source: kBuild/trunk/src/ash/arith.y@ 1158

%{
/*      $NetBSD: arith.y,v 1.17 2003/09/17 17:33:36 jmmv Exp $  */

/*-
 * Copyright (c) 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Kenneth Almquist.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifdef HAVE_SYS_CDEFS_H
#include <sys/cdefs.h>
#endif
#ifndef lint
#if 0
static char sccsid[] = "@(#)arith.y     8.3 (Berkeley) 5/4/95";
#else
__RCSID("$NetBSD: arith.y,v 1.17 2003/09/17 17:33:36 jmmv Exp $");
#endif
#endif /* not lint */

#include <stdlib.h>
#include "expand.h"
#include "shell.h"
#include "error.h"
#include "output.h"
#include "memalloc.h"

const char *arith_buf, *arith_startbuf;

void yyerror(const char *);
#ifdef TESTARITH
int main(int , char *[]);
int error(char *);
#endif

%}
%token ARITH_NUM ARITH_LPAREN ARITH_RPAREN

%left ARITH_OR
%left ARITH_AND
%left ARITH_BOR
%left ARITH_BXOR
%left ARITH_BAND
%left ARITH_EQ ARITH_NE
%left ARITH_LT ARITH_GT ARITH_GE ARITH_LE
%left ARITH_LSHIFT ARITH_RSHIFT
%left ARITH_ADD ARITH_SUB
%left ARITH_MUL ARITH_DIV ARITH_REM
%left ARITH_UNARYMINUS ARITH_UNARYPLUS ARITH_NOT ARITH_BNOT
%%

exp:    expr {
                        return ($1);
                }
        ;


expr:   ARITH_LPAREN expr ARITH_RPAREN { $$ = $2; }
        | expr ARITH_OR expr    { $$ = $1 ? $1 : $3 ? $3 : 0; }
        | expr ARITH_AND expr   { $$ = $1 ? ( $3 ? $3 : 0 ) : 0; }
        | expr ARITH_BOR expr   { $$ = $1 | $3; }
        | expr ARITH_BXOR expr  { $$ = $1 ^ $3; }
        | expr ARITH_BAND expr  { $$ = $1 & $3; }
        | expr ARITH_EQ expr    { $$ = $1 == $3; }
        | expr ARITH_GT expr    { $$ = $1 > $3; }
        | expr ARITH_GE expr    { $$ = $1 >= $3; }
        | expr ARITH_LT expr    { $$ = $1 < $3; }
        | expr ARITH_LE expr    { $$ = $1 <= $3; }
        | expr ARITH_NE expr    { $$ = $1 != $3; }
        | expr ARITH_LSHIFT expr { $$ = $1 << $3; }
        | expr ARITH_RSHIFT expr { $$ = $1 >> $3; }
        | expr ARITH_ADD expr   { $$ = $1 + $3; }
        | expr ARITH_SUB expr   { $$ = $1 - $3; }
        | expr ARITH_MUL expr   { $$ = $1 * $3; }
        | expr ARITH_DIV expr   {
                        if ($3 == 0)
                                yyerror("division by zero");
                        $$ = $1 / $3;
                        }
        | expr ARITH_REM expr   {
                        if ($3 == 0)
                                yyerror("division by zero");
                        $$ = $1 % $3;
                        }
        | ARITH_NOT expr        { $$ = !($2); }
        | ARITH_BNOT expr       { $$ = ~($2); }
        | ARITH_SUB expr %prec ARITH_UNARYMINUS { $$ = -($2); }
        | ARITH_ADD expr %prec ARITH_UNARYPLUS { $$ = $2; }
        | ARITH_NUM
        ;
%%
int
arith(s)
        const char *s;
{
        long result;

        arith_buf = arith_startbuf = s;

        INTOFF;
        result = yyparse();
        arith_lex_reset();      /* reprime lex */
        INTON;

        return (result);
}


/*
 *  The exp(1) builtin.
 */
int
expcmd(argc, argv)
        int argc;
        char **argv;
{
        const char *p;
        char *concat;
        char **ap;
        long i;

        if (argc > 1) {
                p = argv[1];
                if (argc > 2) {
                        /*
                         * concatenate arguments
                         */
                        STARTSTACKSTR(concat);
                        ap = argv + 2;
                        for (;;) {
                                while (*p)
                                        STPUTC(*p++, concat);
                                if ((p = *ap++) == NULL)
                                        break;
                                STPUTC(' ', concat);
                        }
                        STPUTC('\0', concat);
                        p = grabstackstr(concat);
                }
        } else
                p = "";

        i = arith(p);

        out1fmt("%ld\n", i);
        return (! i);
}

/*************************/
#ifdef TEST_ARITH
#include <stdio.h>
main(argc, argv)
        char *argv[];
{
        printf("%d\n", exp(argv[1]));
}
error(s)
        char *s;
{
        fprintf(stderr, "exp: %s\n", s);
        exit(1);
}
#endif

void
yyerror(s)
        const char *s;
{

        yyerrok;
        yyclearin;
        arith_lex_reset();      /* reprime lex */
        error("arithmetic expression: %s: \"%s\"", s, arith_startbuf);
        /* NOTREACHED */
}