11 files changed, 140 insertions, 101 deletions

diff --git a/LICENSE b/LICENSE
index 9c488ad..27faf04 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2014-2015 Sérgio Medeiros
+Copyright (c) 2014-2016 Sérgio Medeiros
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/lpcap.c b/lpcap.c
index b6911cb..c9085de 100644
--- a/lpcap.c
+++ b/lpcap.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lpcap.c,v 1.5 2014/12/12 16:58:47 roberto Exp $
+** $Id: lpcap.c,v 1.6 2015/06/15 16:09:57 roberto Exp $
 ** Copyright 2007, Lua.org & PUC-Rio  (see 'lpeg.html' for license)
 */
 
@@ -126,7 +126,7 @@ static Capture *findback (CapState *cs, Capture *cap) {
       continue; /* opening an enclosing capture: skip and get previous */
     if (captype(cap) == Cgroup) {
       getfromktable(cs, cap->idx);  /* get group name */
-      if (lua_equal(L, -2, -1)) {  /* right group? */
+      if (lp_equal(L, -2, -1)) {  /* right group? */
         lua_pop(L, 2);  /* remove reference name and group name */
         return cap;
       }
diff --git a/lpcode.c b/lpcode.c
index 70a8d3c..2a85e02 100644
--- a/lpcode.c
+++ b/lpcode.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lpcode.c,v 1.21 2014/12/12 17:01:29 roberto Exp $
+** $Id: lpcode.c,v 1.23 2015/06/12 18:36:47 roberto Exp $
 ** Copyright 2007, Lua.org & PUC-Rio  (see 'lpeg.html' for license)
 */
 
@@ -192,7 +192,7 @@ int checkaux (TTree *tree, int pred) {
       if (!checkaux(sib1(tree), pred)) return 0;
       /* else return checkaux(sib2(tree), pred); */
       tree = sib2(tree); goto tailcall;
-    case TChoice: 
+    case TChoice:
       if (checkaux(sib2(tree), pred)) return 1;
       /* else return checkaux(sib1(tree), pred); */
       tree = sib1(tree); goto tailcall;
@@ -425,9 +425,9 @@ int sizei (const Instruction *i) {
     case ITestChar: case ITestAny: case IChoice: case IJmp: case ICall:
     case IOpenCall: case ICommit: case IPartialCommit: case IBackCommit:
     case IThrow:  /* labeled failure */
-      return 2;  
-                case ILabChoice: return 3; /* labeled failure */
       return 2;
+    case ILabChoice: 
+      return 3; /* labeled failure */
     default: return 1;
   }
 }
@@ -444,11 +444,11 @@ typedef struct CompileState {
 
 
 /*
-** code generation is recursive; 'opt' indicates that the code is
-** being generated under a 'IChoice' operator jumping to its end
-** (that is, the match is "optional").
-** 'tt' points to a previous test protecting this code. 'fl' is
-** the follow set of the pattern.
+** 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);
@@ -669,13 +669,13 @@ static void codebehind (CompileState *compst, TTree *tree) {
 
 /*
 ** Choice; optimizations:
-** - when p1 is headfail
-** - when first(p1) and first(p2) are disjoint; than
+** - 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 resuse
+** - 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,
@@ -702,7 +702,7 @@ static void codechoice (CompileState *compst, TTree *p1, TTree *p2, int opt,
   }
   else {
     /* <p1 / p2> == 
-        test(fail(p1)) -> L1; choice L1; <p1>; commit L2; L1: <p2>; L2: */
+        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);
@@ -808,7 +808,7 @@ static void coderep (CompileState *compst, TTree *tree, int opt,
       /* L1: test (fail(p1)) -> L2; <p>; jmp L1; L2: */
       int jmp;
       int test = codetestset(compst, &st, 0);
-      codegen(compst, tree, opt, test, fullset);
+      codegen(compst, tree, 0, test, fullset);
       jmp = addoffsetinst(compst, IJmp);
       jumptohere(compst, test);
       jumptothere(compst, jmp, test);
diff --git a/lpcode.h b/lpcode.h
index 72d2bb9..896d3c7 100644
--- a/lpcode.h
+++ b/lpcode.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lpcode.h,v 1.6 2013/11/28 14:56:02 roberto Exp $
+** $Id: lpcode.h,v 1.7 2015/06/12 18:24:45 roberto Exp $
 */
 
 #if !defined(lpcode_h)
@@ -24,7 +24,15 @@ 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)
 
 #define fixedlen(t)     fixedlenx(t, 0, 0)
diff --git a/lpprint.c b/lpprint.c
index d4a60a8..99cc3ac 100644
--- a/lpprint.c
+++ b/lpprint.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lpprint.c,v 1.7 2013/04/12 16:29:49 roberto Exp $
+** $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)
 */
 
@@ -52,7 +52,7 @@ static void printjmp (const Instruction *op, const Instruction *p) {
 }
 
 
-static void printinst (const Instruction *op, const Instruction *p) {
+void printinst (const Instruction *op, const Instruction *p) {
   const char *const names[] = {
     "any", "char", "set",
     "testany", "testchar", "testset",
@@ -239,10 +239,10 @@ void printtree (TTree *tree, int ident) {
 
 void printktable (lua_State *L, int idx) {
   int n, i;
-  lua_getfenv(L, idx);
+  lua_getuservalue(L, idx);
   if (lua_isnil(L, -1))  /* no ktable? */
     return;
-  n = lua_objlen(L, -1);
+  n = lua_rawlen(L, -1);
   printf("[");
   for (i = 1; i <= n; i++) {
     printf("%d = ", i);
diff --git a/lpprint.h b/lpprint.h
index e640f74..6329760 100644
--- a/lpprint.h
+++ b/lpprint.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lpprint.h,v 1.1 2013/03/21 20:25:12 roberto Exp $
+** $Id: lpprint.h,v 1.2 2015/06/12 18:18:08 roberto Exp $
 */
 
 
@@ -18,6 +18,7 @@ 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
 
diff --git a/lptree.c b/lptree.c
index 548128d..22cf606 100644
--- a/lptree.c
+++ b/lptree.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lptree.c,v 1.15 2015/03/04 17:23:00 roberto Exp $
+** $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)
 */
 
@@ -147,7 +147,7 @@ static void finalfix (lua_State *L, int postable, TTree *g, TTree *t) {
 */
 static void newktable (lua_State *L, int n) {
   lua_createtable(L, n, 0);  /* create a fresh table */
-  lua_setfenv(L, -2);  /* set it as 'ktable' for pattern */
+  lua_setuservalue(L, -2);  /* set it as 'ktable' for pattern */
 }
 
 
@@ -162,8 +162,8 @@ static int addtoktable (lua_State *L, int idx) {
     return 0;
   else {
     int n;
-    lua_getfenv(L, -1);  /* get ktable from pattern */
-    n = lua_objlen(L, -1);
+    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 */
@@ -182,7 +182,7 @@ static int addtoktable (lua_State *L, int idx) {
 */
 static int ktablelen (lua_State *L, int idx) {
   if (!lua_istable(L, idx)) return 0;
-  else return lua_objlen(L, idx);
+  else return lua_rawlen(L, idx);
 }
 
 
@@ -245,18 +245,18 @@ static void correctkeys (TTree *tree, int n) {
 */
 static void joinktables (lua_State *L, int p1, TTree *t2, int p2) {
   int n1, n2;
-  lua_getfenv(L, p1);  /* get ktables */
-  lua_getfenv(L, p2);
+  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 || lua_equal(L, -2, -1)) {  /* 2nd table empty or equal? */
+  else if (n2 == 0 || lp_equal(L, -2, -1)) {  /* 2nd table empty or equal? */
     lua_pop(L, 1);  /* pop 2nd table */
-    lua_setfenv(L, -2);  /* set 1st ktable into new pattern */
+    lua_setuservalue(L, -2);  /* set 1st ktable into new pattern */
   }
   else if (n1 == 0) {  /* first table is empty? */
-    lua_setfenv(L, -3);  /* set 2nd table into new pattern */
+    lua_setuservalue(L, -3);  /* set 2nd table into new pattern */
     lua_pop(L, 1);  /* pop 1st table */
   }
   else {
@@ -264,7 +264,7 @@ static void joinktables (lua_State *L, int p1, TTree *t2, int p2) {
     /* 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_setfenv(L, -4);  /* new ktable becomes 'p' environment */
+    lua_setuservalue(L, -4);  /* new ktable becomes 'p' environment */
     lua_pop(L, 2);  /* pop other ktables */
     correctkeys(t2, n1);  /* correction for indices from p2 */
   }
@@ -275,8 +275,8 @@ static void joinktables (lua_State *L, int p1, TTree *t2, int p2) {
 ** copy 'ktable' of element 'idx' to new tree (on top of stack)
 */
 static void copyktable (lua_State *L, int idx) {
-  lua_getfenv(L, idx);
-  lua_setfenv(L, -2);
+  lua_getuservalue(L, idx);
+  lua_setuservalue(L, -2);
 }
 
 
@@ -287,8 +287,8 @@ static void copyktable (lua_State *L, int idx) {
 */
 static void mergektable (lua_State *L, int idx, TTree *stree) {
   int n;
-  lua_getfenv(L, -1);  /* get ktables */
-  lua_getfenv(L, idx);
+  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);
@@ -339,7 +339,7 @@ static Pattern *getpattern (lua_State *L, int idx) {
 
 
 static int getsize (lua_State *L, int idx) {
-  return (lua_objlen(L, idx) - sizeof(Pattern)) / sizeof(TTree) + 1;
+  return (lua_rawlen(L, idx) - sizeof(Pattern)) / sizeof(TTree) + 1;
 }
 
 
@@ -352,12 +352,16 @@ static TTree *gettree (lua_State *L, int idx, int *len) {
 
 
 /*
-** create a pattern
+** 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);
   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;
@@ -688,7 +692,7 @@ 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, 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);
@@ -822,10 +826,8 @@ static int lp_tablecapture (lua_State *L) {
 static int lp_groupcapture (lua_State *L) {
   if (lua_isnoneornil(L, 2))
     return capture_aux(L, Cgroup, 0);
-  else {
-    luaL_checkstring(L, 2);
+  else
     return capture_aux(L, Cgroup, 2);
-  }
 }
 
 
@@ -856,7 +858,7 @@ static int lp_argcapture (lua_State *L) {
 
 
 static int lp_backref (lua_State *L) {
-  luaL_checkstring(L, 1);
+  luaL_checkany(L, 1);
   newemptycapkey(L, Cbackref, 1);
   return 1;
 }
@@ -954,7 +956,7 @@ static int collectrules (lua_State *L, int arg, int *totalsize) {
   lua_pushnil(L);  /* prepare to traverse grammar table */
   while (lua_next(L, arg) != 0) {
     if (lua_tonumber(L, -2) == 1 ||
-        lua_equal(L, -2, postab + 1)) {  /* initial rule? */
+        lp_equal(L, -2, postab + 1)) {  /* initial rule? */
       lua_pop(L, 1);  /* remove value (keep key for lua_next) */
       continue;
     }
@@ -1031,36 +1033,40 @@ static int verifyerror (lua_State *L, int *passed, int npassed) {
 
 /*
 ** Check whether a rule can be left recursive; raise an error in that
-** case; otherwise return 1 iff pattern is nullable. Assume ktable at
-** the top of the stack.
+** 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 nullable) {
+                       int nb) {
  tailcall:
   switch (tree->tag) {
     case TChar: case TSet: case TAny:
     case TFalse: case TThrow: /* labeled failure */
-      return nullable;  /* cannot pass from here */
+      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); nullable = 1; goto tailcall;
+      tree = sib1(tree); nb = 1; goto tailcall;
     case TCapture: case TRunTime:
-      /* return verifyrule(L, sib1(tree), passed, npassed); */
+      /* return verifyrule(L, sib1(tree), passed, npassed, nb); */
       tree = sib1(tree); goto tailcall;
     case TCall:
-      /* return verifyrule(L, sib2(tree), passed, npassed); */
+      /* return verifyrule(L, sib2(tree), passed, npassed, nb); */
       tree = sib2(tree); goto tailcall;
-    case TSeq:  /* only check 2nd child if first is nullable */
+    case TSeq:  /* only check 2nd child if first is nb */
       if (!verifyrule(L, sib1(tree), passed, npassed, 0))
-        return nullable;
-      /* else return verifyrule(L, sib2(tree), passed, npassed); */
+        return nb;
+      /* else return verifyrule(L, sib2(tree), passed, npassed, nb); */
       tree = sib2(tree); goto tailcall;
     case TChoice: case TLabChoice:  /* must check both children */  /* labeled failure */
-      nullable = verifyrule(L, sib1(tree), passed, npassed, nullable);
-      /* return verifyrule(L, sib2(tree), passed, npassed, nullable); */
+      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)
@@ -1103,7 +1109,7 @@ static void verifygrammar (lua_State *L, TTree *grammar) {
 */
 static void initialrulename (lua_State *L, TTree *grammar, int frule) {
   if (sib1(grammar)->key == 0) {  /* initial rule is not referenced? */
-    int n = lua_objlen(L, -1) + 1;  /* index for name */
+    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;
@@ -1119,9 +1125,9 @@ static TTree *newgrammar (lua_State *L, int arg) {
   luaL_argcheck(L, n <= MAXRULES, arg, "grammar has too many rules");
   g->tag = TGrammar;  g->u.n = n;
   lua_newtable(L);  /* create 'ktable' */
-  lua_setfenv(L, -2);
+  lua_setuservalue(L, -2);
   buildgrammar(L, g, frule, n);
-  lua_getfenv(L, -1);  /* get 'ktable' for new tree */
+  lua_getuservalue(L, -1);  /* get 'ktable' for new tree */
   finalfix(L, frule - 1, g, sib1(g));
   initialrulename(L, g, frule);
   verifygrammar(L, g);
@@ -1135,7 +1141,7 @@ static TTree *newgrammar (lua_State *L, int arg) {
 
 
 static Instruction *prepcompile (lua_State *L, Pattern *p, int idx) {
-  lua_getfenv(L, idx);  /* push 'ktable' (may be used by 'finalfix') */
+  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);
@@ -1146,7 +1152,7 @@ static int lp_printtree (lua_State *L) {
   TTree *tree = getpatt(L, 1, NULL);
   int c = lua_toboolean(L, 2);
   if (c) {
-    lua_getfenv(L, 1);  /* push 'ktable' (may be used by 'finalfix') */
+    lua_getuservalue(L, 1);  /* push 'ktable' (may be used by 'finalfix') */
     finalfix(L, 0, NULL, tree);
     lua_pop(L, 1);  /* remove 'ktable' */
   }
@@ -1201,9 +1207,8 @@ static int lp_match (lua_State *L) {
   const char *sfail = NULL; /* labeled failure */
   lua_pushnil(L);  /* initialize subscache */
   lua_pushlightuserdata(L, capture);  /* initialize caplistidx */
-  lua_getfenv(L, 1);  /* initialize penvidx */
+  lua_getuservalue(L, 1);  /* initialize penvidx */
   r = match(L, s, s + i, s + l, code, capture, ptop, &labelf, &sfail); /* labeled failure */
-        /*printf("sfail = %s\n", sfail);*/
   if (r == NULL) { /* labeled failure begin */
     long long int j = 0;
     int n = 1;
@@ -1230,8 +1235,12 @@ static int lp_match (lua_State *L) {
 ** =======================================================
 */
 
+/* maximum limit for stack size */
+#define MAXLIM          (INT_MAX / 100)
+
 static int lp_setmax (lua_State *L) {
-  luaL_optinteger(L, 1, -1);
+  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;
@@ -1255,8 +1264,7 @@ static int lp_type (lua_State *L) {
 
 int lp_gc (lua_State *L) {
   Pattern *p = getpattern(L, 1);
-  if (p->codesize > 0)
-    realloccode(L, p, 0);
+  realloccode(L, p, 0);  /* delete code block */
   return 0;
 }
 
@@ -1336,13 +1344,13 @@ static struct luaL_Reg metareg[] = {
 };
 
 
-int luaopen_lpeglabel (lua_State *L);  /* labeld failure */
+int luaopen_lpeglabel (lua_State *L);  /* labeled failure */
 int luaopen_lpeglabel (lua_State *L) { /* labeled failure */
   luaL_newmetatable(L, PATTERN_T);
   lua_pushnumber(L, MAXBACK);  /* initialize maximum backtracking */
   lua_setfield(L, LUA_REGISTRYINDEX, MAXSTACKIDX);
-  luaL_register(L, NULL, metareg);
-  luaL_register(L, "lpeglabel", pattreg); /* labeled failure */
+  luaL_setfuncs(L, metareg, 0);
+  luaL_newlib(L, pattreg);
   lua_pushvalue(L, -1);
   lua_setfield(L, -3, "__index");
   return 1;
diff --git a/lptypes.h b/lptypes.h
index 1f30bc4..560ddbb 100644
--- a/lptypes.h
+++ b/lptypes.h
@@ -1,7 +1,7 @@
 /*
-** $Id: lptypes.h,v 1.11 2015/03/04 16:38:00 roberto Exp $
+** $Id: lptypes.h,v 1.14 2015/09/28 17:17:41 roberto Exp $
 ** LPeg - PEG pattern matching for Lua
-** Copyright 2007-2014, Lua.org & PUC-Rio  (see 'lpeg.html' for license)
+** Copyright 2007-2015, Lua.org & PUC-Rio  (see 'lpeg.html' for license)
 ** written by Roberto Ierusalimschy
 */
 
@@ -19,7 +19,7 @@
 #include "lua.h"
 
 
-#define VERSION         "0.12.2"
+#define VERSION         "1.0.0"
 
 
 #define PATTERN_T       "lpeg-pattern"
@@ -27,31 +27,31 @@
 
 
 /*
-** compatibility with Lua 5.2
+** compatibility with Lua 5.1
 */
-#if (LUA_VERSION_NUM >= 502)
+#if (LUA_VERSION_NUM == 501)
 
-#undef lua_equal
-#define lua_equal(L,idx1,idx2)  lua_compare(L,(idx1),(idx2),LUA_OPEQ)
+#define lp_equal        lua_equal
 
-#undef lua_getfenv
-#define lua_getfenv     lua_getuservalue
-#undef lua_setfenv
-#define lua_setfenv     lua_setuservalue
+#define lua_getuservalue        lua_getfenv
+#define lua_setuservalue        lua_setfenv
 
-#undef lua_objlen
-#define lua_objlen      lua_rawlen
+#define lua_rawlen              lua_objlen
 
-#undef luaL_register
-#define luaL_register(L,n,f) \
-        { if ((n) == NULL) luaL_setfuncs(L,f,0); else luaL_newlib(L,f); }
+#define luaL_setfuncs(L,f,n)    luaL_register(L,NULL,f)
+#define luaL_newlib(L,f)        luaL_register(L,"lpeg",f)
 
 #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         100
+#define MAXBACK         400
 #endif
 
 
diff --git a/lpvm.c b/lpvm.c
index 3ae22f5..c15d543 100644
--- a/lpvm.c
+++ b/lpvm.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lpvm.c,v 1.5 2013/04/12 16:29:49 roberto Exp $
+** $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)
 */
 
@@ -18,7 +18,7 @@
 
 /* initial size for call/backtrack stack */
 #if !defined(INITBACK)
-#define INITBACK        100
+#define INITBACK        MAXBACK
 #endif
 
 
@@ -71,7 +71,7 @@ static Stack *doublestack (lua_State *L, Stack **stacklimit, int ptop) {
   max = lua_tointeger(L, -1);  /* maximum allowed size */
   lua_pop(L, 1);
   if (n >= max)  /* already at maximum size? */
-    luaL_error(L, "too many pending calls/choices");
+    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));
diff --git a/makefile b/makefile
index 51d3b15..5728b38 100644
--- a/makefile
+++ b/makefile
@@ -40,7 +40,7 @@ lpeglabel.so: $(FILES)
 
 $(FILES): makefile
 
-test: test.lua relabel.lua lpeglabel.so
+test: test.lua testlabel.lua testerrors.lua relabel.lua lpeglabel.so
         lua test.lua
         lua testlabel.lua
         lua testerrors.lua
diff --git a/test.lua b/test.lua
index 86cda61..73297c6 100755
--- a/test.lua
+++ b/test.lua
@@ -1,6 +1,6 @@
-#!/usr/bin/env lua5.1
+#!/usr/bin/env lua
 
--- $Id: test.lua,v 1.106 2015/03/04 17:31:33 roberto Exp $
+-- $Id: test.lua,v 1.109 2015/09/28 17:01:25 roberto Exp $
 
 -- require"strict"    -- just to be pedantic
 
@@ -16,9 +16,6 @@ local unpack = rawget(table, "unpack") or unpack
 local loadstring = rawget(_G, "loadstring") or load
 
 
--- most tests here do not need much stack space
-m.setmaxstack(5)
-
 local any = m.P(1)
 local space = m.S" \t\n"^0
 
@@ -291,6 +288,13 @@ assert(m.match(m.P"ab"^-1 - "c", "abcd") == 3)
 
 p = ('Aa' * ('Bb' * ('Cc' * m.P'Dd'^0)^0)^0)^-1
 assert(p:match("AaBbCcDdBbCcDdDdDdBb") == 21)
+
+
+-- bug in 0.12.2
+-- p = { ('ab' ('c' 'ef'?)*)? }
+p = m.C(('ab' * ('c' * m.P'ef'^-1)^0)^-1)
+s = "abcefccefc"
+assert(s == p:match(s))
  
 
 pi = "3.14159 26535 89793 23846 26433 83279 50288 41971 69399 37510"
@@ -352,10 +356,16 @@ checkeq(t, {hi = 10, ho = 20})
 t = p:match'abc'
 checkeq(t, {hi = 10, ho = 20, 'a', 'b', 'c'})
 
+-- non-string group names
+p = m.Ct(m.Cg(1, print) * m.Cg(1, 23.5) * m.Cg(1, io))
+t = p:match('abcdefghij')
+assert(t[print] == 'a' and t[23.5] == 'b' and t[io] == 'c')
+
 
 -- test for error messages
 local function checkerr (msg, f, ...)
   local st, err = pcall(f, ...)
+        print(st, err)
   assert(not st and m.match({ m.P(msg) + 1 * m.V(1) }, err))
 end
 
@@ -594,9 +604,9 @@ assert(not p:match(string.rep("011", 10001)))
 -- this grammar does need backtracking info.
 local lim = 10000
 p = m.P{ '0' * m.V(1) + '0' }
-checkerr("too many pending", m.match, p, string.rep("0", lim))
+checkerr("stack overflow", m.match, p, string.rep("0", lim))
 m.setmaxstack(2*lim)
-checkerr("too many pending", m.match, p, string.rep("0", lim))
+checkerr("stack overflow", m.match, p, string.rep("0", lim))
 m.setmaxstack(2*lim + 4)
 assert(m.match(p, string.rep("0", lim)) == lim + 1)
 
@@ -605,7 +615,7 @@ p = m.P{ ('a' * m.V(1))^0 * 'b' + 'c' }
 m.setmaxstack(200)
 assert(p:match(string.rep('a', 180) .. 'c' .. string.rep('b', 180)) == 362)
 
-m.setmaxstack(5)   -- restore original limit
+m.setmaxstack(100)   -- restore low limit
 
 -- tests for optional start position
 assert(m.match("a", "abc", 1))
@@ -737,6 +747,10 @@ t = {m.match(m.Cc(nil,nil,4) * m.Cc(nil,3) * m.Cc(nil, nil) / g / g, "")}
 t1 = {1,1,nil,nil,4,nil,3,nil,nil}
 for i=1,10 do assert(t[i] == t1[i]) end
 
+-- bug in 0.12.2: ktable with only nil could be eliminated when joining
+-- with a pattern without ktable
+assert((m.P"aaa" * m.Cc(nil)):match"aaa" == nil)
+
 t = {m.match((m.C(1) / function (x) return x, x.."x" end)^0, "abc")}
 checkeq(t, {"a", "ax", "b", "bx", "c", "cx"})
 
@@ -944,6 +958,13 @@ p = m.Cg(m.C(1) * m.C(1), "k") * m.Ct(m.Cb("k"))
 t = p:match("ab")
 checkeq(t, {"a", "b"})
 
+p = m.P(true)
+for i = 1, 10 do p = p * m.Cg(1, i) end
+for i = 1, 10 do
+  local p = p * m.Cb(i)
+  assert(p:match('abcdefghij') == string.sub('abcdefghij', i, i))
+end
+
 
 t = {}
 function foo (p) t[#t + 1] = p; return p .. "x" end
@@ -1420,7 +1441,8 @@ errmsg('aaaa', "rule 'aaaa'")
 errmsg('a', 'outside')
 errmsg('b <- a', 'undefined')
 errmsg("x <- 'a'  x <- 'b'", 'already defined')
--- errmsg("'a' -", "near '-'")
+-- error message is different because Matthew rewrote 're.lua'
+--errmsg("'a' -", "near '-'")
 
 
 print"OK"