bison.simple

对pl0语言程序的语法分析源程序

  if (yyssp >= yyss + yystacksize - 1)
    {
      /* 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.  */
# if YYLSP_NEEDED
	YYLTYPE *yyls1 = yyls;
	/* 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),
		    &yyls1, yysize * sizeof (*yylsp),
		    &yystacksize);
	yyls = yyls1;
# else
	yyoverflow ("parser stack overflow",
		    &yyss1, yysize * sizeof (*yyssp),
		    &yyvs1, yysize * sizeof (*yyvsp),
		    &yystacksize);
# endif
	yyss = yyss1;
	yyvs = yyvs1;
      }
#else /* no yyoverflow */
# ifndef YYSTACK_RELOCATE
      goto yyoverflowlab;
# else
      /* Extend the stack our own way.  */
      if (yystacksize >= YYMAXDEPTH)
	goto yyoverflowlab;
      yystacksize *= 2;
      if (yystacksize > YYMAXDEPTH)
	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);
# if YYLSP_NEEDED
	YYSTACK_RELOCATE (yyls);
# endif
# undef YYSTACK_RELOCATE
	if (yyss1 != yyssa)
	  YYSTACK_FREE (yyss1);
      }
# endif
#endif /* no yyoverflow */

      yyssp = yyss + yysize - 1;
      yyvsp = yyvs + yysize - 1;
#if YYLSP_NEEDED
      yylsp = yyls + yysize - 1;
#endif

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

      if (yyssp >= yyss + yystacksize - 1)
	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 == 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)
    {
      YYDPRINTF ((stderr, "Reading a token: "));
      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 */

      YYDPRINTF ((stderr, "Now at end of input.\n"));
    }
  else
    {
      yychar1 = YYTRANSLATE (yychar);

#if YYDEBUG
     /* We have to keep this `#if YYDEBUG', since we use variables
	which are defined only if `YYDEBUG' is set.  */
      if (yydebug)
	{
	  YYFPRINTF (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
	  YYFPRINTF (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.  */
  YYDPRINTF ((stderr, "Shifting token %d (%s), ",
	      yychar, yytname[yychar1]));

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

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

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

  yystate = yyn;
  goto yynewstate;


/*-----------------------------------------------------------.
| yydefault -- do the default action for the current state.  |
`-----------------------------------------------------------*/
yydefault:
  yyn = yydefact[yystate];
  if (yyn == 0)
    goto yyerrlab;
  goto yyreduce;


/*-----------------------------.
| yyreduce -- Do a reduction.  |
`-----------------------------*/
yyreduce:
  /* yyn is the number of a rule to reduce with.  */
  yylen = yyr2[yyn];

  /* If YYLEN is nonzero, implement the default value of the action:
     `$$ = $1'.

     Otherwise, the following line sets YYVAL to the semantic value of
     the lookahead token.  This behavior is undocumented and Bison
     users should not rely upon it.  Assigning to YYVAL
     unconditionally makes the parser a bit smaller, and it avoids a
     GCC warning that YYVAL may be used uninitialized.  */
  yyval = yyvsp[1-yylen];

#if YYLSP_NEEDED
  /* Similarly for the default location.  Let the user run additional
     commands if for instance locations are ranges.  */
  yyloc = yylsp[1-yylen];
  YYLLOC_DEFAULT (yyloc, (yylsp - yylen), yylen);
#endif

#if YYDEBUG
  /* We have to keep this `#if YYDEBUG', since we use variables which
     are defined only if `YYDEBUG' is set.  */
  if (yydebug)
    {
      int yyi;

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

      /* Print the symbols being reduced, and their result.  */
      for (yyi = yyprhs[yyn]; yyrhs[yyi] > 0; yyi++)
	YYFPRINTF (stderr, "%s ", yytname[yyrhs[yyi]]);
      YYFPRINTF (stderr, " -> %s\n", yytname[yyr1[yyn]]);
    }
#endif
%% actions /* The action file replaces this line. */
#line

  yyvsp -= yylen;
  yyssp -= yylen;
#if YYLSP_NEEDED
  yylsp -= yylen;
#endif

#if YYDEBUG
  if (yydebug)
    {
      short *yyssp1 = yyss - 1;
      YYFPRINTF (stderr, "state stack now");
      while (yyssp1 != yyssp)
	YYFPRINTF (stderr, " %d", *++yyssp1);
      YYFPRINTF (stderr, "\n");
    }
#endif

  *++yyvsp = yyval;
#if YYLSP_NEEDED
  *++yylsp = yyloc;
#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 |
`------------------------------------*/
yyerrlab:
  /* If not already recovering from an error, report this error.  */
  if (!yyerrstatus)
    {
      ++yynerrs;

#ifdef YYERROR_VERBOSE
      yyn = yypact[yystate];

      if (yyn > YYFLAG && yyn < YYLAST)
	{
	  YYSIZE_T yysize = 0;
	  char *yymsg;
	  int yyx, yycount;

	  yycount = 0;
	  /* Start YYX at -YYN if negative to avoid negative indexes in
	     YYCHECK.  */
	  for (yyx = yyn < 0 ? -yyn : 0;
	       yyx < (int) (sizeof (yytname) / sizeof (char *)); yyx++)
	    if (yycheck[yyx + yyn] == yyx)
	      yysize += yystrlen (yytname[yyx]) + 15, yycount++;
	  yysize += yystrlen ("parse error, unexpected ") + 1;
	  yysize += yystrlen (yytname[YYTRANSLATE (yychar)]);
	  yymsg = (char *) YYSTACK_ALLOC (yysize);
	  if (yymsg != 0)
	    {
	      char *yyp = yystpcpy (yymsg, "parse error, unexpected ");
	      yyp = yystpcpy (yyp, yytname[YYTRANSLATE (yychar)]);

	      if (yycount < 5)
		{
		  yycount = 0;
		  for (yyx = yyn < 0 ? -yyn : 0;
		       yyx < (int) (sizeof (yytname) / sizeof (char *));
		       yyx++)
		    if (yycheck[yyx + yyn] == yyx)
		      {
			const char *yyq = ! yycount ? ", expecting " : " or ";
			yyp = yystpcpy (yyp, yyq);
			yyp = yystpcpy (yyp, yytname[yyx]);
			yycount++;
		      }
		}
	      yyerror (yymsg);
	      YYSTACK_FREE (yymsg);
	    }
	  else
	    yyerror ("parse error; also virtual memory exhausted");
	}
      else
#endif /* defined (YYERROR_VERBOSE) */
	yyerror ("parse error");
    }
  goto yyerrlab1;


/*--------------------------------------------------.
| yyerrlab1 -- error raised explicitly by an action |
`--------------------------------------------------*/
yyerrlab1:
  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;
      YYDPRINTF ((stderr, "Discarding token %d (%s).\n",
		  yychar, yytname[yychar1]));
      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.                                                       |
`-------------------------------------------------------------------*/
yyerrdefault:
#if 0
  /* This is wrong; only states that explicitly want error tokens
     should shift them.  */

  /* If its default is to accept any token, ok.  Otherwise pop it.  */
  yyn = yydefact[yystate];
  if (yyn)
    goto yydefault;
#endif


/*---------------------------------------------------------------.
| yyerrpop -- pop the current state because it cannot handle the |
| error token                                                    |
`---------------------------------------------------------------*/
yyerrpop:
  if (yyssp == yyss)
    YYABORT;
  yyvsp--;
  yystate = *--yyssp;
#if YYLSP_NEEDED
  yylsp--;
#endif

#if YYDEBUG
  if (yydebug)
    {
      short *yyssp1 = yyss - 1;
      YYFPRINTF (stderr, "Error: state stack now");
      while (yyssp1 != yyssp)
	YYFPRINTF (stderr, " %d", *++yyssp1);
      YYFPRINTF (stderr, "\n");
    }
#endif

/*--------------.
| yyerrhandle.  |
`--------------*/
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;

  YYDPRINTF ((stderr, "Shifting error token, "));

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

  yystate = yyn;
  goto yynewstate;


/*-------------------------------------.
| yyacceptlab -- YYACCEPT comes here.  |
`-------------------------------------*/
yyacceptlab:
  yyresult = 0;
  goto yyreturn;

/*-----------------------------------.
| yyabortlab -- YYABORT comes here.  |
`-----------------------------------*/
yyabortlab:
  yyresult = 1;
  goto yyreturn;

/*---------------------------------------------.
| yyoverflowab -- parser overflow comes here.  |
`---------------------------------------------*/
yyoverflowlab:
  yyerror ("parser stack overflow");
  yyresult = 2;
  /* Fall through.  */

yyreturn:
#ifndef yyoverflow
  if (yyss != yyssa)
    YYSTACK_FREE (yyss);
#endif
  return yyresult;
}