Adding upstream version 3.8.1.upstream/3.8.1upstream

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

14 files changed, 4232 insertions, 0 deletions

diff --git a/contrib/lua-lpeg/CMakeLists.txt b/contrib/lua-lpeg/CMakeLists.txt
new file mode 100644
index 0000000..92dd018
--- /dev/null
+++ b/contrib/lua-lpeg/CMakeLists.txt
@@ -0,0 +1,9 @@
+SET(LPEGSRC lpcap.c
+        lpcode.c
+        lpprint.c
+        lptree.c
+        lpvm.c)
+
+SET(LIB_TYPE STATIC)
+ADD_LIBRARY(rspamd-lpeg ${LIB_TYPE} ${LPEGSRC})
+set_target_properties(rspamd-lpeg PROPERTIES COMPILE_FLAGS "${LPEG_CFLAGS}")
diff --git a/contrib/lua-lpeg/LICENSE b/contrib/lua-lpeg/LICENSE
new file mode 100644
index 0000000..cea2d8b
--- /dev/null
+++ b/contrib/lua-lpeg/LICENSE
@@ -0,0 +1,19 @@
+Copyright © 2007-2015 Lua.org, PUC-Rio.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE. 
diff --git a/contrib/lua-lpeg/lpcap.c b/contrib/lua-lpeg/lpcap.c
new file mode 100644
index 0000000..b332fde
--- /dev/null
+++ b/contrib/lua-lpeg/lpcap.c
@@ -0,0 +1,555 @@
+/*
+** $Id: lpcap.c $
+** Copyright 2007, Lua.org & PUC-Rio  (see 'lpeg.html' for license)
+*/
+
+#include "lua.h"
+#include "lauxlib.h"
+
+#include "lpcap.h"
+#include "lptypes.h"
+
+
+#define captype(cap)	((cap)->kind)
+
+#define isclosecap(cap)	(captype(cap) == Cclose)
+
+#define closeaddr(c)	((c)->s + (c)->siz - 1)
+
+#define isfullcap(cap)	((cap)->siz != 0)
+
+#define getfromktable(cs,v)	lua_rawgeti((cs)->L, ktableidx((cs)->ptop), v)
+
+#define pushluaval(cs)		getfromktable(cs, (cs)->cap->idx)
+
+
+
+/*
+** Put at the cache for Lua values the value indexed by 'v' in ktable
+** of the running pattern (if it is not there yet); returns its index.
+*/
+static int updatecache (CapState *cs, int v) {
+  int idx = cs->ptop + 1;  /* stack index of cache for Lua values */
+  if (v != cs->valuecached) {  /* not there? */
+    getfromktable(cs, v);  /* get value from 'ktable' */
+    lua_replace(cs->L, idx);  /* put it at reserved stack position */
+    cs->valuecached = v;  /* keep track of what is there */
+  }
+  return idx;
+}
+
+
+static int pushcapture (CapState *cs);
+
+
+/*
+** Goes back in a list of captures looking for an open capture
+** corresponding to a close
+*/
+static Capture *findopen (Capture *cap) {
+  int n = 0;  /* number of closes waiting an open */
+  for (;;) {
+    cap--;
+    if (isclosecap(cap)) n++;  /* one more open to skip */
+    else if (!isfullcap(cap))
+      if (n-- == 0) return cap;
+  }
+}
+
+
+/*
+** Go to the next capture
+*/
+static void nextcap (CapState *cs) {
+  Capture *cap = cs->cap;
+  if (!isfullcap(cap)) {  /* not a single capture? */
+    int n = 0;  /* number of opens waiting a close */
+    for (;;) {  /* look for corresponding close */
+      cap++;
+      if (isclosecap(cap)) {
+        if (n-- == 0) break;
+      }
+      else if (!isfullcap(cap)) n++;
+    }
+  }
+  cs->cap = cap + 1;  /* + 1 to skip last close (or entire single capture) */
+}
+
+
+/*
+** Push on the Lua stack all values generated by nested captures inside
+** the current capture. Returns number of values pushed. 'addextra'
+** makes it push the entire match after all captured values. The
+** entire match is pushed also if there are no other nested values,
+** so the function never returns zero.
+*/
+static int pushnestedvalues (CapState *cs, int addextra) {
+  Capture *co = cs->cap;
+  if (isfullcap(cs->cap++)) {  /* no nested captures? */
+    lua_pushlstring(cs->L, co->s, co->siz - 1);  /* push whole match */
+    return 1;  /* that is it */
+  }
+  else {
+    int n = 0;
+    while (!isclosecap(cs->cap))  /* repeat for all nested patterns */
+      n += pushcapture(cs);
+    if (addextra || n == 0) {  /* need extra? */
+      lua_pushlstring(cs->L, co->s, cs->cap->s - co->s);  /* push whole match */
+      n++;
+    }
+    cs->cap++;  /* skip close entry */
+    return n;
+  }
+}
+
+
+/*
+** Push only the first value generated by nested captures
+*/
+static void pushonenestedvalue (CapState *cs) {
+  int n = pushnestedvalues(cs, 0);
+  if (n > 1)
+    lua_pop(cs->L, n - 1);  /* pop extra values */
+}
+
+
+/*
+** Try to find a named group capture with the name given at the top of
+** the stack; goes backward from 'cap'.
+*/
+static Capture *findback (CapState *cs, Capture *cap) {
+  lua_State *L = cs->L;
+  while (cap-- > cs->ocap) {  /* repeat until end of list */
+    if (isclosecap(cap))
+      cap = findopen(cap);  /* skip nested captures */
+    else if (!isfullcap(cap))
+      continue; /* opening an enclosing capture: skip and get previous */
+    if (captype(cap) == Cgroup) {
+      getfromktable(cs, cap->idx);  /* get group name */
+      if (lp_equal(L, -2, -1)) {  /* right group? */
+        lua_pop(L, 2);  /* remove reference name and group name */
+        return cap;
+      }
+      else lua_pop(L, 1);  /* remove group name */
+    }
+  }
+  luaL_error(L, "back reference '%s' not found", lua_tostring(L, -1));
+  return NULL;  /* to avoid warnings */
+}
+
+
+/*
+** Back-reference capture. Return number of values pushed.
+*/
+static int backrefcap (CapState *cs) {
+  int n;
+  Capture *curr = cs->cap;
+  pushluaval(cs);  /* reference name */
+  cs->cap = findback(cs, curr);  /* find corresponding group */
+  n = pushnestedvalues(cs, 0);  /* push group's values */
+  cs->cap = curr + 1;
+  return n;
+}
+
+
+/*
+** Table capture: creates a new table and populates it with nested
+** captures.
+*/
+static int tablecap (CapState *cs) {
+  lua_State *L = cs->L;
+  int n = 0;
+  lua_newtable(L);
+  if (isfullcap(cs->cap++))
+    return 1;  /* table is empty */
+  while (!isclosecap(cs->cap)) {
+    if (captype(cs->cap) == Cgroup && cs->cap->idx != 0) {  /* named group? */
+      pushluaval(cs);  /* push group name */
+      pushonenestedvalue(cs);
+      lua_settable(L, -3);
+    }
+    else {  /* not a named group */
+      int i;
+      int k = pushcapture(cs);
+      for (i = k; i > 0; i--)  /* store all values into table */
+        lua_rawseti(L, -(i + 1), n + i);
+      n += k;
+    }
+  }
+  cs->cap++;  /* skip close entry */
+  return 1;  /* number of values pushed (only the table) */
+}
+
+
+/*
+** Table-query capture
+*/
+static int querycap (CapState *cs) {
+  int idx = cs->cap->idx;
+  pushonenestedvalue(cs);  /* get nested capture */
+  lua_gettable(cs->L, updatecache(cs, idx));  /* query cap. value at table */
+  if (!lua_isnil(cs->L, -1))
+    return 1;
+  else {  /* no value */
+    lua_pop(cs->L, 1);  /* remove nil */
+    return 0;
+  }
+}
+
+
+/*
+** Fold capture
+*/
+static int foldcap (CapState *cs) {
+  int n;
+  lua_State *L = cs->L;
+  int idx = cs->cap->idx;
+  if (isfullcap(cs->cap++) ||  /* no nested captures? */
+      isclosecap(cs->cap) ||  /* no nested captures (large subject)? */
+      (n = pushcapture(cs)) == 0)  /* nested captures with no values? */
+    return luaL_error(L, "no initial value for fold capture");
+  if (n > 1)
+    lua_pop(L, n - 1);  /* leave only one result for accumulator */
+  while (!isclosecap(cs->cap)) {
+    lua_pushvalue(L, updatecache(cs, idx));  /* get folding function */
+    lua_insert(L, -2);  /* put it before accumulator */
+    n = pushcapture(cs);  /* get next capture's values */
+    lua_call(L, n + 1, 1);  /* call folding function */
+  }
+  cs->cap++;  /* skip close entry */
+  return 1;  /* only accumulator left on the stack */
+}
+
+
+/*
+** Function capture
+*/
+static int functioncap (CapState *cs) {
+  int n;
+  int top = lua_gettop(cs->L);
+  pushluaval(cs);  /* push function */
+  n = pushnestedvalues(cs, 0);  /* push nested captures */
+  lua_call(cs->L, n, LUA_MULTRET);  /* call function */
+  return lua_gettop(cs->L) - top;  /* return function's results */
+}
+
+
+/*
+** Select capture
+*/
+static int numcap (CapState *cs) {
+  int idx = cs->cap->idx;  /* value to select */
+  if (idx == 0) {  /* no values? */
+    nextcap(cs);  /* skip entire capture */
+    return 0;  /* no value produced */
+  }
+  else {
+    int n = pushnestedvalues(cs, 0);
+    if (n < idx)  /* invalid index? */
+      return luaL_error(cs->L, "no capture '%d'", idx);
+    else {
+      lua_pushvalue(cs->L, -(n - idx + 1));  /* get selected capture */
+      lua_replace(cs->L, -(n + 1));  /* put it in place of 1st capture */
+      lua_pop(cs->L, n - 1);  /* remove other captures */
+      return 1;
+    }
+  }
+}
+
+
+/*
+** Return the stack index of the first runtime capture in the given
+** list of captures (or zero if no runtime captures)
+*/
+int finddyncap (Capture *cap, Capture *last) {
+  for (; cap < last; cap++) {
+    if (cap->kind == Cruntime)
+      return cap->idx;  /* stack position of first capture */
+  }
+  return 0;  /* no dynamic captures in this segment */
+}
+
+
+/*
+** Calls a runtime capture. Returns number of captures "removed" by the
+** call, that is, those inside the group capture. Captures to be added
+** are on the Lua stack.
+*/
+int runtimecap (CapState *cs, Capture *close, const char *s, int *rem) {
+  int n, id;
+  lua_State *L = cs->L;
+  int otop = lua_gettop(L);
+  Capture *open = findopen(close);  /* get open group capture */
+  assert(captype(open) == Cgroup);
+  id = finddyncap(open, close);  /* get first dynamic capture argument */
+  close->kind = Cclose;  /* closes the group */
+  close->s = s;
+  cs->cap = open; cs->valuecached = 0;  /* prepare capture state */
+  luaL_checkstack(L, 4, "too many runtime captures");
+  pushluaval(cs);  /* push function to be called */
+  lua_pushvalue(L, SUBJIDX);  /* push original subject */
+  lua_pushinteger(L, s - cs->s + 1);  /* push current position */
+  n = pushnestedvalues(cs, 0);  /* push nested captures */
+  lua_call(L, n + 2, LUA_MULTRET);  /* call dynamic function */
+  if (id > 0) {  /* are there old dynamic captures to be removed? */
+    int i;
+    for (i = id; i <= otop; i++)
+      lua_remove(L, id);  /* remove old dynamic captures */
+    *rem = otop - id + 1;  /* total number of dynamic captures removed */
+  }
+  else
+    *rem = 0;  /* no dynamic captures removed */
+  return close - open - 1;  /* number of captures to be removed */
+}
+
+
+/*
+** Auxiliary structure for substitution and string captures: keep
+** information about nested captures for future use, avoiding to push
+** string results into Lua
+*/
+typedef struct StrAux {
+  int isstring;  /* whether capture is a string */
+  union {
+    Capture *cp;  /* if not a string, respective capture */
+    struct {  /* if it is a string... */
+      const char *s;  /* ... starts here */
+      const char *e;  /* ... ends here */
+    } s;
+  } u;
+} StrAux;
+
+#define MAXSTRCAPS	10
+
+/*
+** Collect values from current capture into array 'cps'. Current
+** capture must be Cstring (first call) or Csimple (recursive calls).
+** (In first call, fills %0 with whole match for Cstring.)
+** Returns number of elements in the array that were filled.
+*/
+static int getstrcaps (CapState *cs, StrAux *cps, int n) {
+  int k = n++;
+  cps[k].isstring = 1;  /* get string value */
+  cps[k].u.s.s = cs->cap->s;  /* starts here */
+  if (!isfullcap(cs->cap++)) {  /* nested captures? */
+    while (!isclosecap(cs->cap)) {  /* traverse them */
+      if (n >= MAXSTRCAPS)  /* too many captures? */
+        nextcap(cs);  /* skip extra captures (will not need them) */
+      else if (captype(cs->cap) == Csimple)  /* string? */
+        n = getstrcaps(cs, cps, n);  /* put info. into array */
+      else {
+        cps[n].isstring = 0;  /* not a string */
+        cps[n].u.cp = cs->cap;  /* keep original capture */
+        nextcap(cs);
+        n++;
+      }
+    }
+    cs->cap++;  /* skip close */
+  }
+  cps[k].u.s.e = closeaddr(cs->cap - 1);  /* ends here */
+  return n;
+}
+
+
+/*
+** add next capture value (which should be a string) to buffer 'b'
+*/
+static int addonestring (luaL_Buffer *b, CapState *cs, const char *what);
+
+
+/*
+** String capture: add result to buffer 'b' (instead of pushing
+** it into the stack)
+*/
+static void stringcap (luaL_Buffer *b, CapState *cs) {
+  StrAux cps[MAXSTRCAPS];
+  int n;
+  size_t len, i;
+  const char *fmt;  /* format string */
+  fmt = lua_tolstring(cs->L, updatecache(cs, cs->cap->idx), &len);
+  n = getstrcaps(cs, cps, 0) - 1;  /* collect nested captures */
+  for (i = 0; i < len; i++) {  /* traverse them */
+    if (fmt[i] != '%')  /* not an escape? */
+      luaL_addchar(b, fmt[i]);  /* add it to buffer */
+    else if (fmt[++i] < '0' || fmt[i] > '9')  /* not followed by a digit? */
+      luaL_addchar(b, fmt[i]);  /* add to buffer */
+    else {
+      int l = fmt[i] - '0';  /* capture index */
+      if (l > n)
+        luaL_error(cs->L, "invalid capture index (%d)", l);
+      else if (cps[l].isstring)
+        luaL_addlstring(b, cps[l].u.s.s, cps[l].u.s.e - cps[l].u.s.s);
+      else {
+        Capture *curr = cs->cap;
+        cs->cap = cps[l].u.cp;  /* go back to evaluate that nested capture */
+        if (!addonestring(b, cs, "capture"))
+          luaL_error(cs->L, "no values in capture index %d", l);
+        cs->cap = curr;  /* continue from where it stopped */
+      }
+    }
+  }
+}
+
+
+/*
+** Substitution capture: add result to buffer 'b'
+*/
+static void substcap (luaL_Buffer *b, CapState *cs) {
+  const char *curr = cs->cap->s;
+  if (isfullcap(cs->cap))  /* no nested captures? */
+    luaL_addlstring(b, curr, cs->cap->siz - 1);  /* keep original text */
+  else {
+    cs->cap++;  /* skip open entry */
+    while (!isclosecap(cs->cap)) {  /* traverse nested captures */
+      const char *next = cs->cap->s;
+      luaL_addlstring(b, curr, next - curr);  /* add text up to capture */
+      if (addonestring(b, cs, "replacement"))
+        curr = closeaddr(cs->cap - 1);  /* continue after match */
+      else  /* no capture value */
+        curr = next;  /* keep original text in final result */
+    }
+    luaL_addlstring(b, curr, cs->cap->s - curr);  /* add last piece of text */
+  }
+  cs->cap++;  /* go to next capture */
+}
+
+
+/*
+** Evaluates a capture and adds its first value to buffer 'b'; returns
+** whether there was a value
+*/
+static int addonestring (luaL_Buffer *b, CapState *cs, const char *what) {
+  switch (captype(cs->cap)) {
+    case Cstring:
+      stringcap(b, cs);  /* add capture directly to buffer */
+      return 1;
+    case Csubst:
+      substcap(b, cs);  /* add capture directly to buffer */
+      return 1;
+    default: {
+      lua_State *L = cs->L;
+      int n = pushcapture(cs);
+      if (n > 0) {
+        if (n > 1) lua_pop(L, n - 1);  /* only one result */
+        if (!lua_isstring(L, -1))
+          luaL_error(L, "invalid %s value (a %s)", what, luaL_typename(L, -1));
+        luaL_addvalue(b);
+      }
+      return n;
+    }
+  }
+}
+
+
+#if !defined(MAXRECLEVEL)
+#define MAXRECLEVEL	200
+#endif
+
+
+/*
+** Push all values of the current capture into the stack; returns
+** number of values pushed
+*/
+static int pushcapture (CapState *cs) {
+  lua_State *L = cs->L;
+  int res;
+  luaL_checkstack(L, 4, "too many captures");
+  if (cs->reclevel++ > MAXRECLEVEL)
+    return luaL_error(L, "subcapture nesting too deep");
+  switch (captype(cs->cap)) {
+    case Cposition: {
+      lua_pushinteger(L, cs->cap->s - cs->s + 1);
+      cs->cap++;
+      res = 1;
+      break;
+    }
+    case Cconst: {
+      pushluaval(cs);
+      cs->cap++;
+      res = 1;
+      break;
+    }
+    case Carg: {
+      int arg = (cs->cap++)->idx;
+      if (arg + FIXEDARGS > cs->ptop)
+        return luaL_error(L, "reference to absent extra argument #%d", arg);
+      lua_pushvalue(L, arg + FIXEDARGS);
+      res = 1;
+      break;
+    }
+    case Csimple: {
+      int k = pushnestedvalues(cs, 1);
+      lua_insert(L, -k);  /* make whole match be first result */
+      res = k;
+      break;
+    }
+    case Cruntime: {
+      lua_pushvalue(L, (cs->cap++)->idx);  /* value is in the stack */
+      res = 1;
+      break;
+    }
+    case Cstring: {
+      luaL_Buffer b;
+      luaL_buffinit(L, &b);
+      stringcap(&b, cs);
+      luaL_pushresult(&b);
+      res = 1;
+      break;
+    }
+    case Csubst: {
+      luaL_Buffer b;
+      luaL_buffinit(L, &b);
+      substcap(&b, cs);
+      luaL_pushresult(&b);
+      res = 1;
+      break;
+    }
+    case Cgroup: {
+      if (cs->cap->idx == 0)  /* anonymous group? */
+        res = pushnestedvalues(cs, 0);  /* add all nested values */
+      else {  /* named group: add no values */
+        nextcap(cs);  /* skip capture */
+        res = 0;
+      }
+      break;
+    }
+    case Cbackref: res = backrefcap(cs); break;
+    case Ctable: res = tablecap(cs); break;
+    case Cfunction: res = functioncap(cs); break;
+    case Cnum: res = numcap(cs); break;
+    case Cquery: res = querycap(cs); break;
+    case Cfold: res = foldcap(cs); break;
+    default: assert(0); res = 0;
+  }
+  cs->reclevel--;
+  return res;
+}
+
+
+/*
+** Prepare a CapState structure and traverse the entire list of
+** captures in the stack pushing its results. 's' is the subject
+** string, 'r' is the final position of the match, and 'ptop' 
+** the index in the stack where some useful values were pushed.
+** Returns the number of results pushed. (If the list produces no
+** results, push the final position of the match.)
+*/
+int getcaptures (lua_State *L, const char *s, const char *r, int ptop) {
+  Capture *capture = (Capture *)lua_touserdata(L, caplistidx(ptop));
+  int n = 0;
+  if (!isclosecap(capture)) {  /* is there any capture? */
+    CapState cs;
+    cs.ocap = cs.cap = capture; cs.L = L; cs.reclevel = 0;
+    cs.s = s; cs.valuecached = 0; cs.ptop = ptop;
+    do {  /* collect their values */
+      n += pushcapture(&cs);
+    } while (!isclosecap(cs.cap));
+  }
+  if (n == 0) {  /* no capture values? */
+    lua_pushinteger(L, r - s + 1);  /* return only end position */
+    n = 1;
+  }
+  return n;
+}
+
+
diff --git a/contrib/lua-lpeg/lpcap.h b/contrib/lua-lpeg/lpcap.h
new file mode 100644
index 0000000..dc10d69
--- /dev/null
+++ b/contrib/lua-lpeg/lpcap.h
@@ -0,0 +1,57 @@
+/*
+** $Id: lpcap.h $
+*/
+
+#if !defined(lpcap_h)
+#define lpcap_h
+
+
+#include "lptypes.h"
+
+
+/* kinds of captures */
+typedef enum CapKind {
+  Cclose,  /* not used in trees */
+  Cposition,
+  Cconst,  /* ktable[key] is Lua constant */
+  Cbackref,  /* ktable[key] is "name" of group to get capture */
+  Carg,  /* 'key' is arg's number */
+  Csimple,  /* next node is pattern */
+  Ctable,  /* next node is pattern */
+  Cfunction,  /* ktable[key] is function; next node is pattern */
+  Cquery,  /* ktable[key] is table; next node is pattern */
+  Cstring,  /* ktable[key] is string; next node is pattern */
+  Cnum,  /* numbered capture; 'key' is number of value to return */
+  Csubst,  /* substitution capture; next node is pattern */
+  Cfold,  /* ktable[key] is function; next node is pattern */
+  Cruntime,  /* not used in trees (is uses another type for tree) */
+  Cgroup  /* ktable[key] is group's "name" */
+} CapKind;
+
+
+typedef struct Capture {
+  const char *s;  /* subject position */
+  unsigned short idx;  /* extra info (group name, arg index, etc.) */
+  byte kind;  /* kind of capture */
+  byte siz;  /* size of full capture + 1 (0 = not a full capture) */
+} Capture;
+
+
+typedef struct CapState {
+  Capture *cap;  /* current capture */
+  Capture *ocap;  /* (original) capture list */
+  lua_State *L;
+  int ptop;  /* index of last argument to 'match' */
+  const char *s;  /* original string */
+  int valuecached;  /* value stored in cache slot */
+  int reclevel;  /* recursion level */
+} CapState;
+
+
+int runtimecap (CapState *cs, Capture *close, const char *s, int *rem);
+int getcaptures (lua_State *L, const char *s, const char *r, int ptop);
+int finddyncap (Capture *cap, Capture *last);
+
+#endif
+
+
diff --git a/contrib/lua-lpeg/lpcode.c b/contrib/lua-lpeg/lpcode.c
new file mode 100644
index 0000000..3923459
--- /dev/null
+++ b/contrib/lua-lpeg/lpcode.c
@@ -0,0 +1,1014 @@
+/*
+** $Id: lpcode.c $
+** Copyright 2007, Lua.org & PUC-Rio  (see 'lpeg.html' for license)
+*/
+
+#include <limits.h>
+
+
+#include "lua.h"
+#include "lauxlib.h"
+
+#include "lptypes.h"
+#include "lpcode.h"
+
+
+/* signals a "no-instruction */
+#define NOINST		-1
+
+
+
+static const Charset fullset_ =
+  {{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}};
+
+static const Charset *fullset = &fullset_;
+
+/*
+** {======================================================
+** Analysis and some optimizations
+** =======================================================
+*/
+
+/*
+** Check whether a charset is empty (returns IFail), singleton (IChar),
+** full (IAny), or none of those (ISet). When singleton, '*c' returns
+** which character it is. (When generic set, the set was the input,
+** so there is no need to return it.)
+*/
+static Opcode charsettype (const byte *cs, int *c) {
+  int count = 0;  /* number of characters in the set */
+  int i;
+  int candidate = -1;  /* candidate position for the singleton char */
+  for (i = 0; i < CHARSETSIZE; i++) {  /* for each byte */
+    int b = cs[i];
+    if (b == 0) {  /* is byte empty? */
+      if (count > 1)  /* was set neither empty nor singleton? */
+        return ISet;  /* neither full nor empty nor singleton */
+      /* else set is still empty or singleton */
+    }
+    else if (b == 0xFF) {  /* is byte full? */
+      if (count < (i * BITSPERCHAR))  /* was set not full? */
+        return ISet;  /* neither full nor empty nor singleton */
+      else count += BITSPERCHAR;  /* set is still full */
+    }
+    else if ((b & (b - 1)) == 0) {  /* has byte only one bit? */
+      if (count > 0)  /* was set not empty? */
+        return ISet;  /* neither full nor empty nor singleton */
+      else {  /* set has only one char till now; track it */
+        count++;
+        candidate = i;
+      }
+    }
+    else return ISet;  /* byte is neither empty, full, nor singleton */
+  }
+  switch (count) {
+    case 0: return IFail;  /* empty set */
+    case 1: {  /* singleton; find character bit inside byte */
+      int b = cs[candidate];
+      *c = candidate * BITSPERCHAR;
+      if ((b & 0xF0) != 0) { *c += 4; b >>= 4; }
+      if ((b & 0x0C) != 0) { *c += 2; b >>= 2; }
+      if ((b & 0x02) != 0) { *c += 1; }
+      return IChar;
+    }
+    default: {
+       assert(count == CHARSETSIZE * BITSPERCHAR);  /* full set */
+       return IAny;
+    }
+  }
+}
+
+
+/*
+** A few basic operations on Charsets
+*/
+static void cs_complement (Charset *cs) {
+  loopset(i, cs->cs[i] = ~cs->cs[i]);
+}
+
+static int cs_equal (const byte *cs1, const byte *cs2) {
+  loopset(i, if (cs1[i] != cs2[i]) return 0);
+  return 1;
+}
+
+static int cs_disjoint (const Charset *cs1, const Charset *cs2) {
+  loopset(i, if ((cs1->cs[i] & cs2->cs[i]) != 0) return 0;)
+  return 1;
+}
+
+
+/*
+** If 'tree' is a 'char' pattern (TSet, TChar, TAny), convert it into a
+** charset and return 1; else return 0.
+*/
+int tocharset (TTree *tree, Charset *cs) {
+  switch (tree->tag) {
+    case TSet: {  /* copy set */
+      loopset(i, cs->cs[i] = treebuffer(tree)[i]);
+      return 1;
+    }
+    case TChar: {  /* only one char */
+      assert(0 <= tree->u.n && tree->u.n <= UCHAR_MAX);
+      loopset(i, cs->cs[i] = 0);  /* erase all chars */
+      setchar(cs->cs, tree->u.n);  /* add that one */
+      return 1;
+    }
+    case TAny: {
+      loopset(i, cs->cs[i] = 0xFF);  /* add all characters to the set */
+      return 1;
+    }
+    default: return 0;
+  }
+}
+
+
+/*
+** Visit a TCall node taking care to stop recursion. If node not yet
+** visited, return 'f(sib2(tree))', otherwise return 'def' (default
+** value)
+*/
+static int callrecursive (TTree *tree, int f (TTree *t), int def) {
+  int key = tree->key;
+  assert(tree->tag == TCall);
+  assert(sib2(tree)->tag == TRule);
+  if (key == 0)  /* node already visited? */
+    return def;  /* return default value */
+  else {  /* first visit */
+    int result;
+    tree->key = 0;  /* mark call as already visited */
+    result = f(sib2(tree));  /* go to called rule */
+    tree->key = key;  /* restore tree */
+    return result;
+  }
+}
+
+
+/*
+** Check whether a pattern tree has captures
+*/
+int hascaptures (TTree *tree) {
+ tailcall:
+  switch (tree->tag) {
+    case TCapture: case TRunTime:
+      return 1;
+    case TCall:
+      return callrecursive(tree, hascaptures, 0);
+    case TRule:  /* do not follow siblings */
+      tree = sib1(tree); goto tailcall;
+    case TOpenCall: assert(0);
+    default: {
+      switch (numsiblings[tree->tag]) {
+        case 1:  /* return hascaptures(sib1(tree)); */
+          tree = sib1(tree); goto tailcall;
+        case 2:
+          if (hascaptures(sib1(tree)))
+            return 1;
+          /* else return hascaptures(sib2(tree)); */
+          tree = sib2(tree); goto tailcall;
+        default: assert(numsiblings[tree->tag] == 0); return 0;
+      }
+    }
+  }
+}
+
+
+/*
+** Checks how a pattern behaves regarding the empty string,
+** in one of two different ways:
+** A pattern is *nullable* if it can match without consuming any character;
+** A pattern is *nofail* if it never fails for any string
+** (including the empty string).
+** The difference is only for predicates and run-time captures;
+** for other patterns, the two properties are equivalent.
+** (With predicates, &'a' is nullable but not nofail. Of course,
+** nofail => nullable.)
+** These functions are all convervative in the following way:
+**    p is nullable => nullable(p)
+**    nofail(p) => p cannot fail
+** The function assumes that TOpenCall is not nullable;
+** this will be checked again when the grammar is fixed.
+** Run-time captures can do whatever they want, so the result
+** is conservative.
+*/
+int checkaux (TTree *tree, int pred) {
+ tailcall:
+  switch (tree->tag) {
+    case TChar: case TSet: case TAny:
+    case TFalse: case TOpenCall:
+      return 0;  /* not nullable */
+    case TRep: case TTrue:
+      return 1;  /* no fail */
+    case TNot: case TBehind:  /* can match empty, but can fail */
+      if (pred == PEnofail) return 0;
+      else return 1;  /* PEnullable */
+    case TAnd:  /* can match empty; fail iff body does */
+      if (pred == PEnullable) return 1;
+      /* else return checkaux(sib1(tree), pred); */
+      tree = sib1(tree); goto tailcall;
+    case TRunTime:  /* can fail; match empty iff body does */
+      if (pred == PEnofail) return 0;
+      /* else return checkaux(sib1(tree), pred); */
+      tree = sib1(tree); goto tailcall;
+    case TSeq:
+      if (!checkaux(sib1(tree), pred)) return 0;
+      /* else return checkaux(sib2(tree), pred); */
+      tree = sib2(tree); goto tailcall;
+    case TChoice:
+      if (checkaux(sib2(tree), pred)) return 1;
+      /* else return checkaux(sib1(tree), pred); */
+      tree = sib1(tree); goto tailcall;
+    case TCapture: case TGrammar: case TRule:
+      /* return checkaux(sib1(tree), pred); */
+      tree = sib1(tree); goto tailcall;
+    case TCall:  /* return checkaux(sib2(tree), pred); */
+      tree = sib2(tree); goto tailcall;
+    default: assert(0); return 0;
+  }
+}
+
+
+/*
+** number of characters to match a pattern (or -1 if variable)
+*/
+int fixedlen (TTree *tree) {
+  int len = 0;  /* to accumulate in tail calls */
+ tailcall:
+  switch (tree->tag) {
+    case TChar: case TSet: case TAny:
+      return len + 1;
+    case TFalse: case TTrue: case TNot: case TAnd: case TBehind:
+      return len;
+    case TRep: case TRunTime: case TOpenCall:
+      return -1;
+    case TCapture: case TRule: case TGrammar:
+      /* return fixedlen(sib1(tree)); */
+      tree = sib1(tree); goto tailcall;
+    case TCall: {
+      int n1 = callrecursive(tree, fixedlen, -1);
+      if (n1 < 0)
+        return -1;
+      else
+        return len + n1;
+    }
+    case TSeq: {
+      int n1 = fixedlen(sib1(tree));
+      if (n1 < 0)
+        return -1;
+      /* else return fixedlen(sib2(tree)) + len; */
+      len += n1; tree = sib2(tree); goto tailcall;
+    }
+    case TChoice: {
+      int n1 = fixedlen(sib1(tree));
+      int n2 = fixedlen(sib2(tree));
+      if (n1 != n2 || n1 < 0)
+        return -1;
+      else
+        return len + n1;
+    }
+    default: assert(0); return 0;
+  };
+}
+
+
+/*
+** Computes the 'first set' of a pattern.
+** The result is a conservative aproximation:
+**   match p ax -> x (for some x) ==> a belongs to first(p)
+** or
+**   a not in first(p) ==> match p ax -> fail (for all x)
+**
+** The set 'follow' is the first set of what follows the
+** pattern (full set if nothing follows it).
+**
+** The function returns 0 when this resulting set can be used for
+** test instructions that avoid the pattern altogether.
+** A non-zero return can happen for two reasons:
+** 1) match p '' -> ''            ==> return has bit 1 set
+** (tests cannot be used because they would always fail for an empty input);
+** 2) there is a match-time capture ==> return has bit 2 set
+** (optimizations should not bypass match-time captures).
+*/
+static int getfirst (TTree *tree, const Charset *follow, Charset *firstset) {
+ tailcall:
+  switch (tree->tag) {
+    case TChar: case TSet: case TAny: {
+      tocharset(tree, firstset);
+      return 0;
+    }
+    case TTrue: {
+      loopset(i, firstset->cs[i] = follow->cs[i]);
+      return 1;  /* accepts the empty string */
+    }
+    case TFalse: {
+      loopset(i, firstset->cs[i] = 0);
+      return 0;
+    }
+    case TChoice: {
+      Charset csaux;
+      int e1 = getfirst(sib1(tree), follow, firstset);
+      int e2 = getfirst(sib2(tree), follow, &csaux);
+      loopset(i, firstset->cs[i] |= csaux.cs[i]);
+      return e1 | e2;
+    }
+    case TSeq: {
+      if (!nullable(sib1(tree))) {
+        /* when p1 is not nullable, p2 has nothing to contribute;
+           return getfirst(sib1(tree), fullset, firstset); */
+        tree = sib1(tree); follow = fullset; goto tailcall;
+      }
+      else {  /* FIRST(p1 p2, fl) = FIRST(p1, FIRST(p2, fl)) */
+        Charset csaux;
+        int e2 = getfirst(sib2(tree), follow, &csaux);
+        int e1 = getfirst(sib1(tree), &csaux, firstset);
+        if (e1 == 0) return 0;  /* 'e1' ensures that first can be used */
+        else if ((e1 | e2) & 2)  /* one of the children has a matchtime? */
+          return 2;  /* pattern has a matchtime capture */
+        else return e2;  /* else depends on 'e2' */
+      }
+    }
+    case TRep: {
+      getfirst(sib1(tree), follow, firstset);
+      loopset(i, firstset->cs[i] |= follow->cs[i]);
+      return 1;  /* accept the empty string */
+    }
+    case TCapture: case TGrammar: case TRule: {
+      /* return getfirst(sib1(tree), follow, firstset); */
+      tree = sib1(tree); goto tailcall;
+    }
+    case TRunTime: {  /* function invalidates any follow info. */
+      int e = getfirst(sib1(tree), fullset, firstset);
+      if (e) return 2;  /* function is not "protected"? */
+      else return 0;  /* pattern inside capture ensures first can be used */
+    }
+    case TCall: {
+      /* return getfirst(sib2(tree), follow, firstset); */
+      tree = sib2(tree); goto tailcall;
+    }
+    case TAnd: {
+      int e = getfirst(sib1(tree), follow, firstset);
+      loopset(i, firstset->cs[i] &= follow->cs[i]);
+      return e;
+    }
+    case TNot: {
+      if (tocharset(sib1(tree), firstset)) {
+        cs_complement(firstset);
+        return 1;
+      }
+      /* else go through */
+    }
+    case TBehind: {  /* instruction gives no new information */
+      /* call 'getfirst' only to check for math-time captures */
+      int e = getfirst(sib1(tree), follow, firstset);
+      loopset(i, firstset->cs[i] = follow->cs[i]);  /* uses follow */
+      return e | 1;  /* always can accept the empty string */
+    }
+    default: assert(0); return 0;
+  }
+}
+
+
+/*
+** If 'headfail(tree)' true, then 'tree' can fail only depending on the
+** next character of the subject.
+*/
+static int headfail (TTree *tree) {
+ tailcall:
+  switch (tree->tag) {
+    case TChar: case TSet: case TAny: case TFalse:
+      return 1;
+    case TTrue: case TRep: case TRunTime: case TNot:
+    case TBehind:
+      return 0;
+    case TCapture: case TGrammar: case TRule: case TAnd:
+      tree = sib1(tree); goto tailcall;  /* return headfail(sib1(tree)); */
+    case TCall:
+      tree = sib2(tree); goto tailcall;  /* return headfail(sib2(tree)); */
+    case TSeq:
+      if (!nofail(sib2(tree))) return 0;
+      /* else return headfail(sib1(tree)); */
+      tree = sib1(tree); goto tailcall;
+    case TChoice:
+      if (!headfail(sib1(tree))) return 0;
+      /* else return headfail(sib2(tree)); */
+      tree = sib2(tree); goto tailcall;
+    default: assert(0); return 0;
+  }
+}
+
+
+/*
+** Check whether the code generation for the given tree can benefit
+** from a follow set (to avoid computing the follow set when it is
+** not needed)
+*/
+static int needfollow (TTree *tree) {
+ tailcall:
+  switch (tree->tag) {
+    case TChar: case TSet: case TAny:
+    case TFalse: case TTrue: case TAnd: case TNot:
+    case TRunTime: case TGrammar: case TCall: case TBehind:
+      return 0;
+    case TChoice: case TRep:
+      return 1;
+    case TCapture:
+      tree = sib1(tree); goto tailcall;
+    case TSeq:
+      tree = sib2(tree); goto tailcall;
+    default: assert(0); return 0;
+  } 
+}
+
+/* }====================================================== */
+
+
+
+/*
+** {======================================================
+** Code generation
+** =======================================================
+*/
+
+
+/*
+** size of an instruction
+*/
+int sizei (const Instruction *i) {
+  switch((Opcode)i->i.code) {
+    case ISet: case ISpan: return CHARSETINSTSIZE;
+    case ITestSet: return CHARSETINSTSIZE + 1;
+    case ITestChar: case ITestAny: case IChoice: case IJmp: case ICall:
+    case IOpenCall: case ICommit: case IPartialCommit: case IBackCommit:
+      return 2;
+    default: return 1;
+  }
+}
+
+
+/*
+** state for the compiler
+*/
+typedef struct CompileState {
+  Pattern *p;  /* pattern being compiled */
+  int ncode;  /* next position in p->code to be filled */
+  lua_State *L;
+} CompileState;
+
+
+/*
+** code generation is recursive; 'opt' indicates that the code is being
+** generated as the last thing inside an optional pattern (so, if that
+** code is optional too, it can reuse the 'IChoice' already in place for
+** the outer pattern). 'tt' points to a previous test protecting this
+** code (or NOINST). 'fl' is the follow set of the pattern.
+*/
+static void codegen (CompileState *compst, TTree *tree, int opt, int tt,
+                     const Charset *fl);
+
+
+void realloccode (lua_State *L, Pattern *p, int nsize) {
+  void *ud;
+  lua_Alloc f = lua_getallocf(L, &ud);
+  void *newblock = f(ud, p->code, p->codesize * sizeof(Instruction),
+                                  nsize * sizeof(Instruction));
+  if (newblock == NULL && nsize > 0)
+    luaL_error(L, "not enough memory");
+  p->code = (Instruction *)newblock;
+  p->codesize = nsize;
+}
+
+
+static int nextinstruction (CompileState *compst) {
+  int size = compst->p->codesize;
+  if (compst->ncode >= size)
+    realloccode(compst->L, compst->p, size * 2);
+  return compst->ncode++;
+}
+
+
+#define getinstr(cs,i)		((cs)->p->code[i])
+
+
+static int addinstruction (CompileState *compst, Opcode op, int aux) {
+  int i = nextinstruction(compst);
+  getinstr(compst, i).i.code = op;
+  getinstr(compst, i).i.aux = aux;
+  return i;
+}
+
+
+/*
+** Add an instruction followed by space for an offset (to be set later)
+*/
+static int addoffsetinst (CompileState *compst, Opcode op) {
+  int i = addinstruction(compst, op, 0);  /* instruction */
+  addinstruction(compst, (Opcode)0, 0);  /* open space for offset */
+  assert(op == ITestSet || sizei(&getinstr(compst, i)) == 2);
+  return i;
+}
+
+
+/*
+** Set the offset of an instruction
+*/
+static void setoffset (CompileState *compst, int instruction, int offset) {
+  getinstr(compst, instruction + 1).offset = offset;
+}
+
+
+/*
+** Add a capture instruction:
+** 'op' is the capture instruction; 'cap' the capture kind;
+** 'key' the key into ktable; 'aux' is the optional capture offset
+**
+*/
+static int addinstcap (CompileState *compst, Opcode op, int cap, int key,
+                       int aux) {
+  int i = addinstruction(compst, op, joinkindoff(cap, aux));
+  getinstr(compst, i).i.key = key;
+  return i;
+}
+
+
+#define gethere(compst) 	((compst)->ncode)
+
+#define target(code,i)		((i) + code[i + 1].offset)
+
+
+/*
+** Patch 'instruction' to jump to 'target'
+*/
+static void jumptothere (CompileState *compst, int instruction, int target) {
+  if (instruction >= 0)
+    setoffset(compst, instruction, target - instruction);
+}
+
+
+/*
+** Patch 'instruction' to jump to current position
+*/
+static void jumptohere (CompileState *compst, int instruction) {
+  jumptothere(compst, instruction, gethere(compst));
+}
+
+
+/*
+** Code an IChar instruction, or IAny if there is an equivalent
+** test dominating it
+*/
+static void codechar (CompileState *compst, int c, int tt) {
+  if (tt >= 0 && getinstr(compst, tt).i.code == ITestChar &&
+                 getinstr(compst, tt).i.aux == c)
+    addinstruction(compst, IAny, 0);
+  else
+    addinstruction(compst, IChar, c);
+}
+
+
+/*
+** Add a charset posfix to an instruction
+*/
+static void addcharset (CompileState *compst, const byte *cs) {
+  int p = gethere(compst);
+  int i;
+  for (i = 0; i < (int)CHARSETINSTSIZE - 1; i++)
+    nextinstruction(compst);  /* space for buffer */
+  /* fill buffer with charset */
+  loopset(j, getinstr(compst, p).buff[j] = cs[j]);
+}
+
+
+/*
+** code a char set, optimizing unit sets for IChar, "complete"
+** sets for IAny, and empty sets for IFail; also use an IAny
+** when instruction is dominated by an equivalent test.
+*/
+static void codecharset (CompileState *compst, const byte *cs, int tt) {
+  int c = 0;  /* (=) to avoid warnings */
+  Opcode op = charsettype(cs, &c);
+  switch (op) {
+    case IChar: codechar(compst, c, tt); break;
+    case ISet: {  /* non-trivial set? */
+      if (tt >= 0 && getinstr(compst, tt).i.code == ITestSet &&
+          cs_equal(cs, getinstr(compst, tt + 2).buff))
+        addinstruction(compst, IAny, 0);
+      else {
+        addinstruction(compst, ISet, 0);
+        addcharset(compst, cs);
+      }
+      break;
+    }
+    default: addinstruction(compst, op, c); break;
+  }
+}
+
+
+/*
+** code a test set, optimizing unit sets for ITestChar, "complete"
+** sets for ITestAny, and empty sets for IJmp (always fails).
+** 'e' is true iff test should accept the empty string. (Test
+** instructions in the current VM never accept the empty string.)
+*/
+static int codetestset (CompileState *compst, Charset *cs, int e) {
+  if (e) return NOINST;  /* no test */
+  else {
+    int c = 0;
+    Opcode op = charsettype(cs->cs, &c);
+    switch (op) {
+      case IFail: return addoffsetinst(compst, IJmp);  /* always jump */
+      case IAny: return addoffsetinst(compst, ITestAny);
+      case IChar: {
+        int i = addoffsetinst(compst, ITestChar);
+        getinstr(compst, i).i.aux = c;
+        return i;
+      }
+      case ISet: {
+        int i = addoffsetinst(compst, ITestSet);
+        addcharset(compst, cs->cs);
+        return i;
+      }
+      default: assert(0); return 0;
+    }
+  }
+}
+
+
+/*
+** Find the final destination of a sequence of jumps
+*/
+static int finaltarget (Instruction *code, int i) {
+  while (code[i].i.code == IJmp)
+    i = target(code, i);
+  return i;
+}
+
+
+/*
+** final label (after traversing any jumps)
+*/
+static int finallabel (Instruction *code, int i) {
+  return finaltarget(code, target(code, i));
+}
+
+
+/*
+** <behind(p)> == behind n; <p>   (where n = fixedlen(p))
+*/
+static void codebehind (CompileState *compst, TTree *tree) {
+  if (tree->u.n > 0)
+    addinstruction(compst, IBehind, tree->u.n);
+  codegen(compst, sib1(tree), 0, NOINST, fullset);
+}
+
+
+/*
+** Choice; optimizations:
+** - when p1 is headfail or
+** when first(p1) and first(p2) are disjoint, than
+** a character not in first(p1) cannot go to p1, and a character
+** in first(p1) cannot go to p2 (at it is not in first(p2)).
+** (The optimization is not valid if p1 accepts the empty string,
+** as then there is no character at all...)
+** - when p2 is empty and opt is true; a IPartialCommit can reuse
+** the Choice already active in the stack.
+*/
+static void codechoice (CompileState *compst, TTree *p1, TTree *p2, int opt,
+                        const Charset *fl) {
+  int emptyp2 = (p2->tag == TTrue);
+  Charset cs1, cs2;
+  int e1 = getfirst(p1, fullset, &cs1);
+  if (headfail(p1) ||
+      (!e1 && (getfirst(p2, fl, &cs2), cs_disjoint(&cs1, &cs2)))) {
+    /* <p1 / p2> == test (fail(p1)) -> L1 ; p1 ; jmp L2; L1: p2; L2: */
+    int test = codetestset(compst, &cs1, 0);
+    int jmp = NOINST;
+    codegen(compst, p1, 0, test, fl);
+    if (!emptyp2)
+      jmp = addoffsetinst(compst, IJmp); 
+    jumptohere(compst, test);
+    codegen(compst, p2, opt, NOINST, fl);
+    jumptohere(compst, jmp);
+  }
+  else if (opt && emptyp2) {
+    /* p1? == IPartialCommit; p1 */
+    jumptohere(compst, addoffsetinst(compst, IPartialCommit));
+    codegen(compst, p1, 1, NOINST, fullset);
+  }
+  else {
+    /* <p1 / p2> == 
+        test(first(p1)) -> L1; choice L1; <p1>; commit L2; L1: <p2>; L2: */
+    int pcommit;
+    int test = codetestset(compst, &cs1, e1);
+    int pchoice = addoffsetinst(compst, IChoice);
+    codegen(compst, p1, emptyp2, test, fullset);
+    pcommit = addoffsetinst(compst, ICommit);
+    jumptohere(compst, pchoice);
+    jumptohere(compst, test);
+    codegen(compst, p2, opt, NOINST, fl);
+    jumptohere(compst, pcommit);
+  }
+}
+
+
+/*
+** And predicate
+** optimization: fixedlen(p) = n ==> <&p> == <p>; behind n
+** (valid only when 'p' has no captures)
+*/
+static void codeand (CompileState *compst, TTree *tree, int tt) {
+  int n = fixedlen(tree);
+  if (n >= 0 && n <= MAXBEHIND && !hascaptures(tree)) {
+    codegen(compst, tree, 0, tt, fullset);
+    if (n > 0)
+      addinstruction(compst, IBehind, n);
+  }
+  else {  /* default: Choice L1; p1; BackCommit L2; L1: Fail; L2: */
+    int pcommit;
+    int pchoice = addoffsetinst(compst, IChoice);
+    codegen(compst, tree, 0, tt, fullset);
+    pcommit = addoffsetinst(compst, IBackCommit);
+    jumptohere(compst, pchoice);
+    addinstruction(compst, IFail, 0);
+    jumptohere(compst, pcommit);
+  }
+}
+
+
+/*
+** Captures: if pattern has fixed (and not too big) length, and it
+** has no nested captures, use a single IFullCapture instruction
+** after the match; otherwise, enclose the pattern with OpenCapture -
+** CloseCapture.
+*/
+static void codecapture (CompileState *compst, TTree *tree, int tt,
+                         const Charset *fl) {
+  int len = fixedlen(sib1(tree));
+  if (len >= 0 && len <= MAXOFF && !hascaptures(sib1(tree))) {
+    codegen(compst, sib1(tree), 0, tt, fl);
+    addinstcap(compst, IFullCapture, tree->cap, tree->key, len);
+  }
+  else {
+    addinstcap(compst, IOpenCapture, tree->cap, tree->key, 0);
+    codegen(compst, sib1(tree), 0, tt, fl);
+    addinstcap(compst, ICloseCapture, Cclose, 0, 0);
+  }
+}
+
+
+static void coderuntime (CompileState *compst, TTree *tree, int tt) {
+  addinstcap(compst, IOpenCapture, Cgroup, tree->key, 0);
+  codegen(compst, sib1(tree), 0, tt, fullset);
+  addinstcap(compst, ICloseRunTime, Cclose, 0, 0);
+}
+
+
+/*
+** Repetion; optimizations:
+** When pattern is a charset, can use special instruction ISpan.
+** When pattern is head fail, or if it starts with characters that
+** are disjoint from what follows the repetions, a simple test
+** is enough (a fail inside the repetition would backtrack to fail
+** again in the following pattern, so there is no need for a choice).
+** When 'opt' is true, the repetion can reuse the Choice already
+** active in the stack.
+*/
+static void coderep (CompileState *compst, TTree *tree, int opt,
+                     const Charset *fl) {
+  Charset st;
+  if (tocharset(tree, &st)) {
+    addinstruction(compst, ISpan, 0);
+    addcharset(compst, st.cs);
+  }
+  else {
+    int e1 = getfirst(tree, fullset, &st);
+    if (headfail(tree) || (!e1 && cs_disjoint(&st, fl))) {
+      /* L1: test (fail(p1)) -> L2; <p>; jmp L1; L2: */
+      int jmp;
+      int test = codetestset(compst, &st, 0);
+      codegen(compst, tree, 0, test, fullset);
+      jmp = addoffsetinst(compst, IJmp);
+      jumptohere(compst, test);
+      jumptothere(compst, jmp, test);
+    }
+    else {
+      /* test(fail(p1)) -> L2; choice L2; L1: <p>; partialcommit L1; L2: */
+      /* or (if 'opt'): partialcommit L1; L1: <p>; partialcommit L1; */
+      int commit, l2;
+      int test = codetestset(compst, &st, e1);
+      int pchoice = NOINST;
+      if (opt)
+        jumptohere(compst, addoffsetinst(compst, IPartialCommit));
+      else
+        pchoice = addoffsetinst(compst, IChoice);
+      l2 = gethere(compst);
+      codegen(compst, tree, 0, NOINST, fullset);
+      commit = addoffsetinst(compst, IPartialCommit);
+      jumptothere(compst, commit, l2);
+      jumptohere(compst, pchoice);
+      jumptohere(compst, test);
+    }
+  }
+}
+
+
+/*
+** Not predicate; optimizations:
+** In any case, if first test fails, 'not' succeeds, so it can jump to
+** the end. If pattern is headfail, that is all (it cannot fail
+** in other parts); this case includes 'not' of simple sets. Otherwise,
+** use the default code (a choice plus a failtwice).
+*/
+static void codenot (CompileState *compst, TTree *tree) {
+  Charset st;
+  int e = getfirst(tree, fullset, &st);
+  int test = codetestset(compst, &st, e);
+  if (headfail(tree))  /* test (fail(p1)) -> L1; fail; L1:  */
+    addinstruction(compst, IFail, 0);
+  else {
+    /* test(fail(p))-> L1; choice L1; <p>; failtwice; L1:  */
+    int pchoice = addoffsetinst(compst, IChoice);
+    codegen(compst, tree, 0, NOINST, fullset);
+    addinstruction(compst, IFailTwice, 0);
+    jumptohere(compst, pchoice);
+  }
+  jumptohere(compst, test);
+}
+
+
+/*
+** change open calls to calls, using list 'positions' to find
+** correct offsets; also optimize tail calls
+*/
+static void correctcalls (CompileState *compst, int *positions,
+                          int from, int to) {
+  int i;
+  Instruction *code = compst->p->code;
+  for (i = from; i < to; i += sizei(&code[i])) {
+    if (code[i].i.code == IOpenCall) {
+      int n = code[i].i.key;  /* rule number */
+      int rule = positions[n];  /* rule position */
+      assert(rule == from || code[rule - 1].i.code == IRet);
+      if (code[finaltarget(code, i + 2)].i.code == IRet)  /* call; ret ? */
+        code[i].i.code = IJmp;  /* tail call */
+      else
+        code[i].i.code = ICall;
+      jumptothere(compst, i, rule);  /* call jumps to respective rule */
+    }
+  }
+  assert(i == to);
+}
+
+
+/*
+** Code for a grammar:
+** call L1; jmp L2; L1: rule 1; ret; rule 2; ret; ...; L2:
+*/
+static void codegrammar (CompileState *compst, TTree *grammar) {
+  int positions[MAXRULES];
+  int rulenumber = 0;
+  TTree *rule;
+  int firstcall = addoffsetinst(compst, ICall);  /* call initial rule */
+  int jumptoend = addoffsetinst(compst, IJmp);  /* jump to the end */
+  int start = gethere(compst);  /* here starts the initial rule */
+  jumptohere(compst, firstcall);
+  for (rule = sib1(grammar); rule->tag == TRule; rule = sib2(rule)) {
+    positions[rulenumber++] = gethere(compst);  /* save rule position */
+    codegen(compst, sib1(rule), 0, NOINST, fullset);  /* code rule */
+    addinstruction(compst, IRet, 0);
+  }
+  assert(rule->tag == TTrue);
+  jumptohere(compst, jumptoend);
+  correctcalls(compst, positions, start, gethere(compst));
+}
+
+
+static void codecall (CompileState *compst, TTree *call) {
+  int c = addoffsetinst(compst, IOpenCall);  /* to be corrected later */
+  getinstr(compst, c).i.key = sib2(call)->cap;  /* rule number */
+  assert(sib2(call)->tag == TRule);
+}
+
+
+/*
+** Code first child of a sequence
+** (second child is called in-place to allow tail call)
+** Return 'tt' for second child
+*/
+static int codeseq1 (CompileState *compst, TTree *p1, TTree *p2,
+                     int tt, const Charset *fl) {
+  if (needfollow(p1)) {
+    Charset fl1;
+    getfirst(p2, fl, &fl1);  /* p1 follow is p2 first */
+    codegen(compst, p1, 0, tt, &fl1);
+  }
+  else  /* use 'fullset' as follow */
+    codegen(compst, p1, 0, tt, fullset);
+  if (fixedlen(p1) != 0)  /* can 'p1' consume anything? */
+    return  NOINST;  /* invalidate test */
+  else return tt;  /* else 'tt' still protects sib2 */
+}
+
+
+/*
+** Main code-generation function: dispatch to auxiliar functions
+** according to kind of tree. ('needfollow' should return true
+** only for consructions that use 'fl'.)
+*/
+static void codegen (CompileState *compst, TTree *tree, int opt, int tt,
+                     const Charset *fl) {
+ tailcall:
+  switch (tree->tag) {
+    case TChar: codechar(compst, tree->u.n, tt); break;
+    case TAny: addinstruction(compst, IAny, 0); break;
+    case TSet: codecharset(compst, treebuffer(tree), tt); break;
+    case TTrue: break;
+    case TFalse: addinstruction(compst, IFail, 0); break;
+    case TChoice: codechoice(compst, sib1(tree), sib2(tree), opt, fl); break;
+    case TRep: coderep(compst, sib1(tree), opt, fl); break;
+    case TBehind: codebehind(compst, tree); break;
+    case TNot: codenot(compst, sib1(tree)); break;
+    case TAnd: codeand(compst, sib1(tree), tt); break;
+    case TCapture: codecapture(compst, tree, tt, fl); break;
+    case TRunTime: coderuntime(compst, tree, tt); break;
+    case TGrammar: codegrammar(compst, tree); break;
+    case TCall: codecall(compst, tree); break;
+    case TSeq: {
+      tt = codeseq1(compst, sib1(tree), sib2(tree), tt, fl);  /* code 'p1' */
+      /* codegen(compst, p2, opt, tt, fl); */
+      tree = sib2(tree); goto tailcall;
+    }
+    default: assert(0);
+  }
+}
+
+
+/*
+** Optimize jumps and other jump-like instructions.
+** * Update labels of instructions with labels to their final
+** destinations (e.g., choice L1; ... L1: jmp L2: becomes
+** choice L2)
+** * Jumps to other instructions that do jumps become those
+** instructions (e.g., jump to return becomes a return; jump
+** to commit becomes a commit)
+*/
+static void peephole (CompileState *compst) {
+  Instruction *code = compst->p->code;
+  int i;
+  for (i = 0; i < compst->ncode; i += sizei(&code[i])) {
+   redo:
+    switch (code[i].i.code) {
+      case IChoice: case ICall: case ICommit: case IPartialCommit:
+      case IBackCommit: case ITestChar: case ITestSet:
+      case ITestAny: {  /* instructions with labels */
+        jumptothere(compst, i, finallabel(code, i));  /* optimize label */
+        break;
+      }
+      case IJmp: {
+        int ft = finaltarget(code, i);
+        switch (code[ft].i.code) {  /* jumping to what? */
+          case IRet: case IFail: case IFailTwice:
+          case IEnd: {  /* instructions with unconditional implicit jumps */
+            code[i] = code[ft];  /* jump becomes that instruction */
+            code[i + 1].i.code = IAny;  /* 'no-op' for target position */
+            break;
+          }
+          case ICommit: case IPartialCommit:
+          case IBackCommit: {  /* inst. with unconditional explicit jumps */
+            int fft = finallabel(code, ft);
+            code[i] = code[ft];  /* jump becomes that instruction... */
+            jumptothere(compst, i, fft);  /* but must correct its offset */
+            goto redo;  /* reoptimize its label */
+          }
+          default: {
+            jumptothere(compst, i, ft);  /* optimize label */
+            break;
+          }
+        }
+        break;
+      }
+      default: break;
+    }
+  }
+  assert(code[i - 1].i.code == IEnd);
+}
+
+
+/*
+** Compile a pattern
+*/
+Instruction *compile (lua_State *L, Pattern *p) {
+  CompileState compst;
+  compst.p = p;  compst.ncode = 0;  compst.L = L;
+  realloccode(L, p, 2);  /* minimum initial size */
+  codegen(&compst, p->tree, 0, NOINST, fullset);
+  addinstruction(&compst, IEnd, 0);
+  realloccode(L, p, compst.ncode);  /* set final size */
+  peephole(&compst);
+  return p->code;
+}
+
+
+/* }====================================================== */
+
diff --git a/contrib/lua-lpeg/lpcode.h b/contrib/lua-lpeg/lpcode.h
new file mode 100644
index 0000000..34ee276
--- /dev/null
+++ b/contrib/lua-lpeg/lpcode.h
@@ -0,0 +1,40 @@
+/*
+** $Id: lpcode.h $
+*/
+
+#if !defined(lpcode_h)
+#define lpcode_h
+
+#include "lua.h"
+
+#include "lptypes.h"
+#include "lptree.h"
+#include "lpvm.h"
+
+int tocharset (TTree *tree, Charset *cs);
+int checkaux (TTree *tree, int pred);
+int fixedlen (TTree *tree);
+int hascaptures (TTree *tree);
+int lp_gc (lua_State *L);
+Instruction *compile (lua_State *L, Pattern *p);
+void realloccode (lua_State *L, Pattern *p, int nsize);
+int sizei (const Instruction *i);
+
+
+#define PEnullable      0
+#define PEnofail        1
+
+/*
+** nofail(t) implies that 't' cannot fail with any input
+*/
+#define nofail(t)	checkaux(t, PEnofail)
+
+/*
+** (not nullable(t)) implies 't' cannot match without consuming
+** something
+*/
+#define nullable(t)	checkaux(t, PEnullable)
+
+
+
+#endif
diff --git a/contrib/lua-lpeg/lpegre.lua b/contrib/lua-lpeg/lpegre.lua
new file mode 100644
index 0000000..3bb8af7
--- /dev/null
+++ b/contrib/lua-lpeg/lpegre.lua
@@ -0,0 +1,267 @@
+-- $Id: re.lua $
+
+-- imported functions and modules
+local tonumber, type, print, error = tonumber, type, print, error
+local setmetatable = setmetatable
+local m = require"lpeg"
+
+-- 'm' will be used to parse expressions, and 'mm' will be used to
+-- create expressions; that is, 're' runs on 'm', creating patterns
+-- on 'mm'
+local mm = m
+
+-- pattern's metatable
+local mt = getmetatable(mm.P(0))
+
+
+
+-- No more global accesses after this point
+local version = _VERSION
+if version == "Lua 5.2" then _ENV = nil end
+
+
+local any = m.P(1)
+
+
+-- Pre-defined names
+local Predef = { nl = m.P"\n" }
+
+
+local mem
+local fmem
+local gmem
+
+
+local function updatelocale ()
+  mm.locale(Predef)
+  Predef.a = Predef.alpha
+  Predef.c = Predef.cntrl
+  Predef.d = Predef.digit
+  Predef.g = Predef.graph
+  Predef.l = Predef.lower
+  Predef.p = Predef.punct
+  Predef.s = Predef.space
+  Predef.u = Predef.upper
+  Predef.w = Predef.alnum
+  Predef.x = Predef.xdigit
+  Predef.A = any - Predef.a
+  Predef.C = any - Predef.c
+  Predef.D = any - Predef.d
+  Predef.G = any - Predef.g
+  Predef.L = any - Predef.l
+  Predef.P = any - Predef.p
+  Predef.S = any - Predef.s
+  Predef.U = any - Predef.u
+  Predef.W = any - Predef.w
+  Predef.X = any - Predef.x
+  mem = {}    -- restart memoization
+  fmem = {}
+  gmem = {}
+  local mt = {__mode = "v"}
+  setmetatable(mem, mt)
+  setmetatable(fmem, mt)
+  setmetatable(gmem, mt)
+end
+
+
+updatelocale()
+
+
+
+local I = m.P(function (s,i) print(i, s:sub(1, i-1)); return i end)
+
+
+local function patt_error (s, i)
+  local msg = (#s < i + 20) and s:sub(i)
+                             or s:sub(i,i+20) .. "..."
+  msg = ("pattern error near '%s'"):format(msg)
+  error(msg, 2)
+end
+
+local function mult (p, n)
+  local np = mm.P(true)
+  while n >= 1 do
+    if n%2 >= 1 then np = np * p end
+    p = p * p
+    n = n/2
+  end
+  return np
+end
+
+local function equalcap (s, i, c)
+  if type(c) ~= "string" then return nil end
+  local e = #c + i
+  if s:sub(i, e - 1) == c then return e else return nil end
+end
+
+
+local S = (Predef.space + "--" * (any - Predef.nl)^0)^0
+
+local name = m.R("AZ", "az", "__") * m.R("AZ", "az", "__", "09")^0
+
+local arrow = S * "<-"
+
+local seq_follow = m.P"/" + ")" + "}" + ":}" + "~}" + "|}" + (name * arrow) + -1
+
+name = m.C(name)
+
+
+-- a defined name only have meaning in a given environment
+local Def = name * m.Carg(1)
+
+
+local function getdef (id, defs)
+  local c = defs and defs[id]
+  if not c then error("undefined name: " .. id) end
+  return c
+end
+
+-- match a name and return a group of its corresponding definition
+-- and 'f' (to be folded in 'Suffix')
+local function defwithfunc (f)
+  return m.Cg(Def / getdef * m.Cc(f))
+end
+
+
+local num = m.C(m.R"09"^1) * S / tonumber
+
+local String = "'" * m.C((any - "'")^0) * "'" +
+               '"' * m.C((any - '"')^0) * '"'
+
+
+local defined = "%" * Def / function (c,Defs)
+  local cat =  Defs and Defs[c] or Predef[c]
+  if not cat then error ("name '" .. c .. "' undefined") end
+  return cat
+end
+
+local Range = m.Cs(any * (m.P"-"/"") * (any - "]")) / mm.R
+
+local item = (defined + Range + m.C(any)) / m.P
+
+local Class =
+    "["
+  * (m.C(m.P"^"^-1))    -- optional complement symbol
+  * m.Cf(item * (item - "]")^0, mt.__add) /
+                          function (c, p) return c == "^" and any - p or p end
+  * "]"
+
+local function adddef (t, k, exp)
+  if t[k] then
+    error("'"..k.."' already defined as a rule")
+  else
+    t[k] = exp
+  end
+  return t
+end
+
+local function firstdef (n, r) return adddef({n}, n, r) end
+
+
+local function NT (n, b)
+  if not b then
+    error("rule '"..n.."' used outside a grammar")
+  else return mm.V(n)
+  end
+end
+
+
+local exp = m.P{ "Exp",
+  Exp = S * ( m.V"Grammar"
+            + m.Cf(m.V"Seq" * ("/" * S * m.V"Seq")^0, mt.__add) );
+  Seq = m.Cf(m.Cc(m.P"") * m.V"Prefix"^0 , mt.__mul)
+        * (#seq_follow + patt_error);
+  Prefix = "&" * S * m.V"Prefix" / mt.__len
+         + "!" * S * m.V"Prefix" / mt.__unm
+         + m.V"Suffix";
+  Suffix = m.Cf(m.V"Primary" * S *
+          ( ( m.P"+" * m.Cc(1, mt.__pow)
+            + m.P"*" * m.Cc(0, mt.__pow)
+            + m.P"?" * m.Cc(-1, mt.__pow)
+            + "^" * ( m.Cg(num * m.Cc(mult))
+                    + m.Cg(m.C(m.S"+-" * m.R"09"^1) * m.Cc(mt.__pow))
+                    )
+            + "->" * S * ( m.Cg((String + num) * m.Cc(mt.__div))
+                         + m.P"{}" * m.Cc(nil, m.Ct)
+                         + defwithfunc(mt.__div)
+                         )
+            + "=>" * S * defwithfunc(m.Cmt)
+            + "~>" * S * defwithfunc(m.Cf)
+            ) * S
+          )^0, function (a,b,f) return f(a,b) end );
+  Primary = "(" * m.V"Exp" * ")"
+            + String / mm.P
+            + Class
+            + defined
+            + "{:" * (name * ":" + m.Cc(nil)) * m.V"Exp" * ":}" /
+                     function (n, p) return mm.Cg(p, n) end
+            + "=" * name / function (n) return mm.Cmt(mm.Cb(n), equalcap) end
+            + m.P"{}" / mm.Cp
+            + "{~" * m.V"Exp" * "~}" / mm.Cs
+            + "{|" * m.V"Exp" * "|}" / mm.Ct
+            + "{" * m.V"Exp" * "}" / mm.C
+            + m.P"." * m.Cc(any)
+            + (name * -arrow + "<" * name * ">") * m.Cb("G") / NT;
+  Definition = name * arrow * m.V"Exp";
+  Grammar = m.Cg(m.Cc(true), "G") *
+            m.Cf(m.V"Definition" / firstdef * m.Cg(m.V"Definition")^0,
+              adddef) / mm.P
+}
+
+local pattern = S * m.Cg(m.Cc(false), "G") * exp / mm.P * (-any + patt_error)
+
+
+local function compile (p, defs)
+  if mm.type(p) == "pattern" then return p end   -- already compiled
+  local cp = pattern:match(p, 1, defs)
+  if not cp then error("incorrect pattern", 3) end
+  return cp
+end
+
+local function match (s, p, i)
+  local cp = mem[p]
+  if not cp then
+    cp = compile(p)
+    mem[p] = cp
+  end
+  return cp:match(s, i or 1)
+end
+
+local function find (s, p, i)
+  local cp = fmem[p]
+  if not cp then
+    cp = compile(p) / 0
+    cp = mm.P{ mm.Cp() * cp * mm.Cp() + 1 * mm.V(1) }
+    fmem[p] = cp
+  end
+  local i, e = cp:match(s, i or 1)
+  if i then return i, e - 1
+  else return i
+  end
+end
+
+local function gsub (s, p, rep)
+  local g = gmem[p] or {}   -- ensure gmem[p] is not collected while here
+  gmem[p] = g
+  local cp = g[rep]
+  if not cp then
+    cp = compile(p)
+    cp = mm.Cs((cp / rep + 1)^0)
+    g[rep] = cp
+  end
+  return cp:match(s)
+end
+
+
+-- exported names
+local re = {
+  compile = compile,
+  match = match,
+  find = find,
+  gsub = gsub,
+  updatelocale = updatelocale,
+}
+
+if version == "Lua 5.1" then _G.re = re end
+
+return re
diff --git a/contrib/lua-lpeg/lpprint.c b/contrib/lua-lpeg/lpprint.c
new file mode 100644
index 0000000..174d168
--- /dev/null
+++ b/contrib/lua-lpeg/lpprint.c
@@ -0,0 +1,244 @@
+/*
+** $Id: lpprint.c,v 1.9 2015/06/15 16:09:57 roberto Exp $
+** Copyright 2007, Lua.org & PUC-Rio  (see 'lpeg.html' for license)
+*/
+
+#include <ctype.h>
+#include <limits.h>
+#include <stdio.h>
+
+
+#include "lptypes.h"
+#include "lpprint.h"
+#include "lpcode.h"
+
+
+#if defined(LPEG_DEBUG)
+
+/*
+** {======================================================
+** Printing patterns (for debugging)
+** =======================================================
+*/
+
+
+void printcharset (const byte *st) {
+  int i;
+  printf("[");
+  for (i = 0; i <= UCHAR_MAX; i++) {
+    int first = i;
+    while (testchar(st, i) && i <= UCHAR_MAX) i++;
+    if (i - 1 == first)  /* unary range? */
+      printf("(%02x)", first);
+    else if (i - 1 > first)  /* non-empty range? */
+      printf("(%02x-%02x)", first, i - 1);
+  }
+  printf("]");
+}
+
+
+static void printcapkind (int kind) {
+  const char *const modes[] = {
+    "close", "position", "constant", "backref",
+    "argument", "simple", "table", "function",
+    "query", "string", "num", "substitution", "fold",
+    "runtime", "group"};
+  printf("%s", modes[kind]);
+}
+
+
+static void printjmp (const Instruction *op, const Instruction *p) {
+  printf("-> %d", (int)(p + (p + 1)->offset - op));
+}
+
+
+void printinst (const Instruction *op, const Instruction *p) {
+  const char *const names[] = {
+    "any", "char", "set",
+    "testany", "testchar", "testset",
+    "span", "behind",
+    "ret", "end",
+    "choice", "jmp", "call", "open_call",
+    "commit", "partial_commit", "back_commit", "failtwice", "fail", "giveup",
+     "fullcapture", "opencapture", "closecapture", "closeruntime"
+  };
+  printf("%02ld: %s ", (long)(p - op), names[p->i.code]);
+  switch ((Opcode)p->i.code) {
+    case IChar: {
+      printf("'%c'", p->i.aux);
+      break;
+    }
+    case ITestChar: {
+      printf("'%c'", p->i.aux); printjmp(op, p);
+      break;
+    }
+    case IFullCapture: {
+      printcapkind(getkind(p));
+      printf(" (size = %d)  (idx = %d)", getoff(p), p->i.key);
+      break;
+    }
+    case IOpenCapture: {
+      printcapkind(getkind(p));
+      printf(" (idx = %d)", p->i.key);
+      break;
+    }
+    case ISet: {
+      printcharset((p+1)->buff);
+      break;
+    }
+    case ITestSet: {
+      printcharset((p+2)->buff); printjmp(op, p);
+      break;
+    }
+    case ISpan: {
+      printcharset((p+1)->buff);
+      break;
+    }
+    case IOpenCall: {
+      printf("-> %d", (p + 1)->offset);
+      break;
+    }
+    case IBehind: {
+      printf("%d", p->i.aux);
+      break;
+    }
+    case IJmp: case ICall: case ICommit: case IChoice:
+    case IPartialCommit: case IBackCommit: case ITestAny: {
+      printjmp(op, p);
+      break;
+    }
+    default: break;
+  }
+  printf("\n");
+}
+
+
+void printpatt (Instruction *p, int n) {
+  Instruction *op = p;
+  while (p < op + n) {
+    printinst(op, p);
+    p += sizei(p);
+  }
+}
+
+
+#if defined(LPEG_DEBUG)
+static void printcap (Capture *cap) {
+  printcapkind(cap->kind);
+  printf(" (idx: %d - size: %d) -> %p\n", cap->idx, cap->siz, cap->s);
+}
+
+
+void printcaplist (Capture *cap, Capture *limit) {
+  printf(">======\n");
+  for (; cap->s && (limit == NULL || cap < limit); cap++)
+    printcap(cap);
+  printf("=======\n");
+}
+#endif
+
+/* }====================================================== */
+
+
+/*
+** {======================================================
+** Printing trees (for debugging)
+** =======================================================
+*/
+
+static const char *tagnames[] = {
+  "char", "set", "any",
+  "true", "false",
+  "rep",
+  "seq", "choice",
+  "not", "and",
+  "call", "opencall", "rule", "grammar",
+  "behind",
+  "capture", "run-time"
+};
+
+
+void printtree (TTree *tree, int ident) {
+  int i;
+  for (i = 0; i < ident; i++) printf(" ");
+  printf("%s", tagnames[tree->tag]);
+  switch (tree->tag) {
+    case TChar: {
+      int c = tree->u.n;
+      if (isprint(c))
+        printf(" '%c'\n", c);
+      else
+        printf(" (%02X)\n", c);
+      break;
+    }
+    case TSet: {
+      printcharset(treebuffer(tree));
+      printf("\n");
+      break;
+    }
+    case TOpenCall: case TCall: {
+      printf(" key: %d\n", tree->key);
+      break;
+    }
+    case TBehind: {
+      printf(" %d\n", tree->u.n);
+        printtree(sib1(tree), ident + 2);
+      break;
+    }
+    case TCapture: {
+      printf(" cap: %d  key: %d  n: %d\n", tree->cap, tree->key, tree->u.n);
+      printtree(sib1(tree), ident + 2);
+      break;
+    }
+    case TRule: {
+      printf(" n: %d  key: %d\n", tree->cap, tree->key);
+      printtree(sib1(tree), ident + 2);
+      break;  /* do not print next rule as a sibling */
+    }
+    case TGrammar: {
+      TTree *rule = sib1(tree);
+      printf(" %d\n", tree->u.n);  /* number of rules */
+      for (i = 0; i < tree->u.n; i++) {
+        printtree(rule, ident + 2);
+        rule = sib2(rule);
+      }
+      assert(rule->tag == TTrue);  /* sentinel */
+      break;
+    }
+    default: {
+      int sibs = numsiblings[tree->tag];
+      printf("\n");
+      if (sibs >= 1) {
+        printtree(sib1(tree), ident + 2);
+        if (sibs >= 2)
+          printtree(sib2(tree), ident + 2);
+      }
+      break;
+    }
+  }
+}
+
+
+void printktable (lua_State *L, int idx) {
+  int n, i;
+  lua_getuservalue(L, idx);
+  if (lua_isnil(L, -1))  /* no ktable? */
+    return;
+  n = lua_rawlen(L, -1);
+  printf("[");
+  for (i = 1; i <= n; i++) {
+    printf("%d = ", i);
+    lua_rawgeti(L, -1, i);
+    if (lua_isstring(L, -1))
+      printf("%s  ", lua_tostring(L, -1));
+    else
+      printf("%s  ", lua_typename(L, lua_type(L, -1)));
+    lua_pop(L, 1);
+  }
+  printf("]\n");
+  /* leave ktable at the stack */
+}
+
+/* }====================================================== */
+
+#endif
diff --git a/contrib/lua-lpeg/lpprint.h b/contrib/lua-lpeg/lpprint.h
new file mode 100644
index 0000000..6329760
--- /dev/null
+++ b/contrib/lua-lpeg/lpprint.h
@@ -0,0 +1,36 @@
+/*
+** $Id: lpprint.h,v 1.2 2015/06/12 18:18:08 roberto Exp $
+*/
+
+
+#if !defined(lpprint_h)
+#define lpprint_h
+
+
+#include "lptree.h"
+#include "lpvm.h"
+
+
+#if defined(LPEG_DEBUG)
+
+void printpatt (Instruction *p, int n);
+void printtree (TTree *tree, int ident);
+void printktable (lua_State *L, int idx);
+void printcharset (const byte *st);
+void printcaplist (Capture *cap, Capture *limit);
+void printinst (const Instruction *op, const Instruction *p);
+
+#else
+
+#define printktable(L,idx)  \
+	luaL_error(L, "function only implemented in debug mode")
+#define printtree(tree,i)  \
+	luaL_error(L, "function only implemented in debug mode")
+#define printpatt(p,n)  \
+	luaL_error(L, "function only implemented in debug mode")
+
+#endif
+
+
+#endif
+
diff --git a/contrib/lua-lpeg/lptree.c b/contrib/lua-lpeg/lptree.c
new file mode 100644
index 0000000..df24e3c
--- /dev/null
+++ b/contrib/lua-lpeg/lptree.c
@@ -0,0 +1,1319 @@
+/*
+** $Id: lptree.c,v 1.21 2015/09/28 17:01:25 roberto Exp $
+** Copyright 2013, Lua.org & PUC-Rio  (see 'lpeg.html' for license)
+*/
+
+#include <ctype.h>
+#include <limits.h>
+#include <string.h>
+#include <src/lua/lua_common.h>
+
+
+#include "lua.h"
+#include "lauxlib.h"
+
+#include "lptypes.h"
+#include "lpcap.h"
+#include "lpcode.h"
+#include "lpprint.h"
+#include "lptree.h"
+
+
+/* number of siblings for each tree */
+const byte numsiblings[] = {
+  0, 0, 0,	/* char, set, any */
+  0, 0,		/* true, false */
+  1,		/* rep */
+  2, 2,		/* seq, choice */
+  1, 1,		/* not, and */
+  0, 0, 2, 1,  /* call, opencall, rule, grammar */
+  1,  /* behind */
+  1, 1  /* capture, runtime capture */
+};
+
+
+static TTree *newgrammar (lua_State *L, int arg);
+
+
+/*
+** returns a reasonable name for value at index 'idx' on the stack
+*/
+static const char *val2str (lua_State *L, int idx) {
+  const char *k = lua_tostring(L, idx);
+  if (k != NULL)
+    return lua_pushfstring(L, "%s", k);
+  else
+    return lua_pushfstring(L, "(a %s)", luaL_typename(L, idx));
+}
+
+
+/*
+** Fix a TOpenCall into a TCall node, using table 'postable' to
+** translate a key to its rule address in the tree. Raises an
+** error if key does not exist.
+*/
+static void fixonecall (lua_State *L, int postable, TTree *g, TTree *t) {
+  int n;
+  lua_rawgeti(L, -1, t->key);  /* get rule's name */
+  lua_gettable(L, postable);  /* query name in position table */
+  n = lua_tonumber(L, -1);  /* get (absolute) position */
+  lua_pop(L, 1);  /* remove position */
+  if (n == 0) {  /* no position? */
+    lua_rawgeti(L, -1, t->key);  /* get rule's name again */
+    luaL_error(L, "rule '%s' undefined in given grammar", val2str(L, -1));
+  }
+  t->tag = TCall;
+  t->u.ps = n - (t - g);  /* position relative to node */
+  assert(sib2(t)->tag == TRule);
+  sib2(t)->key = t->key;
+}
+
+
+/*
+** Transform left associative constructions into right
+** associative ones, for sequence and choice; that is:
+** (t11 + t12) + t2  =>  t11 + (t12 + t2)
+** (t11 * t12) * t2  =>  t11 * (t12 * t2)
+** (that is, Op (Op t11 t12) t2 => Op t11 (Op t12 t2))
+*/
+static void correctassociativity (TTree *tree) {
+  TTree *t1 = sib1(tree);
+  assert(tree->tag == TChoice || tree->tag == TSeq);
+  while (t1->tag == tree->tag) {
+    int n1size = tree->u.ps - 1;  /* t1 == Op t11 t12 */
+    int n11size = t1->u.ps - 1;
+    int n12size = n1size - n11size - 1;
+    memmove(sib1(tree), sib1(t1), n11size * sizeof(TTree)); /* move t11 */
+    tree->u.ps = n11size + 1;
+    sib2(tree)->tag = tree->tag;
+    sib2(tree)->u.ps = n12size + 1;
+  }
+}
+
+
+/*
+** Make final adjustments in a tree. Fix open calls in tree 't',
+** making them refer to their respective rules or raising appropriate
+** errors (if not inside a grammar). Correct associativity of associative
+** constructions (making them right associative). Assume that tree's
+** ktable is at the top of the stack (for error messages).
+*/
+static void finalfix (lua_State *L, int postable, TTree *g, TTree *t) {
+ tailcall:
+  switch (t->tag) {
+    case TGrammar:  /* subgrammars were already fixed */
+      return;
+    case TOpenCall: {
+      if (g != NULL)  /* inside a grammar? */
+        fixonecall(L, postable, g, t);
+      else {  /* open call outside grammar */
+        lua_rawgeti(L, -1, t->key);
+        luaL_error(L, "rule '%s' used outside a grammar", val2str(L, -1));
+      }
+      break;
+    }
+    case TSeq: case TChoice:
+      correctassociativity(t);
+      break;
+  }
+  switch (numsiblings[t->tag]) {
+    case 1: /* finalfix(L, postable, g, sib1(t)); */
+      t = sib1(t); goto tailcall;
+    case 2:
+      finalfix(L, postable, g, sib1(t));
+      t = sib2(t); goto tailcall;  /* finalfix(L, postable, g, sib2(t)); */
+    default: assert(numsiblings[t->tag] == 0); break;
+  }
+}
+
+
+
+/*
+** {===================================================================
+** KTable manipulation
+**
+** - The ktable of a pattern 'p' can be shared by other patterns that
+** contain 'p' and no other constants. Because of this sharing, we
+** should not add elements to a 'ktable' unless it was freshly created
+** for the new pattern.
+**
+** - The maximum index in a ktable is USHRT_MAX, because trees and
+** patterns use unsigned shorts to store those indices.
+** ====================================================================
+*/
+
+/*
+** Create a new 'ktable' to the pattern at the top of the stack.
+*/
+static void newktable (lua_State *L, int n) {
+  lua_createtable(L, n, 0);  /* create a fresh table */
+  lua_setuservalue(L, -2);  /* set it as 'ktable' for pattern */
+}
+
+
+/*
+** Add element 'idx' to 'ktable' of pattern at the top of the stack;
+** Return index of new element.
+** If new element is nil, does not add it to table (as it would be
+** useless) and returns 0, as ktable[0] is always nil.
+*/
+static int addtoktable (lua_State *L, int idx) {
+  if (lua_isnil(L, idx))  /* nil value? */
+    return 0;
+  else {
+    int n;
+    lua_getuservalue(L, -1);  /* get ktable from pattern */
+    n = lua_rawlen(L, -1);
+    if (n >= USHRT_MAX)
+      luaL_error(L, "too many Lua values in pattern");
+    lua_pushvalue(L, idx);  /* element to be added */
+    lua_rawseti(L, -2, ++n);
+    lua_pop(L, 1);  /* remove 'ktable' */
+    return n;
+  }
+}
+
+
+/*
+** Return the number of elements in the ktable at 'idx'.
+** In Lua 5.2/5.3, default "environment" for patterns is nil, not
+** a table. Treat it as an empty table. In Lua 5.1, assumes that
+** the environment has no numeric indices (len == 0)
+*/
+static int ktablelen (lua_State *L, int idx) {
+  if (!lua_istable(L, idx)) return 0;
+  else return lua_rawlen(L, idx);
+}
+
+
+/*
+** Concatenate the contents of table 'idx1' into table 'idx2'.
+** (Assume that both indices are negative.)
+** Return the original length of table 'idx2' (or 0, if no
+** element was added, as there is no need to correct any index).
+*/
+static int concattable (lua_State *L, int idx1, int idx2) {
+  int i;
+  int n1 = ktablelen(L, idx1);
+  int n2 = ktablelen(L, idx2);
+  if (n1 + n2 > USHRT_MAX)
+    luaL_error(L, "too many Lua values in pattern");
+  if (n1 == 0) return 0;  /* nothing to correct */
+  for (i = 1; i <= n1; i++) {
+    lua_rawgeti(L, idx1, i);
+    lua_rawseti(L, idx2 - 1, n2 + i);  /* correct 'idx2' */
+  }
+  return n2;
+}
+
+
+/*
+** When joining 'ktables', constants from one of the subpatterns must
+** be renumbered; 'correctkeys' corrects their indices (adding 'n'
+** to each of them)
+*/
+static void correctkeys (TTree *tree, int n) {
+  if (n == 0) return;  /* no correction? */
+ tailcall:
+  switch (tree->tag) {
+    case TOpenCall: case TCall: case TRunTime: case TRule: {
+      if (tree->key > 0)
+        tree->key += n;
+      break;
+    }
+    case TCapture: {
+      if (tree->key > 0 && tree->cap != Carg && tree->cap != Cnum)
+        tree->key += n;
+      break;
+    }
+    default: break;
+  }
+  switch (numsiblings[tree->tag]) {
+    case 1:  /* correctkeys(sib1(tree), n); */
+      tree = sib1(tree); goto tailcall;
+    case 2:
+      correctkeys(sib1(tree), n);
+      tree = sib2(tree); goto tailcall;  /* correctkeys(sib2(tree), n); */
+    default: assert(numsiblings[tree->tag] == 0); break;
+  }
+}
+
+
+/*
+** Join the ktables from p1 and p2 the ktable for the new pattern at the
+** top of the stack, reusing them when possible.
+*/
+static void joinktables (lua_State *L, int p1, TTree *t2, int p2) {
+  int n1, n2;
+  lua_getuservalue(L, p1);  /* get ktables */
+  lua_getuservalue(L, p2);
+  n1 = ktablelen(L, -2);
+  n2 = ktablelen(L, -1);
+  if (n1 == 0 && n2 == 0)  /* are both tables empty? */
+    lua_pop(L, 2);  /* nothing to be done; pop tables */
+  else if (n2 == 0 || lp_equal(L, -2, -1)) {  /* 2nd table empty or equal? */
+    lua_pop(L, 1);  /* pop 2nd table */
+    lua_setuservalue(L, -2);  /* set 1st ktable into new pattern */
+  }
+  else if (n1 == 0) {  /* first table is empty? */
+    lua_setuservalue(L, -3);  /* set 2nd table into new pattern */
+    lua_pop(L, 1);  /* pop 1st table */
+  }
+  else {
+    lua_createtable(L, n1 + n2, 0);  /* create ktable for new pattern */
+    /* stack: new p; ktable p1; ktable p2; new ktable */
+    concattable(L, -3, -1);  /* from p1 into new ktable */
+    concattable(L, -2, -1);  /* from p2 into new ktable */
+    lua_setuservalue(L, -4);  /* new ktable becomes 'p' environment */
+    lua_pop(L, 2);  /* pop other ktables */
+    correctkeys(t2, n1);  /* correction for indices from p2 */
+  }
+}
+
+
+/*
+** copy 'ktable' of element 'idx' to new tree (on top of stack)
+*/
+static void copyktable (lua_State *L, int idx) {
+  lua_getuservalue(L, idx);
+  lua_setuservalue(L, -2);
+}
+
+
+/*
+** merge 'ktable' from 'stree' at stack index 'idx' into 'ktable'
+** from tree at the top of the stack, and correct corresponding
+** tree.
+*/
+static void mergektable (lua_State *L, int idx, TTree *stree) {
+  int n;
+  lua_getuservalue(L, -1);  /* get ktables */
+  lua_getuservalue(L, idx);
+  n = concattable(L, -1, -2);
+  lua_pop(L, 2);  /* remove both ktables */
+  correctkeys(stree, n);
+}
+
+
+/*
+** Create a new 'ktable' to the pattern at the top of the stack, adding
+** all elements from pattern 'p' (if not 0) plus element 'idx' to it.
+** Return index of new element.
+*/
+static int addtonewktable (lua_State *L, int p, int idx) {
+  newktable(L, 1);
+  if (p)
+    mergektable(L, p, NULL);
+  return addtoktable(L, idx);
+}
+
+/* }====================================================== */
+
+
+/*
+** {======================================================
+** Tree generation
+** =======================================================
+*/
+
+/*
+** In 5.2, could use 'luaL_testudata'...
+*/
+static int testpattern (lua_State *L, int idx) {
+  if (lua_touserdata(L, idx)) {  /* value is a userdata? */
+    if (lua_getmetatable(L, idx)) {  /* does it have a metatable? */
+      luaL_getmetatable(L, PATTERN_T);
+      if (lua_rawequal(L, -1, -2)) {  /* does it have the correct mt? */
+        lua_pop(L, 2);  /* remove both metatables */
+        return 1;
+      }
+    }
+  }
+  return 0;
+}
+
+
+static Pattern *getpattern (lua_State *L, int idx) {
+  return (Pattern *)luaL_checkudata(L, idx, PATTERN_T);
+}
+
+
+static int getsize (lua_State *L, int idx) {
+  return (lua_rawlen(L, idx) - sizeof(Pattern)) / sizeof(TTree) + 1;
+}
+
+
+static TTree *gettree (lua_State *L, int idx, int *len) {
+  Pattern *p = getpattern(L, idx);
+  if (len)
+    *len = getsize(L, idx);
+  return p->tree;
+}
+
+
+/*
+** create a pattern. Set its uservalue (the 'ktable') equal to its
+** metatable. (It could be any empty sequence; the metatable is at
+** hand here, so we use it.)
+*/
+static TTree *newtree (lua_State *L, int len) {
+  size_t size = (len - 1) * sizeof(TTree) + sizeof(Pattern);
+  Pattern *p = (Pattern *)lua_newuserdata(L, size);
+  memset(p, 0, size);
+  luaL_getmetatable(L, PATTERN_T);
+  lua_pushvalue(L, -1);
+  lua_setuservalue(L, -3);
+  lua_setmetatable(L, -2);
+  p->code = NULL;  p->codesize = 0;
+  return p->tree;
+}
+
+
+static TTree *newleaf (lua_State *L, int tag) {
+  TTree *tree = newtree(L, 1);
+  tree->tag = tag;
+  return tree;
+}
+
+
+static TTree *newcharset (lua_State *L) {
+  TTree *tree = newtree(L, bytes2slots(CHARSETSIZE) + 1);
+  tree->tag = TSet;
+  loopset(i, treebuffer(tree)[i] = 0);
+  return tree;
+}
+
+
+/*
+** add to tree a sequence where first sibling is 'sib' (with size
+** 'sibsize'); returns position for second sibling
+*/
+static TTree *seqaux (TTree *tree, TTree *sib, int sibsize) {
+  tree->tag = TSeq; tree->u.ps = sibsize + 1;
+  memcpy(sib1(tree), sib, sibsize * sizeof(TTree));
+  return sib2(tree);
+}
+
+
+/*
+** Build a sequence of 'n' nodes, each with tag 'tag' and 'u.n' got
+** from the array 's' (or 0 if array is NULL). (TSeq is binary, so it
+** must build a sequence of sequence of sequence...)
+*/
+static void fillseq (TTree *tree, int tag, int n, const char *s) {
+  int i;
+  for (i = 0; i < n - 1; i++) {  /* initial n-1 copies of Seq tag; Seq ... */
+    tree->tag = TSeq; tree->u.ps = 2;
+    sib1(tree)->tag = tag;
+    sib1(tree)->u.n = s ? (byte)s[i] : 0;
+    tree = sib2(tree);
+  }
+  tree->tag = tag;  /* last one does not need TSeq */
+  tree->u.n = s ? (byte)s[i] : 0;
+}
+
+
+/*
+** Numbers as patterns:
+** 0 == true (always match); n == TAny repeated 'n' times;
+** -n == not (TAny repeated 'n' times)
+*/
+static TTree *numtree (lua_State *L, int n) {
+  if (n == 0)
+    return newleaf(L, TTrue);
+  else {
+    TTree *tree, *nd;
+    if (n > 0)
+      tree = nd = newtree(L, 2 * n - 1);
+    else {  /* negative: code it as !(-n) */
+      n = -n;
+      tree = newtree(L, 2 * n);
+      tree->tag = TNot;
+      nd = sib1(tree);
+    }
+    fillseq(nd, TAny, n, NULL);  /* sequence of 'n' any's */
+    return tree;
+  }
+}
+
+
+/*
+** Convert value at index 'idx' to a pattern
+*/
+static TTree *getpatt (lua_State *L, int idx, int *len) {
+  TTree *tree;
+  switch (lua_type(L, idx)) {
+    case LUA_TSTRING: {
+      size_t slen;
+      const char *s = lua_tolstring(L, idx, &slen);  /* get string */
+      if (slen == 0)  /* empty? */
+        tree = newleaf(L, TTrue);  /* always match */
+      else {
+        tree = newtree(L, 2 * (slen - 1) + 1);
+        fillseq(tree, TChar, slen, s);  /* sequence of 'slen' chars */
+      }
+      break;
+    }
+    case LUA_TNUMBER: {
+      int n = lua_tointeger(L, idx);
+      tree = numtree(L, n);
+      break;
+    }
+    case LUA_TBOOLEAN: {
+      tree = (lua_toboolean(L, idx) ? newleaf(L, TTrue) : newleaf(L, TFalse));
+      break;
+    }
+    case LUA_TTABLE: {
+      tree = newgrammar(L, idx);
+      break;
+    }
+    case LUA_TFUNCTION: {
+      tree = newtree(L, 2);
+      tree->tag = TRunTime;
+      tree->key = addtonewktable(L, 0, idx);
+      sib1(tree)->tag = TTrue;
+      break;
+    }
+    default: {
+      return gettree(L, idx, len);
+    }
+  }
+  lua_replace(L, idx);  /* put new tree into 'idx' slot */
+  if (len)
+    *len = getsize(L, idx);
+  return tree;
+}
+
+
+/*
+** create a new tree, with a new root and one sibling.
+** Sibling must be on the Lua stack, at index 1.
+*/
+static TTree *newroot1sib (lua_State *L, int tag) {
+  int s1;
+  TTree *tree1 = getpatt(L, 1, &s1);
+  TTree *tree = newtree(L, 1 + s1);  /* create new tree */
+  tree->tag = tag;
+  memcpy(sib1(tree), tree1, s1 * sizeof(TTree));
+  copyktable(L, 1);
+  return tree;
+}
+
+
+/*
+** create a new tree, with a new root and 2 siblings.
+** Siblings must be on the Lua stack, first one at index 1.
+*/
+static TTree *newroot2sib (lua_State *L, int tag) {
+  int s1, s2;
+  TTree *tree1 = getpatt(L, 1, &s1);
+  TTree *tree2 = getpatt(L, 2, &s2);
+  TTree *tree = newtree(L, 1 + s1 + s2);  /* create new tree */
+  tree->tag = tag;
+  tree->u.ps =  1 + s1;
+  memcpy(sib1(tree), tree1, s1 * sizeof(TTree));
+  memcpy(sib2(tree), tree2, s2 * sizeof(TTree));
+  joinktables(L, 1, sib2(tree), 2);
+  return tree;
+}
+
+
+static int lp_P (lua_State *L) {
+  luaL_checkany(L, 1);
+  getpatt(L, 1, NULL);
+  lua_settop(L, 1);
+  return 1;
+}
+
+
+/*
+** sequence operator; optimizations:
+** false x => false, x true => x, true x => x
+** (cannot do x . false => false because x may have runtime captures)
+*/
+static int lp_seq (lua_State *L) {
+  TTree *tree1 = getpatt(L, 1, NULL);
+  TTree *tree2 = getpatt(L, 2, NULL);
+  if (tree1->tag == TFalse || tree2->tag == TTrue)
+    lua_pushvalue(L, 1);  /* false . x == false, x . true = x */
+  else if (tree1->tag == TTrue)
+    lua_pushvalue(L, 2);  /* true . x = x */
+  else
+    newroot2sib(L, TSeq);
+  return 1;
+}
+
+
+/*
+** choice operator; optimizations:
+** charset / charset => charset
+** true / x => true, x / false => x, false / x => x
+** (x / true is not equivalent to true)
+*/
+static int lp_choice (lua_State *L) {
+  Charset st1, st2;
+  TTree *t1 = getpatt(L, 1, NULL);
+  TTree *t2 = getpatt(L, 2, NULL);
+  if (tocharset(t1, &st1) && tocharset(t2, &st2)) {
+    TTree *t = newcharset(L);
+    loopset(i, treebuffer(t)[i] = st1.cs[i] | st2.cs[i]);
+  }
+  else if (nofail(t1) || t2->tag == TFalse)
+    lua_pushvalue(L, 1);  /* true / x => true, x / false => x */
+  else if (t1->tag == TFalse)
+    lua_pushvalue(L, 2);  /* false / x => x */
+  else
+    newroot2sib(L, TChoice);
+  return 1;
+}
+
+
+/*
+** p^n
+*/
+static int lp_star (lua_State *L) {
+  int size1;
+  int n = (int)luaL_checkinteger(L, 2);
+  TTree *tree1 = getpatt(L, 1, &size1);
+  if (n >= 0) {  /* seq tree1 (seq tree1 ... (seq tree1 (rep tree1))) */
+    TTree *tree = newtree(L, (n + 1) * (size1 + 1));
+    if (nullable(tree1))
+      luaL_error(L, "loop body may accept empty string");
+    while (n--)  /* repeat 'n' times */
+      tree = seqaux(tree, tree1, size1);
+    tree->tag = TRep;
+    memcpy(sib1(tree), tree1, size1 * sizeof(TTree));
+  }
+  else {  /* choice (seq tree1 ... choice tree1 true ...) true */
+    TTree *tree;
+    n = -n;
+    /* size = (choice + seq + tree1 + true) * n, but the last has no seq */
+    tree = newtree(L, n * (size1 + 3) - 1);
+    for (; n > 1; n--) {  /* repeat (n - 1) times */
+      tree->tag = TChoice; tree->u.ps = n * (size1 + 3) - 2;
+      sib2(tree)->tag = TTrue;
+      tree = sib1(tree);
+      tree = seqaux(tree, tree1, size1);
+    }
+    tree->tag = TChoice; tree->u.ps = size1 + 1;
+    sib2(tree)->tag = TTrue;
+    memcpy(sib1(tree), tree1, size1 * sizeof(TTree));
+  }
+  copyktable(L, 1);
+  return 1;
+}
+
+
+/*
+** #p == &p
+*/
+static int lp_and (lua_State *L) {
+  newroot1sib(L, TAnd);
+  return 1;
+}
+
+
+/*
+** -p == !p
+*/
+static int lp_not (lua_State *L) {
+  newroot1sib(L, TNot);
+  return 1;
+}
+
+
+/*
+** [t1 - t2] == Seq (Not t2) t1
+** If t1 and t2 are charsets, make their difference.
+*/
+static int lp_sub (lua_State *L) {
+  Charset st1, st2;
+  int s1, s2;
+  TTree *t1 = getpatt(L, 1, &s1);
+  TTree *t2 = getpatt(L, 2, &s2);
+  if (tocharset(t1, &st1) && tocharset(t2, &st2)) {
+    TTree *t = newcharset(L);
+    loopset(i, treebuffer(t)[i] = st1.cs[i] & ~st2.cs[i]);
+  }
+  else {
+    TTree *tree = newtree(L, 2 + s1 + s2);
+    tree->tag = TSeq;  /* sequence of... */
+    tree->u.ps =  2 + s2;
+    sib1(tree)->tag = TNot;  /* ...not... */
+    memcpy(sib1(sib1(tree)), t2, s2 * sizeof(TTree));  /* ...t2 */
+    memcpy(sib2(tree), t1, s1 * sizeof(TTree));  /* ... and t1 */
+    joinktables(L, 1, sib1(tree), 2);
+  }
+  return 1;
+}
+
+
+static int lp_set (lua_State *L) {
+  size_t l;
+  const char *s = luaL_checklstring(L, 1, &l);
+  TTree *tree = newcharset(L);
+  while (l--) {
+    setchar(treebuffer(tree), (byte)(*s));
+    s++;
+  }
+  return 1;
+}
+
+
+static int lp_range (lua_State *L) {
+  int arg;
+  int top = lua_gettop(L);
+  TTree *tree = newcharset(L);
+  for (arg = 1; arg <= top; arg++) {
+    int c;
+    size_t l;
+    const char *r = luaL_checklstring(L, arg, &l);
+    luaL_argcheck(L, l == 2, arg, "range must have two characters");
+    for (c = (byte)r[0]; c <= (byte)r[1]; c++)
+      setchar(treebuffer(tree), c);
+  }
+  return 1;
+}
+
+
+/*
+** Look-behind predicate
+*/
+static int lp_behind (lua_State *L) {
+  TTree *tree;
+  TTree *tree1 = getpatt(L, 1, NULL);
+  int n = fixedlen(tree1);
+  luaL_argcheck(L, n >= 0, 1, "pattern may not have fixed length");
+  luaL_argcheck(L, !hascaptures(tree1), 1, "pattern have captures");
+  luaL_argcheck(L, n <= MAXBEHIND, 1, "pattern too long to look behind");
+  tree = newroot1sib(L, TBehind);
+  tree->u.n = n;
+  return 1;
+}
+
+
+/*
+** Create a non-terminal
+*/
+static int lp_V (lua_State *L) {
+  TTree *tree = newleaf(L, TOpenCall);
+  luaL_argcheck(L, !lua_isnoneornil(L, 1), 1, "non-nil value expected");
+  tree->key = addtonewktable(L, 0, 1);
+  return 1;
+}
+
+
+/*
+** Create a tree for a non-empty capture, with a body and
+** optionally with an associated Lua value (at index 'labelidx' in the
+** stack)
+*/
+static int capture_aux (lua_State *L, int cap, int labelidx) {
+  TTree *tree = newroot1sib(L, TCapture);
+  tree->cap = cap;
+  tree->key = (labelidx == 0) ? 0 : addtonewktable(L, 1, labelidx);
+  return 1;
+}
+
+
+/*
+** Fill a tree with an empty capture, using an empty (TTrue) sibling.
+*/
+static TTree *auxemptycap (TTree *tree, int cap) {
+  tree->tag = TCapture;
+  tree->cap = cap;
+  sib1(tree)->tag = TTrue;
+  return tree;
+}
+
+
+/*
+** Create a tree for an empty capture
+*/
+static TTree *newemptycap (lua_State *L, int cap) {
+  return auxemptycap(newtree(L, 2), cap);
+}
+
+
+/*
+** Create a tree for an empty capture with an associated Lua value
+*/
+static TTree *newemptycapkey (lua_State *L, int cap, int idx) {
+  TTree *tree = auxemptycap(newtree(L, 2), cap);
+  tree->key = addtonewktable(L, 0, idx);
+  return tree;
+}
+
+
+/*
+** Captures with syntax p / v
+** (function capture, query capture, string capture, or number capture)
+*/
+static int lp_divcapture (lua_State *L) {
+  switch (lua_type(L, 2)) {
+    case LUA_TFUNCTION: return capture_aux(L, Cfunction, 2);
+    case LUA_TTABLE: return capture_aux(L, Cquery, 2);
+    case LUA_TSTRING: return capture_aux(L, Cstring, 2);
+    case LUA_TNUMBER: {
+      int n = lua_tointeger(L, 2);
+      TTree *tree = newroot1sib(L, TCapture);
+      luaL_argcheck(L, 0 <= n && n <= SHRT_MAX, 1, "invalid number");
+      tree->cap = Cnum;
+      tree->key = n;
+      return 1;
+    }
+    default: return luaL_argerror(L, 2, "invalid replacement value");
+  }
+}
+
+
+static int lp_substcapture (lua_State *L) {
+  return capture_aux(L, Csubst, 0);
+}
+
+
+static int lp_tablecapture (lua_State *L) {
+  return capture_aux(L, Ctable, 0);
+}
+
+
+static int lp_groupcapture (lua_State *L) {
+  if (lua_isnoneornil(L, 2))
+    return capture_aux(L, Cgroup, 0);
+  else
+    return capture_aux(L, Cgroup, 2);
+}
+
+
+static int lp_foldcapture (lua_State *L) {
+  luaL_checktype(L, 2, LUA_TFUNCTION);
+  return capture_aux(L, Cfold, 2);
+}
+
+
+static int lp_simplecapture (lua_State *L) {
+  return capture_aux(L, Csimple, 0);
+}
+
+
+static int lp_poscapture (lua_State *L) {
+  newemptycap(L, Cposition);
+  return 1;
+}
+
+
+static int lp_argcapture (lua_State *L) {
+  int n = (int)luaL_checkinteger(L, 1);
+  TTree *tree = newemptycap(L, Carg);
+  tree->key = n;
+  luaL_argcheck(L, 0 < n && n <= SHRT_MAX, 1, "invalid argument index");
+  return 1;
+}
+
+
+static int lp_backref (lua_State *L) {
+  luaL_checkany(L, 1);
+  newemptycapkey(L, Cbackref, 1);
+  return 1;
+}
+
+
+/*
+** Constant capture
+*/
+static int lp_constcapture (lua_State *L) {
+  int i;
+  int n = lua_gettop(L);  /* number of values */
+  if (n == 0)  /* no values? */
+    newleaf(L, TTrue);  /* no capture */
+  else if (n == 1)
+    newemptycapkey(L, Cconst, 1);  /* single constant capture */
+  else {  /* create a group capture with all values */
+    TTree *tree = newtree(L, 1 + 3 * (n - 1) + 2);
+    newktable(L, n);  /* create a 'ktable' for new tree */
+    tree->tag = TCapture;
+    tree->cap = Cgroup;
+    tree->key = 0;
+    tree = sib1(tree);
+    for (i = 1; i <= n - 1; i++) {
+      tree->tag = TSeq;
+      tree->u.ps = 3;  /* skip TCapture and its sibling */
+      auxemptycap(sib1(tree), Cconst);
+      sib1(tree)->key = addtoktable(L, i);
+      tree = sib2(tree);
+    }
+    auxemptycap(tree, Cconst);
+    tree->key = addtoktable(L, i);
+  }
+  return 1;
+}
+
+
+static int lp_matchtime (lua_State *L) {
+  TTree *tree;
+  luaL_checktype(L, 2, LUA_TFUNCTION);
+  tree = newroot1sib(L, TRunTime);
+  tree->key = addtonewktable(L, 1, 2);
+  return 1;
+}
+
+/* }====================================================== */
+
+
+/*
+** {======================================================
+** Grammar - Tree generation
+** =======================================================
+*/
+
+/*
+** push on the stack the index and the pattern for the
+** initial rule of grammar at index 'arg' in the stack;
+** also add that index into position table.
+*/
+static void getfirstrule (lua_State *L, int arg, int postab) {
+  lua_rawgeti(L, arg, 1);  /* access first element */
+  if (lua_isstring(L, -1)) {  /* is it the name of initial rule? */
+    lua_pushvalue(L, -1);  /* duplicate it to use as key */
+    lua_gettable(L, arg);  /* get associated rule */
+  }
+  else {
+    lua_pushinteger(L, 1);  /* key for initial rule */
+    lua_insert(L, -2);  /* put it before rule */
+  }
+  if (!testpattern(L, -1)) {  /* initial rule not a pattern? */
+    if (lua_isnil(L, -1))
+      luaL_error(L, "grammar has no initial rule");
+    else
+      luaL_error(L, "initial rule '%s' is not a pattern", lua_tostring(L, -2));
+  }
+  lua_pushvalue(L, -2);  /* push key */
+  lua_pushinteger(L, 1);  /* push rule position (after TGrammar) */
+  lua_settable(L, postab);  /* insert pair at position table */
+}
+
+/*
+** traverse grammar at index 'arg', pushing all its keys and patterns
+** into the stack. Create a new table (before all pairs key-pattern) to
+** collect all keys and their associated positions in the final tree
+** (the "position table").
+** Return the number of rules and (in 'totalsize') the total size
+** for the new tree.
+*/
+static int collectrules (lua_State *L, int arg, int *totalsize) {
+  int n = 1;  /* to count number of rules */
+  int postab = lua_gettop(L) + 1;  /* index of position table */
+  int size;  /* accumulator for total size */
+  lua_newtable(L);  /* create position table */
+  getfirstrule(L, arg, postab);
+  size = 2 + getsize(L, postab + 2);  /* TGrammar + TRule + rule */
+  lua_pushnil(L);  /* prepare to traverse grammar table */
+  while (lua_next(L, arg) != 0) {
+    if (lua_tonumber(L, -2) == 1 ||
+        lp_equal(L, -2, postab + 1)) {  /* initial rule? */
+      lua_pop(L, 1);  /* remove value (keep key for lua_next) */
+      continue;
+    }
+    if (!testpattern(L, -1))  /* value is not a pattern? */
+      luaL_error(L, "rule '%s' is not a pattern", val2str(L, -2));
+    luaL_checkstack(L, LUA_MINSTACK, "grammar has too many rules");
+    lua_pushvalue(L, -2);  /* push key (to insert into position table) */
+    lua_pushinteger(L, size);
+    lua_settable(L, postab);
+    size += 1 + getsize(L, -1);  /* update size */
+    lua_pushvalue(L, -2);  /* push key (for next lua_next) */
+    n++;
+  }
+  *totalsize = size + 1;  /* TTrue to finish list of rules */
+  return n;
+}
+
+
+static void buildgrammar (lua_State *L, TTree *grammar, int frule, int n) {
+  int i;
+  TTree *nd = sib1(grammar);  /* auxiliary pointer to traverse the tree */
+  for (i = 0; i < n; i++) {  /* add each rule into new tree */
+    int ridx = frule + 2*i + 1;  /* index of i-th rule */
+    int rulesize;
+    TTree *rn = gettree(L, ridx, &rulesize);
+    nd->tag = TRule;
+    nd->key = 0;
+    nd->cap = i;  /* rule number */
+    nd->u.ps = rulesize + 1;  /* point to next rule */
+    memcpy(sib1(nd), rn, rulesize * sizeof(TTree));  /* copy rule */
+    mergektable(L, ridx, sib1(nd));  /* merge its ktable into new one */
+    nd = sib2(nd);  /* move to next rule */
+  }
+  nd->tag = TTrue;  /* finish list of rules */
+}
+
+
+/*
+** Check whether a tree has potential infinite loops
+*/
+static int checkloops (TTree *tree) {
+ tailcall:
+  if (tree->tag == TRep && nullable(sib1(tree)))
+    return 1;
+  else if (tree->tag == TGrammar)
+    return 0;  /* sub-grammars already checked */
+  else {
+    switch (numsiblings[tree->tag]) {
+      case 1:  /* return checkloops(sib1(tree)); */
+        tree = sib1(tree); goto tailcall;
+      case 2:
+        if (checkloops(sib1(tree))) return 1;
+        /* else return checkloops(sib2(tree)); */
+        tree = sib2(tree); goto tailcall;
+      default: assert(numsiblings[tree->tag] == 0); return 0;
+    }
+  }
+}
+
+
+static int verifyerror (lua_State *L, int *passed, int npassed) {
+  int i, j;
+  for (i = npassed - 1; i >= 0; i--) {  /* search for a repetition */
+    for (j = i - 1; j >= 0; j--) {
+      if (passed[i] == passed[j]) {
+        lua_rawgeti(L, -1, passed[i]);  /* get rule's key */
+        return luaL_error(L, "rule '%s' may be left recursive", val2str(L, -1));
+      }
+    }
+  }
+  return luaL_error(L, "too many left calls in grammar");
+}
+
+
+/*
+** Check whether a rule can be left recursive; raise an error in that
+** case; otherwise return 1 iff pattern is nullable.
+** The return value is used to check sequences, where the second pattern
+** is only relevant if the first is nullable.
+** Parameter 'nb' works as an accumulator, to allow tail calls in
+** choices. ('nb' true makes function returns true.)
+** Assume ktable at the top of the stack.
+*/
+static int verifyrule (lua_State *L, TTree *tree, int *passed, int npassed,
+                       int nb) {
+ tailcall:
+  switch (tree->tag) {
+    case TChar: case TSet: case TAny:
+    case TFalse:
+      return nb;  /* cannot pass from here */
+    case TTrue:
+    case TBehind:  /* look-behind cannot have calls */
+      return 1;
+    case TNot: case TAnd: case TRep:
+      /* return verifyrule(L, sib1(tree), passed, npassed, 1); */
+      tree = sib1(tree); nb = 1; goto tailcall;
+    case TCapture: case TRunTime:
+      /* return verifyrule(L, sib1(tree), passed, npassed, nb); */
+      tree = sib1(tree); goto tailcall;
+    case TCall:
+      /* return verifyrule(L, sib2(tree), passed, npassed, nb); */
+      tree = sib2(tree); goto tailcall;
+    case TSeq:  /* only check 2nd child if first is nb */
+      if (!verifyrule(L, sib1(tree), passed, npassed, 0))
+        return nb;
+      /* else return verifyrule(L, sib2(tree), passed, npassed, nb); */
+      tree = sib2(tree); goto tailcall;
+    case TChoice:  /* must check both children */
+      nb = verifyrule(L, sib1(tree), passed, npassed, nb);
+      /* return verifyrule(L, sib2(tree), passed, npassed, nb); */
+      tree = sib2(tree); goto tailcall;
+    case TRule:
+      if (npassed >= MAXRULES)
+        return verifyerror(L, passed, npassed);
+      else {
+        passed[npassed++] = tree->key;
+        /* return verifyrule(L, sib1(tree), passed, npassed); */
+        tree = sib1(tree); goto tailcall;
+      }
+    case TGrammar:
+      return nullable(tree);  /* sub-grammar cannot be left recursive */
+    default: assert(0); return 0;
+  }
+}
+
+
+static void verifygrammar (lua_State *L, TTree *grammar) {
+  int passed[MAXRULES];
+  TTree *rule;
+  /* check left-recursive rules */
+  for (rule = sib1(grammar); rule->tag == TRule; rule = sib2(rule)) {
+    if (rule->key == 0) continue;  /* unused rule */
+    verifyrule(L, sib1(rule), passed, 0, 0);
+  }
+  assert(rule->tag == TTrue);
+  /* check infinite loops inside rules */
+  for (rule = sib1(grammar); rule->tag == TRule; rule = sib2(rule)) {
+    if (rule->key == 0) continue;  /* unused rule */
+    if (checkloops(sib1(rule))) {
+      lua_rawgeti(L, -1, rule->key);  /* get rule's key */
+      luaL_error(L, "empty loop in rule '%s'", val2str(L, -1));
+    }
+  }
+  assert(rule->tag == TTrue);
+}
+
+
+/*
+** Give a name for the initial rule if it is not referenced
+*/
+static void initialrulename (lua_State *L, TTree *grammar, int frule) {
+  if (sib1(grammar)->key == 0) {  /* initial rule is not referenced? */
+    int n = lua_rawlen(L, -1) + 1;  /* index for name */
+    lua_pushvalue(L, frule);  /* rule's name */
+    lua_rawseti(L, -2, n);  /* ktable was on the top of the stack */
+    sib1(grammar)->key = n;
+  }
+}
+
+
+static TTree *newgrammar (lua_State *L, int arg) {
+  int treesize;
+  int frule = lua_gettop(L) + 2;  /* position of first rule's key */
+  int n = collectrules(L, arg, &treesize);
+  TTree *g = newtree(L, treesize);
+  luaL_argcheck(L, n <= MAXRULES, arg, "grammar has too many rules");
+  g->tag = TGrammar;  g->u.n = n;
+  lua_newtable(L);  /* create 'ktable' */
+  lua_setuservalue(L, -2);
+  buildgrammar(L, g, frule, n);
+  lua_getuservalue(L, -1);  /* get 'ktable' for new tree */
+  finalfix(L, frule - 1, g, sib1(g));
+  initialrulename(L, g, frule);
+  verifygrammar(L, g);
+  lua_pop(L, 1);  /* remove 'ktable' */
+  lua_insert(L, -(n * 2 + 2));  /* move new table to proper position */
+  lua_pop(L, n * 2 + 1);  /* remove position table + rule pairs */
+  return g;  /* new table at the top of the stack */
+}
+
+/* }====================================================== */
+
+
+static Instruction *prepcompile (lua_State *L, Pattern *p, int idx) {
+  lua_getuservalue(L, idx);  /* push 'ktable' (may be used by 'finalfix') */
+  finalfix(L, 0, NULL, p->tree);
+  lua_pop(L, 1);  /* remove 'ktable' */
+  return compile(L, p);
+}
+
+
+static int lp_printtree (lua_State *L) {
+  TTree *tree = getpatt(L, 1, NULL);
+  int c = lua_toboolean(L, 2);
+  if (c) {
+    lua_getuservalue(L, 1);  /* push 'ktable' (may be used by 'finalfix') */
+    finalfix(L, 0, NULL, tree);
+    lua_pop(L, 1);  /* remove 'ktable' */
+  }
+  printktable(L, 1);
+  printtree(tree, 0);
+  return 0;
+}
+
+
+static int lp_printcode (lua_State *L) {
+  Pattern *p = getpattern(L, 1);
+  printktable(L, 1);
+  if (p->code == NULL)  /* not compiled yet? */
+    prepcompile(L, p, 1);
+  printpatt(p->code, p->codesize);
+  return 0;
+}
+
+
+/*
+** Get the initial position for the match, interpreting negative
+** values from the end of the subject
+*/
+static size_t initposition (lua_State *L, size_t len) {
+  lua_Integer ii = luaL_optinteger(L, 3, 1);
+  if (ii > 0) {  /* positive index? */
+    if ((size_t)ii <= len)  /* inside the string? */
+      return (size_t)ii - 1;  /* return it (corrected to 0-base) */
+    else return len;  /* crop at the end */
+  }
+  else {  /* negative index */
+    if ((size_t)(-ii) <= len)  /* inside the string? */
+      return len - ((size_t)(-ii));  /* return position from the end */
+    else return 0;  /* crop at the beginning */
+  }
+}
+
+
+/*
+** Main match function
+*/
+static int lp_match (lua_State *L) {
+  Capture capture[INITCAPSIZE];
+  const char *r;
+  size_t l;
+  const char *s;
+
+  Pattern *p = (getpatt(L, 1, NULL), getpattern(L, 1));
+  Instruction *code = (p->code != NULL) ? p->code : prepcompile(L, p, 1);
+
+  if (lua_type (L, SUBJIDX) == LUA_TSTRING) {
+	  s = luaL_checklstring (L, SUBJIDX, &l);
+  }
+  else if (lua_type (L, SUBJIDX) == LUA_TUSERDATA) {
+  	struct rspamd_lua_text *t = lua_check_text (L, SUBJIDX);
+  	if (!t) {
+		return luaL_error (L, "invalid argument (not a text)");
+  	}
+  	s = t->start;
+  	l = t->len;
+
+  	if (s == NULL) {
+		lua_pushnil(L);
+		return 1;
+  	}
+  }
+  else {
+  	return luaL_error (L, "invalid argument: %s",
+  			lua_typename (L, lua_type (L, SUBJIDX)));
+  }
+  size_t i = initposition(L, l);
+  int ptop = lua_gettop(L), rs;
+  lua_pushnil(L);  /* initialize subscache */
+  lua_pushlightuserdata(L, capture);  /* initialize caplistidx */
+  lua_getuservalue(L, 1);  /* initialize penvidx */
+  r = match(L, s, s + i, s + l, code, capture, ptop);
+  if (r == NULL) {
+    lua_pushnil(L);
+    return 1;
+  }
+  rs = getcaptures(L, s, r, ptop);
+  return rs;
+}
+
+
+
+/*
+** {======================================================
+** Library creation and functions not related to matching
+** =======================================================
+*/
+
+/* maximum limit for stack size */
+#define MAXLIM		(INT_MAX / 100)
+
+static int lp_setmax (lua_State *L) {
+  lua_Integer lim = luaL_checkinteger(L, 1);
+  luaL_argcheck(L, 0 < lim && lim <= MAXLIM, 1, "out of range");
+  lua_settop(L, 1);
+  lua_setfield(L, LUA_REGISTRYINDEX, MAXSTACKIDX);
+  return 0;
+}
+
+
+static int lp_version (lua_State *L) {
+  lua_pushstring(L, VERSION);
+  return 1;
+}
+
+
+static int lp_type (lua_State *L) {
+  if (testpattern(L, 1))
+    lua_pushliteral(L, "pattern");
+  else
+    lua_pushnil(L);
+  return 1;
+}
+
+
+int lp_gc (lua_State *L) {
+  Pattern *p = getpattern(L, 1);
+  realloccode(L, p, 0);  /* delete code block */
+  return 0;
+}
+
+
+static void createcat (lua_State *L, const char *catname, int (catf) (int)) {
+  TTree *t = newcharset(L);
+  int i;
+  for (i = 0; i <= UCHAR_MAX; i++)
+    if (catf(i)) setchar(treebuffer(t), i);
+  lua_setfield(L, -2, catname);
+}
+
+
+static int lp_locale (lua_State *L) {
+  if (lua_isnoneornil(L, 1)) {
+    lua_settop(L, 0);
+    lua_createtable(L, 0, 12);
+  }
+  else {
+    luaL_checktype(L, 1, LUA_TTABLE);
+    lua_settop(L, 1);
+  }
+  createcat(L, "alnum", isalnum);
+  createcat(L, "alpha", isalpha);
+  createcat(L, "cntrl", iscntrl);
+  createcat(L, "digit", isdigit);
+  createcat(L, "graph", isgraph);
+  createcat(L, "lower", islower);
+  createcat(L, "print", isprint);
+  createcat(L, "punct", ispunct);
+  createcat(L, "space", isspace);
+  createcat(L, "upper", isupper);
+  createcat(L, "xdigit", isxdigit);
+  return 1;
+}
+
+
+static struct luaL_Reg pattreg[] = {
+  {"ptree", lp_printtree},
+  {"pcode", lp_printcode},
+  {"match", lp_match},
+  {"B", lp_behind},
+  {"V", lp_V},
+  {"C", lp_simplecapture},
+  {"Cc", lp_constcapture},
+  {"Cmt", lp_matchtime},
+  {"Cb", lp_backref},
+  {"Carg", lp_argcapture},
+  {"Cp", lp_poscapture},
+  {"Cs", lp_substcapture},
+  {"Ct", lp_tablecapture},
+  {"Cf", lp_foldcapture},
+  {"Cg", lp_groupcapture},
+  {"P", lp_P},
+  {"S", lp_set},
+  {"R", lp_range},
+  {"locale", lp_locale},
+  {"version", lp_version},
+  {"setmaxstack", lp_setmax},
+  {"type", lp_type},
+  {NULL, NULL}
+};
+
+
+static struct luaL_Reg metareg[] = {
+  {"__mul", lp_seq},
+  {"__add", lp_choice},
+  {"__pow", lp_star},
+  {"__gc", lp_gc},
+  {"__len", lp_and},
+  {"__div", lp_divcapture},
+  {"__unm", lp_not},
+  {"__sub", lp_sub},
+  {NULL, NULL}
+};
+
+int luaopen_lpeg (lua_State *L) {
+  luaL_newmetatable(L, PATTERN_T);
+  lua_pushnumber(L, MAXBACK);  /* initialize maximum backtracking */
+  lua_setfield(L, LUA_REGISTRYINDEX, MAXSTACKIDX);
+  luaL_setfuncs(L, metareg, 0);
+  luaL_newlib(L, pattreg);
+  lua_pushvalue(L, -1);
+  lua_setfield(L, -3, "__index");
+  return 1;
+}
+
+/* }====================================================== */
diff --git a/contrib/lua-lpeg/lptree.h b/contrib/lua-lpeg/lptree.h
new file mode 100644
index 0000000..38a668e
--- /dev/null
+++ b/contrib/lua-lpeg/lptree.h
@@ -0,0 +1,77 @@
+/*
+** $Id: lptree.h,v 1.2 2013/03/24 13:51:12 roberto Exp $
+*/
+
+#if !defined(lptree_h)
+#define lptree_h
+
+
+#include "lptypes.h"
+
+
+/*
+** types of trees
+*/
+typedef enum TTag {
+  TChar = 0, TSet, TAny,  /* standard PEG elements */
+  TTrue, TFalse,
+  TRep,
+  TSeq, TChoice,
+  TNot, TAnd,
+  TCall,
+  TOpenCall,
+  TRule,  /* sib1 is rule's pattern, sib2 is 'next' rule */
+  TGrammar,  /* sib1 is initial (and first) rule */
+  TBehind,  /* match behind */
+  TCapture,  /* regular capture */
+  TRunTime  /* run-time capture */
+} TTag;
+
+/* number of siblings for each tree */
+extern const byte numsiblings[];
+
+
+/*
+** Tree trees
+** The first sibling of a tree (if there is one) is immediately after
+** the tree.  A reference to a second sibling (ps) is its position
+** relative to the position of the tree itself.  A key in ktable
+** uses the (unique) address of the original tree that created that
+** entry. NULL means no data.
+*/
+typedef struct TTree {
+  byte tag;
+  byte cap;  /* kind of capture (if it is a capture) */
+  unsigned short key;  /* key in ktable for Lua data (0 if no key) */
+  union {
+    int ps;  /* occasional second sibling */
+    int n;  /* occasional counter */
+  } u;
+} TTree;
+
+
+/*
+** A complete pattern has its tree plus, if already compiled,
+** its corresponding code
+*/
+typedef struct Pattern {
+  union Instruction *code;
+  int codesize;
+  TTree tree[1];
+} Pattern;
+
+
+/* number of siblings for each tree */
+extern const byte numsiblings[];
+
+/* access to siblings */
+#define sib1(t)         ((t) + 1)
+#define sib2(t)         ((t) + (t)->u.ps)
+
+
+int luaopen_lpeg (lua_State *L);
+
+
+
+#endif
+
diff --git a/contrib/lua-lpeg/lptypes.h b/contrib/lua-lpeg/lptypes.h
new file mode 100644
index 0000000..f541c7a
--- /dev/null
+++ b/contrib/lua-lpeg/lptypes.h
@@ -0,0 +1,154 @@
+/*
+** $Id: lptypes.h,v 1.14 2015/09/28 17:17:41 roberto Exp $
+** LPeg - PEG pattern matching for Lua
+** Copyright 2007-2015, Lua.org & PUC-Rio  (see 'lpeg.html' for license)
+** written by Roberto Ierusalimschy
+*/
+
+#if !defined(lptypes_h)
+#define lptypes_h
+
+
+#if !defined(LPEG_DEBUG) && !defined(NDEBUG)
+#define NDEBUG
+#endif
+
+#include <assert.h>
+#include <limits.h>
+
+#include "lua.h"
+
+
+#define VERSION         "1.0.0"
+
+
+#define PATTERN_T	"lpeg-pattern"
+#define MAXSTACKIDX	"lpeg-maxstack"
+
+
+/*
+** compatibility with Lua 5.1
+*/
+#if (LUA_VERSION_NUM == 501)
+
+#define lp_equal	lua_equal
+
+#define lua_getuservalue	lua_getfenv
+#define lua_setuservalue	lua_setfenv
+
+#ifndef lua_rawlen
+#define lua_rawlen		lua_objlen
+#endif
+
+#ifndef luaL_setfuncs
+#define luaL_setfuncs(L,f,n)	luaL_register(L,NULL,f)
+#endif
+#ifndef luaL_newlib
+#define luaL_newlib(L,f)	luaL_register(L,"lpeg",f)
+#endif
+#endif
+
+
+#if !defined(lp_equal)
+#define lp_equal(L,idx1,idx2)  lua_compare(L,(idx1),(idx2),LUA_OPEQ)
+#endif
+
+
+/* default maximum size for call/backtrack stack */
+#if !defined(MAXBACK)
+#define MAXBACK         400
+#endif
+
+
+/* maximum number of rules in a grammar */
+#if !defined(MAXRULES)
+#define MAXRULES        1000
+#endif
+
+
+
+/* initial size for capture's list */
+#define INITCAPSIZE	32
+
+
+/* index, on Lua stack, for subject */
+#define SUBJIDX		2
+
+/* number of fixed arguments to 'match' (before capture arguments) */
+#define FIXEDARGS	3
+
+/* index, on Lua stack, for capture list */
+#define caplistidx(ptop)	((ptop) + 2)
+
+/* index, on Lua stack, for pattern's ktable */
+#define ktableidx(ptop)		((ptop) + 3)
+
+/* index, on Lua stack, for backtracking stack */
+#define stackidx(ptop)	((ptop) + 4)
+
+
+
+typedef unsigned char byte;
+
+
+#define BITSPERCHAR		8
+
+#define CHARSETSIZE		((UCHAR_MAX/BITSPERCHAR) + 1)
+
+
+
+typedef struct Charset {
+  byte cs[CHARSETSIZE];
+} Charset;
+
+
+
+#define loopset(v,b)    { int v; for (v = 0; v < CHARSETSIZE; v++) {b;} }
+
+/* access to charset */
+#define treebuffer(t)      ((byte *)((t) + 1))
+
+/* number of slots needed for 'n' bytes */
+#define bytes2slots(n)  (((n) - 1) / sizeof(TTree) + 1)
+
+/* set 'b' bit in charset 'cs' */
+#define setchar(cs,b)   ((cs)[(b) >> 3] |= (1 << ((b) & 7)))
+
+
+/*
+** in capture instructions, 'kind' of capture and its offset are
+** packed in field 'aux', 4 bits for each
+*/
+#define getkind(op)		((op)->i.aux & 0xF)
+#define getoff(op)		(((op)->i.aux >> 4) & 0xF)
+#define joinkindoff(k,o)	((k) | ((o) << 4))
+
+#define MAXOFF		0xF
+#define MAXAUX		0xFF
+
+
+/* maximum number of bytes to look behind */
+#define MAXBEHIND	MAXAUX
+
+
+/* maximum size (in elements) for a pattern */
+#define MAXPATTSIZE	(SHRT_MAX - 10)
+
+
+/* size (in elements) for an instruction plus extra l bytes */
+#define instsize(l)  (((l) + sizeof(Instruction) - 1)/sizeof(Instruction) + 1)
+
+
+/* size (in elements) for a ISet instruction */
+#define CHARSETINSTSIZE		instsize(CHARSETSIZE)
+
+/* size (in elements) for a IFunc instruction */
+#define funcinstsize(p)		((p)->i.aux + 2)
+
+
+
+#define testchar(st,c)	(((int)(st)[((c) >> 3)] & (1 << ((c) & 7))))
+
+
+#endif
+
diff --git a/contrib/lua-lpeg/lpvm.c b/contrib/lua-lpeg/lpvm.c
new file mode 100644
index 0000000..0dfca18
--- /dev/null
+++ b/contrib/lua-lpeg/lpvm.c
@@ -0,0 +1,383 @@
+/*
+** $Id: lpvm.c,v 1.6 2015/09/28 17:01:25 roberto Exp $
+** Copyright 2007, Lua.org & PUC-Rio  (see 'lpeg.html' for license)
+*/
+
+#include "config.h"
+
+#include <limits.h>
+#include <string.h>
+
+
+#include "lua.h"
+#include "lauxlib.h"
+
+#include "lpcap.h"
+#include "lptypes.h"
+#include "lpvm.h"
+#include "lpprint.h"
+
+/* initial size for call/backtrack stack */
+#if !defined(INITBACK)
+#define INITBACK	MAXBACK
+#endif
+
+
+#define getoffset(p)	(((p) + 1)->offset)
+
+static const Instruction giveup = {{IGiveup, 0, 0}};
+
+
+/*
+** {======================================================
+** Virtual Machine
+** =======================================================
+*/
+
+
+typedef struct Stack {
+  const char *s;  /* saved position (or NULL for calls) */
+  const Instruction *p;  /* next instruction */
+  int caplevel;
+} Stack;
+
+
+#define getstackbase(L, ptop)	((Stack *)lua_touserdata(L, stackidx(ptop)))
+
+
+/*
+** Ensures the size of array 'capture' (with size '*capsize' and
+** 'captop' elements being used) is enough to accomodate 'n' extra
+** elements plus one.  (Because several opcodes add stuff to the capture
+** array, it is simpler to ensure the array always has at least one free
+** slot upfront and check its size later.)
+*/
+static Capture *growcap (lua_State *L, Capture *capture, int *capsize,
+                                       int captop, int n, int ptop) {
+  if (*capsize - captop > n)
+    return capture;  /* no need to grow array */
+  else {  /* must grow */
+    Capture *newc;
+    int newsize = captop + n + 1;  /* minimum size needed */
+    if (newsize < INT_MAX/((int)sizeof(Capture) * 2))
+      newsize *= 2;  /* twice that size, if not too big */
+    else if (newsize >= INT_MAX/((int)sizeof(Capture)))
+      luaL_error(L, "too many captures");
+    newc = (Capture *)lua_newuserdata(L, newsize * sizeof(Capture));
+    memcpy(newc, capture, captop * sizeof(Capture));
+    *capsize = newsize;
+    lua_replace(L, caplistidx(ptop));
+    return newc;
+  }
+}
+
+
+/*
+** Double the size of the stack
+*/
+static Stack *doublestack (lua_State *L, Stack **stacklimit, int ptop) {
+  Stack *stack = getstackbase(L, ptop);
+  Stack *newstack;
+  int n = *stacklimit - stack;  /* current stack size */
+  int max, newn;
+  lua_getfield(L, LUA_REGISTRYINDEX, MAXSTACKIDX);
+  max = lua_tointeger(L, -1);  /* maximum allowed size */
+  lua_pop(L, 1);
+  if (n >= max)  /* already at maximum size? */
+    luaL_error(L, "backtrack stack overflow (current limit is %d)", max);
+  newn = 2 * n;  /* new size */
+  if (newn > max) newn = max;
+  newstack = (Stack *)lua_newuserdata(L, newn * sizeof(Stack));
+  memcpy(newstack, stack, n * sizeof(Stack));
+  lua_replace(L, stackidx(ptop));
+  *stacklimit = newstack + newn;
+  return newstack + n;  /* return next position */
+}
+
+
+/*
+** Interpret the result of a dynamic capture: false -> fail;
+** true -> keep current position; number -> next position.
+** Return new subject position. 'fr' is stack index where
+** is the result; 'curr' is current subject position; 'limit'
+** is subject's size.
+*/
+static int resdyncaptures (lua_State *L, int fr, int curr, int limit) {
+  lua_Integer res;
+  if (!lua_toboolean(L, fr)) {  /* false value? */
+    lua_settop(L, fr - 1);  /* remove results */
+    return -1;  /* and fail */
+  }
+  else if (lua_isboolean(L, fr))  /* true? */
+    res = curr;  /* keep current position */
+  else {
+    res = lua_tointeger(L, fr) - 1;  /* new position */
+    if (res < curr || res > limit)
+      luaL_error(L, "invalid position returned by match-time capture");
+  }
+  lua_remove(L, fr);  /* remove first result (offset) */
+  return res;
+}
+
+
+/*
+** Add capture values returned by a dynamic capture to the list
+** 'capture', nested inside a group. 'fd' indexes the first capture
+** value, 'n' is the number of values (at least 1). The open group
+** capture is already in 'capture', before the place for the new entries.
+*/
+static void adddyncaptures (const char *s, Capture *capture, int n, int fd) {
+  int i;
+  assert(capture[-1].kind == Cgroup && capture[-1].siz == 0);
+  capture[-1].idx = 0;  /* make group capture an anonymous group */
+  for (i = 0; i < n; i++) {  /* add runtime captures */
+    capture[i].kind = Cruntime;
+    capture[i].siz = 1;  /* mark it as closed */
+    capture[i].idx = fd + i;  /* stack index of capture value */
+    capture[i].s = s;
+  }
+  capture[n].kind = Cclose;  /* close group */
+  capture[n].siz = 1;
+  capture[n].s = s;
+}
+
+
+/*
+** Remove dynamic captures from the Lua stack (called in case of failure)
+*/
+static int removedyncap (lua_State *L, Capture *capture,
+                         int level, int last) {
+  int id = finddyncap(capture + level, capture + last);  /* index of 1st cap. */
+  int top = lua_gettop(L);
+  if (id == 0) return 0;  /* no dynamic captures? */
+  lua_settop(L, id - 1);  /* remove captures */
+  return top - id + 1;  /* number of values removed */
+}
+
+
+/*
+** Opcode interpreter
+*/
+const char *match (lua_State *L, const char *o, const char *s, const char *e,
+                   Instruction *op, Capture *capture, int ptop) {
+  Stack stackbase[INITBACK];
+  Stack *stacklimit = stackbase + INITBACK;
+  Stack *stack = stackbase;  /* point to first empty slot in stack */
+  int capsize = INITCAPSIZE;
+  int captop = 0;  /* point to first empty slot in captures */
+  int ndyncap = 0;  /* number of dynamic captures (in Lua stack) */
+  const Instruction *p = op;  /* current instruction */
+  stack->p = &giveup; stack->s = s; stack->caplevel = 0; stack++;
+  lua_pushlightuserdata(L, stackbase);
+  for (;;) {
+#if defined(DEBUG)
+      printf("s: |%s| stck:%d, dyncaps:%d, caps:%d  ",
+             s, (int)(stack - getstackbase(L, ptop)), ndyncap, captop);
+      printinst(op, p);
+#endif
+    assert(stackidx(ptop) + ndyncap == lua_gettop(L) && ndyncap <= captop);
+    switch ((Opcode)p->i.code) {
+      case IEnd: {
+        assert(stack == getstackbase(L, ptop) + 1);
+        capture[captop].kind = Cclose;
+        capture[captop].s = NULL;
+        return s;
+      }
+      case IGiveup: {
+        assert(stack == getstackbase(L, ptop));
+        return NULL;
+      }
+      case IRet: {
+        assert(stack > getstackbase(L, ptop) && (stack - 1)->s == NULL);
+        p = (--stack)->p;
+        continue;
+      }
+      case IAny: {
+        if (s < e) { p++; s++; }
+        else goto fail;
+        continue;
+      }
+      case ITestAny: {
+        if (s < e) p += 2;
+        else p += getoffset(p);
+        continue;
+      }
+      case IChar: {
+        if (s < e && (byte)*s == p->i.aux) { p++; s++; }
+        else goto fail;
+        continue;
+      }
+      case ITestChar: {
+        if (s < e && (byte)*s == p->i.aux) p += 2;
+        else p += getoffset(p);
+        continue;
+      }
+      case ISet: {
+      	if (s < e) {
+			int c = (byte) *s;
+			if (testchar((p + 1)->buff, c)) {
+				p += CHARSETINSTSIZE;
+				s++;
+			}
+			else goto fail;
+		}
+      	else {
+      		goto fail;
+      	}
+        continue;
+      }
+      case ITestSet: {
+      	if (s < e) {
+			int c = (byte) *s;
+			if (testchar((p + 2)->buff, c))
+				p += 1 + CHARSETINSTSIZE;
+			else p += getoffset(p);
+		}
+      	else {
+			p += getoffset(p);
+      	}
+        continue;
+      }
+      case IBehind: {
+        int n = p->i.aux;
+        if (n > s - o) goto fail;
+        s -= n; p++;
+        continue;
+      }
+      case ISpan: {
+        for (; s < e; s++) {
+          int c = (byte)*s;
+          if (!testchar((p+1)->buff, c)) break;
+        }
+        p += CHARSETINSTSIZE;
+        continue;
+      }
+      case IJmp: {
+        p += getoffset(p);
+        continue;
+      }
+      case IChoice: {
+        if (stack == stacklimit)
+          stack = doublestack(L, &stacklimit, ptop);
+        stack->p = p + getoffset(p);
+        stack->s = s;
+        stack->caplevel = captop;
+        stack++;
+        p += 2;
+        continue;
+      }
+      case ICall: {
+        if (stack == stacklimit)
+          stack = doublestack(L, &stacklimit, ptop);
+        stack->s = NULL;
+        stack->p = p + 2;  /* save return address */
+        stack++;
+        p += getoffset(p);
+        continue;
+      }
+      case ICommit: {
+        assert(stack > getstackbase(L, ptop) && (stack - 1)->s != NULL);
+        stack--;
+        p += getoffset(p);
+        continue;
+      }
+      case IPartialCommit: {
+        assert(stack > getstackbase(L, ptop) && (stack - 1)->s != NULL);
+        (stack - 1)->s = s;
+        (stack - 1)->caplevel = captop;
+        p += getoffset(p);
+        continue;
+      }
+      case IBackCommit: {
+        assert(stack > getstackbase(L, ptop) && (stack - 1)->s != NULL);
+        s = (--stack)->s;
+        captop = stack->caplevel;
+        p += getoffset(p);
+        continue;
+      }
+      case IFailTwice:
+        assert(stack > getstackbase(L, ptop));
+        stack--;
+        /* go through */
+      case IFail:
+      fail: { /* pattern failed: try to backtrack */
+        do {  /* remove pending calls */
+          assert(stack > getstackbase(L, ptop));
+          s = (--stack)->s;
+        } while (s == NULL);
+        if (ndyncap > 0)  /* is there matchtime captures? */
+          ndyncap -= removedyncap(L, capture, stack->caplevel, captop);
+        captop = stack->caplevel;
+        p = stack->p;
+        continue;
+      }
+      case ICloseRunTime: {
+        CapState cs;
+        int rem, res, n;
+        int fr = lua_gettop(L) + 1;  /* stack index of first result */
+        cs.reclevel = 0; cs.L = L;
+        cs.s = o; cs.ocap = capture; cs.ptop = ptop;
+        n = runtimecap(&cs, capture + captop, s, &rem);  /* call function */
+        captop -= n;  /* remove nested captures */
+        ndyncap -= rem;  /* update number of dynamic captures */
+        fr -= rem;  /* 'rem' items were popped from Lua stack */
+        res = resdyncaptures(L, fr, s - o, e - o);  /* get result */
+        if (res == -1)  /* fail? */
+          goto fail;
+        s = o + res;  /* else update current position */
+        n = lua_gettop(L) - fr + 1;  /* number of new captures */
+        ndyncap += n;  /* update number of dynamic captures */
+        if (n == 0)  /* no new captures? */
+          captop--;  /* remove open group */
+        else {  /* new captures; keep original open group */
+          if (fr + n >= SHRT_MAX)
+            luaL_error(L, "too many results in match-time capture");
+          /* add new captures + close group to 'capture' list */
+          capture = growcap(L, capture, &capsize, captop, n + 1, ptop);
+          adddyncaptures(s, capture + captop, n, fr);
+          captop += n + 1;  /* new captures + close group */
+        }
+        p++;
+        continue;
+      }
+      case ICloseCapture: {
+        const char *s1 = s;
+        assert(captop > 0);
+        /* if possible, turn capture into a full capture */
+        if (capture[captop - 1].siz == 0 &&
+            s1 - capture[captop - 1].s < UCHAR_MAX) {
+          capture[captop - 1].siz = s1 - capture[captop - 1].s + 1;
+          p++;
+          continue;
+        }
+        else {
+          capture[captop].siz = 1;  /* mark entry as closed */
+          capture[captop].s = s;
+          goto pushcapture;
+        }
+      }
+      case IOpenCapture:
+        capture[captop].siz = 0;  /* mark entry as open */
+        capture[captop].s = s;
+        goto pushcapture;
+      case IFullCapture:
+        capture[captop].siz = getoff(p) + 1;  /* save capture size */
+        capture[captop].s = s - getoff(p);
+        /* goto pushcapture; */
+      pushcapture: {
+        capture[captop].idx = p->i.key;
+        capture[captop].kind = getkind(p);
+        captop++;
+        capture = growcap(L, capture, &capsize, captop, 0, ptop);
+        p++;
+        continue;
+      }
+      default: assert(0); return NULL;
+    }
+  }
+
+}
+
+/* }====================================================== */
+
+
diff --git a/contrib/lua-lpeg/lpvm.h b/contrib/lua-lpeg/lpvm.h
new file mode 100644
index 0000000..757b9e1
--- /dev/null
+++ b/contrib/lua-lpeg/lpvm.h
@@ -0,0 +1,58 @@
+/*
+** $Id: lpvm.h,v 1.3 2014/02/21 13:06:41 roberto Exp $
+*/
+
+#if !defined(lpvm_h)
+#define lpvm_h
+
+#include "lpcap.h"
+
+
+/* Virtual Machine's instructions */
+typedef enum Opcode {
+  IAny, /* if no char, fail */
+  IChar,  /* if char != aux, fail */
+  ISet,  /* if char not in buff, fail */
+  ITestAny,  /* in no char, jump to 'offset' */
+  ITestChar,  /* if char != aux, jump to 'offset' */
+  ITestSet,  /* if char not in buff, jump to 'offset' */
+  ISpan,  /* read a span of chars in buff */
+  IBehind,  /* walk back 'aux' characters (fail if not possible) */
+  IRet,  /* return from a rule */
+  IEnd,  /* end of pattern */
+  IChoice,  /* stack a choice; next fail will jump to 'offset' */
+  IJmp,  /* jump to 'offset' */
+  ICall,  /* call rule at 'offset' */
+  IOpenCall,  /* call rule number 'key' (must be closed to a ICall) */
+  ICommit,  /* pop choice and jump to 'offset' */
+  IPartialCommit,  /* update top choice to current position and jump */
+  IBackCommit,  /* "fails" but jump to its own 'offset' */
+  IFailTwice,  /* pop one choice and then fail */
+  IFail,  /* go back to saved state on choice and jump to saved offset */
+  IGiveup,  /* internal use */
+  IFullCapture,  /* complete capture of last 'off' chars */
+  IOpenCapture,  /* start a capture */
+  ICloseCapture,
+  ICloseRunTime
+} Opcode;
+
+
+
+typedef union Instruction {
+  struct Inst {
+    byte code;
+    byte aux;
+    short key;
+  } i;
+  int offset;
+  byte buff[1];
+} Instruction;
+
+
+void printpatt (Instruction *p, int n);
+const char *match (lua_State *L, const char *o, const char *s, const char *e,
+                   Instruction *op, Capture *capture, int ptop);
+
+
+#endif
+