Clearing the screen and other such things.

[Rob MacLachlan <RAM@CMU-CS-C.ARPA>]

    It may or may not be a good idea to have a Common Lisp virtual
terminal, as is being suggested, but in any case, I think it is
important that this idea not be confused with the default stream
terminal I/O.  I think it would be a bad idea to force the default
stream interaction into a fixed-width character-oriented model.
Whatever interface is chosen should be willing to admit the
possibility of virtual terminal emulation being done in a totally
different fashion that default terminal I/O.

    As a case in point, default terminal interaction in Spice Lisp is
done by a remote procedure call interface to the typescript server,
which is basically a base editor.  The Typescript server doesn't
provide any facility such as "cursor positioning" since this doesn't
fit into the stream-oriented paradigm on which it is based.  If we
wanted to provide virtual terminal emulation, we would have to do it
using a totally different mechanism, operating on a different piece of
the screen.

  Rob