term : factor OP_PLUS term
                | factor OP_MINUS term
                | factor OP_TIMES term
                | factor OP_DIVIDE term
                | factor OP_MODULO term
                | factor

def p_term(tok):
        """term : factor OP_PLUS term
                | factor OP_MINUS term
                | factor OP_TIMES term
                | factor OP_DIVIDE term
                | factor OP_MODULO term
                | factor"""
        if len(tok) == 4:
            tok[0] = MathBinOpRule(tok[2], tok[1], tok[3])
        else:
            tok[0] = tok[1]