'match' function now returns the 'nil' plus a list of labels

3 files changed, 22 insertions, 13 deletions

diff --git a/lptree.c b/lptree.c
index 5d2933d..0dd5998 100644
--- a/lptree.c
+++ b/lptree.c
@@ -1142,13 +1142,23 @@ static int lp_match (lua_State *L) {
   const char *s = luaL_checklstring(L, SUBJIDX, &l);
   size_t i = initposition(L, l);
   int ptop = lua_gettop(L);
+  Labelset labelf; /* labeled failure */
   lua_pushnil(L);  /* initialize subscache */
   lua_pushlightuserdata(L, capture);  /* initialize caplistidx */
   lua_getfenv(L, 1);  /* initialize penvidx */
-  r = match(L, s, s + i, s + l, code, capture, ptop);
+  r = match(L, s, s + i, s + l, code, capture, ptop, &labelf);
   if (r == NULL) {
+                int j = 0;
+                int n = 1;
     lua_pushnil(L);
-    return 1;
+                while (j < (int) MAXLABELS) {
+                        if (labelf & (1 << j)) {        
+                                lua_pushinteger(L, j);
+                                n++;
+                        }
+                        j++;
+                }
+    return n;
   }
   return getcaptures(L, s, r, ptop);
 }
diff --git a/lpvm.c b/lpvm.c
index 8d2c98e..d8b854a 100644
--- a/lpvm.c
+++ b/lpvm.c
@@ -146,7 +146,7 @@ static int removedyncap (lua_State *L, Capture *capture,
 ** Opcode interpreter
 */
 const char *match (lua_State *L, const char *o, const char *s, const char *e,
-                   Instruction *op, Capture *capture, int ptop) {
+                   Instruction *op, Capture *capture, int ptop, Labelset *labelf) {
   Stack stackbase[INITBACK];
   Stack *stacklimit = stackbase + INITBACK;
   Stack *stack = stackbase;  /* point to first empty slot in stack */
@@ -154,7 +154,6 @@ const char *match (lua_State *L, const char *o, const char *s, const char *e,
   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 */
-        Labelset labelf;  /* labeled failure */
   stack->p = &giveup; stack->s = s; stack->caplevel = 0; stack++;
   lua_pushlightuserdata(L, stackbase);
   for (;;) {
@@ -184,7 +183,7 @@ const char *match (lua_State *L, const char *o, const char *s, const char *e,
       case IAny: {
         if (s < e) { p++; s++; }
         else {
-                                        labelf = LFAIL; /* labeled failure */
+                                        *labelf = LFAIL; /* labeled failure */
                                         goto fail;
                                 }
         continue;
@@ -197,7 +196,7 @@ const char *match (lua_State *L, const char *o, const char *s, const char *e,
       case IChar: {
         if ((byte)*s == p->i.aux && s < e) { p++; s++; }
         else {
-                                        labelf = LFAIL; /* labeled failure */
+                                        *labelf = LFAIL; /* labeled failure */
                                         goto fail;
                                 }
         continue;
@@ -212,7 +211,7 @@ const char *match (lua_State *L, const char *o, const char *s, const char *e,
         if (testchar((p+1)->buff, c) && s < e)
           { p += CHARSETINSTSIZE; s++; }
         else {
-                                        labelf = LFAIL; /* labeled failure */
+                                        *labelf = LFAIL; /* labeled failure */
                                         goto fail;
                                 }
         continue;
@@ -227,7 +226,7 @@ const char *match (lua_State *L, const char *o, const char *s, const char *e,
       case IBehind: {
         int n = p->i.aux;
         if (n > s - o) {
-                                        labelf = LFAIL; /* labeled failure */
+                                        *labelf = LFAIL; /* labeled failure */
                                         goto fail;
                                 }
         s -= n; p++;
@@ -298,7 +297,7 @@ const char *match (lua_State *L, const char *o, const char *s, const char *e,
         continue;
       }
                         case IThrow: { /* labeled failure */
-                                labelf = (p+1)->labels;
+                                *labelf = (p+1)->labels;
                                 goto fail;
                         }
       case IFailTwice:
@@ -306,14 +305,14 @@ const char *match (lua_State *L, const char *o, const char *s, const char *e,
         stack--;
         /* go through */
       case IFail:
-                                labelf = LFAIL; /* labeled failure */
+                                *labelf = LFAIL; /* labeled failure */
       fail: { /* pattern failed: try to backtrack */
         do {  /* remove pending calls */
           assert(stack > getstackbase(L, ptop));
           s = (--stack)->s;
                                         /*printf("fail (s == NULL => %d), labelf=%d  stack->ls=%d (stack-> == giveup %d)\n",
                  s == NULL, labelf, stack->ls, stack->p == &giveup);*/
-        } while (s == NULL || (!(stack->ls & labelf) && stack->p != &giveup));
+        } while (s == NULL || (!(stack->ls & *labelf) && stack->p != &giveup));
         if (ndyncap > 0)  /* is there matchtime captures? */
           ndyncap -= removedyncap(L, capture, stack->caplevel, captop);
         captop = stack->caplevel;
@@ -330,7 +329,7 @@ const char *match (lua_State *L, const char *o, const char *s, const char *e,
         fr -= rem;  /* 'rem' items were popped from Lua stack */
         res = resdyncaptures(L, fr, s - o, e - o);  /* get result */
         if (res == -1) { /* fail? */ 
-                                        labelf = LFAIL; /* labeled failure */
+                                        *labelf = LFAIL; /* labeled failure */
           goto fail;
                                 }
         s = o + res;  /* else update current position */
diff --git a/lpvm.h b/lpvm.h
index 8024b45..bb485af 100644
--- a/lpvm.h
+++ b/lpvm.h
@@ -55,7 +55,7 @@ typedef union Instruction {
 int getposition (lua_State *L, int t, int i);
 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);
+                   Instruction *op, Capture *capture, int ptop, Labelset *labelf);
 int verify (lua_State *L, Instruction *op, const Instruction *p,
             Instruction *e, int postable, int rule);
 void checkrule (lua_State *L, Instruction *op, int from, int to,