(check_and_convert_grammar): New function.

[bison.git] / src / reader.c

diff --git a/src/reader.c b/src/reader.c
index 9e93cab66718bdb2e667c6aa30cb5c89eb8a5656..0fa162d9ce786c650fad8db949ea0bba2ea3298c 100644 (file)
--- a/src/reader.c
+++ b/src/reader.c
@@ -1,6 +1,7 @@
-/* Input parser for bison
-   Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000, 2001, 2002
-   Free Software Foundation, Inc.
+/* Input parser for Bison
+
+   Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000, 2001, 2002, 2003,
+   2005, 2006 Free Software Foundation, Inc.

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


@@ -16,93 +17,51 @@
 
    You should have received a copy of the GNU General Public License
    along with Bison; see the file COPYING.  If not, write to
 
    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., 59 Temple Place - Suite 330,
-   Boston, MA 02111-1307, USA.  */
-
+   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+   Boston, MA 02110-1301, USA.  */

 
 

+#include <config.h>

 #include "system.h"
 #include "system.h"

-#include "quotearg.h"
-#include "quote.h"
-#include "getargs.h"
+
+#include <quotearg.h>
+
+#include "complain.h"
+#include "conflicts.h"

 #include "files.h"
 #include "files.h"

-#include "symtab.h"
-#include "options.h"
+#include "getargs.h"

 #include "gram.h"
 #include "gram.h"

-#include "complain.h"
+#include "muscle_tab.h"

 #include "output.h"
 #include "reader.h"
 #include "output.h"
 #include "reader.h"

-#include "conflicts.h"
-#include "muscle_tab.h"
+#include "symlist.h"
+#include "symtab.h"

 
 

-int lineno;
-static symbol_list *grammar = NULL;
-static int start_flag = 0;
+static void check_and_convert_grammar (void);

 
 

-/* Nonzero if %union has been seen.  */
-int typed = 0;
+static symbol_list *grammar = NULL;
+static bool start_flag = false;
+merger_list *merge_functions;

 
 

-static symbol_list *
-symbol_list_new (symbol_t *sym)
-{
-  symbol_list *res = XMALLOC (symbol_list, 1);
-  res->next = NULL;
-  res->sym = sym;
-  res->line = lineno;
-  res->action = NULL;
-  res->action_line = 0;
-  res->ruleprec = NULL;
-  return res;
-}
+/* Was %union seen?  */
+bool typed = false;

 
 

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

 \f
 \f

-/*--------------------------------------------------------------.
-| Get the data type (alternative in the union) of the value for |
-| symbol N in rule RULE.                                        |
-`--------------------------------------------------------------*/
-
-char *
-get_type_name (int n, symbol_list *rule)
-{
-  int i;
-  symbol_list *rp;
-
-  if (n < 0)
-    {
-      complain (_("invalid $ value"));
-      return NULL;
-    }
-
-  rp = rule;
-  i = 0;
-
-  while (i < n)
-    {
-      rp = rp->next;
-      if (rp == NULL || rp->sym == NULL)
-       {
-         complain (_("invalid $ value"));
-         return NULL;
-       }
-      ++i;
-    }
-
-  return rp->sym->type_name;
-}
-
-

 /*-----------------------.
 | Set the start symbol.  |
 `-----------------------*/
 
 void
 /*-----------------------.
 | Set the start symbol.  |
 `-----------------------*/
 
 void

-grammar_start_symbol_set (symbol_t *s)
+grammar_start_symbol_set (symbol *sym, location loc)

 {
   if (start_flag)
 {
   if (start_flag)

-    complain (_("multiple %s declarations"), "%start");
+    complain_at (loc, _("multiple %s declarations"), "%start");

   else
     {
   else
     {

-      start_flag = 1;
-      startsymbol = s;
+      start_flag = true;
+      startsymbol = sym;
+      startsymbol_location = loc;

     }
 }
 
     }
 }
 


@@ -113,67 +72,73 @@ grammar_start_symbol_set (symbol_t *s)
 `----------------------------------------------------------------*/
 
 void
 `----------------------------------------------------------------*/
 
 void

-prologue_augment (const char *prologue, int location)
+prologue_augment (const char *prologue, location loc)

 {
   struct obstack *oout =
     !typed ? &pre_prologue_obstack : &post_prologue_obstack;
 
 {
   struct obstack *oout =
     !typed ? &pre_prologue_obstack : &post_prologue_obstack;
 

-  if (!no_lines_flag)
-    {
-      obstack_fgrow2 (oout, muscle_find ("linef"),
-                     location, quotearg_style (c_quoting_style,
-                                               muscle_find ("filename")));
-    }
+  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);
 }
 
   obstack_sgrow (oout, prologue);
 }
 

+\f

 
 

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

 
 

+static int
+get_merge_function (uniqstr name, uniqstr type, location loc)
+{
+  merger_list *syms;
+  merger_list head;
+  int n;

 
 

-/*----------------------.
-| Handle the epilogue.  |
-`----------------------*/
+  if (! glr_parser)
+    return 0;

 
 

-void
-epilogue_set (const char *epilogue, int location)
-{
-  struct obstack el_obstack;
-  obstack_init (&el_obstack);
+  if (type == NULL)
+    type = uniqstr_new ("");

 
 

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

     {
     {

-      obstack_fgrow2 (&el_obstack, muscle_find ("linef"),
-                     location, quotearg_style (c_quoting_style,
-                                               muscle_find ("filename")));
+      syms->next = xmalloc (sizeof syms->next[0]);
+      syms->next->name = uniqstr_new (name);
+      syms->next->type = uniqstr_new (type);
+      syms->next->next = NULL;
+      merge_functions = head.next;

     }
     }

-  obstack_sgrow (&el_obstack, epilogue);
-  obstack_1grow (&el_obstack, 0);
-  muscle_insert ("epilogue", obstack_finish (&el_obstack));
+  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;

 }
 
 }
 

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

 
 

-\f
-
-/*-------------------------------------------------------------------.
-| Generate a dummy symbol, a nonterminal, whose name cannot conflict |
-| with the user's names.                                             |
-`-------------------------------------------------------------------*/
-
-static symbol_t *
-gensym (void)
+void
+free_merger_functions (void)

 {
 {

-  /* Incremented for each generated symbol */
-  static int gensym_count = 0;
-  static char buf[256];
-
-  symbol_t *sym;
-
-  sprintf (buf, "@%d", ++gensym_count);
-  sym = getsym (buf);
-  sym->class = nterm_sym;
-  sym->number = nvars++;
-  return sym;
+  merger_list *L0 = merge_functions;
+  while (L0)
+    {
+      merger_list *L1 = L0->next;
+      free (L0);
+      L0 = L1;
+    }

 }
 }

+

 \f
 /*-------------------------------------------------------------------.
 | Parse the input grammar into a one symbol_list structure.  Each    |
 \f
 /*-------------------------------------------------------------------.
 | Parse the input grammar into a one symbol_list structure.  Each    |


@@ -184,23 +149,16 @@ gensym (void)
 |                                                                    |
 | All actions are copied out, labelled by the rule number they apply |
 | to.                                                                |
 |                                                                    |
 | All actions are copied out, labelled by the rule number they apply |
 | to.                                                                |

-|                                                                    |
-| Bison used to allow some %directives in the rules sections, but    |
-| this is no longer consider appropriate: (i) the documented grammar |
-| doesn't claim it, (ii), it would promote bad style, (iii), error   |
-| recovery for %directives consists in skipping the junk until a `%' |
-| is seen and helrp synchronizing.  This scheme is definitely wrong  |
-| in the rules section.                                              |

 `-------------------------------------------------------------------*/
 
 /* The (currently) last symbol of GRAMMAR. */
 `-------------------------------------------------------------------*/
 
 /* The (currently) last symbol of GRAMMAR. */

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

 
 

-/* Append S to the GRAMMAR. */
-void
-grammar_symbol_append (symbol_t *s)
+/* Append SYM to the grammar.  */
+static void
+grammar_symbol_append (symbol *sym, location loc)

 {
 {

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

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


@@ -208,35 +166,41 @@ grammar_symbol_append (symbol_t *s)
     grammar = p;
 
   grammar_end = p;
     grammar = p;
 
   grammar_end = p;

+
+  /* A null SYM stands for an end of rule; it is not an actual
+     part of it.  */
+  if (sym)
+    ++nritems;

 }
 
 }
 

-/* The rule currently being defined, and the previous rule.  Point to
-   the first symbol of each list: their lhs.  */
+/* 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;
 symbol_list *current_rule = NULL;

-symbol_list *previous_rule = NULL;
+static symbol_list *previous_rule_end = NULL;

 
 
 
 

-/* Create a new rule for LHS in to the GRAMMAR. */
+/*----------------------------------------------.
+| Create a new rule for LHS in to the GRAMMAR.  |
+`----------------------------------------------*/

 
 void
 
 void

-grammar_rule_begin (symbol_t *lhs)
+grammar_current_rule_begin (symbol *lhs, location loc)

 {
   if (!start_flag)
     {
       startsymbol = lhs;
 {
   if (!start_flag)
     {
       startsymbol = lhs;

-      start_flag = 1;
+      startsymbol_location = loc;
+      start_flag = true;

     }
 
   /* Start a new rule and record its lhs.  */
   ++nrules;
     }
 
   /* Start a new rule and record its lhs.  */
   ++nrules;

-  ++nritems;
-
-  previous_rule = grammar_end;
-  grammar_symbol_append (lhs);
+  previous_rule_end = grammar_end;
+  grammar_symbol_append (lhs, loc);

   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.  */

-

   if (lhs->class == unknown_sym)
     {
       lhs->class = nterm_sym;
   if (lhs->class == unknown_sym)
     {
       lhs->class = nterm_sym;


@@ -244,129 +208,203 @@ grammar_rule_begin (symbol_t *lhs)
       ++nvars;
     }
   else if (lhs->class == token_sym)
       ++nvars;
     }
   else if (lhs->class == token_sym)

-    complain (_("rule given for %s, which is a token"), lhs->tag);
+    complain_at (loc, _("rule given for %s, which is a token"), lhs->tag);
+}
+
+
+/*-----------------------------------------------------------------.
+| A symbol is typed if it has a declared %type, 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; |
+| }'.                                                              |
+`-----------------------------------------------------------------*/
+
+static bool
+symbol_typed_p (const symbol_list *s)
+{
+  return (s->sym->type_name
+         || (s->midrule && s->midrule->used));

 }
 
 }
 

-/* Check that the last rule (CURRENT_RULE) 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.                  |
+`----------------------------------------------------------------*/

 
 static void
 
 static void

-grammar_current_rule_check (void)
+grammar_rule_check (const symbol_list *r)

 {
 {

-  symbol_t *lhs = current_rule->sym;
-  symbol_t *first_rhs = current_rule->next->sym;
+  /* Type check.

 
 

-  /* If there is an action, then there is nothing we can do: the user
-     is allowed to shoot in her foot.  */
-  if (current_rule->action)
-    return;
+     If there is an action, then there is nothing we can do: the user
+     is allowed to shoot herself in the foot.

 
 

-  /* If $$ is being set in default way, report if any type mismatch.
-     */
-  if (first_rhs)
+     Don't worry about the default action if $$ is untyped, since $$'s
+     value can't be used.  */
+  if (!r->action && r->sym->type_name)

     {
     {

-      const char *lhs_type = lhs->type_name       ? lhs->type_name       : "";
-      const char *rhs_type = first_rhs->type_name ? first_rhs->type_name : "";
-      if (strcmp (lhs_type, rhs_type))
-       complain (_("type clash (`%s' `%s') on default action"),
-                 lhs_type, rhs_type);
-    }
-  /* Warn if there is no default for $$ but we need one.  */
-  else
-    {
-      if (lhs->type_name)
-       complain (_("empty rule for typed nonterminal, and no action"));
+      symbol *first_rhs = r->next->sym;
+      /* If $$ is being set in default way, report if any type mismatch.  */
+      if (first_rhs)
+       {
+         char const *lhs_type = r->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_at (r->location,
+                _("empty rule for typed nonterminal, and no action"));

     }
     }

+
+  /* Check that typed symbol values are used.  */
+  {
+    symbol_list const *l = r;
+    int n = 0;
+    for (; l && l->sym; l = l->next, ++n)
+      if (! (l->used
+            || !symbol_typed_p (l)
+            /* The default action, $$ = $1, `uses' both.  */
+            || (!r->action && (n == 0 || n == 1))))
+       {
+         if (n)
+           warn_at (r->location, _("unused value: $%d"), n);
+         else
+           warn_at (r->location, _("unset value: $$"));
+       }
+  }

 }
 
 
 }
 
 

-/* End the currently being grown rule. */
+/*-------------------------------------.
+| End the currently being grown rule.  |
+`-------------------------------------*/

 
 void
 
 void

-grammar_rule_end (void)
+grammar_current_rule_end (location loc)

 {
   /* Put an empty link in the list to mark the end of this rule  */
 {
   /* Put an empty link in the list to mark the end of this rule  */

-  grammar_symbol_append (NULL);
-  grammar_current_rule_check ();
+  grammar_symbol_append (NULL, grammar_end->location);
+  current_rule->location = loc;
+  grammar_rule_check (current_rule);

 }
 
 
 }
 
 

-/* The previous action turns out the be a mid-rule action.  Attach it
-   to the current rule, i.e., create a dummy symbol, attach it this
-   mid-rule action, and append this dummy nonterminal to the current
-   rule.  */
+/*-------------------------------------------------------------------.
+| The previous action turns out the be a mid-rule action.  Attach it |
+| to the current rule, i.e., create a dummy symbol, attach it this   |
+| mid-rule action, and append this dummy nonterminal to the current  |
+| rule.                                                              |
+`-------------------------------------------------------------------*/

 
 

-void
+static void

 grammar_midrule_action (void)
 {
   /* Since the action was written out with this rule's number, we must
      give the new rule this number by inserting the new rule before
      it.  */
 
 grammar_midrule_action (void)
 {
   /* Since the action was written out with this rule's number, we must
      give the new rule this number by inserting the new rule before
      it.  */
 

-  /* Make a dummy nonterminal, a gensym.  */
-  symbol_t *sdummy = gensym ();
-  symbol_list *midrule_action = symbol_list_new (sdummy);
+  /* Make a DUMMY nonterminal, whose location is that of the midrule
+     action.  Create the MIDRULE.  */
+  location dummy_location = current_rule->action_location;
+  symbol *dummy = dummy_symbol_get (dummy_location);
+  symbol_list *midrule = symbol_list_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.  */
   ++nrules;
   ++nritems;
 
   /* Make a new rule, whose body is empty, before the current one, so
      that the action just read can belong to it.  */
   ++nrules;
   ++nritems;

-  /* Attach its lineno to that of the host rule.  */
-  midrule_action->line = current_rule->line;
-  /* Move the action from the host rule to this one.  */
-  midrule_action->action = current_rule->action;
-  midrule_action->action_line = current_rule->action_line;
+  /* 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;
   current_rule->action = NULL;

+  /* If $$ was used in the action, the LHS of the enclosing rule was
+     incorrectly flagged as used.  */
+  midrule->used = current_rule->used;
+  current_rule->used = false;

 
 

-  if (previous_rule)
-    previous_rule->next = midrule_action;
+  if (previous_rule_end)
+    previous_rule_end->next = midrule;

   else
   else

-    grammar = midrule_action;
+    grammar = midrule;

 
 

-  /* End of the rule. */
-  previous_rule = symbol_list_new (NULL);
-  previous_rule->next = current_rule;
+  /* End the dummy's rule.  */
+  midrule->next = symbol_list_new (NULL, dummy_location);
+  grammar_rule_check (midrule);
+  midrule->next->next = current_rule;

 
 

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

 
 

-  /* Insert the dummy generated by that rule into this rule.  */
-  ++nritems;
-  grammar_symbol_append (sdummy);
+  /* 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_end->midrule = midrule;

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

-grammar_current_rule_prec_set (symbol_t *precsym)
+grammar_current_rule_prec_set (symbol *precsym, location loc)

 {
   if (current_rule->ruleprec)
 {
   if (current_rule->ruleprec)

-    complain (_("two @prec's in a row"));
+    complain_at (loc, _("only one %s allowed per rule"), "%prec");

   current_rule->ruleprec = precsym;
 }
 
   current_rule->ruleprec = precsym;
 }
 

-/* Attach a SYMBOL to the current rule.  If needed, move the previous
+/* Attach dynamic precedence DPREC to the current rule. */
+
+void
+grammar_current_rule_dprec_set (int dprec, location loc)
+{
+  if (! glr_parser)
+    warn_at (loc, _("%s affects only GLR parsers"), "%dprec");
+  if (dprec <= 0)
+    complain_at (loc, _("%s must be followed by positive number"), "%dprec");
+  else if (current_rule->dprec != 0)
+    complain_at (loc, _("only one %s allowed per rule"), "%dprec");
+  current_rule->dprec = dprec;
+}
+
+/* Attach a merge function NAME with argument type TYPE to current
+   rule. */
+
+void
+grammar_current_rule_merge_set (uniqstr name, location loc)
+{
+  if (! glr_parser)
+    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);
+}
+
+/* Attach SYM to the current rule.  If needed, move the previous

    action as a mid-rule action.  */
 
 void
    action as a mid-rule action.  */
 
 void

-grammar_current_rule_symbol_append (symbol_t *symbol)
+grammar_current_rule_symbol_append (symbol *sym, location loc)

 {
   if (current_rule->action)
     grammar_midrule_action ();
 {
   if (current_rule->action)
     grammar_midrule_action ();

-  ++nritems;
-  grammar_symbol_append (symbol);
+  grammar_symbol_append (sym, loc);

 }
 
 }
 

-

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

-grammar_current_rule_action_append (const char *action, int action_line)
+grammar_current_rule_action_append (const char *action, location loc)

 {
   if (current_rule->action)
     grammar_midrule_action ();
   current_rule->action = action;
 {
   if (current_rule->action)
     grammar_midrule_action ();
   current_rule->action = action;

-  current_rule->action_line = action_line;
+  current_rule->action_location = loc;

 }
 
 \f
 }
 
 \f


@@ -378,38 +416,42 @@ grammar_current_rule_action_append (const char *action, int action_line)
 static void
 packgram (void)
 {
 static void
 packgram (void)
 {

-  unsigned int itemno;
-  int ruleno;
-  symbol_list *p;
+  unsigned int itemno = 0;
+  rule_number ruleno = 0;
+  symbol_list *p = grammar;
+
+  ritem = xnmalloc (nritems + 1, sizeof *ritem);

 
 

-  ritem = XCALLOC (item_number_t, nritems);
-  rules = XCALLOC (rule_t, nrules) - 1;
+  /* This sentinel is used by build_relations in gram.c.  */
+  *ritem++ = 0;

 
 

-  itemno = 0;
-  ruleno = 1;
+  rules = xnmalloc (nrules, sizeof *rules);

 
 

-  p = grammar;

   while (p)
     {
   while (p)
     {

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

       rules[ruleno].user_number = ruleno;
       rules[ruleno].number = ruleno;
       rules[ruleno].lhs = p->sym;
       rules[ruleno].rhs = ritem + itemno;
       rules[ruleno].user_number = ruleno;
       rules[ruleno].number = ruleno;
       rules[ruleno].lhs = p->sym;
       rules[ruleno].rhs = ritem + itemno;

-      rules[ruleno].line = p->line;
-      rules[ruleno].useful = TRUE;
+      rules[ruleno].prec = NULL;
+      rules[ruleno].dprec = p->dprec;
+      rules[ruleno].merger = p->merger;
+      rules[ruleno].precsym = NULL;
+      rules[ruleno].location = p->location;
+      rules[ruleno].useful = true;

       rules[ruleno].action = p->action;
       rules[ruleno].action = p->action;

-      rules[ruleno].action_line = p->action_line;
+      rules[ruleno].action_location = p->action_location;

 
       p = p->next;
       while (p && p->sym)
        {
 
       p = p->next;
       while (p && p->sym)
        {

-         /* item_number_t = symbol_number_t.
+         /* item_number = symbol_number.

             But the former needs to contain more: negative rule numbers. */
          ritem[itemno++] = symbol_number_as_item_number (p->sym->number);
          /* A rule gets by default the precedence and associativity
             of the last token in it.  */
             But the former needs to contain more: negative rule numbers. */
          ritem[itemno++] = symbol_number_as_item_number (p->sym->number);
          /* A rule gets by default the precedence and associativity
             of the last token in it.  */

-         if (p->sym->class == token_sym)
+         if (p->sym->class == token_sym && default_prec)

            rules[ruleno].prec = p->sym;
          if (p)
            p = p->next;
            rules[ruleno].prec = p->sym;
          if (p)
            p = p->next;


@@ -422,7 +464,7 @@ packgram (void)
          rules[ruleno].precsym = ruleprec;
          rules[ruleno].prec = ruleprec;
        }
          rules[ruleno].precsym = ruleprec;
          rules[ruleno].prec = ruleprec;
        }

-      ritem[itemno++] = -ruleno;
+      ritem[itemno++] = rule_number_as_item_number (ruleno);

       ++ruleno;
 
       if (p)
       ++ruleno;
 
       if (p)


@@ -431,7 +473,7 @@ packgram (void)
 
   assert (itemno == nritems);
 
 
   assert (itemno == nritems);
 

-  if (trace_flag)
+  if (trace_flag & trace_sets)

     ritem_print (stderr);
 }
 \f
     ritem_print (stderr);
 }
 \f


@@ -445,84 +487,85 @@ packgram (void)
 void
 reader (void)
 {
 void
 reader (void)
 {

-  gram_control_t gram_control;
-  lineno = 1;
-
-  /* Initialize the muscle obstack.  */
-  obstack_init (&muscle_obstack);
-

   /* Initialize the symbol table.  */
   symbols_new ();
 
   /* Initialize the symbol table.  */
   symbols_new ();
 

-  /* Construct the axiom symbol. */
-  axiom = getsym ("$axiom");
-  axiom->class = nterm_sym;
-  axiom->number = nvars++;
+  /* Construct the accept symbol. */
+  accept = symbol_get ("$accept", empty_location);
+  accept->class = nterm_sym;
+  accept->number = nvars++;

 
   /* Construct the error token */
 
   /* Construct the error token */

-  errtoken = getsym ("error");
+  errtoken = symbol_get ("error", empty_location);

   errtoken->class = token_sym;
   errtoken->number = ntokens++;
 
   /* Construct a token that represents all undefined literal tokens.
      It is always token number 2.  */
   errtoken->class = token_sym;
   errtoken->number = ntokens++;
 
   /* Construct a token that represents all undefined literal tokens.
      It is always token number 2.  */

-  undeftoken = getsym ("$undefined.");
+  undeftoken = symbol_get ("$undefined", empty_location);

   undeftoken->class = token_sym;
   undeftoken->number = ntokens++;
 
   /* Initialize the obstacks. */
   undeftoken->class = token_sym;
   undeftoken->number = ntokens++;
 
   /* Initialize the obstacks. */

-  obstack_init (&action_obstack);
-  obstack_init (&output_obstack);

   obstack_init (&pre_prologue_obstack);
   obstack_init (&post_prologue_obstack);
 
   obstack_init (&pre_prologue_obstack);
   obstack_init (&post_prologue_obstack);
 

-  finput = xfopen (infile, "r");
-  gram_in = finput;
+  gram_in = xfopen (grammar_file, "r");

 
 

-  gram_debug = !!getenv ("parse");
-  gram__flex_debug = !!getenv ("scan");
-  gram_parse (&gram_control);
+  gram__flex_debug = trace_flag & trace_scan;
+  gram_debug = trace_flag & trace_parse;
+  scanner_initialize ();
+  gram_parse ();
+
+  if (! complaint_issued)
+    check_and_convert_grammar ();
+
+  xfclose (gram_in);
+}

 
 

-  /* Grammar has been read.  Do some checking */
+
+/*-------------------------------------------------------------.
+| 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"));
 
   /* Report any undefined symbols and consider them nonterminals.  */
   symbols_check_defined ();
 
   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 EOFTOKEN, do it now. */
-  if (!eoftoken)
+  /* If the user did not define her ENDTOKEN, do it now. */
+  if (!endtoken)

     {
     {

-      eoftoken = getsym ("$");
-      eoftoken->class = token_sym;
-      eoftoken->number = 0;
+      endtoken = symbol_get ("$end", empty_location);
+      endtoken->class = token_sym;
+      endtoken->number = 0;

       /* Value specified by POSIX.  */
       /* Value specified by POSIX.  */

-      eoftoken->user_token_number = 0;
+      endtoken->user_token_number = 0;

     }
 
     }
 

-  /* Insert the initial rule, which line is that of the first rule
+  /* Insert the initial rule, whose line is that of the first rule

      (not that of the start symbol):
 
      (not that of the start symbol):
 

-     axiom: %start EOF.  */
+     accept: %start EOF.  */

   {
   {

-    symbol_list *p = symbol_list_new (axiom);
-    p->line = grammar->line;
-    p->next = symbol_list_new (startsymbol);
-    p->next->next = symbol_list_new (eoftoken);
-    p->next->next->next = symbol_list_new (NULL);
+    symbol_list *p = symbol_list_new (accept, empty_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->next->next->next = grammar;
     nrules += 1;
     nritems += 3;
     grammar = p;
   }
 
     p->next->next->next->next = grammar;
     nrules += 1;
     nritems += 3;
     grammar = p;
   }
 

-  if (nsyms > SHRT_MAX)
-    fatal (_("too many symbols (tokens plus nonterminals); maximum %d"),
-          SHRT_MAX);
-
-  assert (nsyms == ntokens + nvars);
-
-  xfclose (finput);
+  assert (nsyms <= SYMBOL_NUMBER_MAXIMUM && 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.  */