tests: remove quote magic from the bison test wrapper.

[bison.git] / src / reader.c

diff --git a/src/reader.c b/src/reader.c
index 4bbed58f56ed15fadb4ec7a6d041c4380d9c0696..2e0aa5ee81449787635c1af365d39f63cb2472da 100644 (file)
--- a/src/reader.c
+++ b/src/reader.c
@@ -1,42 +1,41 @@
 /* Input parser for Bison
 
 /* Input parser for Bison
 

-   Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000, 2001, 2002, 2003,
-   2005, 2006, 2007 Free Software Foundation, Inc.
+   Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000-2003, 2005-2007,
+   2009-2012 Free Software Foundation, Inc.

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

-   Bison is free software; you can redistribute it and/or modify
+   This program is free software: you can redistribute it and/or modify

    it under the terms of the GNU General Public License as published by
    it under the terms of the GNU General Public License as published by

-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.

 
 

-   Bison is distributed in the hope that it will be useful,
+   This program is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License

-   along with Bison; see the file COPYING.  If not, write to
-   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
-   Boston, MA 02110-1301, USA.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

 
 #include <config.h>
 #include "system.h"
 
 
 #include <config.h>
 #include "system.h"
 

-#include <quotearg.h>
+#include <quote.h>

 
 #include "complain.h"
 #include "conflicts.h"
 #include "files.h"
 #include "getargs.h"
 #include "gram.h"
 
 #include "complain.h"
 #include "conflicts.h"
 #include "files.h"
 #include "getargs.h"
 #include "gram.h"

-#include "muscle_tab.h"
+#include "muscle-tab.h"

 #include "reader.h"
 #include "symlist.h"
 #include "symtab.h"
 #include "scan-gram.h"
 #include "scan-code.h"
 
 #include "reader.h"
 #include "symlist.h"
 #include "symtab.h"
 #include "scan-gram.h"
 #include "scan-code.h"
 

+static void prepare_percent_define_front_end_variables (void);

 static void check_and_convert_grammar (void);
 
 static symbol_list *grammar = NULL;
 static void check_and_convert_grammar (void);
 
 static symbol_list *grammar = NULL;


@@ -69,27 +68,6 @@ 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.                                   |
-`---------------------------------------------------------------------*/
-
-void
-prologue_augment (const char *prologue, location loc, bool post)
-{
-  struct obstack *oout =
-    !post ? &pre_prologue_obstack : &post_prologue_obstack;
-
-  obstack_fgrow1 (oout, "]b4_syncline(%d, [[", loc.start.line);
-  /* FIXME: Protection of M4 characters missing here.  See
-     output.c:escaped_output.  */
-  MUSCLE_OBSTACK_SGROW (oout,
-                       quotearg_style (c_quoting_style, loc.start.file));
-  obstack_sgrow (oout, "]])[\n");
-  obstack_sgrow (oout, prologue);
-}
-

 \f
 
 /*------------------------------------------------------------------------.
 \f
 
 /*------------------------------------------------------------------------.


@@ -116,7 +94,7 @@ get_merge_function (uniqstr name)
       syms->next = xmalloc (sizeof syms->next[0]);
       syms->next->name = uniqstr_new (name);
       /* After all symbol type declarations have been parsed, packgram invokes
       syms->next = xmalloc (sizeof syms->next[0]);
       syms->next->name = uniqstr_new (name);
       /* After all symbol type declarations have been parsed, packgram invokes

-        record_merge_function_type to set the type.  */
+         record_merge_function_type to set the type.  */

       syms->next->type = NULL;
       syms->next->next = NULL;
       merge_functions = head.next;
       syms->next->type = NULL;
       syms->next->next = NULL;
       merge_functions = head.next;


@@ -151,17 +129,17 @@ record_merge_function_type (int merger, uniqstr type, location declaration_loc)
   if (merge_function->type != NULL && !UNIQSTR_EQ (merge_function->type, type))
     {
       complain_at (declaration_loc,
   if (merge_function->type != NULL && !UNIQSTR_EQ (merge_function->type, type))
     {
       complain_at (declaration_loc,

-                  _("result type clash on merge function `%s': <%s> != <%s>"),
-                  merge_function->name, type, merge_function->type);
+                   _("result type clash on merge function %s: <%s> != <%s>"),
+                   quote (merge_function->name), type, merge_function->type);

       complain_at (merge_function->type_declaration_location,
       complain_at (merge_function->type_declaration_location,

-                  _("previous declaration"));
+                   _("previous declaration"));

     }
   merge_function->type = uniqstr_new (type);
   merge_function->type_declaration_location = declaration_loc;
 }
 
 /*--------------------------------------.
     }
   merge_function->type = uniqstr_new (type);
   merge_function->type_declaration_location = declaration_loc;
 }
 
 /*--------------------------------------.

-| Free all merge-function definitions. |
+| Free all merge-function definitions.  |

 `--------------------------------------*/
 
 void
 `--------------------------------------*/
 
 void


@@ -192,7 +170,7 @@ free_merger_functions (void)
 static symbol_list *grammar_end = NULL;
 
 /* Append SYM to the grammar.  */
 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);
 grammar_symbol_append (symbol *sym, location loc)
 {
   symbol_list *p = symbol_list_sym_new (sym, loc);


@@ -208,8 +186,27 @@ grammar_symbol_append (symbol *sym, location loc)
      part of it.  */
   if (sym)
     ++nritems;
      part of it.  */
   if (sym)
     ++nritems;

+
+  return p;

 }
 
 }
 

+static void
+assign_named_ref (symbol_list *p, named_ref *name)
+{
+  symbol *sym = p->content.sym;
+
+  if (name->id == sym->tag)
+    {
+      warn_at (name->loc,
+               _("duplicated symbol name for %s ignored"),
+               quote (sym->tag));
+      named_ref_free (name);
+    }
+  else
+    p->named_ref = name;
+}
+
+

 /* The rule currently being defined, and the previous rule.
    CURRENT_RULE points to the first LHS of the current rule, while
    PREVIOUS_RULE_END points to the *end* of the previous rule (NULL).  */
 /* The rule currently being defined, and the previous rule.
    CURRENT_RULE points to the first LHS of the current rule, while
    PREVIOUS_RULE_END points to the *end* of the previous rule (NULL).  */


@@ -222,12 +219,19 @@ static symbol_list *previous_rule_end = NULL;
 `----------------------------------------------*/
 
 void
 `----------------------------------------------*/
 
 void

-grammar_current_rule_begin (symbol *lhs, location loc)
+grammar_current_rule_begin (symbol *lhs, location loc,
+                            named_ref *lhs_name)

 {
 {

+  symbol_list* p;
+

   /* Start a new rule and record its lhs.  */
   ++nrules;
   previous_rule_end = grammar_end;
   /* 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_name)
+    assign_named_ref (p, named_ref_copy (lhs_name));
+

   current_rule = grammar_end;
 
   /* Mark the rule's lhs as a nonterminal if not already so.  */
   current_rule = grammar_end;
 
   /* Mark the rule's lhs as a nonterminal if not already so.  */


@@ -245,22 +249,25 @@ grammar_current_rule_begin (symbol *lhs, location loc)
 /*----------------------------------------------------------------------.
 | A symbol should be used if either:                                    |
 |   1. It has a destructor.                                             |
 /*----------------------------------------------------------------------.
 | 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; }".      |
+|   2. 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
 `----------------------------------------------------------------------*/
 
 static bool

-symbol_should_be_used (symbol_list const *s)
+symbol_should_be_used (symbol_list const *s, bool *midrule_warning)

 {
 {

-  if (symbol_destructor_get (s->content.sym))
+  if (symbol_destructor_get (s->content.sym)->code)

     return true;
     return true;

-  if (warnings_flag & warnings_midrule_values)
-    return ((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));
+  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))
+    {
+      *midrule_warning = true;
+      return true;
+    }

   return false;
 }
 
   return false;
 }
 


@@ -284,19 +291,19 @@ grammar_rule_check (const symbol_list *r)
       symbol *first_rhs = r->next->content.sym;
       /* If $$ is being set in default way, report if any type mismatch.  */
       if (first_rhs)
       symbol *first_rhs = r->next->content.sym;
       /* If $$ is being set in default way, report if any type mismatch.  */
       if (first_rhs)

-       {
-         char const *lhs_type = r->content.sym->type_name;
-         const char *rhs_type =
-           first_rhs->type_name ? first_rhs->type_name : "";
-         if (!UNIQSTR_EQ (lhs_type, rhs_type))
-           warn_at (r->location,
-                    _("type clash on default action: <%s> != <%s>"),
-                    lhs_type, rhs_type);
-       }
+        {
+          char const *lhs_type = r->content.sym->type_name;
+          const char *rhs_type =
+            first_rhs->type_name ? first_rhs->type_name : "";
+          if (!UNIQSTR_EQ (lhs_type, rhs_type))
+            warn_at (r->location,
+                     _("type clash on default action: <%s> != <%s>"),
+                     lhs_type, rhs_type);
+        }

       /* Warn if there is no default for $$ but we need one.  */
       else
       /* Warn if there is no default for $$ but we need one.  */
       else

-       warn_at (r->location,
-                _("empty rule for typed nonterminal, and no action"));
+        warn_at (r->location,
+                 _("empty rule for typed nonterminal, and no action"));

     }
 
   /* Check that symbol values that should be used are in fact used.  */
     }
 
   /* Check that symbol values that should be used are in fact used.  */


@@ -304,17 +311,31 @@ grammar_rule_check (const symbol_list *r)
     symbol_list const *l = r;
     int n = 0;
     for (; l && l->content.sym; l = l->next, ++n)
     symbol_list const *l = r;
     int n = 0;
     for (; l && l->content.sym; l = l->next, ++n)

-      if (! (l->action_props.is_value_used
-            || !symbol_should_be_used (l)
-            /* The default action, $$ = $1, `uses' both.  */
-            || (!r->action_props.code && (n == 0 || n == 1))))
-       {
-         if (n)
-           warn_at (r->location, _("unused value: $%d"), n);
-         else
-           warn_at (r->location, _("unset value: $$"));
-       }
+      {
+        bool midrule_warning = false;
+        if (!l->action_props.is_value_used
+            && symbol_should_be_used (l, &midrule_warning)
+            /* The default action, $$ = $1, `uses' both.  */
+            && (r->action_props.code || (n != 0 && n != 1)))
+          {
+            void (*warn_at_ptr)(location, char const*, ...) =
+              midrule_warning ? midrule_value_at : warn_at;
+            if (n)
+              warn_at_ptr (r->location, _("unused value: $%d"), n);
+            else
+              warn_at_ptr (r->location, _("unset value: $$"));
+          }
+      }

   }
   }

+
+  /* 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.  */
+  if (r->ruleprec
+      && r->ruleprec->tag[0] != '\'' && r->ruleprec->tag[0] != '"'
+      && !r->ruleprec->declared && !r->ruleprec->prec)
+    warn_at (r->location, _("token for %%prec is not defined: %s"),
+             r->ruleprec->tag);

 }
 
 
 }
 
 


@@ -351,6 +372,9 @@ grammar_midrule_action (void)
   symbol *dummy = dummy_symbol_get (dummy_location);
   symbol_list *midrule = symbol_list_sym_new (dummy, dummy_location);
 
   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 *action_name = 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;
   /* Make a new rule, whose body is empty, before the current one, so
      that the action just read can belong to it.  */
   ++nrules;


@@ -360,7 +384,8 @@ grammar_midrule_action (void)
   code_props_rule_action_init (&midrule->action_props,
                                current_rule->action_props.code,
                                current_rule->action_props.location,
   code_props_rule_action_init (&midrule->action_props,
                                current_rule->action_props.code,
                                current_rule->action_props.location,

-                               midrule);
+                               midrule, 0,
+                               current_rule->action_props.is_predicate);

   code_props_none_init (&current_rule->action_props);
 
   if (previous_rule_end)
   code_props_none_init (&current_rule->action_props);
 
   if (previous_rule_end)


@@ -376,7 +401,8 @@ grammar_midrule_action (void)
 
   /* Insert the dummy nonterminal replacing the midrule action into
      the current rule.  Bind it to its dedicated rule.  */
 
   /* 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,
+                                      action_name);

   grammar_end->midrule = midrule;
   midrule->midrule_parent_rule = current_rule;
   midrule->midrule_parent_rhs_index = symbol_list_length (current_rule->next);
   grammar_end->midrule = midrule;
   midrule->midrule_parent_rule = current_rule;
   midrule->midrule_parent_rhs_index = symbol_list_length (current_rule->next);


@@ -387,6 +413,16 @@ grammar_midrule_action (void)
 void
 grammar_current_rule_prec_set (symbol *precsym, location loc)
 {
 void
 grammar_current_rule_prec_set (symbol *precsym, location loc)
 {

+  /* POSIX says that any identifier is a nonterminal if it does not
+     appear on the LHS of a grammar rule and is not defined by %token
+     or by one of the directives that assigns precedence to a token.  We
+     ignore this here because the only kind of identifier that POSIX
+     allows to follow a %prec is a token and because assuming it's a
+     token now can produce more logical error messages.  Nevertheless,
+     grammar_rule_check does obey what we believe is the real intent of
+     POSIX here: that an error be reported for any identifier that
+     appears after %prec but that is not defined separately as a
+     token.  */

   symbol_class_set (precsym, token_sym, loc, false);
   if (current_rule->ruleprec)
     complain_at (loc, _("only one %s allowed per rule"), "%prec");
   symbol_class_set (precsym, token_sym, loc, false);
   if (current_rule->ruleprec)
     complain_at (loc, _("only one %s allowed per rule"), "%prec");


@@ -425,24 +461,29 @@ grammar_current_rule_merge_set (uniqstr name, location loc)
    action as a mid-rule action.  */
 
 void
    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 *name)

 {
 {

+  symbol_list *p;

   if (current_rule->action_props.code)
     grammar_midrule_action ();
   if (current_rule->action_props.code)
     grammar_midrule_action ();

-  grammar_symbol_append (sym, loc);
+  p = grammar_symbol_append (sym, loc);
+  if (name)
+    assign_named_ref(p, name);

 }
 
 /* Attach an ACTION to the current rule.  */
 
 void
 }
 
 /* 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 *name, bool is_predicate)

 {
   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,
 {
   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, name, is_predicate);

 }
 
 \f
 }
 
 \f


@@ -465,26 +506,12 @@ packgram (void)
 
   rules = xnmalloc (nrules, sizeof *rules);
 
 
   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)
-    {
-      code_props_translate_code (&p->action_props);
-      if (p)
-       p = p->next;
-    }
-
-  p = grammar;

   while (p)
     {
       int rule_length = 0;
       symbol *ruleprec = p->ruleprec;
       record_merge_function_type (p->merger, p->content.sym->type_name,
   while (p)
     {
       int rule_length = 0;
       symbol *ruleprec = p->ruleprec;
       record_merge_function_type (p->merger, p->content.sym->type_name,

-                                 p->merger_declaration_location);
+                                  p->merger_declaration_location);

       rules[ruleno].user_number = ruleno;
       rules[ruleno].number = ruleno;
       rules[ruleno].lhs = p->content.sym;
       rules[ruleno].user_number = ruleno;
       rules[ruleno].number = ruleno;
       rules[ruleno].lhs = p->content.sym;


@@ -497,49 +524,50 @@ packgram (void)
       rules[ruleno].useful = true;
       rules[ruleno].action = p->action_props.code;
       rules[ruleno].action_location = p->action_props.location;
       rules[ruleno].useful = true;
       rules[ruleno].action = p->action_props.code;
       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.  */
+         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
       if (p->midrule_parent_rule
           && (p->action_props.is_value_used

-             || symbol_list_n_get (p->midrule_parent_rule,
-                                   p->midrule_parent_rhs_index)
+              || symbol_list_n_get (p->midrule_parent_rule,
+                                    p->midrule_parent_rhs_index)

                    ->action_props.is_value_used))
                    ->action_props.is_value_used))

-       p->content.sym->tag += 1;
+        p->content.sym->tag += 1;

 
       /* Don't check the generated rule 0.  It has no action, so some rhs
 
       /* 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.  */
+         symbols may appear unused, but the parsing algorithm ensures that
+         %destructor's are invoked appropriately.  */

       if (p != grammar)
       if (p != grammar)

-       grammar_rule_check (p);
+        grammar_rule_check (p);

 
       for (p = p->next; p && p->content.sym; p = p->next)
 
       for (p = p->next; p && p->content.sym; p = p->next)

-       {
-         ++rule_length;
+        {
+          ++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)
-             fatal_at (rules[ruleno].location, _("rule is too long"));
+          /* Don't allow rule_length == INT_MAX, since that might
+             cause confusion with strtol if INT_MAX == LONG_MAX.  */
+          if (rule_length == INT_MAX)
+              fatal_at (rules[ruleno].location, _("rule is too long"));

 
 

-         /* item_number = symbol_number.
-            But the former needs to contain more: negative rule numbers. */
-         ritem[itemno++] =
+          /* 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);
             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;
-       }
+          /* 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 (ruleprec)
 
       /* If this rule has a %prec,
          the specified symbol's precedence replaces the default.  */
       if (ruleprec)

-       {
-         rules[ruleno].precsym = ruleprec;
-         rules[ruleno].prec = ruleprec;
-       }
+        {
+          rules[ruleno].precsym = ruleprec;
+          rules[ruleno].prec = ruleprec;
+        }

       /* An item ends by the rule number (negated).  */
       ritem[itemno++] = rule_number_as_item_number (ruleno);
       aver (itemno < ITEM_NUMBER_MAX);
       /* An item ends by the rule number (negated).  */
       ritem[itemno++] = rule_number_as_item_number (ruleno);
       aver (itemno < ITEM_NUMBER_MAX);


@@ -547,7 +575,7 @@ packgram (void)
       aver (ruleno < RULE_NUMBER_MAX);
 
       if (p)
       aver (ruleno < RULE_NUMBER_MAX);
 
       if (p)

-       p = p->next;
+        p = p->next;

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


@@ -585,16 +613,13 @@ reader (void)
   undeftoken->class = token_sym;
   undeftoken->number = ntokens++;
 
   undeftoken->class = token_sym;
   undeftoken->number = ntokens++;
 

-  /* Initialize the obstacks. */
-  obstack_init (&pre_prologue_obstack);
-  obstack_init (&post_prologue_obstack);
-

   gram_in = xfopen (grammar_file, "r");
 
   gram__flex_debug = trace_flag & trace_scan;
   gram_debug = trace_flag & trace_parse;
   gram_scanner_initialize ();
   gram_parse ();
   gram_in = xfopen (grammar_file, "r");
 
   gram__flex_debug = trace_flag & trace_scan;
   gram_debug = trace_flag & trace_parse;
   gram_scanner_initialize ();
   gram_parse ();

+  prepare_percent_define_front_end_variables ();

 
   if (! complaint_issued)
     check_and_convert_grammar ();
 
   if (! complaint_issued)
     check_and_convert_grammar ();


@@ -602,10 +627,39 @@ reader (void)
   xfclose (gram_in);
 }
 
   xfclose (gram_in);
 }
 

+static void
+prepare_percent_define_front_end_variables (void)
+{
+  /* Set %define front-end 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 (STRNEQ (lr_type, "canonical-lr"))
+      muscle_percent_define_default ("lr.default-reductions", "most");
+    else
+      muscle_percent_define_default ("lr.default-reductions", "accepting");
+    free (lr_type);
+  }
+
+  /* Check %define front-end variables.  */
+  {
+    static char const * const values[] = {
+      "lr.type", "lalr", "ielr", "canonical-lr", NULL,
+      "lr.default-reductions", "most", "consistent", "accepting", NULL,
+      NULL
+    };
+    muscle_percent_define_check_values (values);
+  }
+}
+

 
 /*-------------------------------------------------------------.
 | Check the grammar that has just been read, and convert it to |
 
 /*-------------------------------------------------------------.
 | Check the grammar that has just been read, and convert it to |

-| internal form.                                              |
+| internal form.                                               |

 `-------------------------------------------------------------*/
 
 static void
 `-------------------------------------------------------------*/
 
 static void


@@ -615,9 +669,6 @@ check_and_convert_grammar (void)
   if (nrules == 0)
     fatal (_("no rules in the input grammar"));
 
   if (nrules == 0)
     fatal (_("no rules in the input grammar"));
 

-  /* Report any undefined symbols and consider them nonterminals.  */
-  symbols_check_defined ();
-

   /* If the user did not define her ENDTOKEN, do it now. */
   if (!endtoken)
     {
   /* If the user did not define her ENDTOKEN, do it now. */
   if (!endtoken)
     {


@@ -628,6 +679,9 @@ check_and_convert_grammar (void)
       endtoken->user_token_number = 0;
     }
 
       endtoken->user_token_number = 0;
     }
 

+  /* Report any undefined symbols and consider them nonterminals.  */
+  symbols_check_defined ();
+

   /* Find the start symbol if no %start.  */
   if (!start_flag)
     {
   /* Find the start symbol if no %start.  */
   if (!start_flag)
     {


@@ -668,6 +722,23 @@ check_and_convert_grammar (void)
      token symbols into FDEFINES if requested.  */
   symbols_pack ();
 
      token symbols into FDEFINES if requested.  */
   symbols_pack ();
 

+  /* Scan rule actions after invoking symbol_check_alias_consistency (in
+     symbols_pack above) so that token types are set correctly before the rule
+     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.
+     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
+     packgram).  */
+  {
+    symbol_list *sym;
+    for (sym = grammar; sym; sym = sym->next)
+      code_props_translate_code (&sym->action_props);
+  }
+

   /* Convert the grammar into the format described in gram.h.  */
   packgram ();
 
   /* Convert the grammar into the format described in gram.h.  */
   packgram ();