Pacify "gcc -Wunused" for the input function from Flex.

[bison.git] / src / output.c

diff --git a/src/output.c b/src/output.c
index 78113fd121c426b4e8350c32db9e82c5ae6d9a0e..c5e9aab99948c21c21ed294de50fdec7f3c75353 100644 (file)
--- a/src/output.c
+++ b/src/output.c
@@ -1,169 +1,47 @@
-/* Output the generated parsing program for bison,
-   Copyright (C) 1984, 1986, 1989, 1992, 2000, 2001, 2002
-   Free Software Foundation, Inc.
+/* Output the generated parsing program for Bison.
+
+   Copyright (C) 1984, 1986, 1989, 1992, 2000, 2001, 2002, 2003, 2004,
+   2005, 2006, 2007, 2008, 2009 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 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.
+   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
+   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, 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.
+   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
 
    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 parser tables consist of these tables.  Marked ones needed only
-   for the semantic parser.  Double marked are output only if switches
-   are set.
-
-   YYTRANSLATE = vector mapping yylex's token numbers into bison's
-   token numbers.
-
-   ++ YYTNAME = vector of string-names indexed by bison token number.
-
-   ++ YYTOKNUM = vector of yylex token numbers corresponding to
-   entries in YYTNAME.
-
-   YYRLINE = vector of line-numbers of all rules.  For yydebug
-   printouts.
-
-   YYRHS = vector of items of all rules.  This is exactly what RITEMS
-   contains.  For yydebug and for semantic parser.
-
-   YYPRHS[R] = index in YYRHS of first item for rule R.
-
-   YYR1[R] = symbol number of symbol that rule R derives.
-
-   YYR2[R] = number of symbols composing right hand side of rule R.
-
-   + YYSTOS[S] = the symbol number of the symbol that leads to state
-   S.
-
-   YYDEFACT[S] = default rule to reduce with in state s, when YYTABLE
-   doesn't specify something else to do.  Zero means the default is an
-   error.
-
-   YYDEFGOTO[I] = default state to go to after a reduction of a rule
-   that generates variable NTOKENS + I, except when YYTABLE specifies
-   something else to do.
-
-   YYPACT[S] = index in YYTABLE of the portion describing state S.
-   The lookahead token's type is used to index that portion to find
-   out what to do.
-
-   If the value in YYTABLE is positive, we shift the token and go to
-   that state.
-
-   If the value is negative, it is minus a rule number to reduce by.
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

 
 

-   If the value is zero, the default action from YYDEFACT[S] is used.
-
-   YYPGOTO[I] = the index in YYTABLE of the portion describing what to
-   do after reducing a rule that derives variable I + NTOKENS.  This
-   portion is indexed by the parser state number, S, as of before the
-   text for this nonterminal was read.  The value from YYTABLE is the
-   state to go to if the corresponding value in YYCHECK is S.
-
-   YYTABLE = a vector filled with portions for different uses, found
-   via YYPACT and YYPGOTO.
-
-   YYCHECK = a vector indexed in parallel with YYTABLE.  It indicates,
-   in a roundabout way, the bounds of the portion you are trying to
-   examine.
-
-   Suppose that the portion of yytable starts at index P and the index
-   to be examined within the portion is I.  Then if YYCHECK[P+I] != I,
-   I is outside the bounds of what is actually allocated, and the
-   default (from YYDEFACT or YYDEFGOTO) should be used.  Otherwise,
-   YYTABLE[P+I] should be used.
+#include <config.h>
+#include "system.h"

 
 

-   YYFINAL = the state number of the termination state.  YYFLAG = most
-   negative short int.  Used to flag ??  */
+#include <configmake.h>
+#include <error.h>
+#include <get-errno.h>
+#include <quotearg.h>
+#include <subpipe.h>
+#include <timevar.h>

 
 

-#include "system.h"
-#include "bitsetv.h"
-#include "quotearg.h"
-#include "error.h"
-#include "getargs.h"
+#include "complain.h"

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

+#include "getargs.h"

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

-#include "LR0.h"
-#include "complain.h"
+#include "muscle-tab.h"

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

-#include "lalr.h"

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

+#include "scan-code.h"    /* max_left_semantic_context */
+#include "scan-skel.h"

 #include "symtab.h"
 #include "symtab.h"

-#include "conflicts.h"
-#include "muscle_tab.h"
-
-/* From lib/readpipe.h.  */
-FILE *readpipe PARAMS ((const char *, ...));
-
-/* From src/scan-skel.l. */
-int skel_lex PARAMS ((void));
-extern FILE *skel_in;
-
-static int nvectors;
-static int nentries;
-static short **froms = NULL;
-static short **tos = NULL;
-static short *tally = NULL;
-static short *width = NULL;
-static short *actrow = NULL;
-static short *state_count = NULL;
-static short *order = NULL;
-static short *base = NULL;
-static short *pos = NULL;
-
-/* TABLE_SIZE is the allocated size of both TABLE and CHECK.
-   We start with the original hard-coded value: SHRT_MAX
-   (yes, not USHRT_MAX). */
-static size_t table_size = SHRT_MAX;
-static short *table = NULL;
-static short *check = NULL;
-static int lowzero;
-static int high;
-
-static struct obstack format_obstack;
-
-int error_verbose = 0;
-
-
-/*----------------------------------------------------------------.
-| If TABLE (and CHECK) appear to be small to be addressed at      |
-| DESIRED, grow them.  Note that TABLE[DESIRED] is to be used, so |
-| the desired size is at least DESIRED + 1.                       |
-`----------------------------------------------------------------*/
+#include "tables.h"

 
 

-static void
-table_grow (size_t desired)
-{
-  size_t old_size = table_size;
-
-  while (table_size <= desired)
-    table_size *= 2;
-
-  if (trace_flag)
-    fprintf (stderr, "growing table and check from: %d to %d\n",
-            old_size, table_size);
-
-  table = XREALLOC (table, short, table_size);
-  check = XREALLOC (check, short, table_size);

 
 

-  for (/* Nothing. */; old_size < table_size; ++old_size)
-    {
-      table[old_size] = 0;
-      check[old_size] = -1;
-    }
-}
+static struct obstack format_obstack;

 
 
 /*-------------------------------------------------------------------.
 
 
 /*-------------------------------------------------------------------.


@@ -177,13 +55,16 @@ table_grow (size_t desired)
 #define GENERATE_MUSCLE_INSERT_TABLE(Name, Type)                       \
                                                                        \
 static void                                                            \
 #define GENERATE_MUSCLE_INSERT_TABLE(Name, Type)                       \
                                                                        \
 static void                                                            \

-Name (const char *name,                                                        \
+Name (char const *name,                                                        \

       Type *table_data,                                                        \
       Type first,                                                      \
       int begin,                                                       \
       int end)                                                         \
 {                                                                      \
       Type *table_data,                                                        \
       Type first,                                                      \
       int begin,                                                       \
       int end)                                                         \
 {                                                                      \

+  Type min = first;                                                    \

   Type max = first;                                                    \
   Type max = first;                                                    \

+  long int lmin;                                                       \
+  long int lmax;                                                       \

   int i;                                                               \
   int j = 1;                                                           \
                                                                        \
   int i;                                                               \
   int j = 1;                                                           \
                                                                        \


@@ -199,129 +80,169 @@ Name (const char *name,                                                  \
       else                                                             \
        ++j;                                                            \
       obstack_fgrow1 (&format_obstack, "%6d", table_data[i]);          \
       else                                                             \
        ++j;                                                            \
       obstack_fgrow1 (&format_obstack, "%6d", table_data[i]);          \

-      if (table_data[i] > max)                                         \
+      if (table_data[i] < min)                                         \
+       min = table_data[i];                                            \
+      if (max < table_data[i])                                         \

        max = table_data[i];                                            \
     }                                                                  \
   obstack_1grow (&format_obstack, 0);                                  \
   muscle_insert (name, obstack_finish (&format_obstack));              \
                                                                        \
        max = table_data[i];                                            \
     }                                                                  \
   obstack_1grow (&format_obstack, 0);                                  \
   muscle_insert (name, obstack_finish (&format_obstack));              \
                                                                        \

-  /* Build `NAME_max' in the obstack. */                               \
+  lmin = min;                                                          \
+  lmax = max;                                                          \
+  /* Build `NAME_min' and `NAME_max' in the obstack. */                        \
+  obstack_fgrow1 (&format_obstack, "%s_min", name);                    \
+  obstack_1grow (&format_obstack, 0);                                  \
+  MUSCLE_INSERT_LONG_INT (obstack_finish (&format_obstack), lmin);     \

   obstack_fgrow1 (&format_obstack, "%s_max", name);                    \
   obstack_1grow (&format_obstack, 0);                                  \
   obstack_fgrow1 (&format_obstack, "%s_max", name);                    \
   obstack_1grow (&format_obstack, 0);                                  \

-  MUSCLE_INSERT_LONG_INT (obstack_finish (&format_obstack),            \
-                         (long int) max);                              \
+  MUSCLE_INSERT_LONG_INT (obstack_finish (&format_obstack), lmax);     \

 }
 
 GENERATE_MUSCLE_INSERT_TABLE(muscle_insert_unsigned_int_table, unsigned int)
 }
 
 GENERATE_MUSCLE_INSERT_TABLE(muscle_insert_unsigned_int_table, unsigned int)

-GENERATE_MUSCLE_INSERT_TABLE(muscle_insert_short_table, short)
-GENERATE_MUSCLE_INSERT_TABLE(muscle_insert_symbol_number_table, symbol_number_t)
-GENERATE_MUSCLE_INSERT_TABLE(muscle_insert_item_number_table, item_number_t)
+GENERATE_MUSCLE_INSERT_TABLE(muscle_insert_int_table, int)
+GENERATE_MUSCLE_INSERT_TABLE(muscle_insert_base_table, base_number)
+GENERATE_MUSCLE_INSERT_TABLE(muscle_insert_rule_number_table, rule_number)
+GENERATE_MUSCLE_INSERT_TABLE(muscle_insert_symbol_number_table, symbol_number)
+GENERATE_MUSCLE_INSERT_TABLE(muscle_insert_state_number_table, state_number)
+
+
+/*--------------------------------------------------------------------.
+| Print to OUT a representation of STRING escaped both for C and M4.  |
+`--------------------------------------------------------------------*/
+
+static void
+escaped_output (FILE *out, char const *string)
+{
+  char const *p;
+  fprintf (out, "[[");
+
+  for (p = quotearg_style (c_quoting_style, string); *p; p++)
+    switch (*p)
+      {
+      case '$': fputs ("$][", out); break;
+      case '@': fputs ("@@",  out); break;
+      case '[': fputs ("@{",  out); break;
+      case ']': fputs ("@}",  out); break;
+      default: fputc (*p, out); break;
+      }
+
+  fprintf (out, "]]");
+}

 
 
 
 

-/*-----------------------------------------------------------------.
-| Prepare the muscles related to the tokens: translate, tname, and |
-| toknum.                                                          |
-`-----------------------------------------------------------------*/
+/*------------------------------------------------------------------.
+| Prepare the muscles related to the symbols: translate, tname, and |
+| toknum.                                                           |
+`------------------------------------------------------------------*/

 
 static void
 
 static void

-prepare_tokens (void)
+prepare_symbols (void)

 {
 {

+  MUSCLE_INSERT_BOOL ("token_table", token_table_flag);
+  MUSCLE_INSERT_INT ("tokens_number", ntokens);
+  MUSCLE_INSERT_INT ("nterms_number", nvars);
+  MUSCLE_INSERT_INT ("symbols_number", nsyms);
+  MUSCLE_INSERT_INT ("undef_token_number", undeftoken->number);
+  MUSCLE_INSERT_INT ("user_token_number_max", max_user_token_number);
+

   muscle_insert_symbol_number_table ("translate",
   muscle_insert_symbol_number_table ("translate",

-                                   token_translations,
-                                   0, 1, max_user_token_number + 1);
+                                    token_translations,
+                                    token_translations[0],
+                                    1, max_user_token_number + 1);

 
 

+  /* tname -- token names.  */

   {
     int i;
   {
     int i;

-    int j = 0;
+    /* We assume that the table will be output starting at column 2. */
+    int j = 2;
+    struct quoting_options *qo = clone_quoting_options (0);
+    set_quoting_style (qo, c_quoting_style);
+    set_quoting_flags (qo, QA_SPLIT_TRIGRAPHS);

     for (i = 0; i < nsyms; i++)
       {
     for (i = 0; i < nsyms; i++)
       {

-       /* Be sure not to use twice the same QUOTEARG slot:
-          SYMBOL_TAG_GET uses slot 0.  */
-       const char *cp =
-         quotearg_n_style (1, c_quoting_style,
-                           symbol_tag_get (symbols[i]));
-       /* Width of the next token, including the two quotes, the coma
-          and the space.  */
-       int strsize = strlen (cp) + 2;
-
-       if (j + strsize > 75)
+       char *cp = quotearg_alloc (symbols[i]->tag, -1, qo);
+       /* Width of the next token, including the two quotes, the
+          comma and the space.  */
+       int width = strlen (cp) + 2;
+
+       if (j + width > 75)

          {
          {

-           obstack_sgrow (&format_obstack, "\n  ");
-           j = 2;
+           obstack_sgrow (&format_obstack, "\n ");
+           j = 1;

          }
 
          }
 

-       obstack_sgrow (&format_obstack, cp);
-       obstack_sgrow (&format_obstack, ", ");
-       j += strsize;
+       if (i)
+         obstack_1grow (&format_obstack, ' ');
+       MUSCLE_OBSTACK_SGROW (&format_obstack, cp);
+        free (cp);
+       obstack_1grow (&format_obstack, ',');
+       j += width;

       }
       }

-    /* Add a NULL entry to list of tokens (well, 0, as NULL might not be
-       defined).  */
-    obstack_sgrow (&format_obstack, "0");
+    free (qo);
+    obstack_sgrow (&format_obstack, " ]b4_null[");

 
     /* Finish table and store. */
     obstack_1grow (&format_obstack, 0);
     muscle_insert ("tname", obstack_finish (&format_obstack));
   }
 
 
     /* Finish table and store. */
     obstack_1grow (&format_obstack, 0);
     muscle_insert ("tname", obstack_finish (&format_obstack));
   }
 

-    /* Output YYTOKNUM. */
+  /* Output YYTOKNUM. */

   {
     int i;
   {
     int i;

-    short *values = XCALLOC (short, ntokens + 1);
-    for (i = 0; i < ntokens + 1; ++i)
+    int *values = xnmalloc (ntokens, sizeof *values);
+    for (i = 0; i < ntokens; ++i)

       values[i] = symbols[i]->user_token_number;
       values[i] = symbols[i]->user_token_number;

-    muscle_insert_short_table ("toknum", values,
-                              0, 1, ntokens + 1);
+    muscle_insert_int_table ("toknum", values,
+                            values[0], 1, ntokens);

     free (values);
   }
 }
 
 
     free (values);
   }
 }
 
 

-/*-------------------------------------------------------------.
-| Prepare the muscles related to the rules: rhs, prhs, r1, r2, |
-| rline.                                                       |
-`-------------------------------------------------------------*/
+/*----------------------------------------------------------------.
+| Prepare the muscles related to the rules: r1, r2, rline, dprec, |
+| merger.                                                         |
+`----------------------------------------------------------------*/

 
 static void
 prepare_rules (void)
 {
 
 static void
 prepare_rules (void)
 {

-  int r;
-  unsigned int i = 0;
-  item_number_t *rhs = XMALLOC (item_number_t, nritems);
-  unsigned int *prhs = XMALLOC (unsigned int, nrules + 1);
-  unsigned int *rline = XMALLOC (unsigned int, nrules + 1);
-  symbol_number_t *r1 = XMALLOC (symbol_number_t, nrules + 1);
-  unsigned int *r2 = XMALLOC (unsigned int, nrules + 1);
-
-  for (r = 1; r < nrules + 1; ++r)
+  unsigned int *rline = xnmalloc (nrules, sizeof *rline);
+  symbol_number *r1 = xnmalloc (nrules, sizeof *r1);
+  unsigned int *r2 = xnmalloc (nrules, sizeof *r2);
+  int *dprec = xnmalloc (nrules, sizeof *dprec);
+  int *merger = xnmalloc (nrules, sizeof *merger);
+
+  rule_number r;
+  for (r = 0; r < nrules; ++r)

     {
     {

-      item_number_t *rhsp;
-      /* Index of rule R in RHS. */
-      prhs[r] = i;
-      /* RHS of the rule R. */
-      for (rhsp = rules[r].rhs; *rhsp >= 0; ++rhsp)
-       rhs[i++] = *rhsp;

       /* LHS of the rule R. */
       r1[r] = rules[r].lhs->number;
       /* Length of rule R's RHS. */
       /* LHS of the rule R. */
       r1[r] = rules[r].lhs->number;
       /* Length of rule R's RHS. */

-      r2[r] = i - prhs[r];
-      /* Separator in RHS. */
-      rhs[i++] = -1;
+      r2[r] = rule_rhs_length(&rules[r]);

       /* Line where rule was defined. */
       /* Line where rule was defined. */

-      rline[r] = rules[r].location.first_line;
+      rline[r] = rules[r].location.start.line;
+      /* Dynamic precedence (GLR).  */
+      dprec[r] = rules[r].dprec;
+      /* Merger-function index (GLR).  */
+      merger[r] = rules[r].merger;

     }
     }

-  assert (i == nritems);

 
 

-  muscle_insert_item_number_table ("rhs", rhs, ritem[0], 1, nritems);
-  muscle_insert_unsigned_int_table ("prhs", prhs, 0, 1, nrules + 1);
-  muscle_insert_unsigned_int_table ("rline", rline, 0, 1, nrules + 1);
-  muscle_insert_symbol_number_table ("r1", r1, 0, 1, nrules + 1);
-  muscle_insert_unsigned_int_table ("r2", r2, 0, 1, nrules + 1);
+  muscle_insert_unsigned_int_table ("rline", rline, 0, 0, nrules);
+  muscle_insert_symbol_number_table ("r1", r1, 0, 0, nrules);
+  muscle_insert_unsigned_int_table ("r2", r2, 0, 0, nrules);
+  muscle_insert_int_table ("dprec", dprec, 0, 0, nrules);
+  muscle_insert_int_table ("merger", merger, 0, 0, nrules);
+
+  MUSCLE_INSERT_INT ("rules_number", nrules);
+  MUSCLE_INSERT_INT ("max_left_semantic_context", max_left_semantic_context);

 
 

-  free (rhs);
-  free (prhs);

   free (rline);
   free (r1);
   free (r2);
   free (rline);
   free (r1);
   free (r2);

+  free (dprec);
+  free (merger);

 }
 
 /*--------------------------------------------.
 }
 
 /*--------------------------------------------.


@@ -331,689 +252,307 @@ prepare_rules (void)
 static void
 prepare_states (void)
 {
 static void
 prepare_states (void)
 {

-  size_t i;
-  symbol_number_t *values =
-    (symbol_number_t *) alloca (sizeof (symbol_number_t) * nstates);
+  state_number i;
+  symbol_number *values = xnmalloc (nstates, sizeof *values);

   for (i = 0; i < nstates; ++i)
     values[i] = states[i]->accessing_symbol;
   muscle_insert_symbol_number_table ("stos", values,
   for (i = 0; i < nstates; ++i)
     values[i] = states[i]->accessing_symbol;
   muscle_insert_symbol_number_table ("stos", values,

-                                   0, 1, nstates);
+                                    0, 1, nstates);
+  free (values);
+
+  MUSCLE_INSERT_INT ("last", high);
+  MUSCLE_INSERT_INT ("final_state_number", final_state->number);
+  MUSCLE_INSERT_INT ("states_number", nstates);

 }
 
 
 }
 
 

-/*------------------------------------------------------------------.
-| Decide what to do for each type of token if seen as the lookahead |
-| token in specified state.  The value returned is used as the      |
-| default action (yydefact) for the state.  In addition, actrow is  |
-| filled with what to do for each kind of token, index by symbol    |
-| number, with zero meaning do the default action.  The value       |
-| SHRT_MIN, a very negative number, means this situation is an      |
-| error.  The parser recognizes this value specially.               |
-|                                                                   |
-| This is where conflicts are resolved.  The loop over lookahead    |
-| rules considered lower-numbered rules last, and the last rule     |
-| considered that likes a token gets to handle it.                  |
-`------------------------------------------------------------------*/
+/*-------------------------------------------------------.
+| Compare two symbols by type-name, and then by number.  |
+`-------------------------------------------------------*/

 
 static int
 
 static int

-action_row (state_t *state)
+symbol_type_name_cmp (const symbol **lhs, const symbol **rhs)

 {
 {

-  int i;
-  int default_rule = 0;
-  reductions *redp = state->reductions;
-  shifts *shiftp = state->shifts;
-  errs *errp = state->errs;
-  /* set nonzero to inhibit having any default reduction */
-  int nodefault = 0;
-
-  for (i = 0; i < ntokens; i++)
-    actrow[i] = 0;
-
-  if (redp->nreds >= 1)
-    {
-      int j;
-      /* loop over all the rules available here which require
-        lookahead */
-      for (i = state->nlookaheads - 1; i >= 0; --i)
-       /* and find each token which the rule finds acceptable
-          to come next */
-       for (j = 0; j < ntokens; j++)
-         /* and record this rule as the rule to use if that
-            token follows.  */
-         if (bitset_test (state->lookaheads[i], j))
-           actrow[j] = -state->lookaheads_rule[i]->number;
-    }
-
-  /* Now see which tokens are allowed for shifts in this state.  For
-     them, record the shift as the thing to do.  So shift is preferred
-     to reduce.  */
-  for (i = 0; i < shiftp->nshifts; i++)
-    {
-      symbol_number_t symbol;
-      int shift_state = shiftp->shifts[i];
-      if (!shift_state)
-       continue;
-
-      symbol = states[shift_state]->accessing_symbol;
-
-      if (ISVAR (symbol))
-       break;
-
-      actrow[symbol] = shift_state;
-
-      /* Do not use any default reduction if there is a shift for
-        error */
-      if (symbol == errtoken->number)
-       nodefault = 1;
-    }
-
-  /* See which tokens are an explicit error in this state (due to
-     %nonassoc).  For them, record SHRT_MIN as the action.  */
-  for (i = 0; i < errp->nerrs; i++)
-    {
-      int symbol = errp->errs[i];
-      actrow[symbol] = SHRT_MIN;
-    }
-
-  /* Now find the most common reduction and make it the default action
-     for this state.  */
-
-  if (redp->nreds >= 1 && !nodefault)
-    {
-      if (state->consistent)
-       default_rule = redp->rules[0];
-      else
-       {
-         int max = 0;
-         for (i = 0; i < state->nlookaheads; i++)
-           {
-             int count = 0;
-             int rule = -state->lookaheads_rule[i]->number;
-             int j;
-
-             for (j = 0; j < ntokens; j++)
-               if (actrow[j] == rule)
-                 count++;
-
-             if (count > max)
-               {
-                 max = count;
-                 default_rule = rule;
-               }
-           }
-
-         /* actions which match the default are replaced with zero,
-            which means "use the default" */
-
-         if (max > 0)
-           {
-             int j;
-             for (j = 0; j < ntokens; j++)
-               if (actrow[j] == default_rule)
-                 actrow[j] = 0;
-
-             default_rule = -default_rule;
-           }
-       }
-    }
-
-  /* If have no default rule, the default is an error.
-     So replace any action which says "error" with "use default".  */
-
-  if (default_rule == 0)
-    for (i = 0; i < ntokens; i++)
-      if (actrow[i] == SHRT_MIN)
-       actrow[i] = 0;
-
-  return default_rule;
+  int res = UNIQSTR_CMP((*lhs)->type_name, (*rhs)->type_name);
+  if (res)
+    return res;
+  return (*lhs)->number - (*rhs)->number;

 }
 
 
 }
 
 

-static void
-save_row (int state)
-{
-  int i;
-  int count;
-  short *sp;
-  short *sp1;
-  short *sp2;
-
-  count = 0;
-  for (i = 0; i < ntokens; i++)
-    if (actrow[i] != 0)
-      count++;
-
-  if (count == 0)
-    return;
-
-  froms[state] = sp1 = sp = XCALLOC (short, count);
-  tos[state] = sp2 = XCALLOC (short, count);
-
-  for (i = 0; i < ntokens; i++)
-    if (actrow[i] != 0)
-      {
-       *sp1++ = i;
-       *sp2++ = actrow[i];
-      }
+/*----------------------------------------------------------------.
+| Return a (malloc'ed) table of the symbols sorted by type-name.  |
+`----------------------------------------------------------------*/

 
 

-  tally[state] = count;
-  width[state] = sp1[-1] - sp[0] + 1;
+static symbol **
+symbols_by_type_name (void)
+{
+  typedef int (*qcmp_type) (const void *, const void *);
+  symbol **res = xmemdup (symbols, nsyms * sizeof *res);
+  qsort (res, nsyms, sizeof *res, (qcmp_type) &symbol_type_name_cmp);
+  return res;

 }
 
 
 /*------------------------------------------------------------------.
 }
 
 
 /*------------------------------------------------------------------.

-| Figure out the actions for the specified state, indexed by        |
-| lookahead token type.                                             |
-|                                                                   |
-| The YYDEFACT table is output now.  The detailed info is saved for |
-| putting into YYTABLE later.                                       |
+| Define b4_type_names, which is a list of (lists of the numbers of |
+| symbols with same type-name).                                     |

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

-token_actions (void)
-{
-  size_t i;
-  short *yydefact = XCALLOC (short, nstates);
-
-  actrow = XCALLOC (short, ntokens);
-  for (i = 0; i < nstates; ++i)
-    {
-      yydefact[i] = action_row (states[i]);
-      save_row (i);
-    }
-
-  muscle_insert_short_table ("defact", yydefact,
-                            yydefact[0], 1, nstates);
-  XFREE (actrow);
-  XFREE (yydefact);
-}
-
-
-/*-----------------------------.
-| Output the actions to OOUT.  |
-`-----------------------------*/
-
-void
-actions_output (FILE *out)
-{
-  int rule;
-
-  fputs ("m4_define([b4_actions], \n[[", out);
-  for (rule = 1; rule < nrules + 1; ++rule)
-    if (rules[rule].action)
-      {
-       fprintf (out, "  case %d:\n", rule);
-
-       if (!no_lines_flag)
-         fprintf (out, muscle_find ("linef"),
-                  rules[rule].action_location.first_line,
-                  quotearg_style (c_quoting_style,
-                                  muscle_find ("filename")));
-       fprintf (out, "    %s\n    break;\n\n",
-                rules[rule].action);
-      }
-  fputs ("]])\n\n", out);
-}
-
-
-/*---------------------------------------.
-| Output the tokens definition to OOUT.  |
-`---------------------------------------*/
-
-void
-token_definitions_output (FILE *out)
+type_names_output (FILE *out)

 {
   int i;
 {
   int i;

-  int first = 1;
-
-  fputs ("m4_define([b4_tokens], \n[", out);
-  for (i = 0; i < ntokens; ++i)
+  symbol **syms = symbols_by_type_name ();
+  fputs ("m4_define([b4_type_names],\n[", out);
+  for (i = 0; i < nsyms; /* nothing */)

     {
     {

-      symbol_t *symbol = symbols[i];
-      int number = symbol->user_token_number;
-
-      /* At this stage, if there are literal aliases, they are part of
-        SYMBOLS, so we should not find symbols which are the aliases
-        here.  */
-      assert (number != USER_NUMBER_ALIAS);
-
-      /* Skip error token.  */
-      if (symbol == errtoken)
-       continue;
-
-      /* If this string has an alias, then it is necessarily the alias
-        which is to be output.  */
-      if (symbol->alias)
-       symbol = symbol->alias;
-
-      /* Don't output literal chars or strings (when defined only as a
-        string).  Note that must be done after the alias resolution:
-        think about `%token 'f' "f"'.  */
-      if (symbol->tag[0] == '\'' || symbol->tag[0] == '\"')
-       continue;
-
-      /* Don't #define nonliteral tokens whose names contain periods
-        or '$' (as does the default value of the EOF token).  */
-      if (strchr (symbol->tag, '.') || strchr (symbol->tag, '$'))
-       continue;
-
-      fprintf (out, "%s[[[%s]], [%d]]",
-              first ? "" : ",\n", symbol->tag, number);
-
-      first = 0;
+      // The index of the first symbol of the current type-name.
+      int i0 = i;
+      fputs (i ? ",\n[" : "[", out);
+      for (; i < nsyms && syms[i]->type_name == syms[i0]->type_name; ++i)
+        fprintf (out, "%s%d", i != i0 ? ", " : "", syms[i]->number);
+      fputs ("]", out);

     }
   fputs ("])\n\n", out);
     }
   fputs ("])\n\n", out);

+  free (syms);

 }
 
 
 }
 
 

-/*----------------------------------------.
-| Output the symbol destructors to OOUT.  |
-`----------------------------------------*/
+/*-------------------------------------.
+| The list of all the symbol numbers.  |
+`-------------------------------------*/

 
 static void
 
 static void

-symbol_destructors_output (FILE *out)
+symbol_numbers_output (FILE *out)

 {
   int i;
 {
   int i;

-  int first = 1;
-
-  fputs ("m4_define([b4_symbol_destructors], \n[", out);
+  fputs ("m4_define([b4_symbol_numbers],\n[", out);

   for (i = 0; i < nsyms; ++i)
   for (i = 0; i < nsyms; ++i)

-    if (symbols[i]->destructor)
-      {
-       symbol_t *symbol = symbols[i];
-
-       /* Symbol-number, destructor. */
-       fprintf (out, "%s[[[%d]], [[%s]], [[%s]]]",
-                first ? "" : ",\n",
-                symbol->number, symbol->destructor, symbol->type_name);
-
-       first = 0;
-      }
+    fprintf (out, "%s[%d]", i ? ", " : "", i);

   fputs ("])\n\n", out);
 }
 
 
   fputs ("])\n\n", out);
 }
 
 

-static void
-save_column (int symbol, int default_state)
-{
-  int i;
-  short *sp;
-  short *sp1;
-  short *sp2;
-  int count;
-  int symno = symbol - ntokens + nstates;
-
-  short begin = goto_map[symbol];
-  short end = goto_map[symbol + 1];
-
-  count = 0;
-  for (i = begin; i < end; i++)
-    if (to_state[i] != default_state)
-      count++;
-
-  if (count == 0)
-    return;
-
-  froms[symno] = sp1 = sp = XCALLOC (short, count);
-  tos[symno] = sp2 = XCALLOC (short, count);
-
-  for (i = begin; i < end; i++)
-    if (to_state[i] != default_state)
-      {
-       *sp1++ = from_state[i];
-       *sp2++ = to_state[i];
-      }
-
-  tally[symno] = count;
-  width[symno] = sp1[-1] - sp[0] + 1;
-}
+/*---------------------------------.
+| Output the user actions to OUT.  |
+`---------------------------------*/

 
 

-static int
-default_goto (int symbol)
+static void
+user_actions_output (FILE *out)

 {
 {

-  size_t i;
-  size_t m = goto_map[symbol];
-  size_t n = goto_map[symbol + 1];
-  int default_state = -1;
-  int max = 0;
-
-  if (m == n)
-    return -1;
+  rule_number r;

 
 

-  for (i = 0; i < nstates; i++)
-    state_count[i] = 0;
-
-  for (i = m; i < n; i++)
-    state_count[to_state[i]]++;
-
-  for (i = 0; i < nstates; i++)
-    if (state_count[i] > max)
+  fputs ("m4_define([b4_actions], \n[", out);
+  for (r = 0; r < nrules; ++r)
+    if (rules[r].action)

       {
       {

-       max = state_count[i];
-       default_state = i;
+       fprintf (out, "b4_case(%d, [b4_syncline(%d, ", r + 1,
+                rules[r].action_location.start.line);
+       escaped_output (out, rules[r].action_location.start.file);
+       fprintf (out, ")\n[    %s]])\n\n", rules[r].action);

       }
       }

-
-  return default_state;
+  fputs ("])\n\n", out);

 }
 
 }
 

-
-/*-------------------------------------------------------------------.
-| Figure out what to do after reducing with each rule, depending on  |
-| the saved state from before the beginning of parsing the data that |
-| matched this rule.                                                 |
-|                                                                    |
-| The YYDEFGOTO table is output now.  The detailed info is saved for |
-| putting into YYTABLE later.                                        |
-`-------------------------------------------------------------------*/
+/*------------------------------------.
+| Output the merge functions to OUT.  |
+`------------------------------------*/

 
 static void
 
 static void

-goto_actions (void)
+merger_output (FILE *out)

 {
 {

-  int i;
-  short *yydefgoto = XMALLOC (short, nsyms - ntokens);
+  int n;
+  merger_list* p;

 
 

-  state_count = XCALLOC (short, nstates);
-  for (i = ntokens; i < nsyms; ++i)
+  fputs ("m4_define([b4_mergers], \n[[", out);
+  for (n = 1, p = merge_functions; p != NULL; n += 1, p = p->next)

     {
     {

-      int default_state = default_goto (i);
-      save_column (i, default_state);
-      yydefgoto[i - ntokens] = default_state;
+      if (p->type[0] == '\0')
+       fprintf (out, "  case %d: *yy0 = %s (*yy0, *yy1); break;\n",
+                n, p->name);
+      else
+       fprintf (out, "  case %d: yy0->%s = %s (*yy0, *yy1); break;\n",
+                n, p->type, p->name);

     }
     }

-
-  muscle_insert_short_table ("defgoto", yydefgoto,
-                            yydefgoto[0], 1, nsyms - ntokens);
-  XFREE (state_count);
-  XFREE (yydefgoto);
+  fputs ("]])\n\n", out);

 }
 
 
 }
 
 

-/* The next few functions decide how to pack the actions and gotos
-   information into yytable. */
+/*---------------------------------------------.
+| Prepare the muscles for symbol definitions.  |
+`---------------------------------------------*/

 
 static void
 
 static void

-sort_actions (void)
+prepare_symbol_definitions (void)

 {
   int i;
 {
   int i;

-
-  order = XCALLOC (short, nvectors);
-  nentries = 0;
-
-  for (i = 0; i < nvectors; i++)
-    if (tally[i] > 0)
-      {
-       int k;
-       int t = tally[i];
-       int w = width[i];
-       int j = nentries - 1;
-
-       while (j >= 0 && (width[order[j]] < w))
-         j--;
-
-       while (j >= 0 && (width[order[j]] == w) && (tally[order[j]] < t))
-         j--;
-
-       for (k = nentries - 1; k > j; k--)
-         order[k + 1] = order[k];
-
-       order[j + 1] = i;
-       nentries++;
-      }
-}
-
-
-static int
-matching_state (int vector)
-{
-  int i = order[vector];
-  int t;
-  int w;
-  int prev;
-
-  if (i >= (int) nstates)
-    return -1;
-
-  t = tally[i];
-  w = width[i];
-
-  for (prev = vector - 1; prev >= 0; prev--)
+  for (i = 0; i < nsyms; ++i)

     {
     {

-      int j = order[prev];
-      int k;
-      int match = 1;
-
-      if (width[j] != w || tally[j] != t)
-       return -1;
-
-      for (k = 0; match && k < t; k++)
-       if (tos[j][k] != tos[i][k] || froms[j][k] != froms[i][k])
-         match = 0;
-
-      if (match)
-       return j;
+      symbol *sym = symbols[i];
+      const char *key;
+      const char *value;
+
+#define SET_KEY(Entry)                                                  \
+      obstack_fgrow2 (&format_obstack, "symbol(%d, %s)", i, Entry);     \
+      obstack_1grow (&format_obstack, 0);                               \
+      key = obstack_finish (&format_obstack);
+
+      // Whether the symbol has an identifier.
+      value = symbol_id_get (sym);
+      SET_KEY("has_id");
+      MUSCLE_INSERT_INT (key, !!value);
+
+      // Its identifier.
+      SET_KEY("id");
+      MUSCLE_INSERT_STRING (key, value ? value : "");
+
+      // Its tag.  Typically for documentation purpose.
+      SET_KEY("tag");
+      MUSCLE_INSERT_STRING (key, sym->tag);
+
+      SET_KEY("user_number");
+      MUSCLE_INSERT_INT (key, sym->user_token_number);
+
+      SET_KEY("is_token");
+      MUSCLE_INSERT_INT (key,
+                         i < ntokens && sym != errtoken && sym != undeftoken);
+
+      SET_KEY("number");
+      MUSCLE_INSERT_INT (key, sym->number);
+
+      SET_KEY("has_type");
+      MUSCLE_INSERT_INT (key, !!sym->type_name);
+
+      SET_KEY("type");
+      MUSCLE_INSERT_STRING (key, sym->type_name ? sym->type_name : "");
+
+#define CODE_PROP(PropName)                                             \
+      do {                                                              \
+        code_props const *p = symbol_ ## PropName ## _get (sym);        \
+        SET_KEY("has_" #PropName);                                      \
+        MUSCLE_INSERT_INT (key, !!p->code);                             \
+                                                                        \
+        if (p->code)                                                    \
+          {                                                             \
+            SET_KEY(#PropName "_file");                                 \
+            MUSCLE_INSERT_STRING (key, p->location.start.file);         \
+                                                                        \
+            SET_KEY(#PropName "_line");                                 \
+            MUSCLE_INSERT_INT (key, p->location.start.line);            \
+                                                                        \
+            SET_KEY(#PropName);                                         \
+            MUSCLE_INSERT_STRING_RAW (key, p->code);                    \
+          }                                                             \
+      } while (0)
+
+      CODE_PROP(destructor);
+      CODE_PROP(printer);
+#undef CODE_PROP
+#undef SET_KEY

     }
     }

-
-  return -1;

 }
 
 
 }
 
 

-static int
-pack_vector (int vector)
-{
-  int i = order[vector];
-  int j;
-  int t = tally[i];
-  int loc = 0;
-  short *from = froms[i];
-  short *to = tos[i];
-
-  assert (t);
-
-  for (j = lowzero - from[0]; j < (int) table_size; j++)
-    {
-      int k;
-      int ok = 1;
-
-      for (k = 0; ok && k < t; k++)
-       {
-         loc = j + from[k];
-         if (loc > (int) table_size)
-           table_grow (loc);
-
-         if (table[loc] != 0)
-           ok = 0;
-       }
-
-      for (k = 0; ok && k < vector; k++)
-       if (pos[k] == j)
-         ok = 0;
-
-      if (ok)
-       {
-         for (k = 0; k < t; k++)
-           {
-             loc = j + from[k];
-             table[loc] = to[k];
-             check[loc] = from[k];
-           }
-
-         while (table[lowzero] != 0)
-           lowzero++;
-
-         if (loc > high)
-           high = loc;
-
-         return j;
-       }
-    }
-#define pack_vector_succeeded 0
-  assert (pack_vector_succeeded);
-  return 0;
-}
-
+/*--------------------------------------.
+| Output the tokens definition to OUT.  |
+`--------------------------------------*/

 
 static void
 
 static void

-pack_table (void)
+token_definitions_output (FILE *out)

 {
   int i;
 {
   int i;

-  int place;
-  int state;
-
-  base = XCALLOC (short, nvectors);
-  pos = XCALLOC (short, nentries);
-  table = XCALLOC (short, table_size);
-  check = XCALLOC (short, table_size);
+  char const *sep = "";

 
 

-  lowzero = 0;
-  high = 0;
-
-  for (i = 0; i < nvectors; i++)
-    base[i] = SHRT_MIN;
-
-  for (i = 0; i < (int) table_size; i++)
-    check[i] = -1;
-
-  for (i = 0; i < nentries; i++)
+  fputs ("m4_define([b4_tokens], \n[", out);
+  for (i = 0; i < ntokens; ++i)

     {
     {

-      state = matching_state (i);
-
-      if (state < 0)
-       place = pack_vector (i);
-      else
-       place = base[state];
-
-      pos[i] = place;
-      base[order[i]] = place;
-    }
+      symbol *sym = symbols[i];
+      int number = sym->user_token_number;
+      uniqstr id = symbol_id_get (sym);

 
 

-  for (i = 0; i < nvectors; i++)
-    {
-      XFREE (froms[i]);
-      XFREE (tos[i]);
+      /* At this stage, if there are literal aliases, they are part of
+        SYMBOLS, so we should not find symbols which are the aliases
+        here.  */
+      aver (number != USER_NUMBER_ALIAS);
+
+      /* Skip error token and tokens without identifier.  */
+      if (sym != errtoken && id)
+        {
+          fprintf (out, "%s[[[%s]], %d]",
+                   sep, id, number);
+          sep = ",\n";
+        }

     }
     }

-
-  XFREE (froms);
-  XFREE (tos);
-  XFREE (pos);
-}
-
-/* the following functions output yytable, yycheck
-   and the vectors whose elements index the portion starts */
-
-static void
-output_base (void)
-{
-  /* Output pact. */
-  muscle_insert_short_table ("pact", base,
-                            base[0], 1, nstates);
-
-  /* Output pgoto. */
-  muscle_insert_short_table ("pgoto", base,
-                            base[nstates], nstates + 1, nvectors);
-  XFREE (base);
-}
-
-
-static void
-output_table (void)
-{
-  muscle_insert_short_table ("table", table,
-                            table[0], 1, high + 1);
-  XFREE (table);
-}
-
-
-static void
-output_check (void)
-{
-  muscle_insert_short_table ("check", check,
-                            check[0], 1, high + 1);
-  XFREE (check);
+  fputs ("])\n\n", out);

 }
 
 }
 

-/*-----------------------------------------------------------------.
-| Compute and output yydefact, yydefgoto, yypact, yypgoto, yytable |
-| and yycheck.                                                     |
-`-----------------------------------------------------------------*/

 
 static void
 
 static void

-output_actions (void)
+prepare_actions (void)

 {
 {

-  size_t i;
-  nvectors = nstates + nvars;
-
-  froms = XCALLOC (short *, nvectors);
-  tos = XCALLOC (short *, nvectors);
-  tally = XCALLOC (short, nvectors);
-  width = XCALLOC (short, nvectors);
+  /* Figure out the actions for the specified state, indexed by
+     lookahead token type.  */

 
 

-  token_actions ();
-  bitsetv_free (LA);
-  free (LArule);
+  muscle_insert_rule_number_table ("defact", yydefact,
+                                  yydefact[0], 1, nstates);

 
 

-  goto_actions ();
-  XFREE (goto_map + ntokens);
-  XFREE (from_state);
-  XFREE (to_state);
+  /* Figure out what to do after reducing with each rule, depending on
+     the saved state from before the beginning of parsing the data
+     that matched this rule.  */
+  muscle_insert_state_number_table ("defgoto", yydefgoto,
+                                   yydefgoto[0], 1, nsyms - ntokens);

 
 

-  sort_actions ();
-  pack_table ();

 
 

-  output_base ();
-  output_table ();
+  /* Output PACT. */
+  muscle_insert_base_table ("pact", base,
+                            base[0], 1, nstates);
+  MUSCLE_INSERT_INT ("pact_ninf", base_ninf);

 
 

-  output_check ();
+  /* Output PGOTO. */
+  muscle_insert_base_table ("pgoto", base,
+                            base[nstates], nstates + 1, nvectors);

 
 

-  for (i = 0; i < nstates; ++i)
-    {
-      free (states[i]->shifts);
-      XFREE (states[i]->reductions);
-      free (states[i]->errs);
-      free (states[i]);
-    }
-  XFREE (states);
+  muscle_insert_base_table ("table", table,
+                           table[0], 1, high + 1);
+  MUSCLE_INSERT_INT ("table_ninf", table_ninf);
+
+  muscle_insert_base_table ("check", check,
+                           check[0], 1, high + 1);
+
+  /* GLR parsing slightly modifies YYTABLE and YYCHECK (and thus
+     YYPACT) so that in states with unresolved conflicts, the default
+     reduction is not used in the conflicted entries, so that there is
+     a place to put a conflict pointer.
+
+     This means that YYCONFLP and YYCONFL are nonsense for a non-GLR
+     parser, so we could avoid accidents by not writing them out in
+     that case.  Nevertheless, it seems even better to be able to use
+     the GLR skeletons even without the non-deterministic tables.  */
+  muscle_insert_unsigned_int_table ("conflict_list_heads", conflict_table,
+                                   conflict_table[0], 1, high + 1);
+  muscle_insert_unsigned_int_table ("conflicting_rules", conflict_list,
+                                   0, 1, conflict_list_cnt);

 }
 
 }
 

-\f
-/*----------------------.
-| Run our backend, M4.  |
-`----------------------*/
+
+/*--------------------------------------------.
+| Output the definitions of all the muscles.  |
+`--------------------------------------------*/

 
 static void
 
 static void

-m4_invoke (const char *definitions)
+muscles_output (FILE *out)

 {
 {

-  /* Invoke m4 on the definition of the muscles, and the skeleton. */
-  const char *bison_pkgdatadir = getenv ("BISON_PKGDATADIR");
-  const char *m4 = getenv ("M4");
-  int pkg_data_len;
-  char *full_skeleton;
-
-  if (!m4)
-    m4 = M4;
-  if (!bison_pkgdatadir)
-    bison_pkgdatadir = PKGDATADIR;
-  pkg_data_len = strlen (bison_pkgdatadir);
-  full_skeleton = XMALLOC (char, pkg_data_len + strlen (skeleton) + 2);
-  if (bison_pkgdatadir[pkg_data_len-1] == '/')
-    sprintf (full_skeleton, "%s%s", bison_pkgdatadir, skeleton);
-  else
-    sprintf (full_skeleton, "%s/%s", bison_pkgdatadir, skeleton);
-  if (trace_flag)
-    fprintf (stderr,
-            "running: %s -I %s m4sugar/m4sugar.m4 %s %s\n",
-            m4, bison_pkgdatadir, definitions, full_skeleton);
-  skel_in = readpipe (m4,
-                     "-I", bison_pkgdatadir,
-                     "m4sugar/m4sugar.m4",
-                     definitions,
-                     full_skeleton,
-                     NULL);
-  XFREE (full_skeleton);
-  if (!skel_in)
-    error (EXIT_FAILURE, errno, "cannot run m4");
-  skel_lex ();
-
+  fputs ("m4_init()\n", out);
+  merger_output (out);
+  symbol_numbers_output (out);
+  token_definitions_output (out);
+  type_names_output (out);
+  user_actions_output (out);
+  // Must be last.
+  muscles_m4_output (out);

 }
 }

-
+\f

 /*---------------------------.
 | Call the skeleton parser.  |
 `---------------------------*/
 /*---------------------------.
 | Call the skeleton parser.  |
 `---------------------------*/


@@ -1021,89 +560,169 @@ m4_invoke (const char *definitions)
 static void
 output_skeleton (void)
 {
 static void
 output_skeleton (void)
 {

-  /* Store the definition of all the muscles. */
-  const char *tempdir = getenv ("TMPDIR");
-  char *tempfile = NULL;
-  FILE *out = NULL;
-  int fd;
-
-  if (tempdir == NULL)
-    tempdir = DEFAULT_TMPDIR;
-  tempfile = xmalloc (strlen (tempdir) + 11);
-  sprintf (tempfile, "%s/bsnXXXXXX", tempdir);
-  fd = mkstemp (tempfile);
-  if (fd == -1)
-    error (EXIT_FAILURE, errno, "%s", tempfile);
-
-  out = fdopen (fd, "w");
-  if (out == NULL)
-    error (EXIT_FAILURE, errno, "%s", tempfile);
-
-  /* There are no comments, especially not `#': we do want M4 expansion
-     after `#': think of CPP macros!  */
-  fputs ("m4_changecom()\n", out);
-  fputs ("m4_init()\n", out);
+  FILE *in;
+  int filter_fd[2];
+  char const *argv[9];
+  pid_t pid;
+
+  /* Compute the names of the package data dir and skeleton files.  */
+  char const m4sugar[] = "m4sugar/m4sugar.m4";
+  char const m4bison[] = "bison.m4";
+  char *full_m4sugar;
+  char *full_m4bison;
+  char *full_skeleton;
+  char const *p;
+  char const *m4 = (p = getenv ("M4")) ? p : M4;
+  char const *pkgdatadir = compute_pkgdatadir ();
+  size_t skeleton_size = strlen (skeleton) + 1;
+  size_t pkgdatadirlen = strlen (pkgdatadir);
+  while (pkgdatadirlen && pkgdatadir[pkgdatadirlen - 1] == '/')
+    pkgdatadirlen--;
+  full_skeleton = xmalloc (pkgdatadirlen + 1
+                          + (skeleton_size < sizeof m4sugar
+                             ? sizeof m4sugar : skeleton_size));
+  strncpy (full_skeleton, pkgdatadir, pkgdatadirlen);
+  full_skeleton[pkgdatadirlen] = '/';
+  strcpy (full_skeleton + pkgdatadirlen + 1, m4sugar);
+  full_m4sugar = xstrdup (full_skeleton);
+  strcpy (full_skeleton + pkgdatadirlen + 1, m4bison);
+  full_m4bison = xstrdup (full_skeleton);
+  if (strchr (skeleton, '/'))
+    strcpy (full_skeleton, skeleton);
+  else
+    strcpy (full_skeleton + pkgdatadirlen + 1, skeleton);

 
 

-  actions_output (out);
-  token_definitions_output (out);
-  symbol_destructors_output (out);
+  /* Test whether m4sugar.m4 is readable, to check for proper
+     installation.  A faulty installation can cause deadlock, so a
+     cheap sanity check is worthwhile.  */
+  xfclose (xfopen (full_m4sugar, "r"));

 
 

-  muscles_m4_output (out);
+  /* Create an m4 subprocess connected to us via two pipes.  */

 
 

-  fputs ("m4_wrap([m4_divert_pop(0)])\n", out);
-  fputs ("m4_divert_push(0)dnl\n", out);
-  xfclose (out);
+  if (trace_flag & trace_tools)
+    fprintf (stderr, "running: %s %s - %s %s\n",
+             m4, full_m4sugar, full_m4bison, full_skeleton);

 
 

-  m4_invoke (tempfile);
+  /* Some future version of GNU M4 (most likely 1.6) may treat the -dV in a
+     position-dependent manner.  Keep it as the first argument so that all
+     files are traced.

 
 

-  /* If `debugging', keep this file alive. */
-  if (!trace_flag)
-    unlink (tempfile);
+     See the thread starting at
+     <http://lists.gnu.org/archive/html/bug-bison/2008-07/msg00000.html>
+     for details.  */
+  {
+    int i = 0;
+    argv[i++] = m4;
+    argv[i++] = "-I";
+    argv[i++] = pkgdatadir;
+    if (trace_flag & trace_m4)
+      argv[i++] = "-dV";
+    argv[i++] = full_m4sugar;
+    argv[i++] = "-";
+    argv[i++] = full_m4bison;
+    argv[i++] = full_skeleton;
+    argv[i++] = NULL;
+  }
+  /* When POSIXLY_CORRECT is set, some future versions of GNU M4 (most likely
+     2.0) may drop some of the GNU extensions that Bison's skeletons depend
+     upon.  So that the next release of Bison is forward compatible with those
+     future versions of GNU M4, we unset POSIXLY_CORRECT here.
+
+     FIXME: A user might set POSIXLY_CORRECT to affect processes run from
+     macros like m4_syscmd in a custom skeleton.  For now, Bison makes no
+     promises about the behavior of custom skeletons, so this scenario is not a
+     concern.  However, we eventually want to eliminate this shortcoming.  The
+     next release of GNU M4 (1.4.12 or 1.6) will accept the -g command-line
+     option as a no-op, and later releases will accept it to indicate that
+     POSIXLY_CORRECT should be ignored.  Once the GNU M4 versions that accept
+     -g are pervasive, Bison should use -g instead of unsetting
+     POSIXLY_CORRECT.
+
+     See the thread starting at
+     <http://lists.gnu.org/archive/html/bug-bison/2008-07/msg00000.html>
+     for details.  */
+  unsetenv ("POSIXLY_CORRECT");
+  init_subpipe ();
+  pid = create_subpipe (argv, filter_fd);
+  free (full_m4sugar);
+  free (full_m4bison);
+  free (full_skeleton);
+
+  if (trace_flag & trace_muscles)
+    muscles_output (stderr);
+  {
+    FILE *out = fdopen (filter_fd[0], "w");
+    if (! out)
+      error (EXIT_FAILURE, get_errno (),
+             "fdopen");
+    muscles_output (out);
+    xfclose (out);
+  }

 
 

-  free (tempfile);
+  /* Read and process m4's output.  */
+  timevar_push (TV_M4);
+  end_of_output_subpipe (pid, filter_fd);
+  in = fdopen (filter_fd[1], "r");
+  if (! in)
+    error (EXIT_FAILURE, get_errno (),
+          "fdopen");
+  scan_skel (in);
+  xfclose (in);
+  reap_subpipe (pid, m4);
+  timevar_pop (TV_M4);

 }
 
 static void
 prepare (void)
 {
 }
 
 static void
 prepare (void)
 {

-  MUSCLE_INSERT_INT ("last", high);
-  MUSCLE_INSERT_INT ("flag", SHRT_MIN);
-  MUSCLE_INSERT_INT ("pure", pure_parser);
-  MUSCLE_INSERT_INT ("nsym", nsyms);
-  MUSCLE_INSERT_INT ("debug", debug_flag);
-  MUSCLE_INSERT_INT ("final", final_state);
-  MUSCLE_INSERT_INT ("undef_token_number", undeftoken->number);
-  MUSCLE_INSERT_INT ("user_token_number_max", max_user_token_number);
-  MUSCLE_INSERT_INT ("error_verbose", error_verbose);
-  MUSCLE_INSERT_STRING ("prefix", spec_name_prefix ? spec_name_prefix : "yy");
-
-  /* FIXME: This is wrong: the muscles should decide whether they hold
-     a copy or not, but the situation is too obscure currently.  */
-  MUSCLE_INSERT_STRING ("output_infix", output_infix ? output_infix : "");
-  MUSCLE_INSERT_STRING ("output_prefix", short_base_name);
-  MUSCLE_INSERT_STRING ("output_parser_name", parser_file_name);
-  MUSCLE_INSERT_STRING ("output_header_name", spec_defines_file);
-
-  MUSCLE_INSERT_INT ("nnts", nvars);
-  MUSCLE_INSERT_INT ("nrules", nrules);
-  MUSCLE_INSERT_INT ("nstates", nstates);
-  MUSCLE_INSERT_INT ("ntokens", ntokens);
-
-  MUSCLE_INSERT_INT ("locations_flag", locations_flag);
-  MUSCLE_INSERT_INT ("defines_flag", defines_flag);
-
-  /* Copy definitions in directive.  */
-  obstack_1grow (&pre_prologue_obstack, 0);
-  obstack_1grow (&post_prologue_obstack, 0);
-  muscle_insert ("pre_prologue", obstack_finish (&pre_prologue_obstack));
-  muscle_insert ("post_prologue", obstack_finish (&post_prologue_obstack));
-
-  /* Find the right skeleton file.  */
-  if (!skeleton)
-    skeleton = "bison.simple";
-
-  /* Parse the skeleton file and output the needed parsers.  */
-  muscle_insert ("skeleton", skeleton);
+  /* BISON_USE_PUSH_FOR_PULL is for the test suite and should not be documented
+     for the user.  */
+  char const *use_push_for_pull_env = getenv ("BISON_USE_PUSH_FOR_PULL");
+  bool use_push_for_pull_flag = false;
+  if (use_push_for_pull_env != NULL
+      && use_push_for_pull_env[0] != '\0'
+      && 0 != strcmp (use_push_for_pull_env, "0"))
+    use_push_for_pull_flag = true;
+
+  /* Flags. */
+  MUSCLE_INSERT_BOOL ("defines_flag", defines_flag);
+  MUSCLE_INSERT_BOOL ("glr_flag", glr_parser);
+  MUSCLE_INSERT_BOOL ("nondeterministic_flag", nondeterministic_parser);
+  MUSCLE_INSERT_BOOL ("synclines_flag", !no_lines_flag);
+  MUSCLE_INSERT_BOOL ("tag_seen_flag", tag_seen);
+  MUSCLE_INSERT_BOOL ("use_push_for_pull_flag", use_push_for_pull_flag);
+  MUSCLE_INSERT_BOOL ("yacc_flag", yacc_flag);
+
+  /* File names.  */
+  if (spec_name_prefix)
+    MUSCLE_INSERT_STRING ("prefix", spec_name_prefix);
+
+  MUSCLE_INSERT_STRING ("file_name_all_but_ext", all_but_ext);
+
+#define DEFINE(Name) MUSCLE_INSERT_STRING (#Name, Name ? Name : "")
+  DEFINE (dir_prefix);
+  DEFINE (parser_file_name);
+  DEFINE (spec_defines_file);
+  DEFINE (spec_file_prefix);
+  DEFINE (spec_graph_file);
+  DEFINE (spec_name_prefix);
+  DEFINE (spec_outfile);
+  DEFINE (spec_verbose_file);
+#undef DEFINE
+
+  /* Find the right skeleton file, and add muscles about the skeletons.  */
+  if (skeleton)
+    MUSCLE_INSERT_C_STRING ("skeleton", skeleton);
+  else
+    skeleton = language->skeleton;
+
+  /* About the skeletons.  */
+  {
+    /* b4_pkgdatadir is used inside m4_include in the skeletons, so digraphs
+       would never be expanded.  Hopefully no one has M4-special characters in
+       his Bison installation path.  */
+    MUSCLE_INSERT_STRING_RAW ("pkgdatadir", compute_pkgdatadir ());
+  }

 }
 
 
 }
 
 


@@ -1116,10 +735,11 @@ output (void)
 {
   obstack_init (&format_obstack);
 
 {
   obstack_init (&format_obstack);
 

-  prepare_tokens ();
+  prepare_symbols ();

   prepare_rules ();
   prepare_states ();
   prepare_rules ();
   prepare_states ();

-  output_actions ();
+  prepare_actions ();
+  prepare_symbol_definitions ();

 
   prepare ();
 
 
   prepare ();
 


@@ -1127,6 +747,11 @@ output (void)
   output_skeleton ();
 
   obstack_free (&format_obstack, NULL);
   output_skeleton ();
 
   obstack_free (&format_obstack, NULL);

-  obstack_free (&pre_prologue_obstack, NULL);
-  obstack_free (&post_prologue_obstack, NULL);
+}
+
+char const *
+compute_pkgdatadir (void)
+{
+  char const *pkgdatadir = getenv ("BISON_PKGDATADIR");
+  return pkgdatadir ? pkgdatadir : PKGDATADIR;

 }
 }