y.tab.c

本源码为一个编译原理课程设计程序,它采用了YACC和LEX实现了一个功能强大的计算器编译器!

#define YYFAIL		goto yyerrlab

#define YYRECOVERING()  (!!yyerrstatus)

#define YYBACKUP(Token, Value)					\
do								\
  if (yychar == YYEMPTY && yylen == 1)				\
    {								\
      yychar = (Token);						\
      yylval = (Value);						\
      yytoken = YYTRANSLATE (yychar);				\
      YYPOPSTACK;						\
      goto yybackup;						\
    }								\
  else								\
    { 								\
      yyerror ("syntax error: cannot back up");\
      YYERROR;							\
    }								\
while (0)

#define YYTERROR	1
#define YYERRCODE	256

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

#ifndef YYLLOC_DEFAULT
# define YYLLOC_DEFAULT(Current, Rhs, N)         \
  Current.first_line   = Rhs[1].first_line;      \
  Current.first_column = Rhs[1].first_column;    \
  Current.last_line    = Rhs[N].last_line;       \
  Current.last_column  = Rhs[N].last_column;
#endif

/* YYLEX -- calling `yylex' with the right arguments.  */

#ifdef YYLEX_PARAM
# define YYLEX yylex (YYLEX_PARAM)
#else
# define YYLEX yylex ()
#endif

/* Enable debugging if requested.  */
#if YYDEBUG

# ifndef YYFPRINTF
#  include <stdio.h> /* INFRINGES ON USER NAME SPACE */
#  define YYFPRINTF fprintf
# endif

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

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

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

/*------------------------------------------------------------------.
| yy_stack_print -- Print the state stack from its BOTTOM up to its |
| TOP (cinluded).                                                   |
`------------------------------------------------------------------*/

#if defined (__STDC__) || defined (__cplusplus)
static void
yy_stack_print (short *bottom, short *top)
#else
static void
yy_stack_print (bottom, top)
    short *bottom;
    short *top;
#endif
{
  YYFPRINTF (stderr, "Stack now");
  for (/* Nothing. */; bottom <= top; ++bottom)
    YYFPRINTF (stderr, " %d", *bottom);
  YYFPRINTF (stderr, "\n");
}

# define YY_STACK_PRINT(Bottom, Top)				\
do {								\
  if (yydebug)							\
    yy_stack_print ((Bottom), (Top));				\
} while (0)


/*------------------------------------------------.
| Report that the YYRULE is going to be reduced.  |
`------------------------------------------------*/

#if defined (__STDC__) || defined (__cplusplus)
static void
yy_reduce_print (int yyrule)
#else
static void
yy_reduce_print (yyrule)
    int yyrule;
#endif
{
  int yyi;
  unsigned int yylno = yyrline[yyrule];
  YYFPRINTF (stderr, "Reducing stack by rule %d (line %u), ",
             yyrule - 1, yylno);
  /* Print the symbols being reduced, and their result.  */
  for (yyi = yyprhs[yyrule]; 0 <= yyrhs[yyi]; yyi++)
    YYFPRINTF (stderr, "%s ", yytname [yyrhs[yyi]]);
  YYFPRINTF (stderr, "-> %s\n", yytname [yyr1[yyrule]]);
}

# define YY_REDUCE_PRINT(Rule)		\
do {					\
  if (yydebug)				\
    yy_reduce_print (Rule);		\
} while (0)

/* Nonzero means print parse trace.  It is left uninitialized so that
   multiple parsers can coexist.  */
int yydebug;
#else /* !YYDEBUG */
# define YYDPRINTF(Args)
# define YYDSYMPRINT(Args)
# define YYDSYMPRINTF(Title, Token, Value, Location)
# define YY_STACK_PRINT(Bottom, Top)
# define YY_REDUCE_PRINT(Rule)
#endif /* !YYDEBUG */


/* YYINITDEPTH -- initial size of the parser's stacks.  */
#ifndef	YYINITDEPTH
# define YYINITDEPTH 200
#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 < YYSTACK_BYTES (YYMAXDEPTH)
   evaluated with infinite-precision integer arithmetic.  */

#if YYMAXDEPTH == 0
# undef YYMAXDEPTH
#endif

#ifndef YYMAXDEPTH
# define YYMAXDEPTH 10000
#endif



#if YYERROR_VERBOSE

# ifndef yystrlen
#  if defined (__GLIBC__) && defined (_STRING_H)
#   define yystrlen strlen
#  else
/* Return the length of YYSTR.  */
static YYSIZE_T
#   if defined (__STDC__) || defined (__cplusplus)
yystrlen (const char *yystr)
#   else
yystrlen (yystr)
     const char *yystr;
#   endif
{
  register const char *yys = yystr;

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

  return yys - yystr - 1;
}
#  endif
# endif

# 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 *
#   if defined (__STDC__) || defined (__cplusplus)
yystpcpy (char *yydest, const char *yysrc)
#   else
yystpcpy (yydest, yysrc)
     char *yydest;
     const char *yysrc;
#   endif
{
  register char *yyd = yydest;
  register const char *yys = yysrc;

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

  return yyd - 1;
}
#  endif
# endif

#endif /* !YYERROR_VERBOSE */



#if YYDEBUG
/*--------------------------------.
| Print this symbol on YYOUTPUT.  |
`--------------------------------*/

#if defined (__STDC__) || defined (__cplusplus)
static void
yysymprint (FILE *yyoutput, int yytype, YYSTYPE *yyvaluep)
#else
static void
yysymprint (yyoutput, yytype, yyvaluep)
    FILE *yyoutput;
    int yytype;
    YYSTYPE *yyvaluep;
#endif
{
  /* Pacify ``unused variable'' warnings.  */
  (void) yyvaluep;

  if (yytype < YYNTOKENS)
    {
      YYFPRINTF (yyoutput, "token %s (", yytname[yytype]);
# ifdef YYPRINT
      YYPRINT (yyoutput, yytoknum[yytype], *yyvaluep);
# endif
    }
  else
    YYFPRINTF (yyoutput, "nterm %s (", yytname[yytype]);

  switch (yytype)
    {
      default:
        break;
    }
  YYFPRINTF (yyoutput, ")");
}

#endif /* ! YYDEBUG */
/*-----------------------------------------------.
| Release the memory associated to this symbol.  |
`-----------------------------------------------*/

#if defined (__STDC__) || defined (__cplusplus)
static void
yydestruct (int yytype, YYSTYPE *yyvaluep)
#else
static void
yydestruct (yytype, yyvaluep)
    int yytype;
    YYSTYPE *yyvaluep;
#endif
{
  /* Pacify ``unused variable'' warnings.  */
  (void) yyvaluep;

  switch (yytype)
    {

      default:
        break;
    }
}


/* Prevent warnings from -Wmissing-prototypes.  */

#ifdef YYPARSE_PARAM
# if defined (__STDC__) || defined (__cplusplus)
int yyparse (void *YYPARSE_PARAM);
# else
int yyparse ();
# endif
#else /* ! YYPARSE_PARAM */
#if defined (__STDC__) || defined (__cplusplus)
int yyparse (void);
#else
int yyparse ();
#endif
#endif /* ! YYPARSE_PARAM */



/* The lookahead symbol.  */
int yychar;

/* The semantic value of the lookahead symbol.  */
YYSTYPE yylval;

/* Number of syntax errors so far.  */
int yynerrs;



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

#ifdef YYPARSE_PARAM
# if defined (__STDC__) || defined (__cplusplus)
int yyparse (void *YYPARSE_PARAM)
# else
int yyparse (YYPARSE_PARAM)
  void *YYPARSE_PARAM;
# endif
#else /* ! YYPARSE_PARAM */
#if defined (__STDC__) || defined (__cplusplus)
int
yyparse (void)
#else
int
yyparse ()

#endif
#endif
{
  
  register int yystate;
  register int yyn;
  int yyresult;
  /* Number of tokens to shift before error messages enabled.  */
  int yyerrstatus;
  /* Lookahead token as an internal (translated) token number.  */
  int yytoken = 0;

  /* Three stacks and their tools:
     `yyss': related to states,
     `yyvs': related to semantic values,
     `yyls': related to locations.

     Refer to the stacks thru separate pointers, to allow yyoverflow
     to reallocate them elsewhere.  */

  /* The state stack.  */
  short	yyssa[YYINITDEPTH];
  short *yyss = yyssa;
  register short *yyssp;

  /* The semantic value stack.  */
  YYSTYPE yyvsa[YYINITDEPTH];
  YYSTYPE *yyvs = yyvsa;
  register YYSTYPE *yyvsp;



#define YYPOPSTACK   (yyvsp--, yyssp--)

  YYSIZE_T yystacksize = YYINITDEPTH;

  /* The variables used to return semantic value and location from the
     action routines.  */
  YYSTYPE yyval;


  /* When reducing, the number of symbols on the RHS of the reduced
     rule.  */
  int yylen;

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

  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;
  yyvsp = yyvs;

  goto yysetstate;

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

 yysetstate:
  *yyssp = yystate;

  if (yyss + yystacksize - 1 <= yyssp)
    {
      /* Get the current used size of the three stacks, in elements.  */
      YYSIZE_T yysize = yyssp - yyss + 1;

#ifdef yyoverflow
      {
	/* 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;


	/* Each stack pointer address is followed by the size of the
	   data in use in that stack, in bytes.  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, yysize * sizeof (*yyssp),
		    &yyvs1, yysize * sizeof (*yyvsp),

		    &yystacksize);

	yyss = yyss1;
	yyvs = yyvs1;
      }
#else /* no yyoverflow */
# ifndef YYSTACK_RELOCATE
      goto yyoverflowlab;
# else
      /* Extend the stack our own way.  */
      if (YYMAXDEPTH <= yystacksize)
	goto yyoverflowlab;
      yystacksize *= 2;
      if (YYMAXDEPTH < yystacksize)
	yystacksize = YYMAXDEPTH;

      {
	short *yyss1 = yyss;
	union yyalloc *yyptr =
	  (union yyalloc *) YYSTACK_ALLOC (YYSTACK_BYTES (yystacksize));
	if (! yyptr)
	  goto yyoverflowlab;
	YYSTACK_RELOCATE (yyss);
	YYSTACK_RELOCATE (yyvs);

#  undef YYSTACK_RELOCATE
	if (yyss1 != yyssa)
	  YYSTACK_FREE (yyss1);
      }
# endif
#endif /* no yyoverflow */

      yyssp = yyss + yysize - 1;
      yyvsp = yyvs + yysize - 1;


      YYDPRINTF ((stderr, "Stack size increased to %lu\n",
		  (unsigned long int) yystacksize));

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

  YYDPRINTF ((stderr, "Entering state %d\n", yystate));

  goto yybackup;

/*-----------.
| 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 == YYPACT_NINF)
    goto yydefault;

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

  /* YYCHAR is either YYEMPTY or YYEOF or a valid lookahead symbol.  */
  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);
      YYDSYMPRINTF ("Next token is", yytoken, &yylval, &yylloc);
    }

  /* If the proper action on seeing token YYTOKEN is to reduce or to
     detect an error, take that action.  */
  yyn += yytoken;