A more precise safety after a term.

diff --git a/util/LLgen/src/compute.c b/util/LLgen/src/compute.c
index 04a1e36..9c2c66d 100644 (file)
--- a/util/LLgen/src/compute.c
+++ b/util/LLgen/src/compute.c
@@ -713,7 +713,7 @@ do_safes(p,safe) register p_gram p; {
                        p++;
                        continue;
                  case TERMINAL:
-                       retval = 2;
+                       safe = NOSCANDONE;
                        break;
                  case TERM : {
                        register p_term q;
@@ -727,7 +727,7 @@ do_safes(p,safe) register p_gram p; {
                        if (retval == 2 && (!(q->t_flags & TNOSCAN))) {
                                q->t_flags |= TNOSCAN;
                        }
-                       if (rep != FIXED || retval == 0) retval = 1;
+                       safe = t_after(rep, i, q->t_flags & TNOSCAN);
                        break; }
                  case ALTERNATION : {
                        register p_link l;
@@ -748,27 +748,30 @@ do_safes(p,safe) register p_gram p; {
                        return retval; }
                  case NONTERM : {
                        register p_nont n;
-                       int nsafe;
+                       int nsafe, osafe;;
 
                        n = &nonterms[g_getnont(p)];
                        nsafe = getntsafe(n->n_flags);
-                       if (!(n->n_flags & NNOSCAN)) retval = 1;
-                       else retval = 2;
-                       if (safe == nsafe) break;
+                       osafe = safe;
+                       if (!(n->n_flags & NNOSCAN)) {
+                               safe = SCANDONE;
+                       }
+                       else safe = NOSCANDONE;
+                       if (osafe == nsafe) break;
                        if (nsafe == NOSAFETY) {
                                change = 1;
-                               setntsafe(&(n->n_flags), safe);
+                               setntsafe(&(n->n_flags), osafe);
                                break;
                        }
-                       if (safe == NOSCANDONE || nsafe == NOSCANDONE) {
+                       if (osafe == NOSCANDONE || nsafe == NOSCANDONE) {
                                if (nsafe != SCANDONE) {
                                        change = 1;
                                        setntsafe(&(n->n_flags), SCANDONE);
                                }
                                break;
                        }
-                       if (safe > nsafe) {
-                               setntsafe(&(n->n_flags), safe);
+                       if (osafe > nsafe) {
+                               setntsafe(&(n->n_flags), osafe);
                                change = 1;
                        }
                        break; }
@@ -776,8 +779,8 @@ do_safes(p,safe) register p_gram p; {
                        return retval;
                }
                p++;
-               if (retval == 1) safe = SCANDONE;
-               else safe = NOSCANDONE;
+               if (safe == NOSCANDONE) retval = 2;
+               else retval = 1;
        }
 }
 
@@ -810,3 +813,11 @@ t_safety(rep, count, persistent, safety) {
        }
        /* NOTREACHED */
 }
+
+t_after(rep, count, noscan) {
+       if (count == 0 && (rep == STAR || rep == PLUS)) {
+               return SAFESCANDONE;
+       }
+       if (rep == FIXED && noscan) return NOSCANDONE;
+       return SCANDONE;
+}

diff --git a/util/LLgen/src/gencode.c b/util/LLgen/src/gencode.c
index 260f776..e3fe33d 100644 (file)
--- a/util/LLgen/src/gencode.c
+++ b/util/LLgen/src/gencode.c
@@ -761,8 +761,7 @@ codeforterm(q,safety,toplevel) register p_term q; {
                        fputs(c_close, f);/* Close Register ... */
                }
        }
-       if (rep != FIXED || !noscan) return SCANDONE;
-       return NOSCANDONE;
+       return t_after(rep, i, noscan);
 }
 
 STATIC