Named symbol references.

[bison.git] / src / reader.c

diff --git a/src/reader.c b/src/reader.c
index 7758c772937fd126966ecc13bdf500b21c88de9d..ec560aa55a266638e2cadf499ce6376b1e608051 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, 2001, 2002, 2003,
-   2005, 2006, 2007 Free Software Foundation, Inc.
+   2005, 2006, 2007, 2009 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -21,6 +21,7 @@
 #include <config.h>
 #include "system.h"
 
+#include <quote.h>
 #include <quotearg.h>
 
 #include "complain.h"
@@ -169,7 +170,7 @@ free_merger_functions (void)
 static symbol_list *grammar_end = NULL;
 
 /* Append SYM to the grammar.  */
-static void
+static symbol_list *
 grammar_symbol_append (symbol *sym, location loc)
 {
   symbol_list *p = symbol_list_sym_new (sym, loc);
@@ -185,6 +186,8 @@ grammar_symbol_append (symbol *sym, location loc)
      part of it.  */
   if (sym)
     ++nritems;
+
+  return p;
 }
 
 /* The rule currently being defined, and the previous rule.
@@ -199,12 +202,29 @@ static symbol_list *previous_rule_end = NULL;
 `----------------------------------------------*/
 
 void
-grammar_current_rule_begin (symbol *lhs, location loc)
+grammar_current_rule_begin (symbol *lhs, location loc,
+                           named_ref *lhs_named_ref)
 {
+  symbol_list* p;
+
   /* Start a new rule and record its lhs.  */
   ++nrules;
   previous_rule_end = grammar_end;
-  grammar_symbol_append (lhs, loc);
+
+  p = grammar_symbol_append (lhs, loc);
+  if (lhs_named_ref)
+    {
+      if (lhs_named_ref->id == lhs->tag)
+       {
+         warn_at (lhs_named_ref->loc,
+                  _("duplicated symbol name for %s ignored"),
+                  quote (lhs->tag));
+         named_ref_free (lhs_named_ref);
+       }
+      else
+       p->named_ref = lhs_named_ref;
+    }
+
   current_rule = grammar_end;
 
   /* Mark the rule's lhs as a nonterminal if not already so.  */
@@ -328,6 +348,9 @@ grammar_midrule_action (void)
   symbol *dummy = dummy_symbol_get (dummy_location);
   symbol_list *midrule = symbol_list_sym_new (dummy, dummy_location);
 
+  /* Remember named_ref of previous action */
+  named_ref *named_ref = current_rule->action_props.named_ref;
+
   /* Make a new rule, whose body is empty, before the current one, so
      that the action just read can belong to it.  */
   ++nrules;
@@ -337,7 +360,7 @@ grammar_midrule_action (void)
   code_props_rule_action_init (&midrule->action_props,
                                current_rule->action_props.code,
                                current_rule->action_props.location,
-                               midrule);
+                               midrule, 0);
   code_props_none_init (&current_rule->action_props);
 
   if (previous_rule_end)
@@ -353,7 +376,7 @@ grammar_midrule_action (void)
 
   /* Insert the dummy nonterminal replacing the midrule action into
      the current rule.  Bind it to its dedicated rule.  */
-  grammar_current_rule_symbol_append (dummy, dummy_location);
+  grammar_current_rule_symbol_append (dummy, dummy_location, named_ref);
   grammar_end->midrule = midrule;
   midrule->midrule_parent_rule = current_rule;
   midrule->midrule_parent_rhs_index = symbol_list_length (current_rule->next);
@@ -402,24 +425,40 @@ grammar_current_rule_merge_set (uniqstr name, location loc)
    action as a mid-rule action.  */
 
 void
-grammar_current_rule_symbol_append (symbol *sym, location loc)
+grammar_current_rule_symbol_append (symbol *sym, location loc,
+                                   named_ref *named_ref)
 {
+  symbol_list *p;
   if (current_rule->action_props.code)
     grammar_midrule_action ();
-  grammar_symbol_append (sym, loc);
+  p = grammar_symbol_append (sym, loc);
+
+  if (named_ref)
+    {
+       if (named_ref->id == sym->tag)
+       {
+         warn_at (named_ref->loc,
+                  _("duplicated symbol name for %s ignored"),
+                  quote (sym->tag));
+         named_ref_free (named_ref);
+       }
+       else
+        p->named_ref = named_ref;
+    }
 }
 
 /* Attach an ACTION to the current rule.  */
 
 void
-grammar_current_rule_action_append (const char *action, location loc)
+grammar_current_rule_action_append (const char *action, location loc,
+                                   named_ref *named_ref)
 {
   if (current_rule->action_props.code)
     grammar_midrule_action ();
   /* After all symbol declarations have been parsed, packgram invokes
      code_props_translate_code.  */
   code_props_rule_action_init (&current_rule->action_props, action, loc,
-                               current_rule);
+                               current_rule, named_ref);
 }
 
 \f
@@ -555,6 +594,31 @@ reader (void)
   gram_scanner_initialize ();
   gram_parse ();
 
+  /* Set front-end %define variable defaults.  */
+  muscle_percent_define_default ("lr.keep-unreachable-states", "false");
+  {
+    char *lr_type;
+    /* IELR would be a better default, but LALR is historically the
+       default.  */
+    muscle_percent_define_default ("lr.type", "LALR");
+    lr_type = muscle_percent_define_get ("lr.type");
+    if (0 != strcmp (lr_type, "canonical LR"))
+      muscle_percent_define_default ("lr.default-reductions", "all");
+    else
+      muscle_percent_define_default ("lr.default-reductions", "accepting");
+    free (lr_type);
+  }
+
+  /* Check front-end %define variables.  */
+  {
+    static char const * const values[] = {
+      "lr.type", "LALR", "IELR", "canonical LR", NULL,
+      "lr.default-reductions", "all", "consistent", "accepting", NULL,
+      NULL
+    };
+    muscle_percent_define_check_values (values);
+  }
+
   if (! complaint_issued)
     check_and_convert_grammar ();