[unix-history] / usr / src / bin / sh / arith.y

%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
       ;
%%
/*-
* 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.
*
* %sccs.include.redist.c%
*/

#ifndef lint
static char sccsid[] = "@(#)arith.y     8.2 (Berkeley) %G%";
#endif /* not lint */

#include "shell.h"
#include "error.h"
#include "output.h"
#include "memalloc.h"

char *arith_buf, *arith_startbuf;

arith(s)
       char *s; 
{
       long result;

       arith_buf = arith_startbuf = s;

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

       return (result);
}

yyerror(s)
       char *s;
{
       extern yytext, yylval;

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

/*
*  The exp(1) builtin.
*/
expcmd(argc, argv)
       char **argv;
{
       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("%d\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