* GNUmakefile: Update git-version-gen invocation so make dist

[bison.git] / src / reader.c

diff --git a/src/reader.c b/src/reader.c
index f02e132f635d8414efbbf866b58048310884c00b..7758c772937fd126966ecc13bdf500b21c88de9d 100644 (file)
--- a/src/reader.c
+++ b/src/reader.c
@@ -1,24 +1,22 @@
 /* Input parser for Bison
 
    Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000, 2001, 2002, 2003,
 /* Input parser for Bison
 
    Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000, 2001, 2002, 2003,

-   2005 Free Software Foundation, Inc.
+   2005, 2006, 2007 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"


@@ -31,20 +29,23 @@
 #include "getargs.h"
 #include "gram.h"
 #include "muscle_tab.h"
 #include "getargs.h"
 #include "gram.h"
 #include "muscle_tab.h"

-#include "output.h"

 #include "reader.h"
 #include "symlist.h"
 #include "symtab.h"
 #include "reader.h"
 #include "symlist.h"
 #include "symtab.h"

+#include "scan-gram.h"
+#include "scan-code.h"

 
 

-static void grammar_midrule_action (void);
-static void grammar_symbol_append (symbol *sym, location loc);
+static void check_and_convert_grammar (void);

 
 static symbol_list *grammar = NULL;
 static bool start_flag = false;
 merger_list *merge_functions;
 
 /* Was %union seen?  */
 
 static symbol_list *grammar = NULL;
 static bool start_flag = false;
 merger_list *merge_functions;
 
 /* Was %union seen?  */

-bool typed = false;
+bool union_seen = false;
+
+/* Was a tag seen?  */
+bool tag_seen = false;

 
 /* Should rules have a default precedence?  */
 bool default_prec = true;
 
 /* Should rules have a default precedence?  */
 bool default_prec = true;


@@ -66,35 +67,15 @@ grammar_start_symbol_set (symbol *sym, location loc)
     }
 }
 
     }
 }
 

-
-/*----------------------------------------------------------------.
-| There are two prologues: one before %union, one after.  Augment |
-| the current one.                                                |
-`----------------------------------------------------------------*/
-
-void
-prologue_augment (const char *prologue, location loc)
-{
-  struct obstack *oout =
-    !typed ? &pre_prologue_obstack : &post_prologue_obstack;
-
-  obstack_fgrow1 (oout, "]b4_syncline(%d, [[", loc.start.line);
-  MUSCLE_OBSTACK_SGROW (oout,
-                       quotearg_style (c_quoting_style, loc.start.file));
-  obstack_sgrow (oout, "]])[\n");
-  obstack_sgrow (oout, prologue);
-}
-

 \f
 
 \f
 

-/*-------------------------------------------------------------------.
-| Return the merger index for a merging function named NAME, whose   |
-| arguments have type TYPE.  Records the function, if new, in        |
-| MERGER_LIST.                                                      |
-`-------------------------------------------------------------------*/
+/*------------------------------------------------------------------------.
+| Return the merger index for a merging function named NAME.  Records the |
+| function, if new, in MERGER_LIST.                                       |
+`------------------------------------------------------------------------*/

 
 static int
 
 static int

-get_merge_function (uniqstr name, uniqstr type, location loc)
+get_merge_function (uniqstr name)

 {
   merger_list *syms;
   merger_list head;
 {
   merger_list *syms;
   merger_list head;


@@ -103,9 +84,6 @@ get_merge_function (uniqstr name, uniqstr type, location loc)
   if (! glr_parser)
     return 0;
 
   if (! glr_parser)
     return 0;
 

-  if (type == NULL)
-    type = uniqstr_new ("");
-

   head.next = merge_functions;
   for (syms = &head, n = 1; syms->next; syms = syms->next, n += 1)
     if (UNIQSTR_EQ (name, syms->next->name))
   head.next = merge_functions;
   for (syms = &head, n = 1; syms->next; syms = syms->next, n += 1)
     if (UNIQSTR_EQ (name, syms->next->name))


@@ -114,16 +92,51 @@ get_merge_function (uniqstr name, uniqstr type, location loc)
     {
       syms->next = xmalloc (sizeof syms->next[0]);
       syms->next->name = uniqstr_new (name);
     {
       syms->next = xmalloc (sizeof syms->next[0]);
       syms->next->name = uniqstr_new (name);

-      syms->next->type = uniqstr_new (type);
+      /* After all symbol type declarations have been parsed, packgram invokes
+        record_merge_function_type to set the type.  */
+      syms->next->type = NULL;

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

-  else if (!UNIQSTR_EQ (type, syms->next->type))
-    warn_at (loc, _("result type clash on merge function %s: <%s> != <%s>"),
-            name, type, syms->next->type);

   return n;
 }
 
   return n;
 }
 

+/*-------------------------------------------------------------------------.
+| For the existing merging function with index MERGER, record the result   |
+| type as TYPE as required by the lhs of the rule whose %merge declaration |
+| is at DECLARATION_LOC.                                                   |
+`-------------------------------------------------------------------------*/
+
+static void
+record_merge_function_type (int merger, uniqstr type, location declaration_loc)
+{
+  int merger_find;
+  merger_list *merge_function;
+
+  if (merger <= 0)
+    return;
+
+  if (type == NULL)
+    type = uniqstr_new ("");
+
+  merger_find = 1;
+  for (merge_function = merge_functions;
+       merge_function != NULL && merger_find != merger;
+       merge_function = merge_function->next)
+    merger_find += 1;
+  aver (merge_function != NULL && merger_find == merger);
+  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);
+      complain_at (merge_function->type_declaration_location,
+                  _("previous declaration"));
+    }
+  merge_function->type = uniqstr_new (type);
+  merge_function->type_declaration_location = declaration_loc;
+}
+

 /*--------------------------------------.
 | Free all merge-function definitions. |
 `--------------------------------------*/
 /*--------------------------------------.
 | Free all merge-function definitions. |
 `--------------------------------------*/


@@ -159,7 +172,7 @@ static symbol_list *grammar_end = NULL;
 static void
 grammar_symbol_append (symbol *sym, location loc)
 {
 static void
 grammar_symbol_append (symbol *sym, location loc)
 {

-  symbol_list *p = symbol_list_new (sym, loc);
+  symbol_list *p = symbol_list_sym_new (sym, loc);

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


@@ -168,7 +181,7 @@ grammar_symbol_append (symbol *sym, location loc)
 
   grammar_end = p;
 
 
   grammar_end = p;
 

-  /* SYM = 0 stands for an end of rule, it is not an actual
+  /* A null SYM stands for an end of rule; it is not an actual

      part of it.  */
   if (sym)
     ++nritems;
      part of it.  */
   if (sym)
     ++nritems;


@@ -177,7 +190,7 @@ grammar_symbol_append (symbol *sym, location loc)
 /* 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).  */

-symbol_list *current_rule = NULL;
+static symbol_list *current_rule = NULL;

 static symbol_list *previous_rule_end = NULL;
 
 
 static symbol_list *previous_rule_end = NULL;
 
 


@@ -188,13 +201,6 @@ static symbol_list *previous_rule_end = NULL;
 void
 grammar_current_rule_begin (symbol *lhs, location loc)
 {
 void
 grammar_current_rule_begin (symbol *lhs, location loc)
 {

-  if (!start_flag)
-    {
-      startsymbol = lhs;
-      startsymbol_location = loc;
-      start_flag = true;
-    }
-

   /* 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;


@@ -213,6 +219,28 @@ grammar_current_rule_begin (symbol *lhs, location loc)
 }
 
 
 }
 
 

+/*----------------------------------------------------------------------.
+| 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)
+{
+  if (symbol_destructor_get (s->content.sym)->code)
+    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));
+  return false;
+}
+

 /*----------------------------------------------------------------.
 | Check that the rule R is properly defined.  For instance, there |
 | should be no type clash on the default action.                  |
 /*----------------------------------------------------------------.
 | Check that the rule R is properly defined.  For instance, there |
 | should be no type clash on the default action.                  |


@@ -228,13 +256,13 @@ grammar_rule_check (const symbol_list *r)
 
      Don't worry about the default action if $$ is untyped, since $$'s
      value can't be used.  */
 
      Don't worry about the default action if $$ is untyped, since $$'s
      value can't be used.  */

-  if (!r->action && r->sym->type_name)
+  if (!r->action_props.code && r->content.sym->type_name)

     {
     {

-      symbol *first_rhs = r->next->sym;
+      symbol *first_rhs = r->next->content.sym;

       /* If $$ is being set in default way, report if any type mismatch.  */
       if (first_rhs)
        {
       /* If $$ is being set in default way, report if any type mismatch.  */
       if (first_rhs)
        {

-         char const *lhs_type = r->sym->type_name;
+         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))
          const char *rhs_type =
            first_rhs->type_name ? first_rhs->type_name : "";
          if (!UNIQSTR_EQ (lhs_type, rhs_type))


@@ -247,20 +275,22 @@ grammar_rule_check (const symbol_list *r)
        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 typed symbol values are used.  */
+
+  /* Check that symbol values that should be used are in fact used.  */

   {
   {

-    symbol_list *l = r;
+    symbol_list const *l = r;

     int n = 0;
     int n = 0;

-    for (; l && l->sym; l = l->next, ++n)
-      if (! (l->used
-            || !l->sym->type_name
+    for (; l && l->content.sym; l = l->next, ++n)
+      if (! (l->action_props.is_value_used
+            || !symbol_should_be_used (l)

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

-            || !r->action && (n == 0 || n == 1)))
-       if (n)
-         warn_at (r->location, _("unused value: $%d"), n);
-       else
-         warn_at (r->location, _("unset value: $$"));
+            || (!r->action_props.code && (n == 0 || n == 1))))
+       {
+         if (n)
+           warn_at (r->location, _("unused value: $%d"), n);
+         else
+           warn_at (r->location, _("unset value: $$"));
+       }

   }
 }
 
   }
 }
 


@@ -275,7 +305,6 @@ grammar_current_rule_end (location loc)
   /* Put an empty link in the list to mark the end of this rule  */
   grammar_symbol_append (NULL, grammar_end->location);
   current_rule->location = loc;
   /* Put an empty link in the list to mark the end of this rule  */
   grammar_symbol_append (NULL, grammar_end->location);
   current_rule->location = loc;

-  grammar_rule_check (current_rule);

 }
 
 
 }
 
 


@@ -286,7 +315,7 @@ grammar_current_rule_end (location loc)
 | rule.                                                              |
 `-------------------------------------------------------------------*/
 
 | rule.                                                              |
 `-------------------------------------------------------------------*/
 

-static void
+void

 grammar_midrule_action (void)
 {
   /* Since the action was written out with this rule's number, we must
 grammar_midrule_action (void)
 {
   /* Since the action was written out with this rule's number, we must


@@ -295,9 +324,9 @@ grammar_midrule_action (void)
 
   /* Make a DUMMY nonterminal, whose location is that of the midrule
      action.  Create the MIDRULE.  */
 
   /* Make a DUMMY nonterminal, whose location is that of the midrule
      action.  Create the MIDRULE.  */

-  location dummy_location = current_rule->action_location;
+  location dummy_location = current_rule->action_props.location;

   symbol *dummy = dummy_symbol_get (dummy_location);
   symbol *dummy = dummy_symbol_get (dummy_location);

-  symbol_list *midrule = symbol_list_new (dummy, dummy_location);
+  symbol_list *midrule = symbol_list_sym_new (dummy, dummy_location);

 
   /* Make a new rule, whose body is empty, before the current one, so
      that the action just read can belong to it.  */
 
   /* Make a new rule, whose body is empty, before the current one, so
      that the action just read can belong to it.  */


@@ -305,9 +334,11 @@ grammar_midrule_action (void)
   ++nritems;
   /* Attach its location and actions to that of the DUMMY.  */
   midrule->location = dummy_location;
   ++nritems;
   /* Attach its location and actions to that of the DUMMY.  */
   midrule->location = dummy_location;

-  midrule->action = current_rule->action;
-  midrule->action_location = dummy_location;
-  current_rule->action = NULL;
+  code_props_rule_action_init (&midrule->action_props,
+                               current_rule->action_props.code,
+                               current_rule->action_props.location,
+                               midrule);
+  code_props_none_init (&current_rule->action_props);

 
   if (previous_rule_end)
     previous_rule_end->next = midrule;
 
   if (previous_rule_end)
     previous_rule_end->next = midrule;


@@ -315,14 +346,17 @@ grammar_midrule_action (void)
     grammar = midrule;
 
   /* End the dummy's rule.  */
     grammar = midrule;
 
   /* End the dummy's rule.  */

-  previous_rule_end = symbol_list_new (NULL, dummy_location);
-  previous_rule_end->next = current_rule;
+  midrule->next = symbol_list_sym_new (NULL, dummy_location);
+  midrule->next->next = current_rule;

 
 

-  midrule->next = previous_rule_end;
+  previous_rule_end = midrule->next;

 
   /* Insert the dummy nonterminal replacing the midrule action into
 
   /* Insert the dummy nonterminal replacing the midrule action into

-     the current rule.  */
+     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);

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

 }
 
 /* Set the precedence symbol of the current rule to PRECSYM. */
 }
 
 /* Set the precedence symbol of the current rule to PRECSYM. */


@@ -330,6 +364,7 @@ grammar_midrule_action (void)
 void
 grammar_current_rule_prec_set (symbol *precsym, location loc)
 {
 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;
   if (current_rule->ruleprec)
     complain_at (loc, _("only one %s allowed per rule"), "%prec");
   current_rule->ruleprec = precsym;


@@ -359,8 +394,8 @@ grammar_current_rule_merge_set (uniqstr name, location loc)
     warn_at (loc, _("%s affects only GLR parsers"), "%merge");
   if (current_rule->merger != 0)
     complain_at (loc, _("only one %s allowed per rule"), "%merge");
     warn_at (loc, _("%s affects only GLR parsers"), "%merge");
   if (current_rule->merger != 0)
     complain_at (loc, _("only one %s allowed per rule"), "%merge");

-  current_rule->merger =
-    get_merge_function (name, current_rule->sym->type_name, loc);
+  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


@@ -369,21 +404,22 @@ grammar_current_rule_merge_set (uniqstr name, location loc)
 void
 grammar_current_rule_symbol_append (symbol *sym, location loc)
 {
 void
 grammar_current_rule_symbol_append (symbol *sym, location loc)
 {

-  if (current_rule->action)
+  if (current_rule->action_props.code)

     grammar_midrule_action ();
   grammar_symbol_append (sym, loc);
 }
 
     grammar_midrule_action ();
   grammar_symbol_append (sym, loc);
 }
 

-/* Attach an ACTION to the current rule.  If needed, move the previous
-   action as a mid-rule action.  */
+/* Attach an ACTION to the current rule.  */

 
 void
 grammar_current_rule_action_append (const char *action, location loc)
 {
 
 void
 grammar_current_rule_action_append (const char *action, location loc)
 {

-  if (current_rule->action)
+  if (current_rule->action_props.code)

     grammar_midrule_action ();
     grammar_midrule_action ();

-  current_rule->action = action;
-  current_rule->action_location = loc;
+  /* 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);

 }
 
 \f
 }
 
 \f


@@ -399,15 +435,22 @@ packgram (void)
   rule_number ruleno = 0;
   symbol_list *p = grammar;
 
   rule_number ruleno = 0;
   symbol_list *p = grammar;
 

-  ritem = xnmalloc (nritems, sizeof *ritem);
+  ritem = xnmalloc (nritems + 1, sizeof *ritem);
+
+  /* This sentinel is used by build_relations in gram.c.  */
+  *ritem++ = 0;
+

   rules = xnmalloc (nrules, sizeof *rules);
 
   while (p)
     {
   rules = xnmalloc (nrules, sizeof *rules);
 
   while (p)
     {

+      int rule_length = 0;

       symbol *ruleprec = p->ruleprec;
       symbol *ruleprec = p->ruleprec;

+      record_merge_function_type (p->merger, p->content.sym->type_name,
+                                 p->merger_declaration_location);

       rules[ruleno].user_number = ruleno;
       rules[ruleno].number = ruleno;
       rules[ruleno].user_number = ruleno;
       rules[ruleno].number = ruleno;

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

       rules[ruleno].rhs = ritem + itemno;
       rules[ruleno].prec = NULL;
       rules[ruleno].dprec = p->dprec;
       rules[ruleno].rhs = ritem + itemno;
       rules[ruleno].prec = NULL;
       rules[ruleno].dprec = p->dprec;


@@ -415,21 +458,42 @@ packgram (void)
       rules[ruleno].precsym = NULL;
       rules[ruleno].location = p->location;
       rules[ruleno].useful = true;
       rules[ruleno].precsym = NULL;
       rules[ruleno].location = p->location;
       rules[ruleno].useful = true;

-      rules[ruleno].action = p->action;
-      rules[ruleno].action_location = p->action_location;
-
-      p = p->next;
-      while (p && p->sym)
+      rules[ruleno].action = p->action_props.code;
+      rules[ruleno].action_location = p->action_props.location;
+
+      /* 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_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
+        symbols may appear unused, but the parsing algorithm ensures that
+        %destructor's are invoked appropriately.  */
+      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)
+             fatal_at (rules[ruleno].location, _("rule is too long"));
+

          /* item_number = symbol_number.
             But the former needs to contain more: negative rule numbers. */
          /* item_number = symbol_number.
             But the former needs to contain more: negative rule numbers. */

-         ritem[itemno++] = symbol_number_as_item_number (p->sym->number);
+         ritem[itemno++] =
+            symbol_number_as_item_number (p->content.sym->number);

          /* A rule gets by default the precedence and associativity
          /* A rule gets by default the precedence and associativity

-            of the last token in it.  */
-         if (p->sym->class == token_sym && default_prec)
-           rules[ruleno].prec = p->sym;
-         if (p)
-           p = p->next;
+            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,
        }
 
       /* If this rule has a %prec,


@@ -439,15 +503,17 @@ packgram (void)
          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);
       ritem[itemno++] = rule_number_as_item_number (ruleno);

+      aver (itemno < ITEM_NUMBER_MAX);

       ++ruleno;
       ++ruleno;

+      aver (ruleno < RULE_NUMBER_MAX);

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

-  if (itemno != nritems)
-    abort ();
+  aver (itemno == nritems);

 
   if (trace_flag & trace_sets)
     ritem_print (stderr);
 
   if (trace_flag & trace_sets)
     ritem_print (stderr);


@@ -482,23 +548,29 @@ 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_in = xfopen (grammar_file, "r");
 
   gram__flex_debug = trace_flag & trace_scan;
   gram_debug = trace_flag & trace_parse;

-  scanner_initialize ();
+  gram_scanner_initialize ();

   gram_parse ();
 
   gram_parse ();
 

-  /* If something went wrong during the parsing, don't try to
-     continue.  */
-  if (complaint_issued)
-    return;
+  if (! complaint_issued)
+    check_and_convert_grammar ();

 
 

-  /* Grammar has been read.  Do some checking */
+  xfclose (gram_in);
+}
+
+
+/*-------------------------------------------------------------.
+| Check the grammar that has just been read, and convert it to |
+| internal form.                                              |
+`-------------------------------------------------------------*/
+
+static void
+check_and_convert_grammar (void)
+{
+  /* Grammar has been read.  Do some checking.  */

   if (nrules == 0)
     fatal (_("no rules in the input grammar"));
 
   if (nrules == 0)
     fatal (_("no rules in the input grammar"));
 


@@ -515,34 +587,66 @@ reader (void)
       endtoken->user_token_number = 0;
     }
 
       endtoken->user_token_number = 0;
     }
 

-  /* Insert the initial rule, which line is that of the first rule
+  /* Find the start symbol if no %start.  */
+  if (!start_flag)
+    {
+      symbol_list *node;
+      for (node = grammar;
+           node != NULL && symbol_is_dummy (node->content.sym);
+           node = node->next)
+        {
+          for (node = node->next;
+               node != NULL && node->content.sym != NULL;
+               node = node->next)
+            ;
+        }
+      aver (node != NULL);
+      grammar_start_symbol_set (node->content.sym,
+                                node->content.sym->location);
+    }
+
+  /* Insert the initial rule, whose line is that of the first rule

      (not that of the start symbol):
 
      accept: %start EOF.  */
   {
      (not that of the start symbol):
 
      accept: %start EOF.  */
   {

-    symbol_list *p = symbol_list_new (accept, empty_location);
+    symbol_list *p = symbol_list_sym_new (accept, empty_location);

     p->location = grammar->location;
     p->location = grammar->location;

-    p->next = symbol_list_new (startsymbol, empty_location);
-    p->next->next = symbol_list_new (endtoken, empty_location);
-    p->next->next->next = symbol_list_new (NULL, empty_location);
+    p->next = symbol_list_sym_new (startsymbol, empty_location);
+    p->next->next = symbol_list_sym_new (endtoken, empty_location);
+    p->next->next->next = symbol_list_sym_new (NULL, empty_location);

     p->next->next->next->next = grammar;
     nrules += 1;
     nritems += 3;
     grammar = p;
   }
 
     p->next->next->next->next = grammar;
     nrules += 1;
     nritems += 3;
     grammar = p;
   }
 

-  if (! (nsyms <= SYMBOL_NUMBER_MAXIMUM && nsyms == ntokens + nvars))
-    abort ();
-
-  xfclose (gram_in);
+  aver (nsyms <= SYMBOL_NUMBER_MAXIMUM && nsyms == ntokens + nvars);

 
   /* Assign the symbols their symbol numbers.  Write #defines for the
      token symbols into FDEFINES if requested.  */
   symbols_pack ();
 
 
   /* Assign the symbols their symbol numbers.  Write #defines for the
      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 ();
 
   /* The grammar as a symbol_list is no longer needed. */
   /* Convert the grammar into the format described in gram.h.  */
   packgram ();
 
   /* The grammar as a symbol_list is no longer needed. */

-  LIST_FREE (symbol_list, grammar);
+  symbol_list_free (grammar);

 }
 }