一个加法编译器(bison.simple)

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/* -*-C-*-  Note some compilers choke on comments on `#line' lines.  */
#line 3 "bison.simple"

/* Skeleton output parser for bison,
   Copyright (C) 1984, 1989, 1990 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, 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., 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* As a special exception, when this file is copied by Bison into a
   Bison output file, you may use that output file without restriction.
   This special exception was added by the Free Software Foundation
   in version 1.24 of Bison.  */

#ifndef alloca
#ifdef __GNUC__
#define alloca __builtin_alloca
#else /* not GNU C.  */
#if (!defined (__STDC__) && defined (sparc)) || defined (__sparc__) || defined (__sparc) || defined (__sgi)
#include <alloca.h>
#else /* not sparc */
#if defined (MSDOS) && !defined (__TURBOC__)
#include <malloc.h>
#else /* not MSDOS, or __TURBOC__ */
#if defined(_AIX)
#include <malloc.h>
 #pragma alloca
#else /* not MSDOS, __TURBOC__, or _AIX */
#ifdef __hpux
#ifdef __cplusplus
extern "C" {
void *alloca (unsigned int);
};
#else /* not __cplusplus */
void *alloca ();
#endif /* not __cplusplus */
#endif /* __hpux */
#endif /* not _AIX */
#endif /* not MSDOS, or __TURBOC__ */
#endif /* not sparc.  */
#endif /* not GNU C.  */
#endif /* alloca not defined.  */

/* This is the parser code that is written into each bison parser
  when the %semantic_parser declaration is not specified in the grammar.
  It was written by Richard Stallman by simplifying the hairy parser
  used when %semantic_parser is specified.  */

/* Note: there must be only one dollar sign in this file.
   It is replaced by the list of actions, each action
   as one case of the switch.  */

#define yyerrok  (yyerrstatus = 0)
#define yyclearin (yychar = YYEMPTY)
#define YYEMPTY  -2
#define YYEOF  0
#define YYACCEPT return(0)
#define YYABORT  return(1)
#define YYERROR  goto yyerrlab1
/* Like YYERROR except do call yyerror.
   This remains here temporarily to ease the
   transition to the new meaning of YYERROR, for GCC.
   Once GCC version 2 has supplanted version 1, this can go.  */
#define YYFAIL  goto yyerrlab
#define YYRECOVERING()  (!!yyerrstatus)
#define YYBACKUP(token, value) \
do        \
  if (yychar == YYEMPTY && yylen == 1)    \
    { yychar = (token), yylval = (value);   \
      yychar1 = YYTRANSLATE (yychar);    \
      YYPOPSTACK;      \
      goto yybackup;      \
    }        \
  else        \
    { yyerror ("syntax error: cannot back up"); YYERROR; } \
while (0)

#define YYTERROR 1
#define YYERRCODE 256

#ifndef YYPURE
#define YYLEX  yylex()
#endif

#ifdef YYPURE
#ifdef YYLSP_NEEDED
#ifdef YYLEX_PARAM
#define YYLEX  yylex(&yylval, &yylloc, YYLEX_PARAM)
#else
#define YYLEX  yylex(&yylval, &yylloc)
#endif
#else /* not YYLSP_NEEDED */
#ifdef YYLEX_PARAM
#define YYLEX  yylex(&yylval, YYLEX_PARAM)
#else
#define YYLEX  yylex(&yylval)
#endif
#endif /* not YYLSP_NEEDED */
#endif

/* If nonreentrant, generate the variables here */

#ifndef YYPURE

int yychar;   /*  the lookahead symbol  */
YYSTYPE yylval;   /*  the semantic value of the  */
    /*  lookahead symbol   */

#ifdef YYLSP_NEEDED
YYLTYPE yylloc;   /*  location data for the lookahead */
    /*  symbol    */
#endif

int yynerrs;   /*  number of parse errors so far       */
#endif  /* not YYPURE */

#if YYDEBUG != 0
int yydebug;   /*  nonzero means print parse trace */
/* Since this is uninitialized, it does not stop multiple parsers
   from coexisting.  */
#endif

/*  YYINITDEPTH indicates the initial size of the parser's stacks */

#ifndef YYINITDEPTH
#define YYINITDEPTH 200
#endif

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

#if YYMAXDEPTH == 0
#undef YYMAXDEPTH
#endif

#ifndef YYMAXDEPTH
#define YYMAXDEPTH 10000
#endif

/* Prevent warning if -Wstrict-prototypes.  */
#ifdef __GNUC__
int yyparse (void);
#endif

#if __GNUC__ > 1  /* GNU C and GNU C++ define this.  */
#define __yy_memcpy(FROM,TO,COUNT) __builtin_memcpy(TO,FROM,COUNT)
#else    /* not GNU C or C++ */
#ifndef __cplusplus

/* This is the most reliable way to avoid incompatibilities
   in available built-in functions on various systems.  */
static void
__yy_memcpy (from, to, count)
     char *from;
     char *to;
     int count;
{
  register char *f = from;
  register char *t = to;
  register int i = count;

  while (i-- > 0)
    *t++ = *f++;
}

#else /* __cplusplus */

/* This is the most reliable way to avoid incompatibilities
   in available built-in functions on various systems.  */
static void
__yy_memcpy (char *from, char *to, int count)
{
  register char *f = from;
  register char *t = to;
  register int i = count;

  while (i-- > 0)
    *t++ = *f++;
}

#endif
#endif

#line 192 "bison.simple"

/* The user can define YYPARSE_PARAM as the name of an argument to be passed
   into yyparse.  The argument should have type void *.
   It should actually point to an object.
   Grammar actions can access the variable by casting it
   to the proper pointer type.  */

#ifdef YYPARSE_PARAM
#define YYPARSE_PARAM_DECL void *YYPARSE_PARAM;
#else
#define YYPARSE_PARAM
#define YYPARSE_PARAM_DECL
#endif

int
yyparse(YYPARSE_PARAM)
     YYPARSE_PARAM_DECL
{
  register int yystate;
  register int yyn;
  register short *yyssp;
  register YYSTYPE *yyvsp;
  int yyerrstatus; /*  number of tokens to shift before error messages enabled */
  int yychar1 = 0;  /*  lookahead token as an internal (translated) token number */

  short yyssa[YYINITDEPTH]; /*  the state stack   */
  YYSTYPE yyvsa[YYINITDEPTH]; /*  the semantic value stack  */

  short *yyss = yyssa;  /*  refer to the stacks thru separate pointers */
  YYSTYPE *yyvs = yyvsa; /*  to allow yyoverflow to reallocate them elsewhere */

#ifdef YYLSP_NEEDED
  YYLTYPE yylsa[YYINITDEPTH]; /*  the location stack   */
  YYLTYPE *yyls = yylsa;
  YYLTYPE *yylsp;

#define YYPOPSTACK   (yyvsp--, yyssp--, yylsp--)
#else
#define YYPOPSTACK   (yyvsp--, yyssp--)
#endif

  int yystacksize = YYINITDEPTH;

#ifdef YYPURE
  int yychar;
  YYSTYPE yylval;
  int yynerrs;
#ifdef YYLSP_NEEDED
  YYLTYPE yylloc;
#endif
#endif
  YYSTYPE yyval;  /*  the variable used to return  */
              /*  semantic values from the action */
    /*  routines    */

  int yylen;

#if YYDEBUG != 0
  if (yydebug)
    fprintf(stderr, "Starting parse\n");
#endif
  yyval = 0;
  yystate = 0;
  yyerrstatus = 0;
  yynerrs = 0;
  yychar = YYEMPTY;  /* Cause a token to be read.  */

  /* Initialize stack pointers.
     Waste one element of value and location stack
     so that they stay on the same level as the state stack.
     The wasted elements are never initialized.  */

  yyssp = yyss - 1;
  yyvsp = yyvs;
#ifdef YYLSP_NEEDED
  yylsp = yyls;
#endif

/* Push a new state, which is found in  yystate  .  */
/* In all cases, when you get here, the value and location stacks
   have just been pushed. so pushing a state here evens the stacks.  */
yynewstate:

  *++yyssp = yystate;

  if (yyssp >= yyss + yystacksize - 1)
    {
      /* Give user a chance to reallocate the stack */
      /* Use copies of these so that the &'s don't force the real ones into memory. */
      YYSTYPE *yyvs1 = yyvs;
      short *yyss1 = yyss;
#ifdef YYLSP_NEEDED
      YYLTYPE *yyls1 = yyls;
#endif

      /* Get the current used size of the three stacks, in elements.  */
      int size = yyssp - yyss + 1;

#ifdef yyoverflow
      /* Each stack pointer address is followed by the size of
  the data in use in that stack, in bytes.  */
#ifdef YYLSP_NEEDED
      /* This used to be a conditional around just the two extra args,
  but that might be undefined if yyoverflow is a macro.  */
      yyoverflow("parser stack overflow",
   &yyss1, size * sizeof (*yyssp),
   &yyvs1, size * sizeof (*yyvsp),
   &yyls1, size * sizeof (*yylsp),
   &yystacksize);
#else
      yyoverflow("parser stack overflow",
   &yyss1, size * sizeof (*yyssp),
   &yyvs1, size * sizeof (*yyvsp),
   &yystacksize);
#endif

      yyss = yyss1; yyvs = yyvs1;
#ifdef YYLSP_NEEDED
      yyls = yyls1;
#endif
#else /* no yyoverflow */
      /* Extend the stack our own way.  */
      if (yystacksize >= YYMAXDEPTH)
 {
   yyerror("parser stack overflow");
   return 2;
 }
      yystacksize *= 2;
      if (yystacksize > YYMAXDEPTH)
 yystacksize = YYMAXDEPTH;
      yyss = (short *) alloca (yystacksize * sizeof (*yyssp));
      __yy_memcpy ((char *)yyss1, (char *)yyss, size * sizeof (*yyssp));
      yyvs = (YYSTYPE *) alloca (yystacksize * sizeof (*yyvsp));
      __yy_memcpy ((char *)yyvs1, (char *)yyvs, size * sizeof (*yyvsp));
#ifdef YYLSP_NEEDED
      yyls = (YYLTYPE *) alloca (yystacksize * sizeof (*yylsp));
      __yy_memcpy ((char *)yyls1, (char *)yyls, size * sizeof (*yylsp));
#endif
#endif /* no yyoverflow */

      yyssp = yyss + size - 1;
      yyvsp = yyvs + size - 1;
#ifdef YYLSP_NEEDED
      yylsp = yyls + size - 1;
#endif

#if YYDEBUG != 0
      if (yydebug)
 fprintf(stderr, "Stack size increased to %d\n", yystacksize);
#endif

      if (yyssp >= yyss + yystacksize - 1)
 YYABORT;
    }

#if YYDEBUG != 0
  if (yydebug)
    fprintf(stderr, "Entering state %d\n", yystate);
#endif

  goto yybackup;
 yybackup:

/* Do appropriate processing given the current state.  */
/* Read a lookahead token if we need one and don't already have one.  */
/* yyresume: */

  /* First try to decide what to do without reference to lookahead token.  */

  yyn = yypact[yystate];
  if (yyn == YYFLAG)
    goto yydefault;

  /* Not known => get a lookahead token if don't already have one.  */

  /* yychar is either YYEMPTY or YYEOF
     or a valid token in external form.  */

  if (yychar == YYEMPTY)
    {
#if YYDEBUG != 0
      if (yydebug)
 fprintf(stderr, "Reading a token: ");
#endif
      yychar = YYLEX;
    }

  /* Convert token to internal form (in yychar1) for indexing tables with */

  if (yychar <= 0)  /* This means end of input. */
    {
      yychar1 = 0;
      yychar = YYEOF;  /* Don't call YYLEX any more */

#if YYDEBUG != 0
      if (yydebug)
 fprintf(stderr, "Now at end of input.\n");
#endif
    }
  else
    {
      yychar1 = YYTRANSLATE(yychar);

#if YYDEBUG != 0
      if (yydebug)
 {
   fprintf (stderr, "Next token is %d (%s", yychar, yytname[yychar1]);
   /* Give the individual parser a way to print the precise meaning
      of a token, for further debugging info.  */
#ifdef YYPRINT
   YYPRINT (stderr, yychar, yylval);
#endif
   fprintf (stderr, ")\n");
 }
#endif
    }

  yyn += yychar1;
  if (yyn < 0 || yyn > YYLAST || yycheck[yyn] != yychar1)
    goto yydefault;

  yyn = yytable[yyn];

  /* yyn is what to do for this token type in this state.
     Negative => reduce, -yyn is rule number.
     Positive => shift, yyn is new state.
       New state is final state => don't bother to shift,
       just return success.
     0, or most negative number => error.  */

  if (yyn < 0)
    {
      if (yyn == YYFLAG)
 goto yyerrlab;
      yyn = -yyn;
      goto yyreduce;
    }
  else if (yyn == 0)
    goto yyerrlab;

  if (yyn == YYFINAL)
    YYACCEPT;

  /* Shift the lookahead token.  */

#if YYDEBUG != 0
  if (yydebug)
    fprintf(stderr, "Shifting token %d (%s), ", yychar, yytname[yychar1]);
#endif

  /* Discard the token being shifted unless it is eof.  */
  if (yychar != YYEOF)
    yychar = YYEMPTY;

  *++yyvsp = yylval;
#ifdef YYLSP_NEEDED
  *++yylsp = yylloc;
#endif

  /* count tokens shifted since error; after three, turn off error status.  */
  if (yyerrstatus) yyerrstatus--;

  yystate = yyn;
  goto yynewstate;

/* Do the default action for the current state.  */
yydefault:

  yyn = yydefact[yystate];
  if (yyn == 0)
    goto yyerrlab;

/* Do a reduction.  yyn is the number of a rule to reduce with.  */
yyreduce:
  yylen = yyr2[yyn];
  if (yylen > 0)
    yyval = yyvsp[1-yylen]; /* implement default value of the action */

#if YYDEBUG != 0
  if (yydebug)
    {
      int i;

      fprintf (stderr, "Reducing via rule %d (line %d), ",
        yyn, yyrline[yyn]);

      /* Print the symbols being reduced, and their result.  */
      for (i = yyprhs[yyn]; yyrhs[i] > 0; i++)
 fprintf (stderr, "%s ", yytname[yyrhs[i]]);
      fprintf (stderr, " -> %s\n", yytname[yyr1[yyn]]);
    }
#endif

$   /* the action file gets copied in in place of this dollarsign */
#line 487 "bison.simple"

  yyvsp -= yylen;
  yyssp -= yylen;
#ifdef YYLSP_NEEDED
  yylsp -= yylen;
#endif

#if YYDEBUG != 0
  if (yydebug)
    {
      short *ssp1 = yyss - 1;
      fprintf (stderr, "state stack now");
      while (ssp1 != yyssp)
 fprintf (stderr, " %d", *++ssp1);
      fprintf (stderr, "\n");
    }
#endif

  *++yyvsp = yyval;

#ifdef YYLSP_NEEDED
  yylsp++;
  if (yylen == 0)
    {
      yylsp->first_line = yylloc.first_line;
      yylsp->first_column = yylloc.first_column;
      yylsp->last_line = (yylsp-1)->last_line;
      yylsp->last_column = (yylsp-1)->last_column;
      yylsp->text = 0;
    }
  else
    {
      yylsp->last_line = (yylsp+yylen-1)->last_line;
      yylsp->last_column = (yylsp+yylen-1)->last_column;
    }
#endif

  /* Now "shift" the result of the reduction.
     Determine what state that goes to,
     based on the state we popped back to
     and the rule number reduced by.  */

  yyn = yyr1[yyn];

  yystate = yypgoto[yyn - YYNTBASE] + *yyssp;
  if (yystate >= 0 && yystate <= YYLAST && yycheck[yystate] == *yyssp)
    yystate = yytable[yystate];
  else
    yystate = yydefgoto[yyn - YYNTBASE];

  goto yynewstate;

yyerrlab:   /* here on detecting error */

  if (! yyerrstatus)
    /* If not already recovering from an error, report this error.  */
    {
      ++yynerrs;

#ifdef YYERROR_VERBOSE
      yyn = yypact[yystate];

      if (yyn > YYFLAG && yyn < YYLAST)
 {
   int size = 0;
   char *msg;
   int x, count;

   count = 0;
   /* Start X at -yyn if nec to avoid negative indexes in yycheck.  */
   for (x = (yyn < 0 ? -yyn : 0);
        x < (sizeof(yytname) / sizeof(char *)); x++)
     if (yycheck[x + yyn] == x)
       size += strlen(yytname[x]) + 15, count++;
   msg = (char *) malloc(size + 15);
   if (msg != 0)
     {
       strcpy(msg, "parse error");

       if (count < 5)
  {
    count = 0;
    for (x = (yyn < 0 ? -yyn : 0);
         x < (sizeof(yytname) / sizeof(char *)); x++)
      if (yycheck[x + yyn] == x)
        {
   strcat(msg, count == 0 ? ", expecting `" : " or `");
   strcat(msg, yytname[x]);
   strcat(msg, "'");
   count++;
        }
  }
       yyerror(msg);
       free(msg);
     }
   else
     yyerror ("parse error; also virtual memory exceeded");
 }
      else
#endif /* YYERROR_VERBOSE */
 yyerror("parse error");
    }

  goto yyerrlab1;
yyerrlab1:   /* here on error raised explicitly by an action */

  if (yyerrstatus == 3)
    {
      /* if just tried and failed to reuse lookahead token after an error, discard it.  */

      /* return failure if at end of input */
      if (yychar == YYEOF)
 YYABORT;

#if YYDEBUG != 0
      if (yydebug)
 fprintf(stderr, "Discarding token %d (%s).\n", yychar, yytname[yychar1]);
#endif

      yychar = YYEMPTY;
    }

  /* Else will try to reuse lookahead token
     after shifting the error token.  */

  yyerrstatus = 3;  /* Each real token shifted decrements this */

  goto yyerrhandle;

yyerrdefault:  /* current state does not do anything special for the error token. */

#if 0
  /* This is wrong; only states that explicitly want error tokens
     should shift them.  */
  yyn = yydefact[yystate];  /* If its default is to accept any token, ok.  Otherwise pop it.*/
  if (yyn) goto yydefault;
#endif

yyerrpop:   /* pop the current state because it cannot handle the error token */

  if (yyssp == yyss) YYABORT;
  yyvsp--;
  yystate = *--yyssp;
#ifdef YYLSP_NEEDED
  yylsp--;
#endif

#if YYDEBUG != 0
  if (yydebug)
    {
      short *ssp1 = yyss - 1;
      fprintf (stderr, "Error: state stack now");
      while (ssp1 != yyssp)
 fprintf (stderr, " %d", *++ssp1);
      fprintf (stderr, "\n");
    }
#endif

yyerrhandle:

  yyn = yypact[yystate];
  if (yyn == YYFLAG)
    goto yyerrdefault;

  yyn += YYTERROR;
  if (yyn < 0 || yyn > YYLAST || yycheck[yyn] != YYTERROR)
    goto yyerrdefault;

  yyn = yytable[yyn];
  if (yyn < 0)
    {
      if (yyn == YYFLAG)
 goto yyerrpop;
      yyn = -yyn;
      goto yyreduce;
    }
  else if (yyn == 0)
    goto yyerrpop;

  if (yyn == YYFINAL)
    YYACCEPT;

#if YYDEBUG != 0
  if (yydebug)
    fprintf(stderr, "Shifting error token, ");
#endif

  *++yyvsp = yylval;
#ifdef YYLSP_NEEDED
  *++yylsp = yylloc;
#endif

  yystate = yyn;
  goto yynewstate;
}

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