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bison.lha
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bison++-1.04
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bison++.simple.cc
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C/C++ Source or Header
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1991-03-28
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11KB
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450 lines
// This may look like C code, but it is really -*- C++ -*-
/* Skeleton output parser for bison++,
Copyright (C) 1984 Bob Corbett and Richard Stallman
Copyright (C) 1989 Larry M. Augustin
Adapted from the original for C++ by Larry M. Augustin.
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 1, 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. */
/* 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 YYFAIL goto yyerrlab;
#define YYACCEPT return(0)
#define YYABORT return(1)
#define YYERROR goto yyerrlab
#define YYTERROR 1
#define YYERRCODE 256
#ifndef YYIMPURE
#define YYLEX yylex()
#endif
#ifndef YYPURE
#define YYLEX yylex(&yylval, &yylloc)
#endif
/* YYMAXDEPTH indicates the initial size of the parser's stacks */
#ifndef YYMAXDEPTH
#define YYMAXDEPTH 200
#endif
/* YYMAXLIMIT is the maximum size the stacks can grow to
(effective only if the built-in stack extension method is used). */
#ifndef YYMAXLIMIT
#define YYMAXLIMIT 10000
#endif
int @::yyparse() {
register int yystate;
register int yyn;
register short *yyssp;
register @_YYSTYPE *yyvsp;
@_YYLTYPE *yylsp;
int yyerrstatus; // number of tokens to shift before error messages enabled
int yychar1; // lookahead token as an internal (translated) token number
short yyssa[YYMAXDEPTH]; // the state stack
@_YYSTYPE yyvsa[YYMAXDEPTH]; // the semantic value stack
@_YYLTYPE yylsa[YYMAXDEPTH]; // the location stack
short *yyss = yyssa; // refer to the stacks thru separate pointers
@_YYSTYPE *yyvs = yyvsa; // to allow yyoverflow to reallocate them elsewhere
@_YYLTYPE *yyls = yylsa;
int yymaxdepth = YYMAXDEPTH;
#ifndef YYPURE
int yychar;
@_YYSTYPE yylval;
@_YYLTYPE yylloc;
int yynerrs;
#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
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. */
yyssp = yyss - 1;
yyvsp = yyvs;
yylsp = yyls;
/* 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 + yymaxdepth - 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;
@_YYLTYPE *yyls1 = yyls;
short *yyss1 = yyss;
/* 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. */
yyoverflow("parser stack overflow",
&yyss1, size * sizeof (*yyssp),
&yyvs1, size * sizeof (*yyvsp),
&yyls1, size * sizeof (*yylsp),
&yymaxdepth);
yyss = yyss1; yyvs = yyvs1; yyls = yyls1;
#else /* no yyoverflow */
/* Extend the stack our own way. */
if (yymaxdepth >= YYMAXLIMIT)
yyerror("parser stack overflow");
yymaxdepth *= 2;
if (yymaxdepth > YYMAXLIMIT)
yymaxdepth = YYMAXLIMIT;
yyss = (short *) alloca (yymaxdepth * sizeof (*yyssp));
bcopy ((char *)yyss1, (char *)yyss, size * sizeof (*yyssp));
yyvs = (@_YYSTYPE *) alloca (yymaxdepth * sizeof (*yyvsp));
bcopy ((char *)yyvs1, (char *)yyvs, size * sizeof (*yyvsp));
#ifdef YYLSP_NEEDED
yyls = (@_YYLTYPE *) alloca (yymaxdepth * sizeof (*yylsp));
bcopy ((char *)yyls1, (char *)yyls, size * sizeof (*yylsp));
#endif // YYLSP_NEEDED
#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", yymaxdepth);
#endif
if (yyssp >= yyss + yymaxdepth - 1)
YYABORT;
}
#if YYDEBUG != 0
if (yydebug)
fprintf(stderr, "Entering state %d\n", yystate);
#endif
/* Do appropriate processing given the current state. */
/* Read a lookahead token if we need one and don't already have one. */
/* 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)\n", yychar, yytname[yychar1]);
#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];
yyval = yyvsp[1-yylen]; /* implement default value of the action */
#if YYDEBUG != 0
if (yydebug)
{
if (yylen == 1)
fprintf (stderr, "Reducing 1 value via line %d, ",
yyrline[yyn]);
else
fprintf (stderr, "Reducing %d values via line %d, ",
yylen, yyrline[yyn]);
}
#endif
$ /* the action file gets copied in in place of this dollarsign */
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;
yyerror("parse error");
}
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;
}