Re: [OT] Best way to isolate a GUI? (The final concensous?)

[Dmitry A. Kazakov <mailbox@dmitry-kazakov.de>]

On Thu, 20 Feb 2003 07:40:02 -0500, "Marin David Condic"
<mcondic.auntie.spam@acm.org> wrote:

>I'd put the case statement part in the "Nice to have" category rather than
>view it as the loss of some essential capability. Most of what you get there
>is likely to be dealt with by dispatching & the rest is more of an
>inconvenience than anything else.
>
>I'd agree that you don't want to totally rule out variant records.It is a
>foolish design rule to say "Thou shalt not use feature X - ever." I'd simply
>base the thing on tagged records and as the design evolved if circumstances
>made it look like a variant might be a good answer, go ahead and create one.
>My strategy would be tagged records, but I might use a tactic of a variant
>occasionally.
>
>As for callbacks - I'd rather not see that at all. One or more message
>queues would seem more elegant to me. Maybe that's just me, but callbacks
>seem like some version of a computed goto - I've got to give you intimate
>knowledge of the inside of my code (plus, structure my code according to
>your whims) when I'd rather just have you send me data and let me figure out
>what to do with it.

Callbacks use the caller's context, messages do not. This could be
crucial in some cases. A painful example of this difference is task
entries which are unable to return indefinite objects. Anyway, Ada
offers a great variety of design options to consider.

---
Regards,
Dmitry Kazakov
www.dmitry-kazakov.de