\ \ enrich the serial IO with XON/XOFF \ this is not a complete and fool-proof \ \ #requires is.frt $11 constant XON $13 constant XOFF \ original refill variable xt-refill : refill-xon XON emit xt-refill @ execute XOFF emit ; : +xonxoff ['] refill defer@ xt-refill ! ['] refill-xon is refill ; : -xonxoff xt-refill @ is refill ;