1 files changed, 117 insertions, 0 deletions
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, " }");
+}