Re: X and Ada?

[karsh@nicmad.UUCP (Bruce Karsh)]

In article <1415@bloom-beacon.MIT.EDU> newman@Leo.UUCP (Ron Newman) writes:
>
>*Any* toolkit is going to depend on the use of call-back functions.

  I don't agree with this.  It bothers me that X has two different
mechanisms for sending messages when it would considerably simplify
things if only one were used.  The X event mechanism is sufficient
to handle all the message passing requirements that the callback
mechanism handles.  I think that X events should be extended and
generalized so that they would allow events generated by toolkit
gadgets to be handled in the same way that normal X events are
handled.

  For example, if you move a slidebar, the toolkit should generate a
SlidebarMoved pseudo X event, which gets queued in the same way that
regular X events are queued.  Your event loop would handle this
pseudo event in the same way that it handles regular X events.  There
would not have to be special treatment for X events versus X toolkit
events.

  Does anybody know why X has two different kinds of message passing
mechanisms?  Couldn't we just get rid of call-backs?  Does anybody have
any ideas on what the "right" message passing mechanism for X should be?

[I like the idea that each toolkit gadget should be it's own
lightweight process that sends messages to other interested processes
whenever its state changes].
-- 
Bruce Karsh
{uwvax,ihnp4}!nicmad!karsh