comment changes

[bison.git] / src / reader.c

diff --git a/src/reader.c b/src/reader.c
index fb17b0186c41c6b24fa3bb1712d53aac4d5db15b..95c595ed4e0003aca48655e5097448260371040b 100644 (file)
--- a/src/reader.c
+++ b/src/reader.c
@@ -1,7 +1,7 @@
 /* Input parser for Bison
 
    Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000-2003, 2005-2007,
 /* Input parser for Bison
 
    Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000-2003, 2005-2007,

-   2009-2012 Free Software Foundation, Inc.
+   2009-2013 Free Software Foundation, Inc.

 
    This file is part of Bison, the GNU Compiler Compiler.
 
 
    This file is part of Bison, the GNU Compiler Compiler.
 


@@ -267,9 +267,9 @@ symbol_should_be_used (symbol_list const *s, bool *midrule_warning)
     return true;
   if ((s->midrule && s->midrule->action_props.is_value_used)
       || (s->midrule_parent_rule
     return true;
   if ((s->midrule && s->midrule->action_props.is_value_used)
       || (s->midrule_parent_rule

-          && symbol_list_n_get (s->midrule_parent_rule,
-                                s->midrule_parent_rhs_index)
-               ->action_props.is_value_used))
+          && (symbol_list_n_get (s->midrule_parent_rule,
+                                 s->midrule_parent_rhs_index)
+              ->action_props.is_value_used)))

     {
       *midrule_warning = true;
       return true;
     {
       *midrule_warning = true;
       return true;


@@ -321,18 +321,30 @@ grammar_rule_check (const symbol_list *r)
         bool midrule_warning = false;
         if (!l->action_props.is_value_used
             && symbol_should_be_used (l, &midrule_warning)
         bool midrule_warning = false;
         if (!l->action_props.is_value_used
             && symbol_should_be_used (l, &midrule_warning)

-            /* The default action, $$ = $1, `uses' both.  */
+            /* The default action, $$ = $1, 'uses' both.  */

             && (r->action_props.code || (n != 0 && n != 1)))
           {
             warnings warn_flag = midrule_warning ? Wmidrule_values : Wother;
             if (n)
             && (r->action_props.code || (n != 0 && n != 1)))
           {
             warnings warn_flag = midrule_warning ? Wmidrule_values : Wother;
             if (n)

-              complain (&r->location, warn_flag, _("unused value: $%d"), n);
+              complain (&l->location, warn_flag, _("unused value: $%d"), n);

             else
             else

-              complain (&r->location, warn_flag, _("unset value: $$"));
+              complain (&l->location, warn_flag, _("unset value: $$"));

           }
       }
   }
 
           }
       }
   }
 

+  /* Check that %empty => empty rule.  */
+  if (r->percent_empty_loc.start.file
+      && r->next && r->next->content.sym)
+    complain (&r->percent_empty_loc, complaint,
+              _("%%empty on non-empty rule"));
+
+  /* Check that empty rule => %empty.  */
+  if (!(r->next && r->next->content.sym)
+      && !r->midrule_parent_rule
+      && !r->percent_empty_loc.start.file)
+    complain (&r->location, Wempty_rule, _("empty rule without %%empty"));
+

   /* See comments in grammar_current_rule_prec_set for how POSIX
      mandates this complaint.  It's only for identifiers, so skip
      it for char literals and strings, which are always tokens.  */
   /* See comments in grammar_current_rule_prec_set for how POSIX
      mandates this complaint.  It's only for identifiers, so skip
      it for char literals and strings, which are always tokens.  */


@@ -430,8 +442,26 @@ grammar_current_rule_prec_set (symbol *precsym, location loc)
      token.  */
   symbol_class_set (precsym, token_sym, loc, false);
   if (current_rule->ruleprec)
      token.  */
   symbol_class_set (precsym, token_sym, loc, false);
   if (current_rule->ruleprec)

-    complain (&loc, complaint, _("only one %s allowed per rule"), "%prec");
-  current_rule->ruleprec = precsym;
+    duplicate_directive ("%prec",
+                         current_rule->ruleprec->location, loc);
+  else
+    current_rule->ruleprec = precsym;
+}
+
+/* Set %empty for the current rule. */
+
+void
+grammar_current_rule_empty_set (location loc)
+{
+  /* If %empty is used and -Wno-empty-rule is not, then enable
+     -Wempty-rule.  */
+  if (warning_is_unset (Wempty_rule))
+    warning_argmatch ("empty-rule", 0, 0);
+  if (current_rule->percent_empty_loc.start.file)
+    duplicate_directive ("%empty",
+                         current_rule->percent_empty_loc, loc);
+  else
+    current_rule->percent_empty_loc = loc;

 }
 
 /* Attach dynamic precedence DPREC to the current rule. */
 }
 
 /* Attach dynamic precedence DPREC to the current rule. */


@@ -446,8 +476,13 @@ grammar_current_rule_dprec_set (int dprec, location loc)
     complain (&loc, complaint, _("%s must be followed by positive number"),
               "%dprec");
   else if (current_rule->dprec != 0)
     complain (&loc, complaint, _("%s must be followed by positive number"),
               "%dprec");
   else if (current_rule->dprec != 0)

-    complain (&loc, complaint, _("only one %s allowed per rule"), "%dprec");
-  current_rule->dprec = dprec;
+    duplicate_directive ("%dprec",
+                         current_rule->dprec_location, loc);
+  else
+    {
+      current_rule->dprec = dprec;
+      current_rule->dprec_location = loc;
+    }

 }
 
 /* Attach a merge function NAME with argument type TYPE to current
 }
 
 /* Attach a merge function NAME with argument type TYPE to current


@@ -460,9 +495,13 @@ grammar_current_rule_merge_set (uniqstr name, location loc)
     complain (&loc, Wother, _("%s affects only GLR parsers"),
               "%merge");
   if (current_rule->merger != 0)
     complain (&loc, Wother, _("%s affects only GLR parsers"),
               "%merge");
   if (current_rule->merger != 0)

-    complain (&loc, complaint, _("only one %s allowed per rule"), "%merge");
-  current_rule->merger = get_merge_function (name);
-  current_rule->merger_declaration_location = loc;
+    duplicate_directive ("%merge",
+                         current_rule->merger_declaration_location, loc);
+  else
+    {
+      current_rule->merger = get_merge_function (name);
+      current_rule->merger_declaration_location = loc;
+    }

 }
 
 /* Attach SYM to the current rule.  If needed, move the previous
 }
 
 /* Attach SYM to the current rule.  If needed, move the previous


@@ -477,7 +516,7 @@ grammar_current_rule_symbol_append (symbol *sym, location loc,
     grammar_midrule_action ();
   p = grammar_symbol_append (sym, loc);
   if (name)
     grammar_midrule_action ();
   p = grammar_symbol_append (sym, loc);
   if (name)

-    assign_named_ref(p, name);
+    assign_named_ref (p, name);

   if (sym->status == undeclared || sym->status == used)
     sym->status = needed;
 }
   if (sym->status == undeclared || sym->status == used)
     sym->status = needed;
 }


@@ -507,7 +546,7 @@ packgram (void)
 {
   unsigned int itemno = 0;
   rule_number ruleno = 0;
 {
   unsigned int itemno = 0;
   rule_number ruleno = 0;

-  symbol_list *p = grammar;
+  symbol_list *p;

 
   ritem = xnmalloc (nritems + 1, sizeof *ritem);
 
 
   ritem = xnmalloc (nritems + 1, sizeof *ritem);
 


@@ -516,9 +555,8 @@ packgram (void)
 
   rules = xnmalloc (nrules, sizeof *rules);
 
 
   rules = xnmalloc (nrules, sizeof *rules);
 

-  while (p)
+  for (p = grammar; p; p = p->next)

     {
     {

-      int rule_length = 0;

       symbol *ruleprec = p->ruleprec;
       record_merge_function_type (p->merger, p->content.sym->type_name,
                                   p->merger_declaration_location);
       symbol *ruleprec = p->ruleprec;
       record_merge_function_type (p->merger, p->content.sym->type_name,
                                   p->merger_declaration_location);


@@ -536,14 +574,14 @@ packgram (void)
       rules[ruleno].action_location = p->action_props.location;
       rules[ruleno].is_predicate = p->action_props.is_predicate;
 
       rules[ruleno].action_location = p->action_props.location;
       rules[ruleno].is_predicate = p->action_props.is_predicate;
 

-      /* If the midrule's $$ is set or its $n is used, remove the `$' from the
+      /* If the midrule's $$ 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->action_props.is_value_used
          symbol name so that it's a user-defined symbol so that the default
          %destructor and %printer apply.  */
       if (p->midrule_parent_rule
           && (p->action_props.is_value_used

-              || symbol_list_n_get (p->midrule_parent_rule,
-                                    p->midrule_parent_rhs_index)
-                   ->action_props.is_value_used))
+              || (symbol_list_n_get (p->midrule_parent_rule,
+                                     p->midrule_parent_rhs_index)
+                  ->action_props.is_value_used)))

         p->content.sym->tag += 1;
 
       /* Don't check the generated rule 0.  It has no action, so some rhs
         p->content.sym->tag += 1;
 
       /* Don't check the generated rule 0.  It has no action, so some rhs


@@ -552,24 +590,27 @@ packgram (void)
       if (p != grammar)
         grammar_rule_check (p);
 
       if (p != grammar)
         grammar_rule_check (p);
 

-      for (p = p->next; p && p->content.sym; p = p->next)
-        {
-          ++rule_length;
-
-          /* Don't allow rule_length == INT_MAX, since that might
-             cause confusion with strtol if INT_MAX == LONG_MAX.  */
-          if (rule_length == INT_MAX)
-            complain (&rules[ruleno].location, fatal, _("rule is too long"));
-
-          /* item_number = symbol_number.
-             But the former needs to contain more: negative rule numbers. */
-          ritem[itemno++] =
-            symbol_number_as_item_number (p->content.sym->number);
-          /* A rule gets by default the precedence and associativity
-             of its last token.  */
-          if (p->content.sym->class == token_sym && default_prec)
-            rules[ruleno].prec = p->content.sym;
-        }
+      {
+        size_t rule_length = 0;
+        for (p = p->next; p->content.sym; p = p->next)
+          {
+            ++rule_length;
+
+            /* Don't allow rule_length == INT_MAX, since that might
+               cause confusion with strtol if INT_MAX == LONG_MAX.  */
+            if (rule_length == INT_MAX)
+              complain (&rules[ruleno].location, fatal, _("rule is too long"));
+
+            /* item_number = symbol_number.
+               But the former needs to contain more: negative rule numbers. */
+            ritem[itemno++] =
+              symbol_number_as_item_number (p->content.sym->number);
+            /* A rule gets by default the precedence and associativity
+               of its last token.  */
+            if (p->content.sym->class == token_sym && default_prec)
+              rules[ruleno].prec = p->content.sym;
+          }
+      }

 
       /* If this rule has a %prec,
          the specified symbol's precedence replaces the default.  */
 
       /* If this rule has a %prec,
          the specified symbol's precedence replaces the default.  */


@@ -583,9 +624,6 @@ packgram (void)
       aver (itemno < ITEM_NUMBER_MAX);
       ++ruleno;
       aver (ruleno < RULE_NUMBER_MAX);
       aver (itemno < ITEM_NUMBER_MAX);
       ++ruleno;
       aver (ruleno < RULE_NUMBER_MAX);

-
-      if (p)
-        p = p->next;

     }
 
   aver (itemno == nritems);
     }
 
   aver (itemno == nritems);


@@ -713,7 +751,7 @@ check_and_convert_grammar (void)
   /* Insert the initial rule, whose line is that of the first rule
      (not that of the start symbol):
 
   /* Insert the initial rule, whose line is that of the first rule
      (not that of the start symbol):
 

-     accept: %start EOF.  */
+     $accept: %start $end.  */

   {
     symbol_list *p = symbol_list_sym_new (accept, empty_location);
     p->location = grammar->location;
   {
     symbol_list *p = symbol_list_sym_new (accept, empty_location);
     p->location = grammar->location;


@@ -726,7 +764,8 @@ check_and_convert_grammar (void)
     grammar = p;
   }
 
     grammar = p;
   }
 

-  aver (nsyms <= SYMBOL_NUMBER_MAXIMUM && nsyms == ntokens + nvars);
+  aver (nsyms <= SYMBOL_NUMBER_MAXIMUM);
+  aver (nsyms == ntokens + nvars);

 
   /* Assign the symbols their symbol numbers.  Write #defines for the
      token symbols into FDEFINES if requested.  */
 
   /* Assign the symbols their symbol numbers.  Write #defines for the
      token symbols into FDEFINES if requested.  */


@@ -737,11 +776,11 @@ check_and_convert_grammar (void)
      action type checking.
 
      Before invoking grammar_rule_check (in packgram below) on any rule, make
      action type checking.
 
      Before invoking grammar_rule_check (in packgram below) on any rule, make

-     sure all actions have already been scanned in order to set `used' flags.
+     sure all actions have already been scanned in order to set 'used' flags.

      Otherwise, checking that a midrule's $$ should be set will not always work
      properly because the check must forward-reference the midrule's parent
      Otherwise, checking that a midrule's $$ 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 `$' from any midrule symbol name (also in
+     rule.  For the same reason, all the 'used' flags must be set before
+     checking whether to remove '$' from any midrule symbol name (also in

      packgram).  */
   {
     symbol_list *sym;
      packgram).  */
   {
     symbol_list *sym;