X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/43591cec981a3e7dd87bd1aef63ea0b9ec73c01c..eb1b07409f0ccad9970c8a60ded9f2a56d205b9c:/src/output.c

diff --git a/src/output.c b/src/output.c
index b23ffe8e..ef7683ec 100644
--- a/src/output.c
+++ b/src/output.c
@@ -1,5 +1,7 @@
-/* Output the generated parsing program for bison,
-   Copyright (C) 1984, 1986, 1989, 1992, 2000 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 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -15,1243 +17,602 @@
 
    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.
-   Starred ones needed only for the semantic parser.
-   Double starred 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.
-
-   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.
+   Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+   02110-1301, USA.  */
 
-   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 ??
-   YYNTBASE = ntokens.
-*/
+#include <configmake.h>
+#include <error.h>
+#include <get-errno.h>
+#include <quotearg.h>
+#include <subpipe.h>
+#include <timevar.h>
 
-#include "system.h"
-#include "getargs.h"
-#include "xalloc.h"
+#include "complain.h"
 #include "files.h"
+#include "getargs.h"
 #include "gram.h"
-#include "LR0.h"
-#include "complain.h"
+#include "muscle_tab.h"
 #include "output.h"
-#include "lalr.h"
 #include "reader.h"
-#include "conflicts.h"
-
-extern void berror PARAMS((const char *));
-
-
-
-static int nvectors;
-static int nentries;
-static short **froms;
-static short **tos;
-static short *tally;
-static short *width;
-static short *actrow;
-static short *state_count;
-static short *order;
-static short *base;
-static short *pos;
-static short *table;
-static short *check;
-static int lowzero;
-static int high;
-
-
-
-static inline void
-output_short_or_char_table (FILE *out,
-			    const char *comment,
-			    const char *type,
-			    const char *table_name,
-			    short *short_table,
-			    short first_value,
-			    short begin, short end)
-{
-  int i, j;
+#include "scan-code.h"    /* max_left_semantic_context */
+#include "scan-skel.h"
+#include "symtab.h"
+#include "tables.h"
 
-  if (comment)
-    fprintf (out, "/* %s. */\n", comment);
 
-  fprintf (out, "static const %s %s[] =\n{\n  %6d",
-	   type, table_name, first_value);
+static struct obstack format_obstack;
 
-  j = 1;
-  for (i = begin; i < end; i++)
-    {
-      putc (',', out);
-
-      if (j >= 10)
-	{
-	  fputs ("\n  ", out);
-	  j = 1;
-	}
-      else
-	{
-	  j++;
-	}
-
-      fprintf (out, "%6d", short_table[i]);
-    }
 
-  fprintf (out, "\n};\n");
-}
+/*-------------------------------------------------------------------.
+| Create a function NAME which associates to the muscle NAME the     |
+| result of formatting the FIRST and then TABLE_DATA[BEGIN..END[ (of |
+| TYPE), and to the muscle NAME_max, the max value of the            |
+| TABLE_DATA.                                                        |
+`-------------------------------------------------------------------*/
 
 
-static inline void
-output_short_table (FILE *out,
-		    const char *comment,
-		    const char *table_name,
-		    short *short_table,
-		    short first_value,
-		    short begin, short end)
-{
-  output_short_or_char_table (out, comment, "short", table_name, short_table,
-			      first_value, begin, end);
+#define GENERATE_MUSCLE_INSERT_TABLE(Name, Type)			\
+									\
+static void								\
+Name (char const *name,							\
+      Type *table_data,							\
+      Type first,							\
+      int begin,							\
+      int end)								\
+{									\
+  Type min = first;							\
+  Type max = first;							\
+  long int lmin;							\
+  long int lmax;							\
+  int i;								\
+  int j = 1;								\
+									\
+  obstack_fgrow1 (&format_obstack, "%6d", first);			\
+  for (i = begin; i < end; ++i)						\
+    {									\
+      obstack_1grow (&format_obstack, ',');				\
+      if (j >= 10)							\
+	{								\
+	  obstack_sgrow (&format_obstack, "\n  ");			\
+	  j = 1;							\
+	}								\
+      else								\
+	++j;								\
+      obstack_fgrow1 (&format_obstack, "%6d", table_data[i]);		\
+      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));		\
+									\
+  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);					\
+  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_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_item_number_table, item_number)
+GENERATE_MUSCLE_INSERT_TABLE(muscle_insert_state_number_table, state_number)
 
-/*--------------------------------------------------------------.
-| output_headers -- Output constant strings to the beginning of |
-| certain files.                                                |
-`--------------------------------------------------------------*/
-
-#define	GUARDSTR	\
-"\n\
-#include \"%s\"\n\
-extern int yyerror;\n\
-extern int yycost;\n\
-extern char * yymsg;\n\
-extern YYSTYPE yyval;\n\
-\n\
-yyguard(n, yyvsp, yylsp)\n\
-register int n;\n\
-register YYSTYPE *yyvsp;\n\
-register YYLTYPE *yylsp;\n\
-{\n\
-  yyerror = 0;\n\
-  yycost = 0;\n\
-  yymsg = 0;\n\
-  switch (n)\n\
-    {"
-
-#define	ACTSTR		\
-"\n\
-#include \"%s\"\n\
-extern YYSTYPE yyval;\n\
-extern int yychar;\n\
-\n\
-yyaction(n, yyvsp, yylsp)\n\
-register int n;\n\
-register YYSTYPE *yyvsp;\n\
-register YYLTYPE *yylsp;\n\
-{\n\
-  switch (n)\n\
-    {"
-
-#define	ACTSTR_SIMPLE	"\n  switch (yyn) {\n"
-
-void
-output_headers (void)
-{
-  if (semantic_parser)
-    fprintf (fguard, GUARDSTR, attrsfile);
-
-  if (no_parser_flag)
-    return;
-
-  fprintf (faction, (semantic_parser ? ACTSTR : ACTSTR_SIMPLE), attrsfile);
-/*  if (semantic_parser)	JF moved this below
-    fprintf(ftable, "#include \"%s\"\n", attrsfile);
-  fprintf(ftable, "#include <stdio.h>\n\n");
-*/
-
-  /* Rename certain symbols if -p was specified.  */
-  if (spec_name_prefix)
-    {
-      fprintf (ftable, "#define yyparse %sparse\n", spec_name_prefix);
-      fprintf (ftable, "#define yylex %slex\n", spec_name_prefix);
-      fprintf (ftable, "#define yyerror %serror\n", spec_name_prefix);
-      fprintf (ftable, "#define yylval %slval\n", spec_name_prefix);
-      fprintf (ftable, "#define yychar %schar\n", spec_name_prefix);
-      fprintf (ftable, "#define yydebug %sdebug\n", spec_name_prefix);
-      fprintf (ftable, "#define yynerrs %snerrs\n", spec_name_prefix);
-    }
-}
 
+/*--------------------------------------------------------------------.
+| Print to OUT a representation of STRING escaped both for C and M4.  |
+`--------------------------------------------------------------------*/
 
-/*-------------------------------------------------------.
-| Output constant strings to the ends of certain files.  |
-`-------------------------------------------------------*/
-
-void
-output_trailers (void)
+static void
+escaped_output (FILE *out, char const *string)
 {
-  if (semantic_parser)
-    fprintf (fguard, "\n    }\n}\n");
+  char const *p;
+  fprintf (out, "[[");
 
-  fprintf (faction, "\n");
-
-  if (no_parser_flag)
-    return;
+  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;
+      }
 
-  if (semantic_parser)
-    fprintf (faction, "    }\n");
-  fprintf (faction, "}\n");
+  fprintf (out, "]]");
 }
 
 
+/*------------------------------------------------------------------.
+| Prepare the muscles related to the symbols: translate, tname, and |
+| toknum.                                                           |
+`------------------------------------------------------------------*/
 
 static void
-output_token_translations (void)
-{
-  fputs ("\
-\n\
-/* YYRANSLATE(YYLEX) -- Bison token number corresponding to YYLEX. */\n",
-	 ftable);
-  if (translations)
-    {
-      fprintf (ftable,
-      "#define YYTRANSLATE(x) ((unsigned)(x) <= %d ? yytranslate[x] : %d)\
-\n\
-\n",
-	       max_user_token_number, nsyms);
-
-      output_short_or_char_table (ftable,
-	     "YYRANSLATE[YYLEX] -- Bison token number corresponding to YYLEX",
-		    ntokens < 127 ? "char" : "short",
-		    "yytranslate", token_translations,
-		    0, 1, max_user_token_number + 1);
-    }
-  else
-    {
-      fprintf (ftable, "\n#define YYTRANSLATE(x) (x)\n");
-    }
-}
-
-
-static void
-output_gram (void)
+prepare_symbols (void)
 {
-  /* With the ordinary parser,
-     yyprhs and yyrhs are needed only for yydebug. */
-  /* With the no_parser option, all tables are generated */
-  if (!semantic_parser && !no_parser_flag)
-    fprintf (ftable, "\n#if YYDEBUG != 0\n");
-
-  output_short_table (ftable, NULL, "yyprhs", rrhs,
-		      0, 1, nrules + 1);
-
+  MUSCLE_INSERT_BOOL ("token_table", token_table_flag);
+  MUSCLE_INSERT_INT ("tokens_number", ntokens);
+  MUSCLE_INSERT_INT ("nterms_number", nvars);
+  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",
+				     token_translations,
+				     token_translations[0],
+				     1, max_user_token_number + 1);
+
+  /* tname -- token names.  */
   {
-    size_t yyrhs_size = 1;
-    short *yyrhs, *sp;
     int i;
+    /* We assume that the table will be output starting at column 2. */
+    int j = 2;
+    for (i = 0; i < nsyms; i++)
+      {
+	char const *cp = quotearg_style (c_quoting_style, symbols[i]->tag);
+	/* Width of the next token, including the two quotes, the
+	   comma and the space.  */
+	int width = strlen (cp) + 2;
 
-    for (sp = ritem + 1; *sp; sp++)
-      ++yyrhs_size;
-    yyrhs = XMALLOC (short, yyrhs_size);
+	if (j + width > 75)
+	  {
+	    obstack_sgrow (&format_obstack, "\n ");
+	    j = 1;
+	  }
 
-    for (sp = ritem + 1, i = 1; *sp; ++sp, ++i)
-      yyrhs[i] = *sp > 0 ? *sp : 0;
+	if (i)
+	  obstack_1grow (&format_obstack, ' ');
+	MUSCLE_OBSTACK_SGROW (&format_obstack, cp);
+	obstack_1grow (&format_obstack, ',');
+	j += width;
+      }
+    obstack_sgrow (&format_obstack, " ]b4_null[");
 
-    output_short_table (ftable, NULL, "yyrhs", yyrhs,
-			ritem[0], 1, yyrhs_size);
-    XFREE (yyrhs);
+    /* Finish table and store. */
+    obstack_1grow (&format_obstack, 0);
+    muscle_insert ("tname", obstack_finish (&format_obstack));
   }
 
-  if (!semantic_parser && !no_parser_flag)
-    fprintf (ftable, "\n#endif\n");
-}
-
-
-static void
-output_stos (void)
-{
-  output_short_table (ftable, NULL, "yystos", accessing_symbol,
-		      0, 1, nstates);
-}
-
-
-static void
-output_rule_data (void)
-{
-  int i;
-  int j;
-  short *short_tab = NULL;
-
-  fputs ("\n\
-#if YYDEBUG != 0\n",
-	 ftable);
-
-  output_short_table (ftable,
-           "YYRLINE[YYN] -- source line where rule number YYN was defined",
-		      "yyrline", rline,
-		      0, 1, nrules + 1);
-
-  fputs ("#endif\n\n", ftable);
-
-  if (token_table_flag || no_parser_flag)
-    {
-      fprintf (ftable, "#define YYNTOKENS %d\n", ntokens);
-      fprintf (ftable, "#define YYNNTS %d\n", nvars);
-      fprintf (ftable, "#define YYNRULES %d\n", nrules);
-      fprintf (ftable, "#define YYNSTATES %d\n", nstates);
-      fprintf (ftable, "#define YYMAXUTOK %d\n\n", max_user_token_number);
-    }
-
-  /* Output the table of symbol names.  */
-  if (!token_table_flag && !no_parser_flag)
-    fputs ("\n#if YYDEBUG != 0 || defined YYERROR_VERBOSE\n\n", ftable);
-  fputs ("\
-/* YYTNAME[TOKEN_NUM] -- String name of the token TOKEN_NUM. */\n",
-	 ftable);
-  fprintf (ftable,
-	   "static const char *const yytname[] =\n{\n  ");
-
-  j = 0;
-  for (i = 0; i < nsyms; i++)
-    /* this used to be i<=nsyms, but that output a final "" symbol
-       almost by accident */
-    {
-      /* Width of the next token, including the two quotes, the coma
-	 and the space.  */
-      int strsize = 4;
-      char *p;
-
-      for (p = tags[i]; p && *p; p++)
-	if (*p == '"' || *p == '\\' || *p == '\n' || *p == '\t'
-	    || *p == '\b')
-	  strsize += 2;
-	else if (*p < 040 || *p >= 0177)
-	  strsize += 4;
-	else
-	  strsize++;
-
-      if (j + strsize > 75)
-	{
-	  fputs ("\n  ", ftable);
-	  j = 2;
-	}
-
-      putc ('\"', ftable);
-      for (p = tags[i]; p && *p; p++)
-	{
-	  if (*p == '"' || *p == '\\')
-	    {
-	      fprintf (ftable, "\\%c", *p);
-	    }
-	  else if (*p == '\n')
-	    {
-	      fprintf (ftable, "\\n");
-	    }
-	  else if (*p == '\t')
-	    {
-	      fprintf (ftable, "\\t");
-	    }
-	  else if (*p == '\b')
-	    {
-	      fprintf (ftable, "\\b");
-	    }
-	  else if (*p < 040 || *p >= 0177)
-	    {
-	      fprintf (ftable, "\\%03o", *p);
-	    }
-	  else
-	    {
-	      putc (*p, ftable);
-	    }
-	}
-
-      fputs ("\", ", ftable);
-      j += strsize;
-    }
-  /* add a NULL entry to list of tokens */
-  fprintf (ftable, "NULL\n};\n");
-
-  if (!token_table_flag && !no_parser_flag)
-    fprintf (ftable, "#endif\n\n");
-
   /* Output YYTOKNUM. */
-  if (token_table_flag)
-    {
-      output_short_table (ftable,
-		  "YYTOKNUM[YYLEX] -- Index in YYTNAME corresponding to YYLEX",
-			  "yytoknum", user_toknums,
-			  0, 1, ntokens + 1);
-    }
-
-  /* Output YYR1. */
-  output_short_table (ftable,
-	      "YYR1[YYN] -- Symbol number of symbol that rule YYN derives",
-		      "yyr1", rlhs,
-		      0, 1, nrules + 1);
-  XFREE (rlhs + 1);
-
-  putc ('\n', ftable);
-
-  /* Output YYR2. */
-  short_tab = XMALLOC (short, nrules + 1);
-  for (i = 1; i < nrules; i++)
-    short_tab[i] = rrhs[i + 1] - rrhs[i] - 1;
-  short_tab[nrules] = nitems - rrhs[nrules] - 1;
-  output_short_table (ftable,
-        "YYR2[YYN] -- Number of symbols composing right hand side of rule YYN",
-		      "yyr2", short_tab,
-		      0, 1, nrules + 1);
-  putc ('\n', ftable);
-
-  XFREE (short_tab);
-
-  XFREE (rrhs + 1);
-}
-
-
-static void
-output_defines (void)
-{
-  fprintf (ftable, "\n\n#define\tYYFINAL\t\t%d\n", final_state);
-  fprintf (ftable, "#define\tYYFLAG\t\t%d\n", MINSHORT);
-  fprintf (ftable, "#define\tYYNTBASE\t%d\n", ntokens);
+  {
+    int i;
+    int *values = xnmalloc (ntokens, sizeof *values);
+    for (i = 0; i < ntokens; ++i)
+      values[i] = symbols[i]->user_token_number;
+    muscle_insert_int_table ("toknum", values,
+			     values[0], 1, ntokens);
+    free (values);
+  }
 }
 
 
-/*------------------------------------------------------------------.
-| 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       |
-| MINSHORT, 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.                  |
-`------------------------------------------------------------------*/
-
-static int
-action_row (int state)
-{
-  int i;
-  int j;
-  int k;
-  int m = 0;
-  int n = 0;
-  int count;
-  int default_rule;
-  int nreds;
-  int max;
-  int rule;
-  int shift_state;
-  int symbol;
-  unsigned mask;
-  unsigned *wordp;
-  reductions *redp;
-  shifts *shiftp;
-  errs *errp;
-  int nodefault = 0;		/* set nonzero to inhibit having any default reduction */
-
-  for (i = 0; i < ntokens; i++)
-    actrow[i] = 0;
-
-  default_rule = 0;
-  nreds = 0;
-  redp = reduction_table[state];
-
-  if (redp)
-    {
-      nreds = redp->nreds;
-
-      if (nreds >= 1)
-	{
-	  /* loop over all the rules available here which require
-	     lookahead */
-	  m = lookaheads[state];
-	  n = lookaheads[state + 1];
-
-	  for (i = n - 1; i >= m; i--)
-	    {
-	      rule = -LAruleno[i];
-	      wordp = LA + i * tokensetsize;
-	      mask = 1;
-
-	      /* 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 (mask & *wordp)
-		    actrow[j] = rule;
-
-		  mask <<= 1;
-		  if (mask == 0)
-		    {
-		      mask = 1;
-		      wordp++;
-		    }
-		}
-	    }
-	}
-    }
-
-  shiftp = shift_table[state];
-
-  /* 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.  */
-
-  if (shiftp)
-    {
-      k = shiftp->nshifts;
-
-      for (i = 0; i < k; i++)
-	{
-	  shift_state = shiftp->shifts[i];
-	  if (!shift_state)
-	    continue;
-
-	  symbol = accessing_symbol[shift_state];
-
-	  if (ISVAR (symbol))
-	    break;
-
-	  actrow[symbol] = shift_state;
-
-	  /* Do not use any default reduction if there is a shift for
-	     error */
-	  if (symbol == error_token_number)
-	    nodefault = 1;
-	}
-    }
-
-  errp = err_table[state];
-
-  /* See which tokens are an explicit error in this state (due to
-     %nonassoc).  For them, record MINSHORT as the action.  */
-
-  if (errp)
-    {
-      k = errp->nerrs;
-
-      for (i = 0; i < k; i++)
-	{
-	  symbol = errp->errs[i];
-	  actrow[symbol] = MINSHORT;
-	}
-    }
-
-  /* Now find the most common reduction and make it the default action
-     for this state.  */
-
-  if (nreds >= 1 && !nodefault)
-    {
-      if (consistent[state])
-	default_rule = redp->rules[0];
-      else
-	{
-	  max = 0;
-	  for (i = m; i < n; i++)
-	    {
-	      count = 0;
-	      rule = -LAruleno[i];
-
-	      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)
-	    {
-	      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 (j = 0; j < ntokens; j++)
-      {
-	if (actrow[j] == MINSHORT)
-	  actrow[j] = 0;
-      }
-
-  return default_rule;
-}
-
+/*-------------------------------------------------------------.
+| Prepare the muscles related to the rules: rhs, prhs, r1, r2, |
+| rline, dprec, merger.                                        |
+`-------------------------------------------------------------*/
 
 static void
-save_row (int state)
+prepare_rules (void)
 {
-  int i;
-  int count;
-  short *sp;
-  short *sp1;
-  short *sp2;
-
-  count = 0;
-  for (i = 0; i < ntokens; i++)
+  rule_number r;
+  unsigned int i = 0;
+  item_number *rhs = xnmalloc (nritems, sizeof *rhs);
+  unsigned int *prhs = xnmalloc (nrules, sizeof *prhs);
+  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);
+
+  for (r = 0; r < nrules; ++r)
     {
-      if (actrow[i] != 0)
-	count++;
+      item_number *rhsp = NULL;
+      /* 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. */
+      r2[r] = i - prhs[r];
+      /* Separator in RHS. */
+      rhs[i++] = -1;
+      /* Line where rule was defined. */
+      rline[r] = rules[r].location.start.line;
+      /* Dynamic precedence (GLR).  */
+      dprec[r] = rules[r].dprec;
+      /* Merger-function index (GLR).  */
+      merger[r] = rules[r].merger;
     }
-
-  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];
-	}
-    }
-
-  tally[state] = count;
-  width[state] = sp1[-1] - sp[0] + 1;
+  aver (i == nritems);
+
+  muscle_insert_item_number_table ("rhs", rhs, ritem[0], 1, nritems);
+  muscle_insert_unsigned_int_table ("prhs", prhs, 0, 0, nrules);
+  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 (dprec);
+  free (merger);
 }
 
-
-/*------------------------------------------------------------------.
-| 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.                                       |
-`------------------------------------------------------------------*/
+/*--------------------------------------------.
+| Prepare the muscles related to the states.  |
+`--------------------------------------------*/
 
 static void
-token_actions (void)
+prepare_states (void)
 {
-  int i;
-  short *yydefact = XCALLOC (short, nstates);
-
-  actrow = XCALLOC (short, ntokens);
+  state_number i;
+  symbol_number *values = xnmalloc (nstates, sizeof *values);
   for (i = 0; i < nstates; ++i)
-    {
-      yydefact[i] = action_row (i);
-      save_row (i);
-    }
-  XFREE (actrow);
-
-  output_short_table (ftable,
-  "YYDEFACT[S] -- default rule to reduce with in state S when YYTABLE\n\
-   doesn't specify something else to do.  Zero means the default is an\n\
-   error",
-		      "yydefact", yydefact,
-		      yydefact[0], 1, nstates);
-  putc ('\n', ftable);
-  XFREE (yydefact);
+    values[i] = states[i]->accessing_symbol;
+  muscle_insert_symbol_number_table ("stos", values,
+				     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);
 }
 
 
-static void
-free_shifts (void)
-{
-  shifts *sp, *sptmp;	/* JF derefrenced freed ptr */
-
-  XFREE (shift_table);
-
-  for (sp = first_shift; sp; sp = sptmp)
-    {
-      sptmp = sp->next;
-      XFREE (sp);
-    }
-}
 
+/*---------------------------------.
+| Output the user actions to OUT.  |
+`---------------------------------*/
 
 static void
-free_reductions (void)
+user_actions_output (FILE *out)
 {
-  reductions *rp, *rptmp;	/* JF fixed freed ptr */
-
-  XFREE (reduction_table);
+  rule_number r;
 
-  for (rp = first_reduction; rp; rp = rptmp)
-    {
-      rptmp = rp->next;
-      XFREE (rp);
-    }
+  fputs ("m4_define([b4_actions], \n[", out);
+  for (r = 0; r < nrules; ++r)
+    if (rules[r].action)
+      {
+	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);
+      }
+  fputs ("])\n\n", out);
 }
 
-
+/*--------------------------------------.
+| Output the merge functions to OUT.   |
+`--------------------------------------*/
 
 static void
-save_column (int symbol, int default_state)
-{
-  int i;
-  short *sp;
-  short *sp1;
-  short *sp2;
-  int count;
-  int symno;
-
-  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;
-
-  symno = symbol - ntokens + nstates;
-
-  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;
-}
-
-static int
-default_goto (int symbol)
+merger_output (FILE *out)
 {
-  int i;
-  int m;
   int n;
-  int default_state;
-  int max;
-
-  m = goto_map[symbol];
-  n = goto_map[symbol + 1];
+  merger_list* p;
 
-  if (m == n)
-    return -1;
-
-  for (i = 0; i < nstates; i++)
-    state_count[i] = 0;
-
-  for (i = m; i < n; i++)
-    state_count[to_state[i]]++;
-
-  max = 0;
-  default_state = -1;
-
-  for (i = 0; i < nstates; i++)
+  fputs ("m4_define([b4_mergers], \n[[", out);
+  for (n = 1, p = merge_functions; p != NULL; n += 1, p = p->next)
     {
-      if (state_count[i] > max)
-	{
-	  max = state_count[i];
-	  default_state = i;
-	}
+      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);
     }
-
-  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 tokens definition to OUT.  |
+`--------------------------------------*/
 
 static void
-goto_actions (void)
+token_definitions_output (FILE *out)
 {
   int i;
+  char const *sep = "";
 
-  short *yydefgoto = XMALLOC (short, nsyms - ntokens);
-  state_count = XCALLOC (short, nstates);
-
-  for (i = ntokens; i < nsyms; ++i)
+  fputs ("m4_define([b4_tokens], \n[", out);
+  for (i = 0; i < ntokens; ++i)
     {
-      int default_state = default_goto (i);
-      save_column (i, default_state);
-      yydefgoto[i - ntokens] = default_state;
+      symbol *sym = symbols[i];
+      int number = sym->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.  */
+      aver (number != USER_NUMBER_ALIAS);
+
+      /* Skip error token.  */
+      if (sym == errtoken)
+	continue;
+
+      /* If this string has an alias, then it is necessarily the alias
+	 which is to be output.  */
+      if (sym->alias)
+	sym = sym->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 (sym->tag[0] == '\'' || sym->tag[0] == '\"')
+	continue;
+
+      /* Don't #define nonliteral tokens whose names contain periods
+	 or '$' (as does the default value of the EOF token).  */
+      if (strchr (sym->tag, '.') || strchr (sym->tag, '$'))
+	continue;
+
+      fprintf (out, "%s[[[%s]], %d]",
+	       sep, sym->tag, number);
+      sep = ",\n";
     }
-
-  output_short_table (ftable, NULL, "yydefgoto", 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. */
+/*---------------------------------------------------.
+| Output the symbol destructors or printers to OUT.  |
+`---------------------------------------------------*/
 
 static void
-sort_actions (void)
+symbol_code_props_output (FILE *out, char const *what,
+                          code_props const *(*get)(symbol const *))
 {
   int i;
-  int j;
-  int k;
-  int t;
-  int w;
-
-  order = XCALLOC (short, nvectors);
-  nentries = 0;
+  char const *sep = "";
 
-  for (i = 0; i < nvectors; i++)
+  fputs ("m4_define([b4_symbol_", out);
+  fputs (what, out);
+  fputs ("], \n[", out);
+  for (i = 0; i < nsyms; ++i)
     {
-      if (tally[i] > 0)
-	{
-	  t = tally[i];
-	  w = width[i];
-	  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++;
-	}
+      symbol *sym = symbols[i];
+      char const *code = (*get) (sym)->code;
+      if (code)
+        {
+          location loc = (*get) (sym)->location;
+          /* Filename, lineno,
+             Symbol-name, Symbol-number,
+             code, optional typename.  */
+          fprintf (out, "%s[", sep);
+          sep = ",\n";
+          escaped_output (out, loc.start.file);
+          fprintf (out, ", %d, ", loc.start.line);
+          escaped_output (out, sym->tag);
+          fprintf (out, ", %d, [[%s]]", sym->number, code);
+          if (sym->type_name)
+            fprintf (out, ", [[%s]]", sym->type_name);
+          fputc (']', out);
+        }
     }
-}
-
-
-static int
-matching_state (int vector)
-{
-  int i;
-  int j;
-  int k;
-  int t;
-  int w;
-  int match;
-  int prev;
-
-  i = order[vector];
-  if (i >= nstates)
-    return -1;
-
-  t = tally[i];
-  w = width[i];
-
-  for (prev = vector - 1; prev >= 0; prev--)
-    {
-      j = order[prev];
-      if (width[j] != w || tally[j] != t)
-	return -1;
-
-      match = 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;
-    }
-
-  return -1;
-}
-
-
-static int
-pack_vector (int vector)
-{
-  int i;
-  int j;
-  int k;
-  int t;
-  int loc = 0;
-  int ok;
-  short *from;
-  short *to;
-
-  i = order[vector];
-  t = tally[i];
-
-  assert (t);
-
-  from = froms[i];
-  to = tos[i];
-
-  for (j = lowzero - from[0]; j < MAXTABLE; j++)
-    {
-      ok = 1;
-
-      for (k = 0; ok && k < t; k++)
-	{
-	  loc = j + from[k];
-	  if (loc > MAXTABLE)
-	    fatal (_("maximum table size (%d) exceeded"), MAXTABLE);
-
-	  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;
-	}
-    }
-
-  berror ("pack_vector");
-  return 0;			/* JF keep lint happy */
+  fputs ("])\n\n", out);
 }
 
 
 static void
-pack_table (void)
+prepare_actions (void)
 {
-  int i;
-  int place;
-  int state;
-
-  base = XCALLOC (short, nvectors);
-  pos = XCALLOC (short, nentries);
-  table = XCALLOC (short, MAXTABLE);
-  check = XCALLOC (short, MAXTABLE);
-
-  lowzero = 0;
-  high = 0;
-
-  for (i = 0; i < nvectors; i++)
-    base[i] = MINSHORT;
-
-  for (i = 0; i < MAXTABLE; i++)
-    check[i] = -1;
-
-  for (i = 0; i < nentries; i++)
-    {
-      state = matching_state (i);
-
-      if (state < 0)
-	place = pack_vector (i);
-      else
-	place = base[state];
-
-      pos[i] = place;
-      base[order[i]] = place;
-    }
-
-  for (i = 0; i < nvectors; i++)
-    {
-      if (froms[i])
-	XFREE (froms[i]);
-      if (tos[i])
-	XFREE (tos[i]);
-    }
-
-  XFREE (froms);
-  XFREE (tos);
-  XFREE (pos);
+  /* Figure out the actions for the specified state, indexed by
+     lookahead token type.  */
+
+  muscle_insert_rule_number_table ("defact", yydefact,
+				   yydefact[0], 1, nstates);
+
+  /* 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);
+
+
+  /* Output PACT. */
+  muscle_insert_base_table ("pact", base,
+			     base[0], 1, nstates);
+  MUSCLE_INSERT_INT ("pact_ninf", base_ninf);
+
+  /* Output PGOTO. */
+  muscle_insert_base_table ("pgoto", base,
+			     base[nstates], nstates + 1, nvectors);
+
+  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);
 }
 
-/* the following functions output yytable, yycheck
-   and the vectors whose elements index the portion starts */
+
+/*---------------------------.
+| Call the skeleton parser.  |
+`---------------------------*/
 
 static void
-output_base (void)
+output_skeleton (void)
 {
-  output_short_table (ftable, NULL, "yypact", base,
-		      base[0], 1, nstates);
-
-  putc ('\n', ftable);
-
-  output_short_table (ftable, NULL, "yypgoto", base,
-		      base[nstates], nstates + 1, nvectors);
-
-  XFREE (base);
-}
-
-
-static void
-output_table (void)
-{
-  fprintf (ftable, "\n\n#define\tYYLAST\t\t%d\n\n\n", high);
-  output_short_table (ftable, NULL, "yytable", table,
-		      table[0], 1, high + 1);
-  XFREE (table);
-}
-
-
-static void
-output_check (void)
-{
-  output_short_table (ftable, NULL, "yycheck", check,
-		      check[0], 1, high + 1);
-  XFREE (check);
-}
-
-/* compute and output yydefact, yydefgoto, yypact, yypgoto, yytable
-   and yycheck.  */
-
-static void
-output_actions (void)
-{
-  nvectors = nstates + nvars;
-
-  froms = XCALLOC (short *, nvectors);
-  tos = XCALLOC (short *, nvectors);
-  tally = XCALLOC (short, nvectors);
-  width = XCALLOC (short, nvectors);
-
-  token_actions ();
-  free_shifts ();
-  free_reductions ();
-  XFREE (lookaheads);
-  XFREE (LA);
-  XFREE (LAruleno);
-  XFREE (accessing_symbol);
-
-  goto_actions ();
-  XFREE (goto_map + ntokens);
-  XFREE (from_state);
-  XFREE (to_state);
-
-  sort_actions ();
-  pack_table ();
-  putc ('\n', ftable);
-  output_base ();
-  output_table ();
-  putc ('\n', ftable);
-  output_check ();
-}
-
-/* copy the parser code into the ftable file at the end.  */
-
-static void
-output_parser (void)
-{
-  int c;
-  static int number_of_dollar_signs = 0;
-#ifdef DONTDEF
-  FILE *fpars;
-#else
-#define fpars fparser
-#endif
-
-  if (pure_parser)
-    fprintf (ftable, "#define YYPURE 1\n\n");
-
-#ifdef DONTDEF
-  /* JF no longer needed 'cuz open_extra_files changes the currently
-     open parser from bison.simple to bison.hairy */
-  if (semantic_parser)
-    fpars = fparser;
+  FILE *in;
+  FILE *out;
+  int filter_fd[2];
+  char const *argv[7];
+  pid_t pid;
+
+  /* Compute the names of the package data dir and skeleton file.
+     Test whether m4sugar.m4 is readable, to check for proper
+     installation.  A faulty installation can cause deadlock, so a
+     cheap sanity check is worthwhile.  */
+  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 = (p = getenv ("BISON_PKGDATADIR")) ? p : 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
-    fpars = fparser1;
-#endif
-
-  /* Loop over lines in the standard parser file.  */
-
-  while (1)
-    {
-      int write_line = 1;
-
-      c = getc (fpars);
-
-      /* See if the line starts with `#line.
-         If so, set write_line to 0.  */
-      if (no_lines_flag)
-	if (c == '#')
-	  {
-	    c = getc (fpars);
-	    if (c == 'l')
-	      {
-		c = getc (fpars);
-		if (c == 'i')
-		  {
-		    c = getc (fpars);
-		    if (c == 'n')
-		      {
-			c = getc (fpars);
-			if (c == 'e')
-			  write_line = 0;
-			else
-			  fprintf (ftable, "#lin");
-		      }
-		    else
-		      fprintf (ftable, "#li");
-		  }
-		else
-		  fprintf (ftable, "#l");
-	      }
-	    else
-	      fprintf (ftable, "#");
-	  }
-
-      /* now write out the line... */
-      for (; c != '\n' && c != EOF; c = getc (fpars))
-	if (write_line)
-	  {
-	    if (c == '$')
-	      {
-		number_of_dollar_signs++;
-		assert (number_of_dollar_signs == 1);
-		/* `$' in the parser file indicates where to put the actions.
-		   Copy them in at this point.  */
-		rewind (faction);
-		for (c = getc (faction); c != EOF; c = getc (faction))
-		  putc (c, ftable);
-		/* Skip the end of the line containing `$'. */
-		write_line = 0;
-	      }
-	    else
-	      putc (c, ftable);
-	  }
-      if (c == EOF)
-	break;
-      putc (c, ftable);
-    }
-  assert (number_of_dollar_signs == 1);
-}
-
-static void
-output_program (void)
-{
-  int c;
-
-  if (!no_lines_flag)
-    fprintf (ftable, "#line %d \"%s\"\n", lineno, infile);
-
-  c = getc (finput);
-  while (c != EOF)
-    {
-      putc (c, ftable);
-      c = getc (finput);
-    }
+    strcpy (full_skeleton + pkgdatadirlen + 1, skeleton);
+  xfclose (xfopen (full_m4sugar, "r"));
+
+  /* Create an m4 subprocess connected to us via two pipes.  */
+
+  if (trace_flag & trace_tools)
+    fprintf (stderr, "running: %s %s - %s %s\n",
+	     m4, full_m4sugar, full_m4bison, full_skeleton);
+
+  argv[0] = m4;
+  argv[1] = full_m4sugar;
+  argv[2] = "-";
+  argv[3] = full_m4bison;
+  argv[4] = full_skeleton;
+  argv[5] = trace_flag & trace_m4 ? "-dV" : NULL;
+  argv[6] = NULL;
+
+  init_subpipe ();
+  pid = create_subpipe (argv, filter_fd);
+  free (full_m4bison);
+  free (full_m4sugar);
+  free (full_skeleton);
+
+  out = fdopen (filter_fd[0], "w");
+  if (! out)
+    error (EXIT_FAILURE, get_errno (),
+	   "fdopen");
+
+  /* Output the definitions of all the muscles.  */
+  fputs ("m4_init()\n", out);
+
+  user_actions_output (out);
+  merger_output (out);
+  token_definitions_output (out);
+  symbol_code_props_output (out, "destructors", &symbol_destructor_get);
+  symbol_code_props_output (out, "printers", &symbol_printer_get);
+
+  muscles_m4_output (out);
+  xfclose (out);
+
+  /* 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
-free_itemsets (void)
+prepare (void)
 {
-  core *cp, *cptmp;
-
-  XFREE (state_table);
+  /* 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 ("debug_flag", debug_flag);
+  MUSCLE_INSERT_BOOL ("defines_flag", defines_flag);
+  MUSCLE_INSERT_BOOL ("error_verbose_flag", error_verbose);
+  MUSCLE_INSERT_BOOL ("glr_flag", glr_parser);
+  MUSCLE_INSERT_BOOL ("locations_flag", locations_flag);
+  MUSCLE_INSERT_BOOL ("nondeterministic_flag", nondeterministic_parser);
+  MUSCLE_INSERT_BOOL ("pull_flag", pull_parser);
+  MUSCLE_INSERT_BOOL ("pure_flag", pure_parser);
+  MUSCLE_INSERT_BOOL ("push_flag", push_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;
 
-  for (cp = first_state; cp; cp = cptmp)
-    {
-      cptmp = cp->next;
-      XFREE (cp);
-    }
+  /* About the skeletons.  */
+  {
+    char const *pkgdatadir = getenv ("BISON_PKGDATADIR");
+    /* 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",
+                              pkgdatadir ? pkgdatadir : PKGDATADIR);
+  }
 }
 
 
@@ -1262,52 +623,17 @@ free_itemsets (void)
 void
 output (void)
 {
-  int c;
+  obstack_init (&format_obstack);
 
-  /* output_token_defines(ftable);      / * JF put out token defines FIRST */
-  if (!semantic_parser)		/* JF Put out other stuff */
-    {
-      rewind (fattrs);
-      while ((c = getc (fattrs)) != EOF)
-	putc (c, ftable);
-    }
-  reader_output_yylsp (ftable);
-  if (debug_flag)
-    fputs ("\
-#ifndef YYDEBUG\n\
-# define YYDEBUG 1\n\
-#endif\n\
-\n",
-	   ftable);
-
-  if (semantic_parser)
-    fprintf (ftable, "#include \"%s\"\n", attrsfile);
-
-  if (!no_parser_flag)
-    fprintf (ftable, "#include <stdio.h>\n\n");
-
-  /* Make "const" do nothing if not in ANSI C.  */
-  fputs ("\
-#ifndef __cplusplus\n\
-# ifndef __STDC__\n\
-#  define const\n\
-# endif\n\
-#endif\n\
-\n",
-	 ftable);
-
-  free_itemsets ();
-  output_defines ();
-  output_token_translations ();
-/*   if (semantic_parser) */
-  /* This is now unconditional because debugging printouts can use it.  */
-  output_gram ();
-  XFREE (ritem);
-  if (semantic_parser)
-    output_stos ();
-  output_rule_data ();
-  output_actions ();
-  if (!no_parser_flag)
-    output_parser ();
-  output_program ();
+  prepare_symbols ();
+  prepare_rules ();
+  prepare_states ();
+  prepare_actions ();
+
+  prepare ();
+
+  /* Process the selected skeleton file.  */
+  output_skeleton ();
+
+  obstack_free (&format_obstack, NULL);
 }