Re: Programming challenge: Undo

["Robert Holmgren" holmgren@xxxxxxxx]

** Reply to message from Bill Troop  on
Tue, 01 Jul 2008 21:19:18 +0100


> On the other hand, if it is an external process (what a brilliant
> idea - - I had completely overlooked the fact that we are working in
> a multitasking environment!) and given that we have almost infinite
> reserves of disk space, there could be so many permissible backups
> that it wouldn't be a problem.

The core idea is: an external program CAN signal XyWrite by the
simple device of poking keys into XyWrite's keyboard buffer --
XyWrite will treat these "poked" keys as user, and execute them.
They alert XyWrite, in turn, that an external program is
communicating with it, and in response XyWrite initiates real
2-way communication -- the millisecond unlimited-complexity
quick-event type. (You'll see how quickly UnDo and ReDo
commands are executed.) It's a cool concept, because with real
2-way communication with an external process, you can do a lot
of interesting things -- after all, the external program can do
ANYTHING! -- thus the potential to interact, directly or
indirectly, with any program on your machine.

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Robert Holmgren
holmgren@xxxxxxxx
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