/*
    Very Simple Calculator
	$Id$
 */

#include "s-compile.h"

int  variable[48];

static int  expr();
static int  aexpr();
static int  mexpr();
static int  term();


static int
expr()
{
    int d,assign;

    d = aexpr();
    assign = lvalue;
    while(last_token!=EOF) {
	switch(last_token) {
	case '>': 
	    d = (d > aexpr()); 
	    break;
	case '=': 
	    if(assign>=0) {
		d = expr(); 
		variable[assign] = d;
		break;
	    } else {
		error("Bad assignment");
		break;
	    }
	case ')': 
	    return d;
	default:
	    error("Bad expression");
	    return d;
	}
    }
    return d;
}

static int
aexpr()
{
    int d;

    d = mexpr();
    while(last_token!=EOF) {
	switch(last_token) {
	case '-': 
	    d -= mexpr(); 
	    break;
	case '+': 
	    d += mexpr(); 
	    break;
	default:
	    return d;
	}
    }
    return d;
}

static int
mexpr()
{
    int d;

    d = term();
    while(last_token!=EOF) {
	switch(last_token) {
	case '*': 
	    d *= term(); 
	    break;
	case '/': 
	    d /= term(); 
	    break;
	default:
	    return d;
	}
    }
    return d;
}

static int 
term()
{
    int d;

    lvalue= -1;
    token();
    if(last_token==EOF) {
	error("Term expected");
    }
    switch(last_token) {
    case '0':
	d = value;
	token();
	return d;
    case 'v':
	d = lvalue = value;
	token();
	return variable[d];
    case '(':
	d = expr();
	if(last_token != ')') {
	    error("Unbalanced parenthsis");
	} 
	token(); 
	return d;
    default:
	token();
	error("Unknown term");
	return 0;
    }
}

int
main() 
{
    int d;
    char buf[BUFSIZ];

    while (fgets(buf,BUFSIZ,stdin)) {
	ptr = buf;
	d = expr();
	printf("%s = 0x%08x = %d\n",buf,d,d);
	fflush(stdout);
    }
    return 0;
}

/* end */