🚀 go-pugleaf

From article <10217@scott.ed.ac.uk>, by asch@cogsci.ed.ac.uk (Andreas Schoter):

> In article <3545@keele.keele.ac.uk> csa09@seq1.keele.ac.uk (Paul Singleton):

>>Please can anyone with experience or insight suggest some principles
>>for interfacing Prolog programs to WIMP interfaces, i.e. buttons, sliders,
>>menus, dialog boxes and all that stuff.  I avoid asserting and retracting
>>global state, and try to contain side-effects, and I can't see how to
>>employ WIMP features without compromising this style.  Well, I can, but ...
 
> You don't specify what level of abstraction the WIMP features are
> specified at, low level wiget type facilities, or high level packaged
> utilityies, but...

I am using Quintus Prolog's ProXT - "a Prolog interface to the Motif widget
set and the X Toolkit (Xt)".  I have no X experience, nor do I really
want it :-) and I am presently puzzling over how to combine it with my
Prolog programming style, which I claim is fairly clean and amenable to
debugging, maintenance, evolution etc.  I carry all program state around
as data structures passed from call to call.  All iteration is done with
recursion, not with e.g. failure-driven backtracking and assert/retract.
I am reluctant to sprinkle imperative X calls throughout my code, and not
sure how to handle events.

When I wrote my first SunTools application, in C, I learnt to turn my
program inside out and effectively write a bunch of interrupt routines
which were called by the "Notifier".  Should I do the same with Prolog?
How can I, without global state?

I have considered funnelling all events into a pretend "stream", and
organising my program to recursively digest this stream.  Can anyone
advise me, from experience or dogma, on this or other approaches?

Can WIMP interfaces be treated declaratively?

Paul S.
----
  __   __    Paul Singleton (Mr)           JANET: paul@uk.ac.keele.cs
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