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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: fac41,f66d11aeda114c52 X-Google-Attributes: gidfac41,public X-Google-Thread: 103376,f66d11aeda114c52 X-Google-Attributes: gid103376,public From: Paul Johnson Subject: Re: Building blocks (Was: Design By Contract) Date: 1997/09/12 Message-ID: #1/1 X-Deja-AN: 272153976 Distribution: world X-NNTP-Posting-Host: treetop.demon.co.uk [158.152.55.135] References: <5ulurp$aj8$1@miranda.gmrc.gecm.com> <5un58u$9ih$1@gonzo.sun3.iaf.nl> <5v0bph$n98$2@miranda.gmrc.gecm.com> Organization: home Newsgroups: comp.lang.ada,comp.lang.eiffel Date: 1997-09-12T00:00:00+00:00 List-Id: In article , Robert Dewar writes >Brian Rogoff said > ><<>>In fact the Eiffel exception mechanism is superior to the Ada one >>> because it is built on a theoretical model of software engineering.>> As someone else pointed out, I said that, not Brian. >This is one of the more absurd statements in what is unfortunately becoming >a rather tedious thread. First of all, the idea that being "built on >*a* (i.e. any old) theoretical model of software engineering" is per se >a good thing is a bit laughable. In the original posting I was trying to be brief. I have since explained about design by contract and the Eiffel exception mechanism. >Second, of course the Ada exception mechanism is build on such a model >also -- indeed it *is* a model itself! If I understand you correctly, the Ada exception mechanism looks like it does because that was how the designers designed it. My original point was that the Eiffel mechanism looks like it does because the theory of software contracting required it to work that way. Actually I don't believe that the Ada designers just threw together its exception mechanism without thinking long and hard, and I don't think you really meant to imply it. However the lack of an underlying theory on its use and contribution to program correctness definitely shows up. Ada exceptions seem to have been designed as a way of unwinding the execution stack without letting the programmer break the language. The only reason for including it in the language was that programmers often want to do this. Paul. --------------------------------+--------------------------------- Paul Johnson | You are lost in a maze of twisty Email: Paul@treetop.demon.co.uk | little standards, all different. paul.johnson@gecm.com |