%{
/* $OpenBSD: parser.y,v 1.7 2012/04/12 17:00:11 espie Exp $ */
/*
 * Copyright (c) 2004 Marc Espie <espie@cvs.openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <math.h>
#include <stdint.h>
#define YYSTYPE int32_t
extern int32_t end_result;
extern int yylex(void);
extern int yyerror(const char *);
%}
%token NUMBER
%token ERROR
%left LOR
%left LAND
%left '|'
%left '^'
%left '&'
%left EQ NE
%left '<' LE '>' GE
%left LSHIFT RSHIFT
%left '+' '-'
%left '*' '/' '%'
%right EXPONENT
%right UMINUS UPLUS '!' '~'

%%

top     : expr { end_result = $1; }
        ;
expr    : expr '+' expr { $$ = $1 + $3; }
        | expr '-' expr { $$ = $1 - $3; }
        | expr EXPONENT expr { $$ = pow($1, $3); }
        | expr '*' expr { $$ = $1 * $3; }
        | expr '/' expr {
                if ($3 == 0) {
                        yyerror("division by zero");
                        exit(1);
                }
                $$ = $1 / $3;
        }
        | expr '%' expr { 
                if ($3 == 0) {
                        yyerror("modulo zero");
                        exit(1);
                }
                $$ = $1 % $3;
        }
        | expr LSHIFT expr { $$ = $1 << $3; }
        | expr RSHIFT expr { $$ = $1 >> $3; }
        | expr '<' expr { $$ = $1 < $3; }
        | expr '>' expr { $$ = $1 > $3; }
        | expr LE expr { $$ = $1 <= $3; }
        | expr GE expr { $$ = $1 >= $3; }
        | expr EQ expr { $$ = $1 == $3; }
        | expr NE expr { $$ = $1 != $3; }
        | expr '&' expr { $$ = $1 & $3; }
        | expr '^' expr { $$ = $1 ^ $3; }
        | expr '|' expr { $$ = $1 | $3; }
        | expr LAND expr { $$ = $1 && $3; }
        | expr LOR expr { $$ = $1 || $3; }
        | '(' expr ')' { $$ = $2; }
        | '-' expr %prec UMINUS { $$ = -$2; }
        | '+' expr %prec UPLUS  { $$ = $2; }
        | '!' expr { $$ = !$2; }
        | '~' expr { $$ = ~$2; }
        | NUMBER
        ;
%%