Fix bug such that the first pushed token's value and location are

[bison.git] / src / reader.c

diff --git a/src/reader.c b/src/reader.c
index 4cc6f7b1c04ecb51629bed87fa47c9f3c702458d..7b7692328bdc558d6b6aea82b813cc2a614e66e1 100644 (file)
--- a/src/reader.c
+++ b/src/reader.c
@@ -22,7 +22,6 @@
 
 #include <config.h>
 #include "system.h"
-#include <assert.h>
 
 #include <quotearg.h>
 
@@ -73,7 +72,7 @@ grammar_start_symbol_set (symbol *sym, location loc)
 
 /*---------------------------------------------------------------------.
 | There are two prologues: one before the first %union and one after.  |
-|  Augment the one specified by POST.                                  |
+| Augment the one specified by POST.                                   |
 `---------------------------------------------------------------------*/
 
 void
@@ -148,7 +147,7 @@ record_merge_function_type (int merger, uniqstr type, location declaration_loc)
        merge_function != NULL && merger_find != merger;
        merge_function = merge_function->next)
     merger_find += 1;
-  assert (merge_function != NULL && merger_find == merger);
+  aver (merge_function != NULL && merger_find == merger);
   if (merge_function->type != NULL && !UNIQSTR_EQ (merge_function->type, type))
     {
       complain_at (declaration_loc,
@@ -244,16 +243,24 @@ grammar_current_rule_begin (symbol *lhs, location loc)
 
 
 /*----------------------------------------------------------------------.
-| A symbol should be used if it has a destructor, or if it is a         |
-| mid-rule symbol (i.e., the generated LHS replacing a mid-rule         |
-| action) that was assigned to, as in "exp: { $$ = 1; } { $$ = $1; }".  |
+| A symbol should be used if either:                                    |
+|   1. It has a destructor.                                             |
+|   2. --warnings=midrule-values and the symbol is a mid-rule symbol    |
+|      (i.e., the generated LHS replacing a mid-rule action) that was   |
+|      assigned to or used, as in "exp: { $$ = 1; } { $$ = $1; }".      |
 `----------------------------------------------------------------------*/
 
 static bool
 symbol_should_be_used (symbol_list const *s)
 {
-  return (symbol_destructor_get (s->content.sym)
-         || (s->midrule && s->midrule->used));
+  if (symbol_destructor_get (s->content.sym))
+    return true;
+  if (warnings_flag & warnings_midrule_values)
+    return ((s->midrule && s->midrule->used)
+           || (s->midrule_parent_rule
+               && symbol_list_n_get (s->midrule_parent_rule,
+                                     s->midrule_parent_rhs_index)->used));
+  return false;
 }
 
 /*----------------------------------------------------------------.
@@ -380,6 +387,7 @@ grammar_midrule_action (void)
 void
 grammar_current_rule_prec_set (symbol *precsym, location loc)
 {
+  symbol_class_set (precsym, token_sym, loc, false);
   if (current_rule->ruleprec)
     complain_at (loc, _("only one %s allowed per rule"), "%prec");
   current_rule->ruleprec = precsym;
@@ -457,6 +465,21 @@ packgram (void)
 
   rules = xnmalloc (nrules, sizeof *rules);
 
+  /* Before invoking grammar_rule_check on any rule, make sure all actions have
+     already been scanned in order to set `used' flags.  Otherwise, checking
+     that a midrule's $$ should be set will not always work properly because
+     the check must forward-reference the midrule's parent rule.  For the same
+     reason, all the `used' flags must be set before checking whether to remove
+     `$' from any midrule symbol name.  */
+  while (p)
+    {
+      if (p->action)
+        p->action = translate_rule_action (p);
+      if (p)
+       p = p->next;
+    }
+
+  p = grammar;
   while (p)
     {
       int rule_length = 0;
@@ -473,14 +496,18 @@ packgram (void)
       rules[ruleno].precsym = NULL;
       rules[ruleno].location = p->location;
       rules[ruleno].useful = true;
-      rules[ruleno].action = p->action ? translate_rule_action (p) : NULL;
+      rules[ruleno].action = p->action;
       rules[ruleno].action_location = p->action_location;
 
-      /* If this rule contains midrules, rest assured that
-        grammar_midrule_action inserted the midrules into grammar before this
-        rule.  Thus, the midrule actions have already been scanned in order to
-        set `used' flags for this rule's rhs, so grammar_rule_check will work
-        properly.  */
+      /* If the midrule's $$ is set or its $n is used, remove the `$' from the
+        symbol name so that it's a user-defined symbol so that the default
+        %destructor and %printer apply.  */
+      if (p->midrule_parent_rule
+          && (p->used
+             || symbol_list_n_get (p->midrule_parent_rule,
+                                   p->midrule_parent_rhs_index)->used))
+       p->content.sym->tag += 1;
+
       /* Don't check the generated rule 0.  It has no action, so some rhs
         symbols may appear unused, but the parsing algorithm ensures that
         %destructor's are invoked appropriately.  */
@@ -515,15 +542,15 @@ packgram (void)
        }
       /* An item ends by the rule number (negated).  */
       ritem[itemno++] = rule_number_as_item_number (ruleno);
-      assert (itemno < ITEM_NUMBER_MAX);
+      aver (itemno < ITEM_NUMBER_MAX);
       ++ruleno;
-      assert (ruleno < RULE_NUMBER_MAX);
+      aver (ruleno < RULE_NUMBER_MAX);
 
       if (p)
        p = p->next;
     }
 
-  assert (itemno == nritems);
+  aver (itemno == nritems);
 
   if (trace_flag & trace_sets)
     ritem_print (stderr);
@@ -614,7 +641,7 @@ check_and_convert_grammar (void)
                node = node->next)
             ;
         }
-      assert (node != NULL);
+      aver (node != NULL);
       grammar_start_symbol_set (node->content.sym,
                                 node->content.sym->location);
     }
@@ -635,7 +662,7 @@ check_and_convert_grammar (void)
     grammar = p;
   }
 
-  assert (nsyms <= SYMBOL_NUMBER_MAXIMUM && nsyms == ntokens + nvars);
+  aver (nsyms <= SYMBOL_NUMBER_MAXIMUM && nsyms == ntokens + nvars);
 
   /* Assign the symbols their symbol numbers.  Write #defines for the
      token symbols into FDEFINES if requested.  */
@@ -645,5 +672,5 @@ check_and_convert_grammar (void)
   packgram ();
 
   /* The grammar as a symbol_list is no longer needed. */
-  LIST_FREE (symbol_list, grammar);
+  symbol_list_free (grammar);
 }