Updating lpeglabel to the codebase of LPeg 1.0.1

1 files changed, 12 insertions, 7 deletions

diff --git a/lptree.c b/lptree.c
index 6633035..fcf5ff9 100644
--- a/lptree.c
+++ b/lptree.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lptree.c,v 1.21 2015/09/28 17:01:25 roberto Exp $
+** $Id: lptree.c,v 1.22 2016/09/13 18:10:22 roberto Exp $
 ** Copyright 2013, Lua.org & PUC-Rio  (see 'lpeg.html' for license)
 */
 
@@ -65,7 +65,7 @@ static void fixonecall (lua_State *L, int postable, TTree *g, TTree *t) {
   t->tag = TCall;
   t->u.s.ps = n - (t - g);  /* position relative to node */
   assert(sib2(t)->tag == TRule);
-  sib2(t)->key = t->key;
+  sib2(t)->key = t->key;  /* fix rule's key */
 }
 
 
@@ -542,7 +542,6 @@ static TTree *newrootlab2sib (lua_State *L, int tag) {
 /* labeled failure end */
 
 
-
 static int lp_P (lua_State *L) {
   luaL_checkany(L, 1);
   getpatt(L, 1, NULL);
@@ -728,6 +727,7 @@ static int lp_throw (lua_State *L) {
         return 1;
 }
 
+
 /*
 ** labeled recovery function
 */
@@ -747,7 +747,6 @@ static int lp_recovery (lua_State *L) {
         }
   return 1;
 }
-
 /* labeled failure end */
 
 
@@ -996,7 +995,7 @@ static void buildgrammar (lua_State *L, TTree *grammar, int frule, int n) {
     int rulesize;
     TTree *rn = gettree(L, ridx, &rulesize);
     nd->tag = TRule;
-    nd->key = 0;
+    nd->key = 0;  /* will be fixed when rule is used */
     nd->cap = i;  /* rule number */
     nd->u.s.ps = rulesize + 1;  /* point to next rule */
     memcpy(sib1(nd), rn, rulesize * sizeof(TTree));  /* copy rule */
@@ -1030,6 +1029,11 @@ static int checkloops (TTree *tree) {
 }
 
 
+/*
+** Give appropriate error message for 'verifyrule'. If a rule appears
+** twice in 'passed', there is path from it back to itself without
+** advancing the subject.
+*/
 static int verifyerror (lua_State *L, int *passed, int npassed) {
   int i, j;
   for (i = npassed - 1; i >= 0; i--) {  /* search for a repetition */
@@ -1051,6 +1055,8 @@ static int verifyerror (lua_State *L, int *passed, int npassed) {
 ** 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.)
+** Parameter 'passed' is a list of already visited rules, 'npassed'
+** counts the elements in 'passed'.
 ** Assume ktable at the top of the stack.
 */
 static int verifyrule (lua_State *L, TTree *tree, int *passed, int npassed,
@@ -1330,7 +1336,7 @@ static struct luaL_Reg pattreg[] = {
   {"setmaxstack", lp_setmax},
   {"type", lp_type},
   {"T", lp_throw}, /* labeled failure throw */
-  {"Rec", lp_recovery}, /* labeled failure choice */
+  {"Rec", lp_recovery}, /* labeled failure recovery */
   {NULL, NULL}
 };
 
@@ -1347,7 +1353,6 @@ static struct luaL_Reg metareg[] = {
   {NULL, NULL}
 };
 
-
 int luaopen_lpeglabel (lua_State *L);  /* labeled failure */
 int luaopen_lpeglabel (lua_State *L) { /* labeled failure */
   luaL_newmetatable(L, PATTERN_T);