From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,e429176c9adb07b X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2003-02-20 05:27:46 PST Path: archiver1.google.com!news2.google.com!news1.google.com!newsfeed.stanford.edu!headwall.stanford.edu!fu-berlin.de!uni-berlin.de!tar-alcarin.cbb-automation.DE!not-for-mail From: Dmitry A. Kazakov Newsgroups: comp.lang.ada Subject: Re: [OT] Best way to isolate a GUI? (The final concensous?) Date: Thu, 20 Feb 2003 14:13:34 +0100 Message-ID: References: <3E511C15.1040404@acm.org> <3E5121BD.4010200@cogeco.ca> <3E51A55A.3000101@cogeco.ca> <3E52A1BF.1020809@cogeco.ca> <3E53CE60.1030008@cogeco.ca> NNTP-Posting-Host: tar-alcarin.cbb-automation.de (212.79.194.111) Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: fu-berlin.de 1045746814 52195261 212.79.194.111 (16 [77047]) X-Newsreader: Forte Agent 1.8/32.548 Xref: archiver1.google.com comp.lang.ada:34273 Date: 2003-02-20T14:13:34+01:00 List-Id: On Thu, 20 Feb 2003 07:40:02 -0500, "Marin David Condic" 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