lr.default-reductions: rename "full" value to "most".

[bison.git] / src / tables.c

diff --git a/src/tables.c b/src/tables.c
index e22b0892f320e59e0e2ef87ea08aab4fe8041c48..8f459cfea3f1c0895b5cf4327a6e7117458c0244 100644 (file)
--- a/src/tables.c
+++ b/src/tables.c
@@ -1,7 +1,7 @@
 /* Output the generated parsing program for Bison.
 
-   Copyright (C) 1984, 1986, 1989, 1992, 2000, 2001, 2002, 2003, 2004,
-   2005, 2006 Free Software Foundation, Inc.
+   Copyright (C) 1984, 1986, 1989, 1992, 2000-2006, 2009-2011 Free
+   Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -30,6 +30,7 @@
 #include "getargs.h"
 #include "gram.h"
 #include "lalr.h"
+#include "muscle-tab.h"
 #include "reader.h"
 #include "symtab.h"
 #include "tables.h"
@@ -125,7 +126,7 @@ static int table_size = 32768;
 base_number *table;
 base_number *check;
 /* The value used in TABLE to denote explicit syntax errors
-   (%nonassoc), a negative infinite.  First defaults to ACTION_NUMBER_MININUM,
+   (%nonassoc), a negative infinite.  First defaults to ACTION_NUMBER_MINIMUM,
    but in order to keep small tables, renumbered as TABLE_ERROR, which
    is the smallest (non error) value minus 1.  */
 base_number table_ninf = 0;
@@ -239,7 +240,7 @@ static rule *
 action_row (state *s)
 {
   int i;
-  rule *default_rule = NULL;
+  rule *default_reduction = NULL;
   reductions *reds = s->reductions;
   transitions *trans = s->transitions;
   errs *errp = s->errs;
@@ -303,13 +304,24 @@ action_row (state *s)
       actrow[sym->number] = ACTION_NUMBER_MINIMUM;
     }
 
+  /* Turn off default reductions where requested by the user.  See
+     state_lookahead_tokens_count in lalr.c to understand when states are
+     labeled as consistent.  */
+  {
+    char *default_reductions =
+      muscle_percent_define_get ("lr.default-reductions");
+    if (0 != strcmp (default_reductions, "most") && !s->consistent)
+      nodefault = true;
+    free (default_reductions);
+  }
+
   /* Now find the most common reduction and make it the default action
      for this state.  */
 
   if (reds->num >= 1 && !nodefault)
     {
       if (s->consistent)
-       default_rule = reds->rules[0];
+       default_reduction = reds->rules[0];
       else
        {
          int max = 0;
@@ -326,7 +338,7 @@ action_row (state *s)
              if (count > max)
                {
                  max = count;
-                 default_rule = r;
+                 default_reduction = r;
                }
            }
 
@@ -340,17 +352,18 @@ action_row (state *s)
            {
              int j;
              for (j = 0; j < ntokens; j++)
-               if (actrow[j] == rule_number_as_item_number (default_rule->number)
+               if (actrow[j]
+                    == rule_number_as_item_number (default_reduction->number)
                    && ! (nondeterministic_parser && conflrow[j]))
                  actrow[j] = 0;
            }
        }
     }
 
-  /* If have no default rule, the default is an error.
+  /* If have no default reduction, the default is an error.
      So replace any action which says "error" with "use default".  */
 
-  if (!default_rule)
+  if (!default_reduction)
     for (i = 0; i < ntokens; i++)
       if (actrow[i] == ACTION_NUMBER_MINIMUM)
        actrow[i] = 0;
@@ -358,7 +371,7 @@ action_row (state *s)
   if (conflicted)
     conflict_row (s);
 
-  return default_rule;
+  return default_reduction;
 }
 
 
@@ -439,8 +452,8 @@ token_actions (void)
 
   for (i = 0; i < nstates; ++i)
     {
-      rule *default_rule = action_row (states[i]);
-      yydefact[i] = default_rule ? default_rule->number + 1 : 0;
+      rule *default_reduction = action_row (states[i]);
+      yydefact[i] = default_reduction ? default_reduction->number + 1 : 0;
       save_row (i);
 
       /* Now that the parser was computed, we can find which rules are