KEYP
KEY?

	predicate, outputs TRUE if there are characters waiting to be
	read from the read stream.  If the read stream is a file, this
	is equivalent to NOT EOFP.  If the read stream is the terminal,
	then echoing is turned off and the terminal is set to CBREAK
	(character at a time instead of line at a time) mode.  It
	remains in this mode until some line-mode reading is requested
	(e.g., READLIST).  The Unix operating system forgets about any
	pending characters when it switches modes, so the first KEYP
	invocation will always output FALSE.