New experimental feature: display the lookaheads in the report and

[bison.git] / src / print.c

diff --git a/src/print.c b/src/print.c
index ec5a12ad8fa60a37f0d3b80c6f2cc1a8d3903919..cfc047f17e73462752fa58c5e4639b58672c1359 100644 (file)
--- a/src/print.c
+++ b/src/print.c
@@ -105,6 +105,32 @@ print_core (FILE *out, state_t *state)
          for (/* Nothing */; *sp >= 0; ++sp)
            fprintf (out, " %s", escape (symbols[*sp]->tag));
 
+         /* Experimental feature: display the lookaheads. */
+         if (trace_flag && state->nlookaheads)
+           {
+             int j, k;
+             int nlookaheads = 0;
+             /* Look for lookaheads corresponding to this rule. */
+             for (j = 0; j < state->nlookaheads; ++j)
+               for (k = 0; k < ntokens; ++k)
+                 if (bitset_test (LA[state->lookaheadsp + j], k)
+                     && LArule[state->lookaheadsp + j]->number == rule)
+                   nlookaheads++;
+             if (nlookaheads)
+               {
+                 fprintf (out, "  [");
+                 for (j = 0; j < state->nlookaheads; ++j)
+                   for (k = 0; k < ntokens; ++k)
+                     if (bitset_test (LA[state->lookaheadsp + j], k)
+                         && LArule[state->lookaheadsp + j]->number == rule)
+                       fprintf (out, "%s%s",
+                                quotearg_style (escape_quoting_style,
+                                                symbols[k]->tag),
+                                --nlookaheads ? ", " : "");
+                 fprintf (out, "]");
+               }
+           }
+
          fprintf (out, _("   (rule %d)"), rule - 1);
          fputc ('\n', out);
        }