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/*
* cook - file construction tool
* Copyright (C) 1997, 1998 Peter Miller;
* All rights reserved.
*
* 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 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
*
* MANIFEST: functions to parse expression grammar
*/
%{
#include <ac/stdarg.h>
#include <ac/stdio.h>
#include <str.h>
#include <sub/expr_gram.h>
#include <sub/expr_lex.h>
#include <sub/private.h>
#include <trace.h>
#ifdef DEBUG
#define YYDEBUG 1
#endif
%}
%token DIV
%token JUNK
%token LP
%token MINUS
%token MUL
%token NUMBER
%token PLUS
%token RP
%union
{
long lv_number;
}
%type <lv_number> NUMBER expr
%left PLUS MINUS
%left MUL DIV
%right UNARY
%{
static long result;
static sub_context_ty *scp;
string_ty *
sub_expr_gram(p, s)
sub_context_ty *p;
string_ty *s;
{
int bad;
extern int yyparse _((void));
#ifdef DEBUG
extern int yydebug;
#endif
trace(("sub_expr_gram()\n{\n"/*}*/));
scp = p;
#ifdef DEBUG
yydebug = trace_pretest_;
#endif
sub_expr_lex_open(s);
bad = yyparse();
sub_expr_lex_close();
trace(("bad = %d\n", bad));
scp = 0;
trace((/*{*/"}\n"));
if (bad)
return 0;
return str_format("%ld", result);
}
void yyerror _((char *));
void
yyerror(s)
char *s;
{
trace(("yyerror(\"%s\")\n{\n", s));
sub_context_error_set(scp, s);
trace((/*{*/"}\n"));
}
#ifdef DEBUG
/*
* jiggery-pokery for yacc
*
* Replace all calls to printf with a call to trace_printf. The
* trace_where_ is needed to set the location, and is safe, because
* yacc only invokes the printf with an if (be careful, the printf
* is not in a compound statement).
*/
#define printf trace_where_, trace_printf
/*
* jiggery-pokery for bison
*
* Replace all calls to fprintf with a call to yydebugger. Ignore
* the first argument, it will be ``stderr''. The trace_where_ is
* needed to set the location, and is safe, because bison only
* invokes the printf with an if (be careful, the fprintf is not in
* a compound statement).
*/
#define fprintf trace_where_, yydebugger
void yydebugger _((void *, char *, ...));
void
yydebugger(junk, fmt sva_last)
void *junk;
char *fmt;
sva_last_decl
{
va_list ap;
string_ty *s;
sva_init(ap, fmt);
s = str_vformat(fmt, ap);
va_end(ap);
trace_printf("%s", s->str_text);
str_free(s);
}
#endif
%}
%%
grammar:
expr
{ result = $1; }
;
expr
: LP expr RP
{ $$ = $2; trace(("$$ = %ld;\n", $$)); }
| NUMBER
{ $$ = $1; trace(("$$ = %ld;\n", $$)); }
| MINUS expr
%prec UNARY
{ $$ = -$2; trace(("$$ = %ld;\n", $$)); }
| expr PLUS expr
{ $$ = $1 + $3; trace(("$$ = %ld;\n", $$)); }
| expr MINUS expr
{ $$ = $1 - $3; trace(("$$ = %ld;\n", $$)); }
| expr MUL expr
{ $$ = $1 * $3; trace(("$$ = %ld;\n", $$)); }
| expr DIV expr
{ $$ = $3 ? $1 / $3 : 0; trace(("$$ = %ld;\n", $$)); }
;
|