[bison.git] / data / glr.c

m4_divert(-1)                                                       -*- C -*-

# GLR skeleton for Bison
# Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.

# 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 2 of the License, or
# (at your option) any later version.

# 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
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
# 02111-1307  USA


## ---------------- ##
## Default values.  ##
## ---------------- ##

# Stack parameters.
m4_define_default([b4_stack_depth_max], [10000])
m4_define_default([b4_stack_depth_init],  [200])


## ------------------------ ##
## Pure/impure interfaces.  ##
## ------------------------ ##


# b4_lex_param
# ------------
# Accumule in b4_lex_param all the yylex arguments.
# Yes, this is quite ugly...
m4_define([b4_lex_param],
m4_dquote(b4_pure_if([[[[YYSTYPE *]], [[yylvalp]]][]dnl
b4_location_if([, [[YYLTYPE *], [yyllocp]]])])dnl
m4_ifdef([b4_lex_param], [, ]b4_lex_param)))


# b4_user_formals
# ---------------
m4_define([b4_user_formals],
[m4_ifset([b4_parse_param], [, b4_c_ansi_formals(b4_parse_param)])])


# b4_yyerror_args
# ---------------
# Arguments passed to yyerror: user args plus yylloc.
m4_define([b4_yyerror_args],
[b4_pure_if([b4_location_if([yylocp, ])])dnl
m4_ifset([b4_parse_param], [b4_c_args(b4_parse_param), ])])


# b4_lyyerror_args
# ----------------
# Same as above, but on the lookahead, hence yyllocp instead of yylocp.
m4_define([b4_lyyerror_args],
[b4_pure_if([b4_location_if([yyllocp, ])])dnl
m4_ifset([b4_parse_param], [b4_c_args(b4_parse_param), ])])


# b4_pure_args
# ------------
# Arguments needed by yyerror: user args plus yylloc.
m4_define([b4_pure_args],
[b4_pure_if([b4_location_if([, yylocp])])[]b4_user_args])


# b4_pure_formals
# ---------------
# Arguments passed to yyerror: user formals plus yyllocp.
m4_define([b4_pure_formals],
[b4_pure_if([b4_location_if([, YYLTYPE *yylocp])])[]b4_user_formals])


# b4_lpure_args
# -------------
# Same as above, but on the lookahead, hence yyllocp instead of yylocp.
m4_define([b4_lpure_args],
[b4_pure_if([b4_location_if([, yyllocp])])[]b4_user_args])


# b4_lpure_formals
# ----------------
# Same as above, but on the lookahead, hence yyllocp instead of yylocp.
m4_define([b4_lpure_formals],
[b4_pure_if([b4_location_if([YYLTYPE *yyllocp])])[]b4_user_formals])


## ----------------- ##
## Semantic Values.  ##
## ----------------- ##


# b4_lhs_value([TYPE])
# --------------------
# Expansion of $<TYPE>$.
m4_define([b4_lhs_value],
[(*yyvalp)[]m4_ifval([$1], [.$1])])


# b4_rhs_value(RULE-LENGTH, NUM, [TYPE])
# --------------------------------------
# Expansion of $<TYPE>NUM, where the current rule has RULE-LENGTH
# symbols on RHS.
m4_define([b4_rhs_value],
[((yyGLRStackItem const *)yyvsp)@{YYFILL (m4_eval([$2 - $1]))@}.yystate.yysemantics.yysval[]m4_ifval([$3], [.$3])])


## ----------- ##
## Locations.  ##
## ----------- ##

# b4_lhs_location()
# -----------------
# Expansion of @$.
m4_define([b4_lhs_location],
[(*yylocp)])


# b4_rhs_location(RULE-LENGTH, NUM)
# ---------------------------------
# Expansion of @NUM, where the current rule has RULE-LENGTH symbols
# on RHS.
m4_define([b4_rhs_location],
[((yyGLRStackItem const *)yyvsp)@{YYFILL (m4_eval([$2 - $1]))@}.yystate.yyloc])

# We do want M4 expansion after # for CPP macros.
m4_changecom()
m4_divert(0)dnl
@output @output_parser_name@
b4_copyright([Skeleton parser for GLR parsing with Bison], [2002, 2003, 2004])
[
/* This is the parser code for GLR (Generalized LR) parser. */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <setjmp.h>

]b4_identification
m4_if(b4_prefix[], [yy], [],
[/* If NAME_PREFIX is specified substitute the variables and functions
   names.  */
#define yyparse b4_prefix[]parse
#define yylex   b4_prefix[]lex
#define yyerror b4_prefix[]error
#define yylval  b4_prefix[]lval
#define yychar  b4_prefix[]char
#define yydebug b4_prefix[]debug
#define yynerrs b4_prefix[]nerrs
b4_location_if([#define yylloc b4_prefix[]lloc])])

b4_token_defines(b4_tokens)

/* Copy the first part of user declarations.  */
b4_pre_prologue[

/* Enabling traces.  */
#ifndef YYDEBUG
# define YYDEBUG ]b4_debug[
#endif

/* Enabling verbose error messages.  */
#ifdef YYERROR_VERBOSE
# undef YYERROR_VERBOSE
# define YYERROR_VERBOSE 1
#else
# define YYERROR_VERBOSE ]b4_error_verbose[
#endif

#if ! defined (YYSTYPE) && ! defined (YYSTYPE_IS_DECLARED)
]m4_ifdef([b4_stype],
[b4_syncline([b4_stype_line], [b4_filename])
typedef union m4_bregexp(b4_stype, [^{], [YYSTYPE ])b4_stype YYSTYPE;
/* Line __line__ of glr.c.  */
b4_syncline([@oline@], [@ofile@])],
[typedef int YYSTYPE;])[
# define YYSTYPE_IS_DECLARED 1
# define YYSTYPE_IS_TRIVIAL 1
#endif

#if ! defined (YYLTYPE) && ! defined (YYLTYPE_IS_DECLARED)
typedef struct YYLTYPE
{
]b4_location_if([
  int first_line;
  int first_column;
  int last_line;
  int last_column;
],[
  char yydummy;
])[
} YYLTYPE;
# define YYLTYPE_IS_DECLARED 1
# define YYLTYPE_IS_TRIVIAL 1
#endif

/* Default (constant) values used for initialization for null
   right-hand sides.  Unlike the standard yacc.c template,
   here we set the default values of $$ and $@@ to zeroed-out
   values.  Since the default value of these quantities is undefined,
   this behavior is technically correct. */
static YYSTYPE yyval_default;
static YYLTYPE yyloc_default;

/* Copy the second part of user declarations.  */
]b4_post_prologue[

]/* Line __line__ of glr.c.  */
b4_syncline([@oline@], [@ofile@])
[
#ifndef YYFREE
# define YYFREE free
#endif
#ifndef YYMALLOC
# define YYMALLOC malloc
#endif
#ifndef YYREALLOC
# define YYREALLOC realloc
#endif

#ifdef __cplusplus
   typedef bool yybool;
#else
   typedef unsigned char yybool;
#endif
#define yytrue 1
#define yyfalse 0

/*-----------------.
| GCC extensions.  |
`-----------------*/

#ifndef __attribute__
/* This feature is available in gcc versions 2.5 and later.  */
# if !defined (__GNUC__) || __GNUC__ < 2 || \
(__GNUC__ == 2 && __GNUC_MINOR__ < 5) || __STRICT_ANSI__
#  define __attribute__(Spec) /* empty */
# endif
#endif

#ifndef YYASSERT
# define YYASSERT(condition) ((void) ((condition) || (abort (), 0)))
#endif

#ifndef ATTRIBUTE_UNUSED
# define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
#endif

/* YYFINAL -- State number of the termination state. */
#define YYFINAL  ]b4_final_state_number[
/* YYLAST -- Last index in YYTABLE.  */
#define YYLAST   ]b4_last[

/* YYNTOKENS -- Number of terminals. */
#define YYNTOKENS  ]b4_tokens_number[
/* YYNNTS -- Number of nonterminals. */
#define YYNNTS  ]b4_nterms_number[
/* YYNRULES -- Number of rules. */
#define YYNRULES  ]b4_rules_number[
/* YYNRULES -- Number of states. */
#define YYNSTATES  ]b4_states_number[
/* YYMAXRHS -- Maximum number of symbols on right-hand side of rule. */
#define YYMAXRHS ]b4_r2_max[
/* YYMAXLEFT -- Maximum number of symbols to the left of a handle
   accessed by $0, $-1, etc., in any rule. */
#define YYMAXLEFT ]b4_max_left_semantic_context[

/* YYTRANSLATE(X) -- Bison symbol number corresponding to X.  */
#define YYUNDEFTOK  ]b4_undef_token_number[
#define YYMAXUTOK   ]b4_user_token_number_max[

#define YYTRANSLATE(YYX)						\
  ((YYX <= 0) ? YYEOF :							\
   (unsigned int) (YYX) <= YYMAXUTOK ? yytranslate[YYX] : YYUNDEFTOK)

/* YYTRANSLATE[YYLEX] -- Bison symbol number corresponding to YYLEX.  */
static const ]b4_int_type_for([b4_translate])[ yytranslate[] =
{
  ]b4_translate[
};

#if YYDEBUG
/* YYPRHS[YYN] -- Index of the first RHS symbol of rule number YYN in
   YYRHS.  */
static const ]b4_int_type_for([b4_prhs])[ yyprhs[] =
{
  ]b4_prhs[
};

/* YYRHS -- A `-1'-separated list of the rules' RHS. */
static const ]b4_int_type_for([b4_rhs])[ yyrhs[] =
{
  ]b4_rhs[
};

/* YYRLINE[YYN] -- source line where rule number YYN was defined.  */
static const ]b4_int_type_for([b4_rline])[ yyrline[] =
{
  ]b4_rline[
};
#endif

#if (YYDEBUG) || YYERROR_VERBOSE
/* YYTNME[SYMBOL-NUM] -- String name of the symbol SYMBOL-NUM.
   First, the terminals, then, starting at YYNTOKENS, nonterminals. */
static const char *const yytname[] =
{
  ]b4_tname[
};
#endif

/* YYR1[YYN] -- Symbol number of symbol that rule YYN derives.  */
static const ]b4_int_type_for([b4_r1])[ yyr1[] =
{
  ]b4_r1[
};

/* YYR2[YYN] -- Number of symbols composing right hand side of rule YYN.  */
static const ]b4_int_type_for([b4_r2])[ yyr2[] =
{
  ]b4_r2[
};

/* YYDPREC[RULE-NUM] -- Dynamic precedence of rule #RULE-NUM (0 if none). */
static const ]b4_int_type_for([b4_dprec])[ yydprec[] =
{
  ]b4_dprec[
};

/* YYMERGER[RULE-NUM] -- Index of merging function for rule #RULE-NUM. */
static const ]b4_int_type_for([b4_merger])[ yymerger[] =
{
  ]b4_merger[
};

/* 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.  */
static const ]b4_int_type_for([b4_defact])[ yydefact[] =
{
  ]b4_defact[
};

/* YYPDEFGOTO[NTERM-NUM]. */
static const ]b4_int_type_for([b4_defgoto])[ yydefgoto[] =
{
  ]b4_defgoto[
};

/* YYPACT[STATE-NUM] -- Index in YYTABLE of the portion describing
   STATE-NUM.  */
#define YYPACT_NINF ]b4_pact_ninf[
static const ]b4_int_type_for([b4_pact])[ yypact[] =
{
  ]b4_pact[
};

/* YYPGOTO[NTERM-NUM].  */
static const ]b4_int_type_for([b4_pgoto])[ yypgoto[] =
{
  ]b4_pgoto[
};

/* YYTABLE[YYPACT[STATE-NUM]].  What to do in state STATE-NUM.  If
   positive, shift that token.  If negative, reduce the rule which
   number is the opposite.  If zero, do what YYDEFACT says.
   If YYTABLE_NINF, syntax error.  */
#define YYTABLE_NINF ]b4_table_ninf[
static const ]b4_int_type_for([b4_table])[ yytable[] =
{
  ]b4_table[
};

/* YYCONFLP[YYPACT[STATE-NUM]] -- Pointer into YYCONFL of start of
   list of conflicting reductions corresponding to action entry for
   state STATE-NUM in yytable.  0 means no conflicts.  The list in
   yyconfl is terminated by a rule number of 0.  */
static const ]b4_int_type_for([b4_conflict_list_heads])[ yyconflp[] =
{
  ]b4_conflict_list_heads[
};

/* YYCONFL[I] -- lists of conflicting rule numbers, each terminated by
   0, pointed into by YYCONFLP.  */
]dnl Do not use b4_int_type_for here, since there are places where
dnl pointers onto yyconfl are taken, which type is "short int *".
dnl We probably ought to introduce a type for confl.
[static const short int yyconfl[] =
{
  ]b4_conflicting_rules[
};

static const ]b4_int_type_for([b4_check])[ yycheck[] =
{
  ]b4_check[
};

/* YYSTOS[STATE-NUM] -- The (internal number of the) accessing
   symbol of state STATE-NUM.  */
static const ]b4_int_type_for([b4_stos])[ yystos[] =
{
  ]b4_stos[
};

\f
/* Prevent warning if -Wmissing-prototypes.  */
]b4_c_ansi_function_decl([yyparse], [int], b4_parse_param)[

/* Error token number */
#define YYTERROR 1

/* YYLLOC_DEFAULT -- Compute the default location (before the actions
   are run).  */

]b4_location_if([[
#define YYRHSLOC(yyRhs,YYK) ((yyRhs)[YYK].yystate.yyloc)

#ifndef YYLLOC_DEFAULT
# define YYLLOC_DEFAULT(yyCurrent, yyRhs, YYN)			\
   ((yyCurrent).first_line = YYRHSLOC(yyRhs, 1).first_line,	\
    (yyCurrent).first_column = YYRHSLOC(yyRhs, 1).first_column,	\
    (yyCurrent).last_line = YYRHSLOC(yyRhs, YYN).last_line,	\
    (yyCurrent).last_column  = YYRHSLOC(yyRhs, YYN).last_column)
#endif
]],[
#ifndef YYLLOC_DEFAULT
# define YYLLOC_DEFAULT(yyCurrent, yyRhs, YYN) ((void) 0)
#endif
])[


/* YYLEX -- calling `yylex' with the right arguments.  */
#define YYLEX ]b4_c_function_call([yylex], [int], b4_lex_param)[

]b4_pure_if(
[
#undef yynerrs
#define yynerrs (yystack->yyerrcnt)
#undef yychar
#define yychar (yystack->yyrawchar)],
[YYSTYPE yylval;

YYLTYPE yylloc;

int yynerrs;
int yychar;])[

static const int YYEOF = 0;
static const int YYEMPTY = -2;

typedef enum { yyok, yyaccept, yyabort, yyerr } YYRESULTTAG;

#define YYCHK(YYE)							     \
   do { YYRESULTTAG yyflag = YYE; if (yyflag != yyok) return yyflag; }	     \
   while (0)

#if YYDEBUG

#if ! defined (YYFPRINTF)
#  define YYFPRINTF fprintf
#endif

# define YYDPRINTF(Args)			\
do {						\
  if (yydebug)					\
    YYFPRINTF Args;				\
} while (0)

]b4_yysymprint_generate([b4_c_ansi_function_def])[

# define YYDSYMPRINT(Args)			\
do {						\
  if (yydebug)					\
    yysymprint Args;				\
} while (0)

# define YYDSYMPRINTF(Title, Token, Value, Location)		\
do {								\
  if (yydebug)							\
    {								\
      YYFPRINTF (stderr, "%s ", Title);				\
      yysymprint (stderr,					\
                  Token, Value]b4_location_if([, Location])[);	\
      YYFPRINTF (stderr, "\n");					\
    }								\
} while (0)

/* Nonzero means print parse trace.  It is left uninitialized so that
   multiple parsers can coexist.  */
int yydebug;

#else /* !YYDEBUG */

  /* Avoid empty `if' bodies.  */
# define YYDPRINTF(Args)
# define YYDSYMPRINT(Args)
# define YYDSYMPRINTF(Title, Token, Value, Location)

#endif /* !YYDEBUG */

/* YYINITDEPTH -- initial size of the parser's stacks.  */
#ifndef	YYINITDEPTH
# define YYINITDEPTH ]b4_stack_depth_init[
#endif

/* YYMAXDEPTH -- maximum size the stacks can grow to (effective only
   if the built-in stack extension method is used).

   Do not make this value too large; the results are undefined if
   SIZE_MAX < YYMAXDEPTH * sizeof (GLRStackItem)
   evaluated with infinite-precision integer arithmetic.  */

#if YYMAXDEPTH == 0
# undef YYMAXDEPTH
#endif

#ifndef YYMAXDEPTH
# define YYMAXDEPTH ]b4_stack_depth_max[
#endif

/* Minimum number of free items on the stack allowed after an
   allocation.  This is to allow allocation and initialization
   to be completed by functions that call expandGLRStack before the
   stack is expanded, thus insuring that all necessary pointers get
   properly redirected to new data. */
#define YYHEADROOM 2

#if (! defined (YYSTACKEXPANDABLE) \
     && (! defined (__cplusplus) \
	 || (]b4_location_if([[defined (YYLTYPE_IS_TRIVIAL) && YYLTYPE_IS_TRIVIAL \
	     && ]])[defined (YYSTYPE_IS_TRIVIAL) && YYSTYPE_IS_TRIVIAL)))
#define YYSTACKEXPANDABLE 1
#else
#define YYSTACKEXPANDABLE 0
#endif

/** State numbers, as in LALR(1) machine */
typedef int yyStateNum;

/** Rule numbers, as in LALR(1) machine */
typedef int yyRuleNum;

/** Grammar symbol */
typedef short int yySymbol;

/** Item references, as in LALR(1) machine */
typedef short int yyItemNum;

typedef struct yyGLRState yyGLRState;
typedef struct yySemanticOption yySemanticOption;
typedef union yyGLRStackItem yyGLRStackItem;
typedef struct yyGLRStack yyGLRStack;
typedef struct yyGLRStateSet yyGLRStateSet;

struct yyGLRState {
  yybool yyisState;
  yybool yyresolved;
  yyStateNum yylrState;
  yyGLRState* yypred;
  size_t yyposn;
  union {
    yySemanticOption* yyfirstVal;
    YYSTYPE yysval;
  } yysemantics;
  YYLTYPE yyloc;
};

struct yyGLRStateSet {
  yyGLRState** yystates;
  size_t yysize, yycapacity;
};

struct yySemanticOption {
  yybool yyisState;
  yyRuleNum yyrule;
  yyGLRState* yystate;
  yySemanticOption* yynext;
};

union yyGLRStackItem {
  yyGLRState yystate;
  yySemanticOption yyoption;
};

struct yyGLRStack {
  int yyerrflag;
  int yyerrState;
]b4_pure_if(
[
  int yyerrcnt;
  int yyrawchar;
])[
  yySymbol* yytokenp;
  jmp_buf yyexception_buffer;
  yyGLRStackItem* yyitems;
  yyGLRStackItem* yynextFree;
  int yyspaceLeft;
  yyGLRState* yysplitPoint;
  yyGLRState* yylastDeleted;
  yyGLRStateSet yytops;
};

static void yyinitGLRStack (yyGLRStack* yystack, size_t yysize);
static void yyexpandGLRStack (yyGLRStack* yystack]b4_pure_formals[);
static void yyfreeGLRStack (yyGLRStack* yystack);

static void
yyFail (yyGLRStack* yystack]b4_pure_formals[, const char* yyformat, ...)
{
  yystack->yyerrflag = 1;
  if (yyformat != NULL)
    {
      char yymsg[256];
      va_list yyap;
      va_start (yyap, yyformat);
      vsprintf (yymsg, yyformat, yyap);
      yyerror (]b4_yyerror_args[yymsg);
    }
  longjmp (yystack->yyexception_buffer, 1);
}

#if YYDEBUG || YYERROR_VERBOSE
/** A printable representation of TOKEN.  Valid until next call to
 *  tokenName. */
static inline const char*
yytokenName (yySymbol yytoken)
{
  if (yytoken == YYEMPTY)
    return "";

  return yytname[yytoken];
}
#endif

/** Fill in YYVSP[YYLOW1 .. YYLOW0-1] from the chain of states starting
 *  at YYVSP[YYLOW0].yystate.yypred.  Leaves YYVSP[YYLOW1].yystate.yypred
 *  containing the pointer to the next state in the chain. Assumes
 *  YYLOW1 < YYLOW0.  */
static void yyfillin (yyGLRStackItem *, int, int) ATTRIBUTE_UNUSED;
static void
yyfillin (yyGLRStackItem *yyvsp, int yylow0, int yylow1)
{
  yyGLRState* s;
  int i;
  s = yyvsp[yylow0].yystate.yypred;
  for (i = yylow0-1; i >= yylow1; i -= 1)
    {
      YYASSERT (s->yyresolved);
      yyvsp[i].yystate.yyresolved = yytrue;
      yyvsp[i].yystate.yysemantics.yysval = s->yysemantics.yysval;
      yyvsp[i].yystate.yyloc = s->yyloc;
      s = yyvsp[i].yystate.yypred = s->yypred;
    }
}

/* Do nothing if YYNORMAL or if *YYLOW <= YYLOW1.  Otherwise, fill in
   YYVSP[YYLOW1 .. *YYLOW-1] as in yyfillin and set *YYLOW = YYLOW1.
   For convenience, always return YYLOW1.  */
static inline int yyfill (yyGLRStackItem *, int *, int, yybool)
     ATTRIBUTE_UNUSED;
static inline int
yyfill (yyGLRStackItem *yyvsp, int *yylow, int yylow1, yybool yynormal)
{
  if (!yynormal && yylow1 < *yylow)
    {
      yyfillin (yyvsp, *yylow, yylow1);
      *yylow = yylow1;
    }
  return yylow1;
}

/** Perform user action for rule number YYN, with RHS length YYRHSLEN,
 *  and top stack item YYVSP.  YYLVALP points to place to put semantic
 *  value ($$), and yylocp points to place for location information
 *  (@@$). Returns yyok for normal return, yyaccept for YYACCEPT,
 *  yyerr for YYERROR, yyabort for YYABORT. */
static YYRESULTTAG
yyuserAction (yyRuleNum yyn, int yyrhslen, yyGLRStackItem* yyvsp,
	      YYSTYPE* yyvalp, YYLTYPE* yylocp, yyGLRStack* yystack
              ]b4_user_formals[)
{
  yybool yynormal ATTRIBUTE_UNUSED = (yystack->yysplitPoint == NULL);
  int yylow;

# undef yyerrok
# define yyerrok (yystack->yyerrState = 0)
# undef YYACCEPT
# define YYACCEPT return yyaccept
# undef YYABORT
# define YYABORT return yyabort
# undef YYERROR
# define YYERROR return yyerrok, yyerr
# undef YYRECOVERING
# define YYRECOVERING (yystack->yyerrState != 0)
# undef yyclearin
# define yyclearin (yychar = *(yystack->yytokenp) = YYEMPTY)
# undef YYFILL
# define YYFILL(N) yyfill (yyvsp, &yylow, N, yynormal)
# undef YYBACKUP
# define YYBACKUP(Token, Value)						     \
  return yyerror (]b4_yyerror_args["syntax error: cannot back up"),	     \
	 yyerrok, yyerr

  yylow = 1;
  if (yyrhslen == 0)
    {
      *yyvalp = yyval_default;
      *yylocp = yyloc_default;
    }
  else
    {
      *yyvalp = yyvsp[YYFILL (1-yyrhslen)].yystate.yysemantics.yysval;
      YYLLOC_DEFAULT (*yylocp, yyvsp - yyrhslen, yyrhslen);
    }

]
  switch (yyn)
    {
      b4_actions
    }

  return yyok;
# undef yyerrok
# undef YYABORT
# undef YYACCEPT
# undef YYERROR
# undef YYBACKUP
# undef yyclearin
# undef YYRECOVERING
/* Line __line__ of glr.c.  */
b4_syncline([@oline@], [@ofile@])
}
\f

static void
yyuserMerge (int yyn, YYSTYPE* yy0, YYSTYPE* yy1)
{
  /* `Use' the arguments.  */
  (void) yy0;
  (void) yy1;

  switch (yyn)
    {
      b4_mergers
    }
}
[
			      /* Bison grammar-table manipulation.  */

]b4_yydestruct_generate([b4_c_ansi_function_def])[

/** Number of symbols composing the right hand side of rule #RULE. */
static inline int
yyrhsLength (yyRuleNum yyrule)
{
  return yyr2[yyrule];
}

/** Left-hand-side symbol for rule #RULE. */
static inline yySymbol
yylhsNonterm (yyRuleNum yyrule)
{
  return yyr1[yyrule];
}

#define yyis_pact_ninf(yystate) \
  ]m4_if(m4_eval(b4_pact_ninf < b4_pact_min), 1,
	 0,
	 ((yystate) == YYPACT_NINF))[

/** True iff LR state STATE has only a default reduction (regardless
 *  of token). */
static inline yybool
yyisDefaultedState (yyStateNum yystate)
{
  return yyis_pact_ninf (yypact[yystate]);
}

/** The default reduction for STATE, assuming it has one. */
static inline yyRuleNum
yydefaultAction (yyStateNum yystate)
{
  return yydefact[yystate];
}

#define yyis_table_ninf(yytable_value) \
  ]m4_if(m4_eval(b4_table_ninf < b4_table_min), 1,
	 0,
	 ((yytable_value) == YYTABLE_NINF))[

/** Set *YYACTION to the action to take in YYSTATE on seeing YYTOKEN.
 *  Result R means
 *    R < 0:  Reduce on rule -R.
 *    R = 0:  Error.
 *    R > 0:  Shift to state R.
 *  Set *CONFLICTS to a pointer into yyconfl to 0-terminated list of
 *  conflicting reductions.
 */
static inline void
yygetLRActions (yyStateNum yystate, int yytoken,
	        int* yyaction, const short int** yyconflicts)
{
  int yyindex = yypact[yystate] + yytoken;
  if (yyindex < 0 || YYLAST < yyindex || yycheck[yyindex] != yytoken)
    {
      *yyaction = -yydefact[yystate];
      *yyconflicts = yyconfl;
    }
  else if (! yyis_table_ninf (yytable[yyindex]))
    {
      *yyaction = yytable[yyindex];
      *yyconflicts = yyconfl + yyconflp[yyindex];
    }
  else
    {
      *yyaction = 0;
      *yyconflicts = yyconfl + yyconflp[yyindex];
    }
}

static inline yyStateNum
yyLRgotoState (yyStateNum yystate, yySymbol yylhs)
{
  int yyr;
  yyr = yypgoto[yylhs - YYNTOKENS] + yystate;
  if (0 <= yyr && yyr <= YYLAST && yycheck[yyr] == yystate)
    return yytable[yyr];
  else
    return yydefgoto[yylhs - YYNTOKENS];
}

static inline yybool
yyisShiftAction (int yyaction)
{
  return 0 < yyaction;
}

static inline yybool
yyisErrorAction (int yyaction)
{
  return yyaction == 0;
}

				/* GLRStates */

static void
yyaddDeferredAction (yyGLRStack* yystack, yyGLRState* yystate,
		     yyGLRState* rhs, yyRuleNum yyrule]b4_pure_formals[)
{
  yySemanticOption* yynewItem;
  yynewItem = &yystack->yynextFree->yyoption;
  yystack->yyspaceLeft -= 1;
  yystack->yynextFree += 1;
  yynewItem->yyisState = yyfalse;
  yynewItem->yystate = rhs;
  yynewItem->yyrule = yyrule;
  yynewItem->yynext = yystate->yysemantics.yyfirstVal;
  yystate->yysemantics.yyfirstVal = yynewItem;
  if (yystack->yyspaceLeft < YYHEADROOM)
    yyexpandGLRStack (yystack]b4_pure_args[);
}

				/* GLRStacks */

/** Initialize SET to a singleton set containing an empty stack. */
static void
yyinitStateSet (yyGLRStateSet* yyset)
{
  yyset->yysize = 1;
  yyset->yycapacity = 16;
  yyset->yystates = (yyGLRState**) YYMALLOC (16 * sizeof yyset->yystates[0]);
  yyset->yystates[0] = NULL;
}

static void yyfreeStateSet (yyGLRStateSet* yyset)
{
  YYFREE (yyset->yystates);
}

/** Initialize STACK to a single empty stack, with total maximum
 *  capacity for all stacks of SIZE. */
static void
yyinitGLRStack (yyGLRStack* yystack, size_t yysize)
{
  yystack->yyerrflag = 0;
  yystack->yyerrState = 0;
  yynerrs = 0;
  yystack->yyspaceLeft = yysize;
  yystack->yynextFree = yystack->yyitems =
    (yyGLRStackItem*) YYMALLOC (yysize * sizeof yystack->yynextFree[0]);
  yystack->yysplitPoint = NULL;
  yystack->yylastDeleted = NULL;
  yyinitStateSet (&yystack->yytops);
}

#define YYRELOC(YYFROMITEMS,YYTOITEMS,YYX,YYTYPE) \
  &((YYTOITEMS) - ((YYFROMITEMS) - (yyGLRStackItem*) (YYX)))->YYTYPE

/** If STACK is expandable, extend it.  WARNING: Pointers into the
    stack from outside should be considered invalid after this call.
    We always expand when there are 1 or fewer items left AFTER an
    allocation, so that we can avoid having external pointers exist
    across an allocation. */
static void
yyexpandGLRStack (yyGLRStack* yystack]b4_pure_formals[)
{
#if YYSTACKEXPANDABLE
  yyGLRStack yynewStack;
  yyGLRStackItem* yyp0, *yyp1;
  size_t yysize, yynewSize;
  size_t yyn;
  yysize = yystack->yynextFree - yystack->yyitems;
  if (YYMAXDEPTH <= yysize)
    yyFail (yystack][]b4_pure_args[, "parser stack overflow");
  yynewSize = 2*yysize;
  if (YYMAXDEPTH < yynewSize)
    yynewSize = YYMAXDEPTH;
  yyinitGLRStack (&yynewStack, yynewSize);
  for (yyp0 = yystack->yyitems, yyp1 = yynewStack.yyitems, yyn = yysize;
       0 < yyn;
       yyn -= 1, yyp0 += 1, yyp1 += 1)
    {
      *yyp1 = *yyp0;
      if (*(yybool *) yyp0)
	{
	  yyGLRState* yys0 = &yyp0->yystate;
	  yyGLRState* yys1 = &yyp1->yystate;
	  if (yys0->yypred != NULL)
	    yys1->yypred =
	      YYRELOC (yyp0, yyp1, yys0->yypred, yystate);
	  if (! yys0->yyresolved && yys0->yysemantics.yyfirstVal != NULL)
	    yys1->yysemantics.yyfirstVal =
	      YYRELOC(yyp0, yyp1, yys0->yysemantics.yyfirstVal, yyoption);
	}
      else
	{
	  yySemanticOption* yyv0 = &yyp0->yyoption;
	  yySemanticOption* yyv1 = &yyp1->yyoption;
	  if (yyv0->yystate != NULL)
	    yyv1->yystate = YYRELOC (yyp0, yyp1, yyv0->yystate, yystate);
	  if (yyv0->yynext != NULL)
	    yyv1->yynext = YYRELOC (yyp0, yyp1, yyv0->yynext, yyoption);
	}
    }
  if (yystack->yysplitPoint != NULL)
    yystack->yysplitPoint = YYRELOC (yystack->yyitems, yynewStack.yyitems,
				 yystack->yysplitPoint, yystate);

  for (yyn = 0; yyn < yystack->yytops.yysize; yyn += 1)
    if (yystack->yytops.yystates[yyn] != NULL)
      yystack->yytops.yystates[yyn] =
	YYRELOC (yystack->yyitems, yynewStack.yyitems,
		 yystack->yytops.yystates[yyn], yystate);
  YYFREE (yystack->yyitems);
  yystack->yyitems = yynewStack.yyitems;
  yystack->yynextFree = yynewStack.yynextFree + yysize;
  yystack->yyspaceLeft = yynewStack.yyspaceLeft - yysize;

#else

  yyFail (yystack][]b4_pure_args[, "parser stack overflow");
#endif
}

static void
yyfreeGLRStack (yyGLRStack* yystack)
{
  YYFREE (yystack->yyitems);
  yyfreeStateSet (&yystack->yytops);
}

/** Assuming that S is a GLRState somewhere on STACK, update the
 *  splitpoint of STACK, if needed, so that it is at least as deep as
 *  S. */
static inline void
yyupdateSplit (yyGLRStack* yystack, yyGLRState* yys)
{
  if (yystack->yysplitPoint != NULL && yystack->yysplitPoint > yys)
    yystack->yysplitPoint = yys;
}

/** Invalidate stack #K in STACK. */
static inline void
yymarkStackDeleted (yyGLRStack* yystack, int yyk)
{
  if (yystack->yytops.yystates[yyk] != NULL)
    yystack->yylastDeleted = yystack->yytops.yystates[yyk];
  yystack->yytops.yystates[yyk] = NULL;
}

/** Undelete the last stack that was marked as deleted.  Can only be
    done once after a deletion, and only when all other stacks have
    been deleted. */
static void
yyundeleteLastStack (yyGLRStack* yystack)
{
  if (yystack->yylastDeleted == NULL || yystack->yytops.yysize != 0)
    return;
  yystack->yytops.yystates[0] = yystack->yylastDeleted;
  yystack->yytops.yysize = 1;
  YYDPRINTF ((stderr, "Restoring last deleted stack as stack #0.\n"));
  yystack->yylastDeleted = NULL;
}

static inline void
yyremoveDeletes (yyGLRStack* yystack)
{
  size_t yyi, yyj;
  yyi = yyj = 0;
  while (yyj < yystack->yytops.yysize)
    {
      if (yystack->yytops.yystates[yyi] == NULL)
	{
	  if (yyi == yyj)
	    {
	      YYDPRINTF ((stderr, "Removing dead stacks.\n"));
	    }
	  yystack->yytops.yysize -= 1;
	}
      else
	{
	  yystack->yytops.yystates[yyj] = yystack->yytops.yystates[yyi];
	  if (yyj != yyi)
	    {
	      YYDPRINTF ((stderr, "Rename stack %lu -> %lu.\n",
			  (unsigned long int) yyi, (unsigned long int) yyj));
	    }
	  yyj += 1;
	}
      yyi += 1;
    }
}

/** Shift to a new state on stack #K of STACK, corresponding to LR state
 * LRSTATE, at input position POSN, with (resolved) semantic value SVAL. */
static inline void
yyglrShift (yyGLRStack* yystack, int yyk, yyStateNum yylrState, size_t yyposn,
	    YYSTYPE yysval, YYLTYPE* yylocp]b4_user_formals[)
{
  yyGLRStackItem* yynewItem;

  yynewItem = yystack->yynextFree;
  yystack->yynextFree += 1;
  yystack->yyspaceLeft -= 1;
  yynewItem->yystate.yyisState = yytrue;
  yynewItem->yystate.yylrState = yylrState;
  yynewItem->yystate.yyposn = yyposn;
  yynewItem->yystate.yyresolved = yytrue;
  yynewItem->yystate.yypred = yystack->yytops.yystates[yyk];
  yystack->yytops.yystates[yyk] = &yynewItem->yystate;
  yynewItem->yystate.yysemantics.yysval = yysval;
  yynewItem->yystate.yyloc = *yylocp;
  if (yystack->yyspaceLeft < YYHEADROOM)
    yyexpandGLRStack (yystack]b4_pure_args[);
}

/** Shift stack #K of YYSTACK, to a new state corresponding to LR
 *  state YYLRSTATE, at input position YYPOSN, with the (unresolved)
 *  semantic value of YYRHS under the action for YYRULE. */
static inline void
yyglrShiftDefer (yyGLRStack* yystack, int yyk, yyStateNum yylrState,
		 size_t yyposn, yyGLRState* rhs, yyRuleNum yyrule]b4_pure_formals[)
{
  yyGLRStackItem* yynewItem;

  yynewItem = yystack->yynextFree;
  yynewItem->yystate.yyisState = yytrue;
  yynewItem->yystate.yylrState = yylrState;
  yynewItem->yystate.yyposn = yyposn;
  yynewItem->yystate.yyresolved = yyfalse;
  yynewItem->yystate.yypred = yystack->yytops.yystates[yyk];
  yynewItem->yystate.yysemantics.yyfirstVal = NULL;
  yystack->yytops.yystates[yyk] = &yynewItem->yystate;
  yystack->yynextFree += 1;
  yystack->yyspaceLeft -= 1;
  yyaddDeferredAction (yystack, &yynewItem->yystate, rhs, yyrule]b4_pure_args[);
}

/** Pop the symbols consumed by reduction #RULE from the top of stack
 *  #K of STACK, and perform the appropriate semantic action on their
 *  semantic values.  Assumes that all ambiguities in semantic values
 *  have been previously resolved. Set *VALP to the resulting value,
 *  and *LOCP to the computed location (if any).  Return value is as
 *  for userAction. */
static inline YYRESULTTAG
yydoAction (yyGLRStack* yystack, int yyk, yyRuleNum yyrule,
	    YYSTYPE* yyvalp, YYLTYPE* yylocp]b4_user_formals[)
{
  int yynrhs = yyrhsLength (yyrule);

  if (yystack->yysplitPoint == NULL)
    {
      /* Standard special case: single stack. */
      yyGLRStackItem* rhs = (yyGLRStackItem*) yystack->yytops.yystates[yyk];
      YYASSERT (yyk == 0);
      yystack->yynextFree -= yynrhs;
      yystack->yyspaceLeft += yynrhs;
      yystack->yytops.yystates[0] = & yystack->yynextFree[-1].yystate;
      return yyuserAction (yyrule, yynrhs, rhs,
			   yyvalp, yylocp, yystack]b4_user_args[);
    }
  else
    {
      int yyi;
      yyGLRState* yys;
      yyGLRStackItem yyrhsVals[YYMAXRHS + YYMAXLEFT + 1];
      yys = yyrhsVals[YYMAXRHS + YYMAXLEFT].yystate.yypred
	= yystack->yytops.yystates[yyk];
      for (yyi = 0; yyi < yynrhs; yyi += 1)
	{
	  yys = yys->yypred;
	  YYASSERT (yys);
	}
      yyupdateSplit (yystack, yys);
      yystack->yytops.yystates[yyk] = yys;
      return yyuserAction (yyrule, yynrhs, yyrhsVals + YYMAXRHS + YYMAXLEFT - 1,
			   yyvalp, yylocp, yystack]b4_user_args[);
    }
}

#if !YYDEBUG
# define YY_REDUCE_PRINT(K, Rule)
#else
# define YY_REDUCE_PRINT(K, Rule)	\
do {					\
  if (yydebug)				\
    yy_reduce_print (K, Rule);		\
} while (0)

/*----------------------------------------------------------.
| Report that the RULE is going to be reduced on stack #K.  |
`----------------------------------------------------------*/

static inline void
yy_reduce_print (size_t yyk, yyRuleNum yyrule)
{
  int yyi;
  YYFPRINTF (stderr, "Reducing stack %lu by rule %d (line %lu), ",
	     (unsigned long int) yyk, yyrule - 1,
	     (unsigned long int) yyrline[yyrule]);
  /* Print the symbols being reduced, and their result.  */
  for (yyi = yyprhs[yyrule]; 0 <= yyrhs[yyi]; yyi++)
    YYFPRINTF (stderr, "%s ", yytokenName (yyrhs[yyi]));
  YYFPRINTF (stderr, "-> %s\n", yytokenName (yyr1[yyrule]));
}
#endif

/** Pop items off stack #K of STACK according to grammar rule RULE,
 *  and push back on the resulting nonterminal symbol.  Perform the
 *  semantic action associated with RULE and store its value with the
 *  newly pushed state, if FORCEEVAL or if STACK is currently
 *  unambiguous.  Otherwise, store the deferred semantic action with
 *  the new state.  If the new state would have an identical input
 *  position, LR state, and predecessor to an existing state on the stack,
 *  it is identified with that existing state, eliminating stack #K from
 *  the STACK. In this case, the (necessarily deferred) semantic value is
 *  added to the options for the existing state's semantic value.
 */
static inline YYRESULTTAG
yyglrReduce (yyGLRStack* yystack, size_t yyk, yyRuleNum yyrule,
             yybool yyforceEval]b4_pure_formals[)
{
  size_t yyposn = yystack->yytops.yystates[yyk]->yyposn;

  if (yyforceEval || yystack->yysplitPoint == NULL)
    {
      YYSTYPE yysval;
      YYLTYPE yyloc;

      YY_REDUCE_PRINT (yyk, yyrule);
      YYCHK (yydoAction (yystack, yyk, yyrule, &yysval, &yyloc]b4_user_args[));
      yyglrShift (yystack, yyk,
		  yyLRgotoState (yystack->yytops.yystates[yyk]->yylrState,
				 yylhsNonterm (yyrule)),
		  yyposn, yysval, &yyloc]b4_user_args[);
    }
  else
    {
      size_t yyi;
      int yyn;
      yyGLRState* yys, *yys0 = yystack->yytops.yystates[yyk];
      yyStateNum yynewLRState;

      for (yys = yystack->yytops.yystates[yyk], yyn = yyrhsLength (yyrule);
	   0 < yyn; yyn -= 1)
	{
	  yys = yys->yypred;
	  YYASSERT (yys);
	}
      yyupdateSplit (yystack, yys);
      yynewLRState = yyLRgotoState (yys->yylrState, yylhsNonterm (yyrule));
      YYDPRINTF ((stderr,
		  "Reduced stack %lu by rule #%d; action deferred. Now in state %d.\n",
		  (unsigned long int) yyk, yyrule - 1, yynewLRState));
      for (yyi = 0; yyi < yystack->yytops.yysize; yyi += 1)
	if (yyi != yyk && yystack->yytops.yystates[yyi] != NULL)
	  {
	    yyGLRState* yyp, *yysplit = yystack->yysplitPoint;
	    yyp = yystack->yytops.yystates[yyi];
	    while (yyp != yys && yyp != yysplit && yyp->yyposn >= yyposn)
	      {
		if (yyp->yylrState == yynewLRState && yyp->yypred == yys)
		  {
		    yyaddDeferredAction (yystack, yyp, yys0, yyrule]b4_pure_args[);
		    yymarkStackDeleted (yystack, yyk);
		    YYDPRINTF ((stderr, "Merging stack %lu into stack %lu.\n",
				(unsigned long int) yyk,
				(unsigned long int) yyi));
		    return yyok;
		  }
		yyp = yyp->yypred;
	      }
	  }
      yystack->yytops.yystates[yyk] = yys;
      yyglrShiftDefer (yystack, yyk, yynewLRState, yyposn, yys0, yyrule]b4_pure_args[);
    }
  return yyok;
}

static int
yysplitStack (yyGLRStack* yystack, int yyk)
{
  if (yystack->yysplitPoint == NULL)
    {
      YYASSERT (yyk == 0);
      yystack->yysplitPoint = yystack->yytops.yystates[yyk];
    }
  if (yystack->yytops.yysize >= yystack->yytops.yycapacity)
    {
      yystack->yytops.yycapacity *= 2;
      yystack->yytops.yystates =
	(yyGLRState**) YYREALLOC (yystack->yytops.yystates,
				  (yystack->yytops.yycapacity
				   * sizeof yystack->yytops.yystates[0]));
    }
  yystack->yytops.yystates[yystack->yytops.yysize]
    = yystack->yytops.yystates[yyk];
  yystack->yytops.yysize += 1;
  return yystack->yytops.yysize-1;
}

/** True iff Y0 and Y1 represent identical options at the top level.
 *  That is, they represent the same rule applied to RHS symbols
 *  that produce the same terminal symbols. */
static yybool
yyidenticalOptions (yySemanticOption* yyy0, yySemanticOption* yyy1)
{
  if (yyy0->yyrule == yyy1->yyrule)
    {
      yyGLRState *yys0, *yys1;
      int yyn;
      for (yys0 = yyy0->yystate, yys1 = yyy1->yystate,
	   yyn = yyrhsLength (yyy0->yyrule);
	   yyn > 0;
	   yys0 = yys0->yypred, yys1 = yys1->yypred, yyn -= 1)
	if (yys0->yyposn != yys1->yyposn)
	  return yyfalse;
      return yytrue;
    }
  else
    return yyfalse;
}

/** Assuming identicalOptions (Y0,Y1), (destructively) merge the
 *  alternative semantic values for the RHS-symbols of Y1 into the
 *  corresponding semantic value sets of the symbols of Y0. */
static void
yymergeOptionSets (yySemanticOption* yyy0, yySemanticOption* yyy1)
{
  yyGLRState *yys0, *yys1;
  int yyn;
  for (yys0 = yyy0->yystate, yys1 = yyy1->yystate,
       yyn = yyrhsLength (yyy0->yyrule);
       yyn > 0;
       yys0 = yys0->yypred, yys1 = yys1->yypred, yyn -= 1)
    if (yys0 == yys1)
      break;
    else if (! yys0->yyresolved && ! yys1->yyresolved)
      {
	yySemanticOption* yyz;
	for (yyz = yys0->yysemantics.yyfirstVal; yyz->yynext != NULL;
	     yyz = yyz->yynext)
	  continue;
	yyz->yynext = yys1->yysemantics.yyfirstVal;
      }
}

/** Y0 and Y1 represent two possible actions to take in a given
 *  parsing state; return 0 if no combination is possible,
 *  1 if user-mergeable, 2 if Y0 is preferred, 3 if Y1 is preferred. */
static int
yypreference (yySemanticOption* y0, yySemanticOption* y1)
{
  yyRuleNum r0 = y0->yyrule, r1 = y1->yyrule;
  int p0 = yydprec[r0], p1 = yydprec[r1];

  if (p0 == p1)
    {
      if (yymerger[r0] == 0 || yymerger[r0] != yymerger[r1])
	return 0;
      else
	return 1;
    }
  if (p0 == 0 || p1 == 0)
    return 0;
  if (p0 < p1)
    return 3;
  if (p1 < p0)
    return 2;
  return 0;
}

static YYRESULTTAG yyresolveValue (yySemanticOption* yyoptionList,
				   yyGLRStack* yystack, YYSTYPE* yyvalp,
				   YYLTYPE* yylocp]b4_user_formals[);

static YYRESULTTAG
yyresolveStates (yyGLRState* yys, int yyn, yyGLRStack* yystack]b4_user_formals[)
{
  YYRESULTTAG yyflag;
  if (0 < yyn)
    {
      YYASSERT (yys->yypred);
      yyflag = yyresolveStates (yys->yypred, yyn-1, yystack]b4_user_args[);
      if (yyflag != yyok)
	return yyflag;
      if (! yys->yyresolved)
	{
	  yyflag = yyresolveValue (yys->yysemantics.yyfirstVal, yystack,
				   &yys->yysemantics.yysval, &yys->yyloc
				  ]b4_user_args[);
	  if (yyflag != yyok)
	    return yyflag;
	  yys->yyresolved = yytrue;
	}
    }
  return yyok;
}

static YYRESULTTAG
yyresolveAction (yySemanticOption* yyopt, yyGLRStack* yystack,
	         YYSTYPE* yyvalp, YYLTYPE* yylocp]b4_user_formals[)
{
  yyGLRStackItem yyrhsVals[YYMAXRHS + YYMAXLEFT + 1];
  int yynrhs;

  yynrhs = yyrhsLength (yyopt->yyrule);
  YYCHK (yyresolveStates (yyopt->yystate, yynrhs, yystack]b4_user_args[));
  yyrhsVals[YYMAXRHS + YYMAXLEFT].yystate.yypred = yyopt->yystate;
  return yyuserAction (yyopt->yyrule, yynrhs,
		       yyrhsVals + YYMAXRHS + YYMAXLEFT - 1,
		       yyvalp, yylocp, yystack]b4_user_args[);
}

#if YYDEBUG
static void
yyreportTree (yySemanticOption* yyx, int yyindent)
{
  int yynrhs = yyrhsLength (yyx->yyrule);
  int yyi;
  yyGLRState* yys;
  yyGLRState* yystates[YYMAXRHS];
  yyGLRState yyleftmost_state;

  for (yyi = yynrhs, yys = yyx->yystate; 0 < yyi; yyi -= 1, yys = yys->yypred)
    yystates[yyi] = yys;
  if (yys == NULL)
    {
      yyleftmost_state.yyposn = 0;
      yystates[0] = &yyleftmost_state;
    }
  else
    yystates[0] = yys;

  if (yyx->yystate->yyposn < yys->yyposn + 1)
    YYFPRINTF (stderr, "%*s%s -> <Rule %d, empty>\n",
	       yyindent, "", yytokenName (yylhsNonterm (yyx->yyrule)),
	       yyx->yyrule);
  else
    YYFPRINTF (stderr, "%*s%s -> <Rule %d, tokens %lu .. %lu>\n",
	       yyindent, "", yytokenName (yylhsNonterm (yyx->yyrule)),
	       yyx->yyrule, (unsigned long int) (yys->yyposn + 1),
	       (unsigned long int) yyx->yystate->yyposn);
  for (yyi = 1; yyi <= yynrhs; yyi += 1)
    {
      if (yystates[yyi]->yyresolved)
	{
	  if (yystates[yyi-1]->yyposn+1 > yystates[yyi]->yyposn)
	    YYFPRINTF (stderr, "%*s%s <empty>\n", yyindent+2, "",
		       yytokenName (yyrhs[yyprhs[yyx->yyrule]+yyi-1]));
	  else
	    YYFPRINTF (stderr, "%*s%s <tokens %lu .. %lu>\n", yyindent+2, "",
		       yytokenName (yyrhs[yyprhs[yyx->yyrule]+yyi-1]),
		       (unsigned long int) (yystates[yyi - 1]->yyposn + 1),
		       (unsigned long int) yystates[yyi]->yyposn);
	}
      else
	yyreportTree (yystates[yyi]->yysemantics.yyfirstVal, yyindent+2);
    }
}
#endif

static void
yyreportAmbiguity (yySemanticOption* yyx0, yySemanticOption* yyx1,
		   yyGLRStack* yystack]b4_pure_formals[)
{
  /* `Unused' warnings.  */
  (void) yyx0;
  (void) yyx1;

#if YYDEBUG
  YYFPRINTF (stderr, "Ambiguity detected.\n");
  YYFPRINTF (stderr, "Option 1,\n");
  yyreportTree (yyx0, 2);
  YYFPRINTF (stderr, "\nOption 2,\n");
  yyreportTree (yyx1, 2);
  YYFPRINTF (stderr, "\n");
#endif
  yyFail (yystack][]b4_pure_args[, "ambiguity detected");
}


/** Resolve the ambiguity represented by OPTIONLIST, perform the indicated
 *  actions, and return the result. */
static YYRESULTTAG
yyresolveValue (yySemanticOption* yyoptionList, yyGLRStack* yystack,
		YYSTYPE* yyvalp, YYLTYPE* yylocp]b4_user_formals[)
{
  yySemanticOption* yybest;
  yySemanticOption* yyp;
  int yymerge;

  yybest = yyoptionList;
  yymerge = 0;
  for (yyp = yyoptionList->yynext; yyp != NULL; yyp = yyp->yynext)
    {
      if (yyidenticalOptions (yybest, yyp))
	yymergeOptionSets (yybest, yyp);
      else
	switch (yypreference (yybest, yyp))
	  {
	  case 0:
	    yyreportAmbiguity (yybest, yyp, yystack]b4_pure_args[);
	    break;
	  case 1:
	    yymerge = 1;
	    break;
	  case 2:
	    break;
	  case 3:
	    yybest = yyp;
	    yymerge = 0;
	    break;
	  }
    }

  if (yymerge)
    {
      int yyprec = yydprec[yybest->yyrule];
      YYCHK (yyresolveAction (yybest, yystack, yyvalp, yylocp]b4_user_args[));
      for (yyp = yybest->yynext; yyp != NULL; yyp = yyp->yynext)
	{
	  if (yyprec == yydprec[yyp->yyrule])
	    {
	      YYSTYPE yyval1;
	      YYLTYPE yydummy;
	      YYCHK (yyresolveAction (yyp, yystack, &yyval1, &yydummy]b4_user_args[));
	      yyuserMerge (yymerger[yyp->yyrule], yyvalp, &yyval1);
	    }
	}
      return yyok;
    }
  else
    return yyresolveAction (yybest, yystack, yyvalp, yylocp]b4_user_args[);
}

static YYRESULTTAG
yyresolveStack (yyGLRStack* yystack]b4_user_formals[)
{
  if (yystack->yysplitPoint != NULL)
    {
      yyGLRState* yys;
      int yyn;

      for (yyn = 0, yys = yystack->yytops.yystates[0];
	   yys != yystack->yysplitPoint;
	   yys = yys->yypred, yyn += 1)
	continue;
      YYCHK (yyresolveStates (yystack->yytops.yystates[0], yyn, yystack
			     ]b4_user_args[));
    }
  return yyok;
}

static void
yycompressStack (yyGLRStack* yystack)
{
  yyGLRState* yyp, *yyq, *yyr;

  if (yystack->yytops.yysize != 1 || yystack->yysplitPoint == NULL)
    return;

  for (yyp = yystack->yytops.yystates[0], yyq = yyp->yypred, yyr = NULL;
       yyp != yystack->yysplitPoint;
       yyr = yyp, yyp = yyq, yyq = yyp->yypred)
    yyp->yypred = yyr;

  yystack->yyspaceLeft += yystack->yynextFree - yystack->yyitems;
  yystack->yynextFree = ((yyGLRStackItem*) yystack->yysplitPoint) + 1;
  yystack->yyspaceLeft -= yystack->yynextFree - yystack->yyitems;
  yystack->yysplitPoint = NULL;
  yystack->yylastDeleted = NULL;

  while (yyr != NULL)
    {
      yystack->yynextFree->yystate = *yyr;
      yyr = yyr->yypred;
      yystack->yynextFree->yystate.yypred = & yystack->yynextFree[-1].yystate;
      yystack->yytops.yystates[0] = &yystack->yynextFree->yystate;
      yystack->yynextFree += 1;
      yystack->yyspaceLeft -= 1;
    }
}

static YYRESULTTAG
yyprocessOneStack (yyGLRStack* yystack, int yyk,
	           size_t yyposn, YYSTYPE* yylvalp, YYLTYPE* yyllocp
		  ]b4_user_formals[)
{
  int yyaction;
  const short int* yyconflicts;
  yyRuleNum yyrule;
  yySymbol* const yytokenp = yystack->yytokenp;

  while (yystack->yytops.yystates[yyk] != NULL)
    {
      yyStateNum yystate = yystack->yytops.yystates[yyk]->yylrState;
      YYDPRINTF ((stderr, "Stack %d Entering state %d\n", yyk, yystate));

      YYASSERT (yystate != YYFINAL);

      if (yyisDefaultedState (yystate))
	{
	  yyrule = yydefaultAction (yystate);
	  if (yyrule == 0)
	    {
	      YYDPRINTF ((stderr, "Stack %d dies.\n", yyk));
	      yymarkStackDeleted (yystack, yyk);
	      return yyok;
	    }
	  YYCHK (yyglrReduce (yystack, yyk, yyrule, yyfalse]b4_lpure_args[));
	}
      else
	{
	  if (*yytokenp == YYEMPTY)
	    {
	      YYDPRINTF ((stderr, "Reading a token: "));
	      yychar = YYLEX;
	      *yytokenp = YYTRANSLATE (yychar);
	      YYDSYMPRINTF ("Next token is", *yytokenp, yylvalp, yyllocp);
	    }
	  yygetLRActions (yystate, *yytokenp, &yyaction, &yyconflicts);

	  while (*yyconflicts != 0)
	    {
	      int yynewStack = yysplitStack (yystack, yyk);
	      YYDPRINTF ((stderr, "Splitting off stack %d from %d.\n",
			  yynewStack, yyk));
	      YYCHK (yyglrReduce (yystack, yynewStack,
				  *yyconflicts, yyfalse]b4_lpure_args[));
	      YYCHK (yyprocessOneStack (yystack, yynewStack, yyposn,
					yylvalp, yyllocp]b4_user_args[));
	      yyconflicts += 1;
	    }

	  if (yyisShiftAction (yyaction))
	    {
	      YYDPRINTF ((stderr, "Shifting token %s on stack %d, ",
			  yytokenName (*yytokenp), yyk));
	      yyglrShift (yystack, yyk, yyaction, yyposn+1,
			  *yylvalp, yyllocp]b4_user_args[);
	      YYDPRINTF ((stderr, "which is now in state #%d\n",
			  yystack->yytops.yystates[yyk]->yylrState));
	      break;
	    }
	  else if (yyisErrorAction (yyaction))
	    {
	      YYDPRINTF ((stderr, "Stack %d dies.\n", yyk));
	      yymarkStackDeleted (yystack, yyk);
	      break;
	    }
	  else
	    YYCHK (yyglrReduce (yystack, yyk, -yyaction, yyfalse]b4_lpure_args[));
	}
    }
  return yyok;
}

static void
yyreportSyntaxError (yyGLRStack* yystack,
		     YYSTYPE* yylvalp, YYLTYPE* yyllocp]b4_user_formals[)
{
  /* `Unused' warnings. */
  (void) yylvalp;
  (void) yyllocp;

  if (yystack->yyerrState == 0)
    {
#if YYERROR_VERBOSE
      yySymbol* const yytokenp = yystack->yytokenp;
      int yyn;
      yyn = yypact[yystack->yytops.yystates[0]->yylrState];
      if (YYPACT_NINF < yyn && yyn < YYLAST)
	{
	  size_t yysize = 0;
	  const char* yyprefix;
	  char* yymsg;
	  int yyx;

	  /* Start YYX at -YYN if negative to avoid negative indexes in
	     YYCHECK.  */
	  int yyxbegin = yyn < 0 ? -yyn : 0;

	  /* Stay within bounds of both yycheck and yytname.  */
	  int yychecklim = YYLAST - yyn;
	  int yyxend = yychecklim < YYNTOKENS ? yychecklim : YYNTOKENS;
	  int yycount = 0;

	  yyprefix = ", expecting ";
	  for (yyx = yyxbegin; yyx < yyxend; ++yyx)
	    if (yycheck[yyx + yyn] == yyx && yyx != YYTERROR)
	      {
		yysize += strlen (yyprefix) + strlen (yytokenName (yyx));
		yycount += 1;
		if (yycount == 5)
		  {
		    yysize = 0;
		    break;
		  }
		yyprefix = " or ";
	      }
	  yysize += (sizeof ("syntax error, unexpected ")
		     + strlen (yytokenName (*yytokenp)));
	  yymsg = (char*) YYMALLOC (yysize);
	  if (yymsg != 0)
	    {
	      char* yyp = yymsg;
	      sprintf (yyp, "syntax error%s%s",
		       (*yytokenp == YYEMPTY ? "" : ", unexpected "),
		       yytokenName (*yytokenp));
	      yyp += strlen (yyp);
	      if (yycount < 5)
		{
		  yyprefix = ", expecting ";
		  for (yyx = yyxbegin; yyx < yyxend; ++yyx)
		    if (yycheck[yyx + yyn] == yyx && yyx != YYTERROR)
		      {
			sprintf (yyp, "%s%s", yyprefix, yytokenName (yyx));
			yyp += strlen (yyp);
			yyprefix = " or ";
		      }
		}
	      yyerror (]b4_lyyerror_args[yymsg);
	      YYFREE (yymsg);
	    }
	  else
	    yyerror (]b4_lyyerror_args["syntax error; also virtual memory exhausted");
	}
      else
#endif /* YYERROR_VERBOSE */
	yyerror (]b4_lyyerror_args["syntax error");
      yynerrs += 1;
    }
}

/* Recover from a syntax error on YYSTACK, assuming that YYTOKENP,
   YYLVALP, and YYLLOCP point to the syntactic category, semantic
   value, and location of the lookahead.  */
static void
yyrecoverSyntaxError (yyGLRStack* yystack,
		      YYSTYPE* yylvalp, YYLTYPE* yyllocp]b4_user_formals[)
{
  yySymbol* const yytokenp = yystack->yytokenp;
  size_t yyk;
  int yyj;

  if (yystack->yyerrState == 3)
    /* We just shifted the error token and (perhaps) took some
       reductions.  Skip tokens until we can proceed.  */
    while (yytrue)
      {
	if (*yytokenp == YYEOF)
	  {
	    /* Now pop stack until empty and fail. */
	    while (yystack->yytops.yystates[0] != NULL)
	      {
		yyGLRState *yys = yystack->yytops.yystates[0];
		YYDSYMPRINTF ("Error: popping",
			      yystos[yys->yylrState],
			      &yys->yysemantics.yysval, &yys->yyloc);
		yydestruct (yystos[yys->yylrState],
			    &yys->yysemantics.yysval]b4_location_if([, &yys->yyloc])[);
		yystack->yytops.yystates[0] = yys->yypred;
		yystack->yynextFree -= 1;
		yystack->yyspaceLeft += 1;
	      }
	    yyFail (yystack][]b4_lpure_args[, NULL);
	  }
	if (*yytokenp != YYEMPTY)
	  {
	    YYDSYMPRINTF ("Error: discarding", *yytokenp, yylvalp, yyllocp);
	    yydestruct (*yytokenp, yylvalp]b4_location_if([, yyllocp])[);
	  }
	YYDPRINTF ((stderr, "Reading a token: "));
	yychar = YYLEX;
	*yytokenp = YYTRANSLATE (yychar);
	YYDSYMPRINTF ("Next token is", *yytokenp, yylvalp, yyllocp);
	yyj = yypact[yystack->yytops.yystates[0]->yylrState];
	if (yyis_pact_ninf (yyj))
	  return;
	yyj += *yytokenp;
	if (yyj < 0 || YYLAST < yyj || yycheck[yyj] != *yytokenp)
	  {
	    if (yydefact[yystack->yytops.yystates[0]->yylrState] != 0)
	      return;
	  }
	else if (yytable[yyj] != 0 && ! yyis_table_ninf (yytable[yyj]))
	  return;
      }

  /* Reduce to one stack.  */
  for (yyk = 0; yyk < yystack->yytops.yysize; yyk += 1)
    if (yystack->yytops.yystates[yyk] != NULL)
      break;
  if (yyk >= yystack->yytops.yysize)
    yyFail (yystack][]b4_lpure_args[, NULL);
  for (yyk += 1; yyk < yystack->yytops.yysize; yyk += 1)
    yymarkStackDeleted (yystack, yyk);
  yyremoveDeletes (yystack);
  yycompressStack (yystack);

  /* Now pop stack until we find a state that shifts the error token. */
  yystack->yyerrState = 3;
  while (yystack->yytops.yystates[0] != NULL)
    {
      yyGLRState *yys = yystack->yytops.yystates[0];
      yyj = yypact[yys->yylrState];
      if (! yyis_pact_ninf (yyj))
	{
	  yyj += YYTERROR;
	  if (0 <= yyj && yyj <= YYLAST && yycheck[yyj] == YYTERROR
	      && yyisShiftAction (yytable[yyj]))
	    {
	      YYDPRINTF ((stderr, "Shifting error token, "));
	      yyglrShift (yystack, 0, yytable[yyj],
			  yys->yyposn, *yylvalp, yyllocp]b4_user_args[);
	      break;
	    }
	}
      YYDSYMPRINTF ("Error: popping",
		    yystos[yys->yylrState],
		    &yys->yysemantics.yysval, &yys->yyloc);
      yydestruct (yystos[yys->yylrState],
	          &yys->yysemantics.yysval]b4_location_if([, &yys->yyloc])[);
      yystack->yytops.yystates[0] = yys->yypred;
      yystack->yynextFree -= 1;
      yystack->yyspaceLeft += 1;
    }
  if (yystack->yytops.yystates[0] == NULL)
    yyFail (yystack][]b4_lpure_args[, NULL);
}

#define YYCHK1(YYE)							     \
  do {									     \
    switch (YYE) {							     \
    default:								     \
      break;								     \
    case yyabort:							     \
      yystack.yyerrflag = 1;						     \
      goto yyDone;							     \
    case yyaccept:							     \
      yystack.yyerrflag = 0;						     \
      goto yyDone;							     \
    case yyerr:								     \
      goto yyuser_error;						     \
    }									     \
  } while (0)


/*----------.
| yyparse.  |
`----------*/

]b4_c_ansi_function_def([yyparse], [int], b4_parse_param)[
{
  yySymbol yytoken;
  yyGLRStack yystack;
  size_t yyposn;
]b4_pure_if(
[
  YYSTYPE yylval;
  YYLTYPE yylloc;
  #undef yychar
  #define yychar (yystack.yyrawchar)
])[

  YYSTYPE* const yylvalp = &yylval;
  YYLTYPE* const yyllocp = &yylloc;

  yyinitGLRStack (&yystack, YYINITDEPTH);
  yystack.yytokenp = &yytoken;

  YYDPRINTF ((stderr, "Starting parse\n"));

  if (setjmp (yystack.yyexception_buffer) != 0)
    goto yyDone;

  yyglrShift (&yystack, 0, 0, 0, yyval_default, &yyloc_default]b4_user_args[);
  yytoken = YYEMPTY;
  yyposn = 0;

  while (yytrue)
    {
      /* For efficiency, we have two loops, the first of which is
	 specialized to deterministic operation (single stack, no
	 potential ambiguity).  */
      /* Standard mode */
      while (yytrue)
	{
	  yyRuleNum yyrule;
	  int yyaction;
	  const short int* yyconflicts;

	  yyStateNum yystate = yystack.yytops.yystates[0]->yylrState;
          YYDPRINTF ((stderr, "Entering state %d\n", yystate));
	  if (yystate == YYFINAL)
	    goto yyDone;
	  if (yyisDefaultedState (yystate))
	    {
	      yyrule = yydefaultAction (yystate);
	      if (yyrule == 0)
		{
		  yyreportSyntaxError (&yystack, yylvalp, yyllocp]b4_user_args[);
		  goto yyuser_error;
		}
	      YYCHK1 (yyglrReduce (&yystack, 0, yyrule, yytrue]b4_lpure_args[));
	    }
	  else
	    {
	      if (yytoken == YYEMPTY)
		{
		  YYDPRINTF ((stderr, "Reading a token: "));
		  yychar = YYLEX;
		  yytoken = YYTRANSLATE (yychar);
                  YYDSYMPRINTF ("Next token is", yytoken, yylvalp, yyllocp);
		}
	      yygetLRActions (yystate, yytoken, &yyaction, &yyconflicts);
	      if (*yyconflicts != 0)
		break;
	      if (yyisShiftAction (yyaction))
		{
		  YYDPRINTF ((stderr, "Shifting token %s, ",
			      yytokenName (yytoken)));
		  if (yytoken != YYEOF)
		    yytoken = YYEMPTY;
		  yyposn += 1;
		  yyglrShift (&yystack, 0, yyaction, yyposn,
		              yylval, yyllocp]b4_user_args[);
		  if (0 < yystack.yyerrState)
		    yystack.yyerrState -= 1;
		}
	      else if (yyisErrorAction (yyaction))
		{
		  yyreportSyntaxError (&yystack, yylvalp, yyllocp]b4_user_args[);
		  goto yyuser_error;
		}
	      else
		YYCHK1 (yyglrReduce (&yystack, 0, -yyaction, yytrue]b4_lpure_args[));
	    }
	}

      while (yytrue)
	{
	  int yys;
	  int yyn = yystack.yytops.yysize;
	  for (yys = 0; yys < yyn; yys += 1)
	    YYCHK1 (yyprocessOneStack (&yystack, yys, yyposn,
				       yylvalp, yyllocp]b4_user_args[));
	  yytoken = YYEMPTY;
	  yyposn += 1;
	  yyremoveDeletes (&yystack);
	  if (yystack.yytops.yysize == 0)
	    {
	      yyundeleteLastStack (&yystack);
	      if (yystack.yytops.yysize == 0)
		yyFail (&yystack][]b4_lpure_args[, "syntax error");
	      YYCHK1 (yyresolveStack (&yystack]b4_user_args[));
	      YYDPRINTF ((stderr, "Returning to deterministic operation.\n"));
	      yyreportSyntaxError (&yystack, yylvalp, yyllocp]b4_user_args[);
	      goto yyuser_error;
	    }
	  else if (yystack.yytops.yysize == 1)
	    {
	      YYCHK1 (yyresolveStack (&yystack]b4_user_args[));
	      YYDPRINTF ((stderr, "Returning to deterministic operation.\n"));
	      yycompressStack (&yystack);
	      break;
	    }
	}
      continue;
    yyuser_error:
      yyrecoverSyntaxError (&yystack, yylvalp, yyllocp]b4_user_args[);
      yyposn = yystack.yytops.yystates[0]->yyposn;
    }
 yyDone:
  ;

  yyfreeGLRStack (&yystack);
  return yystack.yyerrflag;
}

/* DEBUGGING ONLY */
static void yypstack (yyGLRStack* yystack, int yyk) ATTRIBUTE_UNUSED;
static void yypdumpstack (yyGLRStack* yystack) ATTRIBUTE_UNUSED;

static void
yy_yypstack (yyGLRState* yys)
{
  if (yys->yypred)
    {
      yy_yypstack (yys->yypred);
      fprintf (stderr, " -> ");
    }
  fprintf (stderr, "%d@@%lu", yys->yylrState, (unsigned long int) yys->yyposn);
}

static void
yypstates (yyGLRState* yyst)
{
  if (yyst == NULL)
    fprintf (stderr, "<null>");
  else
    yy_yypstack (yyst);
  fprintf (stderr, "\n");
}

static void
yypstack (yyGLRStack* yystack, int yyk)
{
  yypstates (yystack->yytops.yystates[yyk]);
}

#define YYINDEX(YYX)							     \
    ((YYX) == NULL ? -1 : (yyGLRStackItem*) (YYX) - yystack->yyitems)


static void
yypdumpstack (yyGLRStack* yystack)
{
  yyGLRStackItem* yyp;
  size_t yyi;
  for (yyp = yystack->yyitems; yyp < yystack->yynextFree; yyp += 1)
    {
      fprintf (stderr, "%3lu. ", (unsigned long int) (yyp - yystack->yyitems));
      if (*(yybool *) yyp)
	{
	  fprintf (stderr, "Res: %d, LR State: %d, posn: %lu, pred: %ld",
		   yyp->yystate.yyresolved, yyp->yystate.yylrState,
		   (unsigned long int) yyp->yystate.yyposn,
		   (long int) YYINDEX (yyp->yystate.yypred));
	  if (! yyp->yystate.yyresolved)
	    fprintf (stderr, ", firstVal: %ld",
		     (long int) YYINDEX (yyp->yystate.yysemantics.yyfirstVal));
	}
      else
	{
	  fprintf (stderr, "Option. rule: %d, state: %ld, next: %ld",
		   yyp->yyoption.yyrule,
		   (long int) YYINDEX (yyp->yyoption.yystate),
		   (long int) YYINDEX (yyp->yyoption.yynext));
	}
      fprintf (stderr, "\n");
    }
  fprintf (stderr, "Tops:");
  for (yyi = 0; yyi < yystack->yytops.yysize; yyi += 1)
    fprintf (stderr, "%lu: %ld; ", (unsigned long int) yyi,
	     (long int) YYINDEX (yystack->yytops.yystates[yyi]));
  fprintf (stderr, "\n");
}
]

b4_epilogue
m4_if(b4_defines_flag, 0, [],
[@output @output_header_name@
b4_copyright([Skeleton parser for GLR parsing with Bison], [2002, 2003, 2004])

b4_token_defines(b4_tokens)

#if ! defined (YYSTYPE) && ! defined (YYSTYPE_IS_DECLARED)
m4_ifdef([b4_stype],
[b4_syncline([b4_stype_line], [b4_filename])
typedef union m4_bregexp(b4_stype, [^{], [YYSTYPE ])b4_stype YYSTYPE;
/* Line __line__ of glr.c.  */
b4_syncline([@oline@], [@ofile@])],
[typedef int YYSTYPE;])
# define YYSTYPE_IS_DECLARED 1
# define YYSTYPE_IS_TRIVIAL 1
#endif

b4_pure_if([],
[extern YYSTYPE b4_prefix[]lval;])

#if ! defined (YYLTYPE) && ! defined (YYLTYPE_IS_DECLARED)
typedef struct YYLTYPE
{
b4_location_if([
  int first_line;
  int first_column;
  int last_line;
  int last_column;
],[
  char yydummy;
])
} YYLTYPE;
# define YYLTYPE_IS_DECLARED 1
# define YYLTYPE_IS_TRIVIAL 1
#endif

b4_location_if([m4_if(b4_pure, [0],
[extern YYLTYPE b4_prefix[]lloc;])
])
])