertical rule on both ends and interior rule
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+expand tab(@);
+| L L L | L L |.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking unboxed table with both edge and interior rules" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+echo "$output" | sed -n '3p' \
+    | grep -Eqx \
+    '\| abcdef {7}abcdef {7}abcdef {4}\| {3}abcdef {8}abcdef \|' || wail
+
+# Case 6: boxed table
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+box expand tab(@);
+L L L L L.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking boxed table without interior rules" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+echo "$output" | sed -n '3p' \
+    | grep -Eqx '\| abcdef {7}abcdef {7}abcdef {8}abcdef {8}abcdef \|' \
+    || wail
+
+# Case 7: boxed table with interior vertical rule
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+box expand tab(@);
+L L L | L L.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking boxed table with interior rule" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+echo "$output" | sed -n '3p' \
+    | grep -Eqx \
+    '\| abcdef {7}abcdef {7}abcdef {4}\| {3}abcdef {8}abcdef \|' || wail
+
+test -z "$fail"
+
+# vim:set ai et sw=4 ts=4 tw=72:
diff --git a/src/preproc/tbl/tests/format-time-diagnostics-work.sh b/src/preproc/tbl/tests/format-time-diagnostics-work.sh
new file mode 100755
index 0000000..9d422bd
--- /dev/null
+++ b/src/preproc/tbl/tests/format-time-diagnostics-work.sh
@@ -0,0 +1,268 @@
+#!/bin/sh
+#
+# Copyright (C) 2022 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+groff="${abs_top_builddir:-.}/test-groff"
+
+set -e
+
+# Ensure we get diagnostics when we expect to, and not when we don't.
+#
+# Do NOT pattern-match the text of the diagnostic messages; those should
+# be left flexible.  (Some day they might even be localized.)
+
+# As of this writing, there are 5 distinct format-time diagnostic
+# messages that tbl writes roff code to generate, one of which can be
+# produced two different ways.
+
+# Diagnostic #1: a row overruns the page bottom
+input='.pl 2v
+.TS
+;
+L.
+T{
+.nf
+1
+2
+3
+T}
+.TE
+'
+
+echo "checking for diagnostic when row with text box overruns page" \
+    "bottom"
+output=$(printf "%s" "$input" | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 1
+
+echo "checking 'nowarn' suppression of  diagnostic when row with text" \
+    "box overruns page bottom"
+input_nowarn=$(printf "%s" "$input" | sed 's/;/nowarn;/')
+output=$(printf "%s" "$input_nowarn" \
+    | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 0
+
+echo "checking 'nokeep' suppression of diagnostic when row with text" \
+    "box overruns page bottom"
+input_nowarn=$(printf "%s" "$input" | sed 's/;/nokeep;/')
+output=$(printf "%s" "$input_nowarn" \
+    | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 0
+
+# The other way to get "diagnostic #1" is to have a row that is too
+# tall _without_ involving a text block, for instance by having a font
+# or vertical spacing that is too high.
+input='.pl 2v
+.vs 3v
+.TS
+;
+L.
+1
+.TE
+'
+
+echo "checking for diagnostic when row with large vertical spacing" \
+    "overruns page bottom"
+output=$(printf "%s" "$input" | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 1
+
+echo "checking 'nowarn' suppression of diagnostic when row with large" \
+    "vertical spacing overruns page bottom"
+input_nowarn=$(printf "%s" "$input" | sed 's/;/nowarn;/')
+output=$(printf "%s" "$input_nowarn" \
+    | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 0
+
+echo "checking 'nokeep' suppression of diagnostic when row with large" \
+    "vertical spacing overruns page bottom"
+input_nowarn=$(printf "%s" "$input" | sed 's/;/nokeep;/')
+output=$(printf "%s" "$input_nowarn" \
+    | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 0
+
+# Diagnostic #2: a boxed table won't fit on a page
+
+input='.pl 2v
+.vs 3v
+.TS
+box;
+L.
+1
+.TE
+'
+
+echo "checking for diagnostic when boxed table won't fit on page"
+output=$(printf "%s" "$input" | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 1
+
+# The above is an error, so the "nowarn" region option won't shut it up.
+#
+# However, "nokeep" does--but arguably shouldn't.  See
+# <https://savannah.gnu.org/bugs/?61878>.  If that gets fixed, we should
+# test that we still get a diagnostic even with the option given.
+
+# Diagnostic #3: unexpanded columns overrun the line length
+#
+# Case 1: no 'x' column modifiers used
+
+input='.pl 2v
+.ll 10n
+.TS
+;
+L.
+12345678901
+.TE
+'
+
+echo "checking for diagnostic when unexpanded columns overrun line" \
+    "length (1)"
+output=$(printf "%s" "$input" | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 1
+
+echo "checking 'nowarn' suppression of diagnostic when unexpanded" \
+    "columns overrun line length (1)"
+input_nowarn=$(printf "%s" "$input" | sed 's/;/nowarn;/')
+output=$(printf "%s" "$input_nowarn" \
+    | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 0
+
+# Avoiding keeps won't get you out of this one.
+echo "checking 'nokeep' NON-suppression of diagnostic when unexpanded" \
+    "columns overrun line length (1)"
+input_nowarn=$(printf "%s" "$input" | sed 's/;/nokeep;/')
+output=$(printf "%s" "$input_nowarn" \
+    | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 1
+
+# Case 2: 'x' column modifier used
+#
+# This worked as a "get out of jail (warning) free" card in groff 1.22.4
+# and earlier; i.e., it incorrectly suppressed the warning.  See
+# Savannah #61854.
+
+input='.pl 2v
+.ll 10n
+.TS
+;
+Lx.
+12345678901
+.TE
+'
+
+echo "checking for diagnostic when unexpanded columns overrun line" \
+    "length (2)"
+output=$(printf "%s" "$input" | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 1
+
+echo "checking 'nowarn' suppression of diagnostic when unexpanded" \
+    "columns overrun line length (2)"
+input_nowarn=$(printf "%s" "$input" | sed 's/;/nowarn;/')
+output=$(printf "%s" "$input_nowarn" \
+    | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 0
+
+# Avoiding keeps won't get you out of this one.
+echo "checking 'nokeep' NON-suppression of diagnostic when unexpanded" \
+    "columns overrun line length (2)"
+input_nowarn=$(printf "%s" "$input" | sed 's/;/nokeep;/')
+output=$(printf "%s" "$input_nowarn" \
+    | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 1
+
+# Diagnostic #4: expanded table gets all column separation squashed out
+
+input='.pl 3v
+.ll 10n
+.TS
+tab(;) expand;
+L L.
+abcde;fghij
+.TE
+'
+
+echo "checking for diagnostic when region-expanded table has column" \
+    "separation eliminated"
+output=$(printf "%s" "$input" | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 1
+
+echo "checking 'nowarn' suppression of diagnostic when" \
+    "region-expanded table has column separation eliminated"
+input_nowarn=$(printf "%s" "$input" | sed 's/;$/ nowarn;/')
+output=$(printf "%s" "$input_nowarn" \
+    | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 0
+
+# Avoiding keeps won't get you out of this one.
+echo "checking 'nokeep' NON-suppression of diagnostic when" \
+    "region-expanded table has column separation eliminated"
+input_nowarn=$(printf "%s" "$input" | sed 's/;$/ nokeep;/')
+output=$(printf "%s" "$input_nowarn" \
+    | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 1
+
+# Diagnostic #5: expanded table gets column separation reduced
+
+input='.pl 3v
+.ll 10n
+.TS
+tab(;) expand;
+L L.
+abcd;efgh
+.TE
+'
+
+echo "checking for diagnostic when region-expanded table has column" \
+    "separation reduced"
+output=$(printf "%s" "$input" | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 1
+
+echo "checking 'nowarn' suppression of diagnostic when" \
+    "region-expanded table has column separation reduced"
+input_nowarn=$(printf "%s" "$input" | sed 's/;$/ nowarn;/')
+output=$(printf "%s" "$input_nowarn" \
+    | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 0
+
+# Avoiding keeps won't get you out of this one.
+echo "checking 'nokeep' NON-suppression of diagnostic when" \
+    "region-expanded table has column separation reduced"
+input_nowarn=$(printf "%s" "$input" | sed 's/;$/ nokeep;/')
+output=$(printf "%s" "$input_nowarn" \
+    | "$groff" -Tascii -t 2>&1 >/dev/null)
+nlines=$(echo "$output" | grep . | wc -l)
+test $nlines -eq 1
+
+# vim:set ai et sw=4 ts=4 tw=72:
diff --git a/src/preproc/tbl/tests/save-and-restore-hyphenation-parameters.sh b/src/preproc/tbl/tests/save-and-restore-hyphenation-parameters.sh
new file mode 100755
index 0000000..e368b31
--- /dev/null
+++ b/src/preproc/tbl/tests/save-and-restore-hyphenation-parameters.sh
@@ -0,0 +1,58 @@
+#!/bin/sh
+#
+# Copyright (C) 2021 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+groff="${abs_top_builddir:-.}/test-groff"
+
+set -e
+
+# Regression-test Savannah #59971.
+#
+# Hyphenation needs to be restored between (and after) text blocks just
+# as adjustment is.
+
+EXAMPLE='.nr LL 78n
+.hw a-bc-def-ghij-klmno-pqrstu-vwxyz
+.LP
+Here is a table with hyphenation disabled in its text block.
+.
+.TS
+l lx.
+foo	T{
+.nh
+abcdefghijklmnopqrstuvwxyz
+abcdefghijklmnopqrstuvwxyz
+abcdefghijklmnopqrstuvwxyz
+T}
+.TE
+.
+Let us see if hyphenation is enabled again as it should be.
+abcdefghijklmnopqrstuvwxyz'
+
+OUTPUT=$(printf "%s\n" "$EXAMPLE" | "$groff" -Tascii -P-cbou -t -ms)
+
+echo "$OUTPUT"
+
+echo "testing whether hyphenation disabled in table text block" >&2
+! echo "$OUTPUT" | grep '^foo' | grep -- '-$'
+
+echo "testing whether hyphenation enabled after table" >&2
+echo "$OUTPUT" | grep -qx 'Let us see.*lmno-'
+
+# vim:set ai noet sw=4 ts=4 tw=72:
diff --git a/src/preproc/tbl/tests/save-and-restore-inter-sentence-space.sh b/src/preproc/tbl/tests/save-and-restore-inter-sentence-space.sh
new file mode 100755
index 0000000..e9a06d8
--- /dev/null
+++ b/src/preproc/tbl/tests/save-and-restore-inter-sentence-space.sh
@@ -0,0 +1,79 @@
+#!/bin/sh
+#
+# Copyright (C) 2022 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+groff="${abs_top_builddir:-.}/test-groff"
+
+fail=
+
+wail () {
+    echo ...FAILED >&2
+    fail=YES
+}
+
+# Regression-test Savannah #61909.
+#
+# Inter-sentence space should not be applied to the content of ordinary
+# table entries.  They are set "rigidly" (tbl(1)), also without filling,
+# adjustment, hyphenation or breaking.  If you want those things, use a
+# text block.
+
+input='.ss 12 120
+Before one.
+Before two.
+.TS
+L.
+.\" two spaces
+Foo.  Bar.
+.\" four spaces
+Baz.    Qux.
+.\" two spaces
+T{
+Ack.  Nak.
+T}
+.TE
+After one.
+After two.
+'
+
+output=$(printf "%s\n" "$input" | "$groff" -Tascii -P-cbou -t)
+echo "$output"
+
+echo "checking that inter-sentence space is altered too early"
+echo "$output" \
+    | grep -Fqx 'Before one.           Before two.' || wail # 11 spaces
+
+echo "checking that inter-sentence space is not applied to ordinary" \
+    "table entries (1)"
+echo "$output" | grep -Fqx 'Foo.  Bar.' || wail # 2 spaces
+
+echo "checking that inter-sentence space is not applied to ordinary" \
+    "table entries (2)"
+echo "$output" | grep -Fqx 'Baz.    Qux.' || wail # 4 spaces
+
+echo "checking that inter-sentence space is applied to text blocks"
+echo "$output" | grep -Fqx 'Ack.           Nak.' || wail # 11 spaces
+
+echo "checking that inter-sentence space is restored after table"
+echo "$output" \
+    | grep -Fqx 'After one.           After two.' || wail # 11 spaces
+
+test -z "$fail"
+
+# vim:set ai et sw=4 ts=4 tw=72:
diff --git a/src/preproc/tbl/tests/save-and-restore-line-numbering.sh b/src/preproc/tbl/tests/save-and-restore-line-numbering.sh
new file mode 100755
index 0000000..592b43a
--- /dev/null
+++ b/src/preproc/tbl/tests/save-and-restore-line-numbering.sh
@@ -0,0 +1,85 @@
+#!/bin/sh
+#
+# Copyright (C) 2022 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+groff="${abs_top_builddir:-.}/test-groff"
+
+fail=
+
+wail () {
+    echo ...FAILED >&2
+    fail=YES
+}
+
+# Regression-test Savannah #60140.
+#
+# Line numbering needs to be suspended within a table and restored
+# afterward.  Historical implementations handled line numbering in
+# tables badly when text blocks were used.
+
+input='.nm 1
+Here is a line of output.
+Sic transit adispicing meatballs.
+We pad it out with more content to ensure that the line breaks.
+.TS
+L.
+This is my table.
+There are many like it but this one is mine.
+T{
+Ut enim ad minima veniam,
+quis nostrum exercitationem ullam corporis suscipitlaboriosam,
+nisi ut aliquid ex ea commodi consequatur?
+T}
+.TE
+What is the line number now?'
+
+output=$(printf "%s\n" "$input" | "$groff" -Tascii -P-cbou -t)
+echo "$output"
+
+echo "testing that line numbering is suppressed in table" >&2
+echo "$output" | grep -Fqx 'This is my table.' || wail
+
+echo "testing that line numbering is restored after table" >&2
+echo "$output" | grep -Eq '3 +What is the line number now\?' || wail
+
+input='.nf
+.nm 1
+test of line numbering suppression
+five
+four
+.nn 3
+three
+.TS
+L.
+I am a table.
+I have two rows.
+.TE
+two
+one
+numbering returns here'
+
+output=$(printf "%s\n" "$input" | "$groff" -Tascii -P-cbou -t)
+echo "$output"
+
+echo "testing that suppressed numbering is restored correctly" >&2
+echo "$output" | grep -Eq '4 +numbering returns here' || wail
+
+test -z "$fail"
+
+# vim:set ai et sw=4 ts=4 tw=72:
diff --git a/src/preproc/tbl/tests/save-and-restore-tab-stops.sh b/src/preproc/tbl/tests/save-and-restore-tab-stops.sh
new file mode 100755
index 0000000..b98922a
--- /dev/null
+++ b/src/preproc/tbl/tests/save-and-restore-tab-stops.sh
@@ -0,0 +1,84 @@
+#!/bin/sh
+#
+# Copyright (C) 2020 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+groff="${abs_top_builddir:-.}/test-groff"
+
+# Regression-test Savannah #42978.
+#
+# When tbl changes the tab stops, it needs to restore them.
+#
+# Based on an example by Bjarni Igni Gislason.
+
+EXAMPLE='.TH tbl\-tabs\-test 1 2020-10-20 "groff test suite"
+.SH Name
+tbl\-tabs\-test \- see if tbl messes up the tab stops
+.SH Description
+Do not use tabs in man pages outside of
+.BR .TS / .TE
+regions.
+.PP
+But	if	you	do.\|.\|.
+.PP
+.TS
+l l l.
+table entries	long enough	to change the tab stops
+.TE
+.PP
+.EX
+#!/bin/sh
+case $#
+1)
+	if foo
+	then
+		bar
+	else
+		if baz
+		then
+			qux
+		fi
+	fi
+;;
+esac
+.EE'
+
+OUTPUT=$(printf "%s\n" "$EXAMPLE" | "$groff" -Tascii -P-cbou -t -man)
+FAIL=
+
+if ! echo "$OUTPUT" | grep -Eq '^ {12}if foo$'
+then
+    FAIL=yes
+    echo "first tab stop is wrong" >&2
+fi
+
+if ! echo "$OUTPUT" | grep -Eq '^ {17}bar$'
+then
+    FAIL=yes
+    echo "second tab stop is wrong" >&2
+fi
+
+if ! echo "$OUTPUT" | grep -Eq '^ {22}qux$'
+then
+    FAIL=yes
+    echo "third tab stop is wrong" >&2
+fi
+
+test -z "$FAIL"
+
+# vim:set ai noet sw=4 ts=4 tw=72:
diff --git a/src/preproc/tbl/tests/warn-on-long-boxed-unkept-table.sh b/src/preproc/tbl/tests/warn-on-long-boxed-unkept-table.sh
new file mode 100755
index 0000000..621a752
--- /dev/null
+++ b/src/preproc/tbl/tests/warn-on-long-boxed-unkept-table.sh
@@ -0,0 +1,56 @@
+#!/bin/sh
+#
+# Copyright (C) 2022 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+groff="${abs_top_builddir:-.}/test-groff"
+
+fail=
+
+wail () {
+    echo ...FAILED >&2
+    fail=YES
+}
+
+# Regression-test Savannah #61878.
+#
+# A boxed, unkept table that overruns the page bottom will produce ugly
+# output; it looks especially bizarre in nroff mode.
+#
+# We set the page length to 2v to force a problem (any boxed table in
+# nroff mode needs 3 vees minimum), and put a page break at the start to
+# catch an incorrectly initialized starting page number for the table.
+
+input='.pl 2v
+.bp
+.TS
+box nokeep;
+L.
+Z
+.TE'
+
+output=$(printf "%s" "$input" | "$groff" -t -Tascii 2>/dev/null)
+error=$(printf "%s" "$input" | "$groff" -t -Tascii 2>&1 >/dev/null)
+echo "$output"
+
+echo "checking that a diagnostic message is produced"
+echo "$error" | grep -q 'warning: boxed.*page 2$' || wail
+
+test -z "$fail"
+
+# vim:set ai et sw=4 ts=4 tw=72:
diff --git a/src/preproc/tbl/tests/x-column-modifier-works.sh b/src/preproc/tbl/tests/x-column-modifier-works.sh
new file mode 100755
index 0000000..da9b890
--- /dev/null
+++ b/src/preproc/tbl/tests/x-column-modifier-works.sh
@@ -0,0 +1,172 @@
+#!/bin/sh
+#
+# Copyright (C) 2023 Free Software Foundation, Inc.
+#
+# This file is part of groff.
+#
+# groff is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# groff is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+groff="${abs_top_builddir:-.}/test-groff"
+
+fail=
+
+wail () {
+    echo ...FAILED >&2
+    fail=YES
+}
+
+# Ensure that the "x" column modifier causes table expansion to the line
+# length.
+
+# Case 1: "naked" table
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+tab(@);
+Lx L L L L.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking unboxed table without vertical rules" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+echo "$output" | sed -n '2p' \
+    | grep -Eqx 'abcdef {25}(abcdef {3}){3}abcdef' || wail
+
+# Case 2: left-hand vertical rule
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+tab(@);
+| Lx L L L L.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking unboxed table with left-hand rule" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+echo "$output" | sed -n '3p' \
+    | grep -Eqx '\| abcdef {23}(abcdef {3}){3}abcdef' || wail
+
+# Case 3: right-hand vertical rule
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+tab(@);
+Lx L L L L |.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking unboxed table with right-hand rule" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+echo "$output" | sed -n '3p' \
+    | grep -Eqx 'abcdef {23}(abcdef {3}){3}abcdef \|' || wail
+
+# Case 4: vertical rule on both ends
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+tab(@);
+| Lx L L L L |.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking unboxed table with both rules" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+echo "$output" | sed -n '3p' \
+    | grep -Eqx '\| abcdef {21}(abcdef {3}){3}abcdef \|' || wail
+
+# Case 5: vertical rule on both ends and interior rule
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+tab(@);
+| Lx L L | L L |.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking unboxed table with both edge and interior rules" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+echo "$output" | sed -n '3p' \
+    | grep -Eqx \
+    '\| abcdef {21}abcdef {3}abcdef \| abcdef {3}abcdef \|' \
+    || wail
+
+# Case 6: boxed table
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+box tab(@);
+Lx L L L L.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking boxed table without interior rules" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+echo "$output" | sed -n '3p' \
+    | grep -Eqx '\| abcdef {21}(abcdef {3}){3}abcdef \|' || wail
+
+# Case 7: boxed table with interior vertical rule
+
+input='.ll 64n
+.nf
+1234567890123456789012345678901234567890123456789012345678901234
+.fi
+.TS
+box tab(@);
+Lx L L | L L.
+abcdef@abcdef@abcdef@abcdef@abcdef
+.TE
+.pl \n(nlu'
+
+echo "checking boxed table with interior rules" >&2
+output=$(printf "%s\n" "$input" | "$groff" -t -Tascii)
+echo "$output"
+echo "$output" | sed -n '3p' \
+    | grep -Eqx \
+    '\| abcdef {21}abcdef {3}abcdef \| abcdef {3}abcdef \|' \
+    || wail
+
+test -z "$fail"
+
+# vim:set ai et sw=4 ts=4 tw=72: