1 files changed, 49 insertions, 52 deletions

diff --git a/src/prc1/parse.c b/src/prc1/parse.c
index 1c3aba2..db4bdcc 100644
--- a/src/prc1/parse.c
+++ b/src/prc1/parse.c
@@ -4,6 +4,7 @@
 #include "fn.h"
 #include "lex.h"
 #include "lit.h"
+#include "sym.h"
 #include "prv.h"
 #include "type.h"
 #include <stddef.h>
@@ -45,6 +46,29 @@ static const char *expected(const struct step *s)
     return s->id ? s->id : tmap[s->type];
 }
 
+static int unexpected(const struct tk *tk)
+{
+    switch (tk->type)
+    {
+    case LIT:
+        errloc(tk, "unexpected literal \"%s\"", tk->s);
+        break;
+    case NUM:
+        errloc(tk, "unexpected number %s", tk->s);
+        break;
+    case ID:
+        errloc(tk, "unexpected %s \"%s\"", kw(tk->s) ?
+            "keyword" : "identifier", tk->s);
+        break;
+    case ANY:
+    case UNDEF:
+        errloc(tk, "%s: unreachable", __func__);
+        break;
+    }
+
+    return -1;
+}
+
 static int iter(const struct lex *l, struct prv *p)
 {
     struct pos *pos = p->pos;
@@ -52,41 +76,28 @@ static int iter(const struct lex *l, struct prv *p)
     const struct tk *tk = p->tk;
 
     if (!pos)
-        return p->entry(l, p);
+    {
+        if (lex_eof(l, p->stk))
+            return 0;
+
+        return p->entry(l, p) ? -1 : 1;
+    }
 
     pos = &p->pos[p->i];
 
+    /* no rules have matched the current token */
     if (!(s = pos->step))
     {
-        if (lex_eof(l, tk))
-            return 0;
-        else if (p->n > 1)
+        if (p->n > 1)
             return pop(l, p) ? -1 : 1;
+        else if (lex_eof(l, tk))
+            return 0;
         else
-        {
-            switch (tk->type)
-            {
-                case LIT:
-                    errloc(tk, "unexpected literal \"%s\"", tk->s);
-                    break;
-                case NUM:
-                    errloc(tk, "unexpected number %s", tk->s);
-                    break;
-                case ID:
-                    errloc(tk, "unexpected %s %s", kw(tk->s) ?
-                        "keyword" : "identifier", tk->s);
-                    break;
-                case ANY:
-                case UNDEF:
-                    errloc(tk, "%s: unreachable", __func__);
-                    break;
-            }
-
-            return -1;
-        }
+            return unexpected(tk);
     }
     else if (lex_eof(l, tk))
     {
+        /* pop all remaining rules */
         if (p->stk == p->tk)
             return pop(l, p) ? -1 : 1;
         else if (s->type)
@@ -101,41 +112,26 @@ static int iter(const struct lex *l, struct prv *p)
         }
     }
 
+    /* rule has been completely parsed, execute */
     if (!s->type)
-        return pos->seq->fn(l, p);
-    else if ((s->type == ID || s->type == ANY) && !s->id && kw(tk->s)
-        && !s->chain)
-    {
-        if (tk != p->stk || !p->n)
-        {
-            errloc(tk, "unexpected keyword %s", tk->s);
-            return -1;
-        }
-        else if (pop(l, p))
-            return -1;
-
-        pos = &p->pos[p->i];
-    }
-    else if ((s->type != tk->type && s->type != ANY)
+        return pos->seq->fn(l, p) ? -1 : 1;
+    /* skip if: */
+    else if (
+        /* rule type does not match */
+        s->type != tk->type
+        /* ID does not match */
         || (s->type == ID && s->id && strcmp(s->id, tk->s))
-        || (s->type == ID && kw(tk->s) && s->chain))
+        /* rule does not expect a keyword */
+        || (s->type == ID && !s->id && kw(tk->s)))
     {
+        /* move to next rule on no match */
         pos->step = (++pos->seq)->steps;
         p->tk = p->stk;
     }
+    /* move to next step */
     else
     {
-        const struct tk *next = tk + 1;
-
-        if (!s->chain)
-            pos->step++;
-        else if (!lex_eof(l, next))
-        {
-            if (s->chain && kw(next->s))
-                pos->step++;
-        }
-        else
-            pos->step++;
+        pos->step++;
 
         if (!lex_eof(l, p->tk))
             p->tk++;
@@ -146,6 +142,7 @@ static int iter(const struct lex *l, struct prv *p)
 
 static void free_prv(struct prv *p)
 {
+    sym_free(p->s);
     free(p->tdc);
     free(p->pos);
 }