source: trunk/contrib/bison-2.4.2/share/bison/glr.c @ 1933 Tweet

                                                                    -*- C -*-

# GLR skeleton for Bison
# Copyright (C) 2002-2010 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 3 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, see <http://www.gnu.org/licenses/>.


m4_include(b4_pkgdatadir/[c.m4])

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

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



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

b4_define_flag_if([pure])
# If glr.cc is including this file and thus has already set b4_pure_flag, don't
# change the value of b4_pure_flag, and don't record a use of api.pure.
m4_ifndef([b4_pure_flag],
[b4_percent_define_default([[api.pure]], [[false]])
 m4_define([b4_pure_flag],
           [b4_percent_define_flag_if([[api.pure]], [[1]], [[0]])])])

# b4_user_formals
# ---------------
# The possible parse-params formal arguments preceded by a comma.
#
# This is not shared with yacc.c in c.m4 because  GLR relies on ISO C
# formal argument declarations.
m4_define([b4_user_formals],
[m4_ifset([b4_parse_param], [, b4_c_ansi_formals(b4_parse_param)])])


# 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 *]], [[&yylval]]][]dnl
b4_locations_if([, [[YYLTYPE *], [&yylloc]]])])dnl
m4_ifdef([b4_lex_param], [, ]b4_lex_param)))


# b4_yyerror_args
# ---------------
# Optional effective arguments passed to yyerror: user args plus yylloc, and
# a trailing comma.
m4_define([b4_yyerror_args],
[b4_pure_if([b4_locations_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 &yylloc instead of yylocp.
m4_define([b4_lyyerror_args],
[b4_pure_if([b4_locations_if([&yylloc, ])])dnl
m4_ifset([b4_parse_param], [b4_c_args(b4_parse_param), ])])


# b4_pure_args
# ------------
# Same as b4_yyerror_args, but with a leading comma.
m4_define([b4_pure_args],
[b4_pure_if([b4_locations_if([, yylocp])])[]b4_user_args])


# b4_lpure_args
# -------------
# Same as above, but on the lookahead, hence &yylloc instead of yylocp.
m4_define([b4_lpure_args],
[b4_pure_if([b4_locations_if([, &yylloc])])[]b4_user_args])


# b4_pure_formals
# ---------------
# Arguments passed to yyerror: user formals plus yylocp.
m4_define([b4_pure_formals],
[b4_pure_if([b4_locations_if([, YYLTYPE *yylocp])])[]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 (($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 (($2) - ($1))@}.yystate.yyloc)])



## -------------- ##
## Output files.  ##
## -------------- ##

# We do want M4 expansion after # for CPP macros.
m4_changecom()
m4_divert_push(0)dnl
@output(b4_parser_file_name@)@
b4_copyright([Skeleton implementation for Bison GLR parsers in C],
             [2002-2006, 2009-2010])
[
/* C GLR parser skeleton written by Paul Hilfinger.  */

]b4_identification

b4_percent_code_get([[top]])[]dnl
m4_if(b4_prefix, [yy], [],
[/* Substitute the variable and function 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
#define yylloc  b4_prefix[]lloc])[

/* Copy the first part of user declarations.  */
]b4_user_pre_prologue

dnl # b4_shared_declarations
dnl # ----------------------
dnl # Declaration that might either go into the header (if --defines)
dnl # or open coded in the parser body.
m4_define([b4_shared_declarations],
[b4_percent_code_get([[requires]])[]dnl

b4_token_enums(b4_tokens)

[#ifndef YYSTYPE
]m4_ifdef([b4_stype],
[[typedef union ]b4_union_name[
{
]b4_user_stype[
} YYSTYPE;
# define YYSTYPE_IS_TRIVIAL 1]],
[m4_if(b4_tag_seen_flag, 0,
[[typedef int YYSTYPE;
# define YYSTYPE_IS_TRIVIAL 1]])])[
#endif

#if ! defined YYLTYPE && ! defined YYLTYPE_IS_DECLARED
typedef struct YYLTYPE
{
]b4_locations_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_percent_code_get([[provides]])[]dnl
])

b4_defines_if([[#include "@basename(]b4_spec_defines_file[@)"]],
              [b4_shared_declarations])[

/* Enabling traces.  */
#ifndef YYDEBUG
# define YYDEBUG ]b4_debug_flag[
#endif

/* Enabling verbose error messages.  */
#ifdef YYERROR_VERBOSE
# undef YYERROR_VERBOSE
# define YYERROR_VERBOSE 1
#else
# define YYERROR_VERBOSE ]b4_error_verbose_flag[
#endif

/* Enabling the token table.  */
#ifndef YYTOKEN_TABLE
# define YYTOKEN_TABLE ]b4_token_table[
#endif

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

/* Copy the second part of user declarations.  */
]b4_user_post_prologue
b4_percent_code_get[]dnl

[#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifndef YY_
# if defined YYENABLE_NLS && YYENABLE_NLS
#  if ENABLE_NLS
#   include <libintl.h> /* INFRINGES ON USER NAME SPACE */
#   define YY_(msgid) dgettext ("bison-runtime", msgid)
#  endif
# endif
# ifndef YY_
#  define YY_(msgid) msgid
# endif
#endif

/* Suppress unused-variable warnings by "using" E.  */
#if ! defined lint || defined __GNUC__
# define YYUSE(e) ((void) (e))
#else
# define YYUSE(e) /* empty */
#endif

/* Identity function, used to suppress warnings about constant conditions.  */
#ifndef lint
# define YYID(n) (n)
#else
]b4_c_function_def([YYID], [static int], [[int i], [i]])[
{
  return i;
}
#endif

#ifndef YYFREE
# define YYFREE free
#endif
#ifndef YYMALLOC
# define YYMALLOC malloc
#endif
#ifndef YYREALLOC
# define YYREALLOC realloc
#endif

#define YYSIZEMAX ((size_t) -1)

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

#ifndef YYSETJMP
# include <setjmp.h>
# define YYJMP_BUF jmp_buf
# define YYSETJMP(env) setjmp (env)
# define YYLONGJMP(env, val) longjmp (env, val)
#endif

/*-----------------.
| 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) \
      || (defined __STRICT_ANSI__ && __STRICT_ANSI__))
#  define __attribute__(Spec) /* empty */
# endif
#endif

]b4_locations_if([#define YYOPTIONAL_LOC(Name) Name],[
#ifdef __cplusplus
# define YYOPTIONAL_LOC(Name) /* empty */
#else
# define YYOPTIONAL_LOC(Name) Name __attribute__ ((__unused__))
#endif])[

#ifndef YYASSERT
# define YYASSERT(condition) ((void) ((condition) || (abort (), 0)))
#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)                                                \
  ((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 || YYTOKEN_TABLE
/* YYTNAME[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[
};


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

/* Error token number */
#define YYTERROR 1

/* YYLLOC_DEFAULT -- Set CURRENT to span from RHS[1] to RHS[N].
   If N is 0, then set CURRENT to the empty location which ends
   the previous symbol: RHS[0] (always defined).  */

]b4_locations_if([[
#define YYRHSLOC(Rhs, K) ((Rhs)[K].yystate.yyloc)
#ifndef YYLLOC_DEFAULT
# define YYLLOC_DEFAULT(Current, Rhs, N)                                \
    do                                                                  \
      if (YYID (N))                                                     \
        {                                                               \
          (Current).first_line   = YYRHSLOC (Rhs, 1).first_line;        \
          (Current).first_column = YYRHSLOC (Rhs, 1).first_column;      \
          (Current).last_line    = YYRHSLOC (Rhs, N).last_line;         \
          (Current).last_column  = YYRHSLOC (Rhs, N).last_column;       \
        }                                                               \
      else                                                              \
        {                                                               \
          (Current).first_line   = (Current).last_line   =              \
            YYRHSLOC (Rhs, 0).last_line;                                \
          (Current).first_column = (Current).last_column =              \
            YYRHSLOC (Rhs, 0).last_column;                              \
        }                                                               \
    while (YYID (0))

/* YY_LOCATION_PRINT -- Print the location on the stream.
   This macro was not mandated originally: define only if we know
   we won't break user code: when these are the locations we know.  */

# define YY_LOCATION_PRINT(File, Loc)                   \
    fprintf (File, "%d.%d-%d.%d",                       \
             (Loc).first_line, (Loc).first_column,      \
             (Loc).last_line,  (Loc).last_column)
#endif
]],[
#ifndef YYLLOC_DEFAULT
# define YYLLOC_DEFAULT(Current, Rhs, N) ((void) 0)
#endif
])[

#ifndef YY_LOCATION_PRINT
# define YY_LOCATION_PRINT(File, Loc) ((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 (yystackp->yyerrcnt)
#undef yychar
#define yychar (yystackp->yyrawchar)
#undef yylval
#define yylval (yystackp->yyval)
#undef yylloc
#define yylloc (yystackp->yyloc)
m4_if(b4_prefix[], [yy], [],
[#define b4_prefix[]nerrs yynerrs
#define b4_prefix[]char yychar
#define b4_prefix[]lval yylval
#define b4_prefix[]lloc yylloc])],
[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 (YYID (0))

#if YYDEBUG

# ifndef YYFPRINTF
#  define YYFPRINTF fprintf
# endif

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

]b4_yy_symbol_print_generate([b4_c_ansi_function_def])[

# define YY_SYMBOL_PRINT(Title, Type, Value, Location)                      \
do {                                                                        \
  if (yydebug)                                                              \
    {                                                                       \
      YYFPRINTF (stderr, "%s ", Title);                                     \
      yy_symbol_print (stderr, Type,                                        \
                       Value]b4_locations_if([, Location])[]b4_user_args[);  \
      YYFPRINTF (stderr, "\n");                                             \
    }                                                                       \
} while (YYID (0))

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

#else /* !YYDEBUG */

# define YYDPRINTF(Args)
# define YY_SYMBOL_PRINT(Title, Type, 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.  */

#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 yyexpandGLRStack before the
   stack is expanded, thus insuring that all necessary pointers get
   properly redirected to new data.  */
#define YYHEADROOM 2

#ifndef YYSTACKEXPANDABLE
# if (! defined __cplusplus \
      || (]b4_locations_if([[defined YYLTYPE_IS_TRIVIAL && YYLTYPE_IS_TRIVIAL \
          && ]])[defined YYSTYPE_IS_TRIVIAL && YYSTYPE_IS_TRIVIAL))
#  define YYSTACKEXPANDABLE 1
# else
#  define YYSTACKEXPANDABLE 0
# endif
#endif

#if YYSTACKEXPANDABLE
# define YY_RESERVE_GLRSTACK(Yystack)                   \
  do {                                                  \
    if (Yystack->yyspaceLeft < YYHEADROOM)              \
      yyexpandGLRStack (Yystack);                       \
  } while (YYID (0))
#else
# define YY_RESERVE_GLRSTACK(Yystack)                   \
  do {                                                  \
    if (Yystack->yyspaceLeft < YYHEADROOM)              \
      yyMemoryExhausted (Yystack);                      \
  } while (YYID (0))
#endif


#if YYERROR_VERBOSE

# ifndef yystpcpy
#  if defined __GLIBC__ && defined _STRING_H && defined _GNU_SOURCE
#   define yystpcpy stpcpy
#  else
/* Copy YYSRC to YYDEST, returning the address of the terminating '\0' in
   YYDEST.  */
static char *
yystpcpy (char *yydest, const char *yysrc)
{
  char *yyd = yydest;
  const char *yys = yysrc;

  while ((*yyd++ = *yys++) != '\0')
    continue;

  return yyd - 1;
}
#  endif
# endif

# ifndef yytnamerr
/* Copy to YYRES the contents of YYSTR after stripping away unnecessary
   quotes and backslashes, so that it's suitable for yyerror.  The
   heuristic is that double-quoting is unnecessary unless the string
   contains an apostrophe, a comma, or backslash (other than
   backslash-backslash).  YYSTR is taken from yytname.  If YYRES is
   null, do not copy; instead, return the length of what the result
   would have been.  */
static size_t
yytnamerr (char *yyres, const char *yystr)
{
  if (*yystr == '"')
    {
      size_t yyn = 0;
      char const *yyp = yystr;

      for (;;)
        switch (*++yyp)
          {
          case '\'':
          case ',':
            goto do_not_strip_quotes;

          case '\\':
            if (*++yyp != '\\')
              goto do_not_strip_quotes;
            /* Fall through.  */
          default:
            if (yyres)
              yyres[yyn] = *yyp;
            yyn++;
            break;

          case '"':
            if (yyres)
              yyres[yyn] = '\0';
            return yyn;
          }
    do_not_strip_quotes: ;
    }

  if (! yyres)
    return strlen (yystr);

  return yystpcpy (yyres, yystr) - yyres;
}
# endif

#endif /* !YYERROR_VERBOSE */

/** 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 yyGLRStateSet yyGLRStateSet;
typedef struct yySemanticOption yySemanticOption;
typedef union yyGLRStackItem yyGLRStackItem;
typedef struct yyGLRStack yyGLRStack;

struct yyGLRState {
  /** Type tag: always true.  */
  yybool yyisState;
  /** Type tag for yysemantics.  If true, yysval applies, otherwise
   *  yyfirstVal applies.  */
  yybool yyresolved;
  /** Number of corresponding LALR(1) machine state.  */
  yyStateNum yylrState;
  /** Preceding state in this stack */
  yyGLRState* yypred;
  /** Source position of the first token produced by my symbol */
  size_t yyposn;
  union {
    /** First in a chain of alternative reductions producing the
     *  non-terminal corresponding to this state, threaded through
     *  yynext.  */
    yySemanticOption* yyfirstVal;
    /** Semantic value for this state.  */
    YYSTYPE yysval;
  } yysemantics;
  /** Source location for this state.  */
  YYLTYPE yyloc;
};

struct yyGLRStateSet {
  yyGLRState** yystates;
  /** During nondeterministic operation, yylookaheadNeeds tracks which
   *  stacks have actually needed the current lookahead.  During deterministic
   *  operation, yylookaheadNeeds[0] is not maintained since it would merely
   *  duplicate yychar != YYEMPTY.  */
  yybool* yylookaheadNeeds;
  size_t yysize, yycapacity;
};

struct yySemanticOption {
  /** Type tag: always false.  */
  yybool yyisState;
  /** Rule number for this reduction */
  yyRuleNum yyrule;
  /** The last RHS state in the list of states to be reduced.  */
  yyGLRState* yystate;
  /** The lookahead for this reduction.  */
  int yyrawchar;
  YYSTYPE yyval;
  YYLTYPE yyloc;
  /** Next sibling in chain of options.  To facilitate merging,
   *  options are chained in decreasing order by address.  */
  yySemanticOption* yynext;
};

/** Type of the items in the GLR stack.  The yyisState field
 *  indicates which item of the union is valid.  */
union yyGLRStackItem {
  yyGLRState yystate;
  yySemanticOption yyoption;
};

struct yyGLRStack {
  int yyerrState;
]b4_locations_if([[  /* To compute the location of the error token.  */
  yyGLRStackItem yyerror_range[3];]])[
]b4_pure_if(
[
  int yyerrcnt;
  int yyrawchar;
  YYSTYPE yyval;
  YYLTYPE yyloc;
])[
  YYJMP_BUF yyexception_buffer;
  yyGLRStackItem* yyitems;
  yyGLRStackItem* yynextFree;
  size_t yyspaceLeft;
  yyGLRState* yysplitPoint;
  yyGLRState* yylastDeleted;
  yyGLRStateSet yytops;
};

#if YYSTACKEXPANDABLE
static void yyexpandGLRStack (yyGLRStack* yystackp);
#endif

static void yyFail (yyGLRStack* yystackp]b4_pure_formals[, const char* yymsg)
  __attribute__ ((__noreturn__));
static void
yyFail (yyGLRStack* yystackp]b4_pure_formals[, const char* yymsg)
{
  if (yymsg != NULL)
    yyerror (]b4_yyerror_args[yymsg);
  YYLONGJMP (yystackp->yyexception_buffer, 1);
}

static void yyMemoryExhausted (yyGLRStack* yystackp)
  __attribute__ ((__noreturn__));
static void
yyMemoryExhausted (yyGLRStack* yystackp)
{
  YYLONGJMP (yystackp->yyexception_buffer, 2);
}

#if YYDEBUG || YYERROR_VERBOSE
/** A printable representation of TOKEN.  */
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.  */
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.  */
/*ARGSUSED*/ static YYRESULTTAG
yyuserAction (yyRuleNum yyn, int yyrhslen, yyGLRStackItem* yyvsp,
              YYSTYPE* yyvalp,
              YYLTYPE* YYOPTIONAL_LOC (yylocp),
              yyGLRStack* yystackp
              ]b4_user_formals[)
{
  yybool yynormal __attribute__ ((__unused__)) =
    (yystackp->yysplitPoint == NULL);
  int yylow;
]b4_parse_param_use[]dnl
[# undef yyerrok
# define yyerrok (yystackp->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() (yystackp->yyerrState != 0)
# undef yyclearin
# define yyclearin (yychar = YYEMPTY)
# undef YYFILL
# define YYFILL(N) yyfill (yyvsp, &yylow, N, yynormal)
# undef YYBACKUP
# define YYBACKUP(Token, Value)                                              \
  return yyerror (]b4_yyerror_args[YY_("syntax error: cannot back up")),     \
         yyerrok, yyerr

  yylow = 1;
  if (yyrhslen == 0)
    *yyvalp = yyval_default;
  else
    *yyvalp = yyvsp[YYFILL (1-yyrhslen)].yystate.yysemantics.yysval;
  YYLLOC_DEFAULT ((*yylocp), (yyvsp - yyrhslen), yyrhslen);
]b4_locations_if([[  yystackp->yyerror_range[1].yystate.yyloc = *yylocp;
]])[
  switch (yyn)
    {
      ]b4_user_actions[
      default: break;
    }

  return yyok;
# undef yyerrok
# undef YYABORT
# undef YYACCEPT
# undef YYERROR
# undef YYBACKUP
# undef yyclearin
# undef YYRECOVERING
}


/*ARGSUSED*/ static void
yyuserMerge (int yyn, YYSTYPE* yy0, YYSTYPE* yy1)
{
  YYUSE (yy0);
  YYUSE (yy1);

  switch (yyn)
    {
      ]b4_mergers[
      default: break;
    }
}

                              /* 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];
}

static void
yydestroyGLRState (char const *yymsg, yyGLRState *yys]b4_user_formals[)
{
  if (yys->yyresolved)
    yydestruct (yymsg, yystos[yys->yylrState],
                &yys->yysemantics.yysval]b4_locations_if([, &yys->yyloc])[]b4_user_args[);
  else
    {
#if YYDEBUG
      if (yydebug)
        {
          if (yys->yysemantics.yyfirstVal)
            YYFPRINTF (stderr, "%s unresolved ", yymsg);
          else
            YYFPRINTF (stderr, "%s incomplete ", yymsg);
          yy_symbol_print (stderr, yystos[yys->yylrState],
                           NULL]b4_locations_if([, &yys->yyloc])[]b4_user_args[);
          YYFPRINTF (stderr, "\n");
        }
#endif

      if (yys->yysemantics.yyfirstVal)
        {
          yySemanticOption *yyoption = yys->yysemantics.yyfirstVal;
          yyGLRState *yyrh;
          int yyn;
          for (yyrh = yyoption->yystate, yyn = yyrhsLength (yyoption->yyrule);
               yyn > 0;
               yyrh = yyrh->yypred, yyn -= 1)
            yydestroyGLRState (yymsg, yyrh]b4_user_args[);
        }
    }
}

/** 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],
         [YYID (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 */

/** Return a fresh GLRStackItem.  Callers should call
 * YY_RESERVE_GLRSTACK afterwards to make sure there is sufficient
 * headroom.  */

static inline yyGLRStackItem*
yynewGLRStackItem (yyGLRStack* yystackp, yybool yyisState)
{
  yyGLRStackItem* yynewItem = yystackp->yynextFree;
  yystackp->yyspaceLeft -= 1;
  yystackp->yynextFree += 1;
  yynewItem->yystate.yyisState = yyisState;
  return yynewItem;
}

/** Add a new semantic action that will execute the action for rule
 *  RULENUM on the semantic values in RHS to the list of
 *  alternative actions for STATE.  Assumes that RHS comes from
 *  stack #K of *STACKP. */
static void
yyaddDeferredAction (yyGLRStack* yystackp, size_t yyk, yyGLRState* yystate,
                     yyGLRState* rhs, yyRuleNum yyrule)
{
  yySemanticOption* yynewOption =
    &yynewGLRStackItem (yystackp, yyfalse)->yyoption;
  yynewOption->yystate = rhs;
  yynewOption->yyrule = yyrule;
  if (yystackp->yytops.yylookaheadNeeds[yyk])
    {
      yynewOption->yyrawchar = yychar;
      yynewOption->yyval = yylval;
      yynewOption->yyloc = yylloc;
    }
  else
    yynewOption->yyrawchar = YYEMPTY;
  yynewOption->yynext = yystate->yysemantics.yyfirstVal;
  yystate->yysemantics.yyfirstVal = yynewOption;

  YY_RESERVE_GLRSTACK (yystackp);
}

                                /* GLRStacks */

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

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

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


#if YYSTACKEXPANDABLE
# 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* yystackp)
{
  yyGLRStackItem* yynewItems;
  yyGLRStackItem* yyp0, *yyp1;
  size_t yysize, yynewSize;
  size_t yyn;
  yysize = yystackp->yynextFree - yystackp->yyitems;
  if (YYMAXDEPTH - YYHEADROOM < yysize)
    yyMemoryExhausted (yystackp);
  yynewSize = 2*yysize;
  if (YYMAXDEPTH < yynewSize)
    yynewSize = YYMAXDEPTH;
  yynewItems = (yyGLRStackItem*) YYMALLOC (yynewSize * sizeof yynewItems[0]);
  if (! yynewItems)
    yyMemoryExhausted (yystackp);
  for (yyp0 = yystackp->yyitems, yyp1 = yynewItems, 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 (yystackp->yysplitPoint != NULL)
    yystackp->yysplitPoint = YYRELOC (yystackp->yyitems, yynewItems,
                                 yystackp->yysplitPoint, yystate);

  for (yyn = 0; yyn < yystackp->yytops.yysize; yyn += 1)
    if (yystackp->yytops.yystates[yyn] != NULL)
      yystackp->yytops.yystates[yyn] =
        YYRELOC (yystackp->yyitems, yynewItems,
                 yystackp->yytops.yystates[yyn], yystate);
  YYFREE (yystackp->yyitems);
  yystackp->yyitems = yynewItems;
  yystackp->yynextFree = yynewItems + yysize;
  yystackp->yyspaceLeft = yynewSize - yysize;
}
#endif

static void
yyfreeGLRStack (yyGLRStack* yystackp)
{
  YYFREE (yystackp->yyitems);
  yyfreeStateSet (&yystackp->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* yystackp, yyGLRState* yys)
{
  if (yystackp->yysplitPoint != NULL && yystackp->yysplitPoint > yys)
    yystackp->yysplitPoint = yys;
}

/** Invalidate stack #K in STACK.  */
static inline void
yymarkStackDeleted (yyGLRStack* yystackp, size_t yyk)
{
  if (yystackp->yytops.yystates[yyk] != NULL)
    yystackp->yylastDeleted = yystackp->yytops.yystates[yyk];
  yystackp->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* yystackp)
{
  if (yystackp->yylastDeleted == NULL || yystackp->yytops.yysize != 0)
    return;
  yystackp->yytops.yystates[0] = yystackp->yylastDeleted;
  yystackp->yytops.yysize = 1;
  YYDPRINTF ((stderr, "Restoring last deleted stack as stack #0.\n"));
  yystackp->yylastDeleted = NULL;
}

static inline void
yyremoveDeletes (yyGLRStack* yystackp)
{
  size_t yyi, yyj;
  yyi = yyj = 0;
  while (yyj < yystackp->yytops.yysize)
    {
      if (yystackp->yytops.yystates[yyi] == NULL)
        {
          if (yyi == yyj)
            {
              YYDPRINTF ((stderr, "Removing dead stacks.\n"));
            }
          yystackp->yytops.yysize -= 1;
        }
      else
        {
          yystackp->yytops.yystates[yyj] = yystackp->yytops.yystates[yyi];
          /* In the current implementation, it's unnecessary to copy
             yystackp->yytops.yylookaheadNeeds[yyi] since, after
             yyremoveDeletes returns, the parser immediately either enters
             deterministic operation or shifts a token.  However, it doesn't
             hurt, and the code might evolve to need it.  */
          yystackp->yytops.yylookaheadNeeds[yyj] =
            yystackp->yytops.yylookaheadNeeds[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* yystackp, size_t yyk, yyStateNum yylrState,
            size_t yyposn,
            YYSTYPE* yyvalp, YYLTYPE* yylocp)
{
  yyGLRState* yynewState = &yynewGLRStackItem (yystackp, yytrue)->yystate;

  yynewState->yylrState = yylrState;
  yynewState->yyposn = yyposn;
  yynewState->yyresolved = yytrue;
  yynewState->yypred = yystackp->yytops.yystates[yyk];
  yynewState->yysemantics.yysval = *yyvalp;
  yynewState->yyloc = *yylocp;
  yystackp->yytops.yystates[yyk] = yynewState;

  YY_RESERVE_GLRSTACK (yystackp);
}

/** 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* yystackp, size_t yyk, yyStateNum yylrState,
                 size_t yyposn, yyGLRState* rhs, yyRuleNum yyrule)
{
  yyGLRState* yynewState = &yynewGLRStackItem (yystackp, yytrue)->yystate;

  yynewState->yylrState = yylrState;
  yynewState->yyposn = yyposn;
  yynewState->yyresolved = yyfalse;
  yynewState->yypred = yystackp->yytops.yystates[yyk];
  yynewState->yysemantics.yyfirstVal = NULL;
  yystackp->yytops.yystates[yyk] = yynewState;

  /* Invokes YY_RESERVE_GLRSTACK.  */
  yyaddDeferredAction (yystackp, yyk, yynewState, rhs, yyrule);
}

/** 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* yystackp, size_t yyk, yyRuleNum yyrule,
            YYSTYPE* yyvalp, YYLTYPE* yylocp]b4_user_formals[)
{
  int yynrhs = yyrhsLength (yyrule);

  if (yystackp->yysplitPoint == NULL)
    {
      /* Standard special case: single stack.  */
      yyGLRStackItem* rhs = (yyGLRStackItem*) yystackp->yytops.yystates[yyk];
      YYASSERT (yyk == 0);
      yystackp->yynextFree -= yynrhs;
      yystackp->yyspaceLeft += yynrhs;
      yystackp->yytops.yystates[0] = & yystackp->yynextFree[-1].yystate;
      return yyuserAction (yyrule, yynrhs, rhs,
                           yyvalp, yylocp, yystackp]b4_user_args[);
    }
  else
    {
      /* At present, doAction is never called in nondeterministic
       * mode, so this branch is never taken.  It is here in
       * anticipation of a future feature that will allow immediate
       * evaluation of selected actions in nondeterministic mode.  */
      int yyi;
      yyGLRState* yys;
      yyGLRStackItem yyrhsVals[YYMAXRHS + YYMAXLEFT + 1];
      yys = yyrhsVals[YYMAXRHS + YYMAXLEFT].yystate.yypred
        = yystackp->yytops.yystates[yyk];]b4_locations_if([[
      if (yynrhs == 0)
        /* Set default location.  */
        yyrhsVals[YYMAXRHS + YYMAXLEFT - 1].yystate.yyloc = yys->yyloc;]])[
      for (yyi = 0; yyi < yynrhs; yyi += 1)
        {
          yys = yys->yypred;
          YYASSERT (yys);
        }
      yyupdateSplit (yystackp, yys);
      yystackp->yytops.yystates[yyk] = yys;
      return yyuserAction (yyrule, yynrhs, yyrhsVals + YYMAXRHS + YYMAXLEFT - 1,
                           yyvalp, yylocp, yystackp]b4_user_args[);
    }
}

#if !YYDEBUG
# define YY_REDUCE_PRINT(Args)
#else
# define YY_REDUCE_PRINT(Args)          \
do {                                    \
  if (yydebug)                          \
    yy_reduce_print Args;               \
} while (YYID (0))

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

/*ARGSUSED*/ static inline void
yy_reduce_print (yyGLRStack* yystackp, size_t yyk, yyRuleNum yyrule,
                 YYSTYPE* yyvalp, YYLTYPE* yylocp]b4_user_formals[)
{
  int yynrhs = yyrhsLength (yyrule);
  yybool yynormal __attribute__ ((__unused__)) =
    (yystackp->yysplitPoint == NULL);
  yyGLRStackItem* yyvsp = (yyGLRStackItem*) yystackp->yytops.yystates[yyk];
  int yylow = 1;
  int yyi;
  YYUSE (yyvalp);
  YYUSE (yylocp);
]b4_parse_param_use[]dnl
[  YYFPRINTF (stderr, "Reducing stack %lu by rule %d (line %lu):\n",
             (unsigned long int) yyk, yyrule - 1,
             (unsigned long int) yyrline[yyrule]);
  /* The symbols being reduced.  */
  for (yyi = 0; yyi < yynrhs; yyi++)
    {
      YYFPRINTF (stderr, "   $%d = ", yyi + 1);
      yy_symbol_print (stderr, yyrhs[yyprhs[yyrule] + yyi],
                       &]b4_rhs_value(yynrhs, yyi + 1)[
                       ]b4_locations_if([, &]b4_rhs_location(yynrhs, yyi + 1))[]dnl
                       b4_user_args[);
      YYFPRINTF (stderr, "\n");
    }
}
#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* yystackp, size_t yyk, yyRuleNum yyrule,
             yybool yyforceEval]b4_user_formals[)
{
  size_t yyposn = yystackp->yytops.yystates[yyk]->yyposn;

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

      YY_REDUCE_PRINT ((yystackp, yyk, yyrule, &yysval, &yyloc]b4_user_args[));
      YYCHK (yydoAction (yystackp, yyk, yyrule, &yysval,
                         &yyloc]b4_user_args[));
      YY_SYMBOL_PRINT ("-> $$ =", yyr1[yyrule], &yysval, &yyloc);
      yyglrShift (yystackp, yyk,
                  yyLRgotoState (yystackp->yytops.yystates[yyk]->yylrState,
                                 yylhsNonterm (yyrule)),
                  yyposn, &yysval, &yyloc);
    }
  else
    {
      size_t yyi;
      int yyn;
      yyGLRState* yys, *yys0 = yystackp->yytops.yystates[yyk];
      yyStateNum yynewLRState;

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

static size_t
yysplitStack (yyGLRStack* yystackp, size_t yyk)
{
  if (yystackp->yysplitPoint == NULL)
    {
      YYASSERT (yyk == 0);
      yystackp->yysplitPoint = yystackp->yytops.yystates[yyk];
    }
  if (yystackp->yytops.yysize >= yystackp->yytops.yycapacity)
    {
      yyGLRState** yynewStates;
      yybool* yynewLookaheadNeeds;

      yynewStates = NULL;

      if (yystackp->yytops.yycapacity
          > (YYSIZEMAX / (2 * sizeof yynewStates[0])))
        yyMemoryExhausted (yystackp);
      yystackp->yytops.yycapacity *= 2;

      yynewStates =
        (yyGLRState**) YYREALLOC (yystackp->yytops.yystates,
                                  (yystackp->yytops.yycapacity
                                   * sizeof yynewStates[0]));
      if (yynewStates == NULL)
        yyMemoryExhausted (yystackp);
      yystackp->yytops.yystates = yynewStates;

      yynewLookaheadNeeds =
        (yybool*) YYREALLOC (yystackp->yytops.yylookaheadNeeds,
                             (yystackp->yytops.yycapacity
                              * sizeof yynewLookaheadNeeds[0]));
      if (yynewLookaheadNeeds == NULL)
        yyMemoryExhausted (yystackp);
      yystackp->yytops.yylookaheadNeeds = yynewLookaheadNeeds;
    }
  yystackp->yytops.yystates[yystackp->yytops.yysize]
    = yystackp->yytops.yystates[yyk];
  yystackp->yytops.yylookaheadNeeds[yystackp->yytops.yysize]
    = yystackp->yytops.yylookaheadNeeds[yyk];
  yystackp->yytops.yysize += 1;
  return yystackp->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 and 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 = yytrue;
          yys1->yysemantics.yysval = yys0->yysemantics.yysval;
        }
      else if (yys1->yyresolved)
        {
          yys0->yyresolved = yytrue;
          yys0->yysemantics.yysval = yys1->yysemantics.yysval;
        }
      else
        {
          yySemanticOption** yyz0p;
          yySemanticOption* yyz1;
          yyz0p = &yys0->yysemantics.yyfirstVal;
          yyz1 = yys1->yysemantics.yyfirstVal;
          while (YYID (yytrue))
            {
              if (yyz1 == *yyz0p || yyz1 == NULL)
                break;
              else if (*yyz0p == NULL)
                {
                  *yyz0p = yyz1;
                  break;
                }
              else if (*yyz0p < yyz1)
                {
                  yySemanticOption* yyz = *yyz0p;
                  *yyz0p = yyz1;
                  yyz1 = yyz1->yynext;
                  (*yyz0p)->yynext = yyz;
                }
              yyz0p = &(*yyz0p)->yynext;
            }
          yys1->yysemantics.yyfirstVal = yys0->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 (yyGLRState* yys,
                                   yyGLRStack* yystackp]b4_user_formals[);


/** Resolve the previous N states starting at and including state S.  If result
 *  != yyok, some states may have been left unresolved possibly with empty
 *  semantic option chains.  Regardless of whether result = yyok, each state
 *  has been left with consistent data so that yydestroyGLRState can be invoked
 *  if necessary.  */
static YYRESULTTAG
yyresolveStates (yyGLRState* yys, int yyn,
                 yyGLRStack* yystackp]b4_user_formals[)
{
  if (0 < yyn)
    {
      YYASSERT (yys->yypred);
      YYCHK (yyresolveStates (yys->yypred, yyn-1, yystackp]b4_user_args[));
      if (! yys->yyresolved)
        YYCHK (yyresolveValue (yys, yystackp]b4_user_args[));
    }
  return yyok;
}

/** Resolve the states for the RHS of OPT, perform its user action, and return
 *  the semantic value and location.  Regardless of whether result = yyok, all
 *  RHS states have been destroyed (assuming the user action destroys all RHS
 *  semantic values if invoked).  */
static YYRESULTTAG
yyresolveAction (yySemanticOption* yyopt, yyGLRStack* yystackp,
                 YYSTYPE* yyvalp, YYLTYPE* yylocp]b4_user_formals[)
{
  yyGLRStackItem yyrhsVals[YYMAXRHS + YYMAXLEFT + 1];
  int yynrhs;
  int yychar_current;
  YYSTYPE yylval_current;
  YYLTYPE yylloc_current;
  YYRESULTTAG yyflag;

  yynrhs = yyrhsLength (yyopt->yyrule);
  yyflag = yyresolveStates (yyopt->yystate, yynrhs, yystackp]b4_user_args[);
  if (yyflag != yyok)
    {
      yyGLRState *yys;
      for (yys = yyopt->yystate; yynrhs > 0; yys = yys->yypred, yynrhs -= 1)
        yydestroyGLRState ("Cleanup: popping", yys]b4_user_args[);
      return yyflag;
    }

  yyrhsVals[YYMAXRHS + YYMAXLEFT].yystate.yypred = yyopt->yystate;]b4_locations_if([[
  if (yynrhs == 0)
    /* Set default location.  */
    yyrhsVals[YYMAXRHS + YYMAXLEFT - 1].yystate.yyloc = yyopt->yystate->yyloc;]])[
  yychar_current = yychar;
  yylval_current = yylval;
  yylloc_current = yylloc;
  yychar = yyopt->yyrawchar;
  yylval = yyopt->yyval;
  yylloc = yyopt->yyloc;
  yyflag = yyuserAction (yyopt->yyrule, yynrhs,
                           yyrhsVals + YYMAXRHS + YYMAXLEFT - 1,
                           yyvalp, yylocp, yystackp]b4_user_args[);
  yychar = yychar_current;
  yylval = yylval_current;
  yylloc = yylloc_current;
  return yyflag;
}

#if YYDEBUG
static void
yyreportTree (yySemanticOption* yyx, int yyindent)
{
  int yynrhs = yyrhsLength (yyx->yyrule);
  int yyi;
  yyGLRState* yys;
  yyGLRState* yystates[1 + 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 - 1);
  else
    YYFPRINTF (stderr, "%*s%s -> <Rule %d, tokens %lu .. %lu>\n",
               yyindent, "", yytokenName (yylhsNonterm (yyx->yyrule)),
               yyx->yyrule - 1, (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

/*ARGSUSED*/ static YYRESULTTAG
yyreportAmbiguity (yySemanticOption* yyx0,
                   yySemanticOption* yyx1]b4_pure_formals[)
{
  YYUSE (yyx0);
  YYUSE (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

  yyerror (]b4_yyerror_args[YY_("syntax is ambiguous"));
  return yyabort;
}

/** Starting at and including state S1, resolve the location for each of the
 *  previous N1 states that is unresolved.  The first semantic option of a state
 *  is always chosen.  */
static void
yyresolveLocations (yyGLRState* yys1, int yyn1,
                    yyGLRStack *yystackp]b4_user_formals[)
{
  if (0 < yyn1)
    {
      yyresolveLocations (yys1->yypred, yyn1 - 1, yystackp]b4_user_args[);
      if (!yys1->yyresolved)
        {
          yySemanticOption *yyoption;
          yyGLRStackItem yyrhsloc[1 + YYMAXRHS];
          int yynrhs;
          int yychar_current;
          YYSTYPE yylval_current;
          YYLTYPE yylloc_current;
          yyoption = yys1->yysemantics.yyfirstVal;
          YYASSERT (yyoption != NULL);
          yynrhs = yyrhsLength (yyoption->yyrule);
          if (yynrhs > 0)
            {
              yyGLRState *yys;
              int yyn;
              yyresolveLocations (yyoption->yystate, yynrhs,
                                  yystackp]b4_user_args[);
              for (yys = yyoption->yystate, yyn = yynrhs;
                   yyn > 0;
                   yys = yys->yypred, yyn -= 1)
                yyrhsloc[yyn].yystate.yyloc = yys->yyloc;
            }
          else
            {
              /* Both yyresolveAction and yyresolveLocations traverse the GSS
                 in reverse rightmost order.  It is only necessary to invoke
                 yyresolveLocations on a subforest for which yyresolveAction
                 would have been invoked next had an ambiguity not been
                 detected.  Thus the location of the previous state (but not
                 necessarily the previous state itself) is guaranteed to be
                 resolved already.  */
              yyGLRState *yyprevious = yyoption->yystate;
              yyrhsloc[0].yystate.yyloc = yyprevious->yyloc;
            }
          yychar_current = yychar;
          yylval_current = yylval;
          yylloc_current = yylloc;
          yychar = yyoption->yyrawchar;
          yylval = yyoption->yyval;
          yylloc = yyoption->yyloc;
          YYLLOC_DEFAULT ((yys1->yyloc), yyrhsloc, yynrhs);
          yychar = yychar_current;
          yylval = yylval_current;
          yylloc = yylloc_current;
        }
    }
}

/** Resolve the ambiguity represented in state S, perform the indicated
 *  actions, and set the semantic value of S.  If result != yyok, the chain of
 *  semantic options in S has been cleared instead or it has been left
 *  unmodified except that redundant options may have been removed.  Regardless
 *  of whether result = yyok, S has been left with consistent data so that
 *  yydestroyGLRState can be invoked if necessary.  */
static YYRESULTTAG
yyresolveValue (yyGLRState* yys, yyGLRStack* yystackp]b4_user_formals[)
{
  yySemanticOption* yyoptionList = yys->yysemantics.yyfirstVal;
  yySemanticOption* yybest;
  yySemanticOption** yypp;
  yybool yymerge;
  YYSTYPE yysval;
  YYRESULTTAG yyflag;
  YYLTYPE *yylocp = &yys->yyloc;

  yybest = yyoptionList;
  yymerge = yyfalse;
  for (yypp = &yyoptionList->yynext; *yypp != NULL; )
    {
      yySemanticOption* yyp = *yypp;

      if (yyidenticalOptions (yybest, yyp))
        {
          yymergeOptionSets (yybest, yyp);
          *yypp = yyp->yynext;
        }
      else
        {
          switch (yypreference (yybest, yyp))
            {
            case 0:
              yyresolveLocations (yys, 1, yystackp]b4_user_args[);
              return yyreportAmbiguity (yybest, yyp]b4_pure_args[);
              break;
            case 1:
              yymerge = yytrue;
              break;
            case 2:
              break;
            case 3:
              yybest = yyp;
              yymerge = yyfalse;
              break;
            default:
              /* This cannot happen so it is not worth a YYASSERT (yyfalse),
                 but some compilers complain if the default case is
                 omitted.  */
              break;
            }
          yypp = &yyp->yynext;
        }
    }

  if (yymerge)
    {
      yySemanticOption* yyp;
      int yyprec = yydprec[yybest->yyrule];
      yyflag = yyresolveAction (yybest, yystackp, &yysval,
                                yylocp]b4_user_args[);
      if (yyflag == yyok)
        for (yyp = yybest->yynext; yyp != NULL; yyp = yyp->yynext)
          {
            if (yyprec == yydprec[yyp->yyrule])
              {
                YYSTYPE yysval_other;
                YYLTYPE yydummy;
                yyflag = yyresolveAction (yyp, yystackp, &yysval_other,
                                          &yydummy]b4_user_args[);
                if (yyflag != yyok)
                  {
                    yydestruct ("Cleanup: discarding incompletely merged value for",
                                yystos[yys->yylrState],
                                &yysval]b4_locations_if([, yylocp])[]b4_user_args[);
                    break;
                  }
                yyuserMerge (yymerger[yyp->yyrule], &yysval, &yysval_other);
              }
          }
    }
  else
    yyflag = yyresolveAction (yybest, yystackp, &yysval, yylocp]b4_user_args[);

  if (yyflag == yyok)
    {
      yys->yyresolved = yytrue;
      yys->yysemantics.yysval = yysval;
    }
  else
    yys->yysemantics.yyfirstVal = NULL;
  return yyflag;
}

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

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

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

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

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

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

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

static YYRESULTTAG
yyprocessOneStack (yyGLRStack* yystackp, size_t yyk,
                   size_t yyposn]b4_pure_formals[)
{
  int yyaction;
  const short int* yyconflicts;
  yyRuleNum yyrule;

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

      YYASSERT (yystate != YYFINAL);

      if (yyisDefaultedState (yystate))
        {
          yyrule = yydefaultAction (yystate);
          if (yyrule == 0)
            {
              YYDPRINTF ((stderr, "Stack %lu dies.\n",
                          (unsigned long int) yyk));
              yymarkStackDeleted (yystackp, yyk);
              return yyok;
            }
          YYCHK (yyglrReduce (yystackp, yyk, yyrule, yyfalse]b4_user_args[));
        }
      else
        {
          yySymbol yytoken;
          yystackp->yytops.yylookaheadNeeds[yyk] = yytrue;
          if (yychar == YYEMPTY)
            {
              YYDPRINTF ((stderr, "Reading a token: "));
              yychar = YYLEX;
            }

          if (yychar <= YYEOF)
            {
              yychar = yytoken = YYEOF;
              YYDPRINTF ((stderr, "Now at end of input.\n"));
            }
          else
            {
              yytoken = YYTRANSLATE (yychar);
              YY_SYMBOL_PRINT ("Next token is", yytoken, &yylval, &yylloc);
            }

          yygetLRActions (yystate, yytoken, &yyaction, &yyconflicts);

          while (*yyconflicts != 0)
            {
              size_t yynewStack = yysplitStack (yystackp, yyk);
              YYDPRINTF ((stderr, "Splitting off stack %lu from %lu.\n",
                          (unsigned long int) yynewStack,
                          (unsigned long int) yyk));
              YYCHK (yyglrReduce (yystackp, yynewStack,
                                  *yyconflicts, yyfalse]b4_user_args[));
              YYCHK (yyprocessOneStack (yystackp, yynewStack,
                                        yyposn]b4_pure_args[));
              yyconflicts += 1;
            }

          if (yyisShiftAction (yyaction))
            break;
          else if (yyisErrorAction (yyaction))
            {
              YYDPRINTF ((stderr, "Stack %lu dies.\n",
                          (unsigned long int) yyk));
              yymarkStackDeleted (yystackp, yyk);
              break;
            }
          else
            YYCHK (yyglrReduce (yystackp, yyk, -yyaction,
                                yyfalse]b4_user_args[));
        }
    }
  return yyok;
}

/*ARGSUSED*/ static void
yyreportSyntaxError (yyGLRStack* yystackp]b4_user_formals[)
{
  if (yystackp->yyerrState == 0)
    {
#if YYERROR_VERBOSE
      int yyn;
      yyn = yypact[yystackp->yytops.yystates[0]->yylrState];
      if (YYPACT_NINF < yyn && yyn <= YYLAST)
        {
          yySymbol yytoken = YYTRANSLATE (yychar);
          size_t yysize0 = yytnamerr (NULL, yytokenName (yytoken));
          size_t yysize = yysize0;
          size_t yysize1;
          yybool yysize_overflow = yyfalse;
          char* yymsg = NULL;
          enum { YYERROR_VERBOSE_ARGS_MAXIMUM = 5 };
          char const *yyarg[YYERROR_VERBOSE_ARGS_MAXIMUM];
          int yyx;
          char *yyfmt;
          char const *yyf;
          static char const yyunexpected[] = "syntax error, unexpected %s";
          static char const yyexpecting[] = ", expecting %s";
          static char const yyor[] = " or %s";
          char yyformat[sizeof yyunexpected
                        + sizeof yyexpecting - 1
                        + ((YYERROR_VERBOSE_ARGS_MAXIMUM - 2)
                           * (sizeof yyor - 1))];
          char const *yyprefix = yyexpecting;

          /* 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 + 1;
          int yyxend = yychecklim < YYNTOKENS ? yychecklim : YYNTOKENS;
          int yycount = 1;

          yyarg[0] = yytokenName (yytoken);
          yyfmt = yystpcpy (yyformat, yyunexpected);

          for (yyx = yyxbegin; yyx < yyxend; ++yyx)
            if (yycheck[yyx + yyn] == yyx && yyx != YYTERROR)
              {
                if (yycount == YYERROR_VERBOSE_ARGS_MAXIMUM)
                  {
                    yycount = 1;
                    yysize = yysize0;
                    yyformat[sizeof yyunexpected - 1] = '\0';
                    break;
                  }
                yyarg[yycount++] = yytokenName (yyx);
                yysize1 = yysize + yytnamerr (NULL, yytokenName (yyx));
                yysize_overflow |= yysize1 < yysize;
                yysize = yysize1;
                yyfmt = yystpcpy (yyfmt, yyprefix);
                yyprefix = yyor;
              }

          yyf = YY_(yyformat);
          yysize1 = yysize + strlen (yyf);
          yysize_overflow |= yysize1 < yysize;
          yysize = yysize1;

          if (!yysize_overflow)
            yymsg = (char *) YYMALLOC (yysize);

          if (yymsg)
            {
              char *yyp = yymsg;
              int yyi = 0;
              while ((*yyp = *yyf))
                {
                  if (*yyp == '%' && yyf[1] == 's' && yyi < yycount)
                    {
                      yyp += yytnamerr (yyp, yyarg[yyi++]);
                      yyf += 2;
                    }
                  else
                    {
                      yyp++;
                      yyf++;
                    }
                }
              yyerror (]b4_lyyerror_args[yymsg);
              YYFREE (yymsg);
            }
          else
            {
              yyerror (]b4_lyyerror_args[YY_("syntax error"));
              yyMemoryExhausted (yystackp);
            }
        }
      else
#endif /* YYERROR_VERBOSE */
        yyerror (]b4_lyyerror_args[YY_("syntax error"));
      yynerrs += 1;
    }
}

/* Recover from a syntax error on *YYSTACKP, assuming that *YYSTACKP->YYTOKENP,
   yylval, and yylloc are the syntactic category, semantic value, and location
   of the lookahead.  */
/*ARGSUSED*/ static void
yyrecoverSyntaxError (yyGLRStack* yystackp]b4_user_formals[)
{
  size_t yyk;
  int yyj;

  if (yystackp->yyerrState == 3)
    /* We just shifted the error token and (perhaps) took some
       reductions.  Skip tokens until we can proceed.  */
    while (YYID (yytrue))
      {
        yySymbol yytoken;
        if (yychar == YYEOF)
          yyFail (yystackp][]b4_lpure_args[, NULL);
        if (yychar != YYEMPTY)
          {]b4_locations_if([[
            /* We throw away the lookahead, but the error range
               of the shifted error token must take it into account.  */
            yyGLRState *yys = yystackp->yytops.yystates[0];
            yyGLRStackItem yyerror_range[3];
            yyerror_range[1].yystate.yyloc = yys->yyloc;
            yyerror_range[2].yystate.yyloc = yylloc;
            YYLLOC_DEFAULT ((yys->yyloc), yyerror_range, 2);]])[
            yytoken = YYTRANSLATE (yychar);
            yydestruct ("Error: discarding",
                        yytoken, &yylval]b4_locations_if([, &yylloc])[]b4_user_args[);
          }
        YYDPRINTF ((stderr, "Reading a token: "));
        yychar = YYLEX;
        if (yychar <= YYEOF)
          {
            yychar = yytoken = YYEOF;
            YYDPRINTF ((stderr, "Now at end of input.\n"));
          }
        else
          {
            yytoken = YYTRANSLATE (yychar);
            YY_SYMBOL_PRINT ("Next token is", yytoken, &yylval, &yylloc);
          }
        yyj = yypact[yystackp->yytops.yystates[0]->yylrState];
        if (yyis_pact_ninf (yyj))
          return;
        yyj += yytoken;
        if (yyj < 0 || YYLAST < yyj || yycheck[yyj] != yytoken)
          {
            if (yydefact[yystackp->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 < yystackp->yytops.yysize; yyk += 1)
    if (yystackp->yytops.yystates[yyk] != NULL)
      break;
  if (yyk >= yystackp->yytops.yysize)
    yyFail (yystackp][]b4_lpure_args[, NULL);
  for (yyk += 1; yyk < yystackp->yytops.yysize; yyk += 1)
    yymarkStackDeleted (yystackp, yyk);
  yyremoveDeletes (yystackp);
  yycompressStack (yystackp);

  /* Now pop stack until we find a state that shifts the error token.  */
  yystackp->yyerrState = 3;
  while (yystackp->yytops.yystates[0] != NULL)
    {
      yyGLRState *yys = yystackp->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]))
            {
              /* Shift the error token having adjusted its location.  */
              YYLTYPE yyerrloc;]b4_locations_if([[
              yystackp->yyerror_range[2].yystate.yyloc = yylloc;
              YYLLOC_DEFAULT (yyerrloc, (yystackp->yyerror_range), 2);]])[
              YY_SYMBOL_PRINT ("Shifting", yystos[yytable[yyj]],
                               &yylval, &yyerrloc);
              yyglrShift (yystackp, 0, yytable[yyj],
                          yys->yyposn, &yylval, &yyerrloc);
              yys = yystackp->yytops.yystates[0];
              break;
            }
        }
]b4_locations_if([[      yystackp->yyerror_range[1].yystate.yyloc = yys->yyloc;]])[
      if (yys->yypred != NULL)
        yydestroyGLRState ("Error: popping", yys]b4_user_args[);
      yystackp->yytops.yystates[0] = yys->yypred;
      yystackp->yynextFree -= 1;
      yystackp->yyspaceLeft += 1;
    }
  if (yystackp->yytops.yystates[0] == NULL)
    yyFail (yystackp][]b4_lpure_args[, NULL);
}

#define YYCHK1(YYE)                                                          \
  do {                                                                       \
    switch (YYE) {                                                           \
    case yyok:                                                               \
      break;                                                                 \
    case yyabort:                                                            \
      goto yyabortlab;                                                       \
    case yyaccept:                                                           \
      goto yyacceptlab;                                                      \
    case yyerr:                                                              \
      goto yyuser_error;                                                     \
    default:                                                                 \
      goto yybuglab;                                                         \
    }                                                                        \
  } while (YYID (0))


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

]b4_c_ansi_function_def([yyparse], [int], b4_parse_param)[
{
  int yyresult;
  yyGLRStack yystack;
  yyGLRStack* const yystackp = &yystack;
  size_t yyposn;

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

  yychar = YYEMPTY;
  yylval = yyval_default;
]b4_locations_if([
#if defined YYLTYPE_IS_TRIVIAL && YYLTYPE_IS_TRIVIAL
  yylloc.first_line   = yylloc.last_line   = ]b4_location_initial_line[;
  yylloc.first_column = yylloc.last_column = ]b4_location_initial_column[;
#endif
])
m4_ifdef([b4_initial_action], [
m4_pushdef([b4_at_dollar],     [yylloc])dnl
m4_pushdef([b4_dollar_dollar], [yylval])dnl
  /* User initialization code.  */
  b4_user_initial_action
m4_popdef([b4_dollar_dollar])dnl
m4_popdef([b4_at_dollar])])dnl
[
  if (! yyinitGLRStack (yystackp, YYINITDEPTH))
    goto yyexhaustedlab;
  switch (YYSETJMP (yystack.yyexception_buffer))
    {
    case 0: break;
    case 1: goto yyabortlab;
    case 2: goto yyexhaustedlab;
    default: goto yybuglab;
    }
  yyglrShift (&yystack, 0, 0, 0, &yylval, &yylloc);
  yyposn = 0;

  while (YYID (yytrue))
    {
      /* For efficiency, we have two loops, the first of which is
         specialized to deterministic operation (single stack, no
         potential ambiguity).  */
      /* Standard mode */
      while (YYID (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 yyacceptlab;
          if (yyisDefaultedState (yystate))
            {
              yyrule = yydefaultAction (yystate);
              if (yyrule == 0)
                {
]b4_locations_if([[               yystack.yyerror_range[1].yystate.yyloc = yylloc;]])[
                  yyreportSyntaxError (&yystack]b4_user_args[);
                  goto yyuser_error;
                }
              YYCHK1 (yyglrReduce (&yystack, 0, yyrule, yytrue]b4_user_args[));
            }
          else
            {
              yySymbol yytoken;
              if (yychar == YYEMPTY)
                {
                  YYDPRINTF ((stderr, "Reading a token: "));
                  yychar = YYLEX;
                }

              if (yychar <= YYEOF)
                {
                  yychar = yytoken = YYEOF;
                  YYDPRINTF ((stderr, "Now at end of input.\n"));
                }
              else
                {
                  yytoken = YYTRANSLATE (yychar);
                  YY_SYMBOL_PRINT ("Next token is", yytoken, &yylval, &yylloc);
                }

              yygetLRActions (yystate, yytoken, &yyaction, &yyconflicts);
              if (*yyconflicts != 0)
                break;
              if (yyisShiftAction (yyaction))
                {
                  YY_SYMBOL_PRINT ("Shifting", yytoken, &yylval, &yylloc);
                  yychar = YYEMPTY;
                  yyposn += 1;
                  yyglrShift (&yystack, 0, yyaction, yyposn, &yylval, &yylloc);
                  if (0 < yystack.yyerrState)
                    yystack.yyerrState -= 1;
                }
              else if (yyisErrorAction (yyaction))
                {
]b4_locations_if([[               yystack.yyerror_range[1].yystate.yyloc = yylloc;]])[
                  yyreportSyntaxError (&yystack]b4_user_args[);
                  goto yyuser_error;
                }
              else
                YYCHK1 (yyglrReduce (&yystack, 0, -yyaction, yytrue]b4_user_args[));
            }
        }

      while (YYID (yytrue))
        {
          yySymbol yytoken_to_shift;
          size_t yys;

          for (yys = 0; yys < yystack.yytops.yysize; yys += 1)
            yystackp->yytops.yylookaheadNeeds[yys] = yychar != YYEMPTY;

          /* yyprocessOneStack returns one of three things:

              - An error flag.  If the caller is yyprocessOneStack, it
                immediately returns as well.  When the caller is finally
                yyparse, it jumps to an error label via YYCHK1.

              - yyok, but yyprocessOneStack has invoked yymarkStackDeleted
                (&yystack, yys), which sets the top state of yys to NULL.  Thus,
                yyparse's following invocation of yyremoveDeletes will remove
                the stack.

              - yyok, when ready to shift a token.

             Except in the first case, yyparse will invoke yyremoveDeletes and
             then shift the next token onto all remaining stacks.  This
             synchronization of the shift (that is, after all preceding
             reductions on all stacks) helps prevent double destructor calls
             on yylval in the event of memory exhaustion.  */

          for (yys = 0; yys < yystack.yytops.yysize; yys += 1)
            YYCHK1 (yyprocessOneStack (&yystack, yys, yyposn]b4_lpure_args[));
          yyremoveDeletes (&yystack);
          if (yystack.yytops.yysize == 0)
            {
              yyundeleteLastStack (&yystack);
              if (yystack.yytops.yysize == 0)
                yyFail (&yystack][]b4_lpure_args[, YY_("syntax error"));
              YYCHK1 (yyresolveStack (&yystack]b4_user_args[));
              YYDPRINTF ((stderr, "Returning to deterministic operation.\n"));
]b4_locations_if([[           yystack.yyerror_range[1].yystate.yyloc = yylloc;]])[
              yyreportSyntaxError (&yystack]b4_user_args[);
              goto yyuser_error;
            }

          /* If any yyglrShift call fails, it will fail after shifting.  Thus,
             a copy of yylval will already be on stack 0 in the event of a
             failure in the following loop.  Thus, yychar is set to YYEMPTY
             before the loop to make sure the user destructor for yylval isn't
             called twice.  */
          yytoken_to_shift = YYTRANSLATE (yychar);
          yychar = YYEMPTY;
          yyposn += 1;
          for (yys = 0; yys < yystack.yytops.yysize; yys += 1)
            {
              int yyaction;
              const short int* yyconflicts;
              yyStateNum yystate = yystack.yytops.yystates[yys]->yylrState;
              yygetLRActions (yystate, yytoken_to_shift, &yyaction,
                              &yyconflicts);
              /* Note that yyconflicts were handled by yyprocessOneStack.  */
              YYDPRINTF ((stderr, "On stack %lu, ", (unsigned long int) yys));
              YY_SYMBOL_PRINT ("shifting", yytoken_to_shift, &yylval, &yylloc);
              yyglrShift (&yystack, yys, yyaction, yyposn,
                          &yylval, &yylloc);
              YYDPRINTF ((stderr, "Stack %lu now in state #%d\n",
                          (unsigned long int) yys,
                          yystack.yytops.yystates[yys]->yylrState));
            }

          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]b4_user_args[);
      yyposn = yystack.yytops.yystates[0]->yyposn;
    }

 yyacceptlab:
  yyresult = 0;
  goto yyreturn;

 yybuglab:
  YYASSERT (yyfalse);
  goto yyabortlab;

 yyabortlab:
  yyresult = 1;
  goto yyreturn;

 yyexhaustedlab:
  yyerror (]b4_lyyerror_args[YY_("memory exhausted"));
  yyresult = 2;
  goto yyreturn;

 yyreturn:
  if (yychar != YYEMPTY)
    yydestruct ("Cleanup: discarding lookahead",
                YYTRANSLATE (yychar),
                &yylval]b4_locations_if([, &yylloc])[]b4_user_args[);

  /* If the stack is well-formed, pop the stack until it is empty,
     destroying its entries as we go.  But free the stack regardless
     of whether it is well-formed.  */
  if (yystack.yyitems)
    {
      yyGLRState** yystates = yystack.yytops.yystates;
      if (yystates)
        {
          size_t yysize = yystack.yytops.yysize;
          size_t yyk;
          for (yyk = 0; yyk < yysize; yyk += 1)
            if (yystates[yyk])
              {
                while (yystates[yyk])
                  {
                    yyGLRState *yys = yystates[yyk];
]b4_locations_if([[                 yystack.yyerror_range[1].yystate.yyloc = yys->yyloc;]]
)[                  if (yys->yypred != NULL)
                      yydestroyGLRState ("Cleanup: popping", yys]b4_user_args[);
                    yystates[yyk] = yys->yypred;
                    yystack.yynextFree -= 1;
                    yystack.yyspaceLeft += 1;
                  }
                break;
              }
        }
      yyfreeGLRStack (&yystack);
    }

  /* Make sure YYID is used.  */
  return YYID (yyresult);
}

/* DEBUGGING ONLY */
#if YYDEBUG
static void yypstack (yyGLRStack* yystackp, size_t yyk)
  __attribute__ ((__unused__));
static void yypdumpstack (yyGLRStack* yystackp) __attribute__ ((__unused__));

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

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

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

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


static void
yypdumpstack (yyGLRStack* yystackp)
{
  yyGLRStackItem* yyp;
  size_t yyi;
  for (yyp = yystackp->yyitems; yyp < yystackp->yynextFree; yyp += 1)
    {
      YYFPRINTF (stderr, "%3lu. ",
                 (unsigned long int) (yyp - yystackp->yyitems));
      if (*(yybool *) yyp)
        {
          YYFPRINTF (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)
            YYFPRINTF (stderr, ", firstVal: %ld",
                       (long int) YYINDEX (yyp->yystate
                                             .yysemantics.yyfirstVal));
        }
      else
        {
          YYFPRINTF (stderr, "Option. rule: %d, state: %ld, next: %ld",
                     yyp->yyoption.yyrule - 1,
                     (long int) YYINDEX (yyp->yyoption.yystate),
                     (long int) YYINDEX (yyp->yyoption.yynext));
        }
      YYFPRINTF (stderr, "\n");
    }
  YYFPRINTF (stderr, "Tops:");
  for (yyi = 0; yyi < yystackp->yytops.yysize; yyi += 1)
    YYFPRINTF (stderr, "%lu: %ld; ", (unsigned long int) yyi,
               (long int) YYINDEX (yystackp->yytops.yystates[yyi]));
  YYFPRINTF (stderr, "\n");
}
#endif
]

b4_epilogue
dnl
dnl glr.cc produces its own header.
dnl
m4_if(b4_skeleton, ["glr.c"],
[b4_defines_if(
[@output(b4_spec_defines_file@)@
b4_copyright([Skeleton interface for Bison GLR parsers in C],
             [2002-2006, 2009-2010])

b4_shared_declarations

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

b4_locations_if([b4_pure_if([],
[extern YYLTYPE ]b4_prefix[lloc;])
])
])])
m4_divert_pop(0)