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=-0.3 required=5.0 tests=BAYES_00, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Thread: 103376,24d7acf9b853aac8 X-Google-NewGroupId: yes X-Google-Attributes: gida07f3367d7,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news3.google.com!feeder3.cambriumusenet.nl!feed.tweaknews.nl!193.201.147.68.MISMATCH!feeder.news-service.com!newsfeed.straub-nv.de!noris.net!newsfeed.arcor.de!newsspool3.arcor-online.net!news.arcor.de.POSTED!not-for-mail From: "Dmitry A. Kazakov" Subject: Re: S-expression I/O in Ada Newsgroups: comp.lang.ada User-Agent: 40tude_Dialog/2.0.15.1 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Reply-To: mailbox@dmitry-kazakov.de Organization: cbb software GmbH References: <547afa6b-731e-475f-a7f2-eaefefb25861@k8g2000prh.googlegroups.com> <984db477-973c-4a66-9bf6-e5348c9b95f2@n19g2000prf.googlegroups.com> <46866b8yq8nn$.151lqiwa0y2k6.dlg@40tude.net> <13b07f2c-2f35-43e0-83c5-1b572c65d323@y11g2000yqm.googlegroups.com> <13tpf7ya3evig$.h05p3x08059s$.dlg@40tude.net> <1omt2srxtpsga$.c3hbxthzo6cf.dlg@40tude.net> <1e4cch2df5uyb.18brqdd16dhv8.dlg@40tude.net> <14y70ke8am9qw$.2csc9eflvigg.dlg@40tude.net> <4c601b5c$0$7665$9b4e6d93@newsspool1.arcor-online.net> <9czktq4ntzq7.fhbsnocx0x4w$.dlg@40tude.net> <4c6030e3$0$7659$9b4e6d93@newsspool1.arcor-online.net> Date: Mon, 9 Aug 2010 22:40:07 +0200 Message-ID: <1lnii9xhuibax$.1a88c1xje8p09.dlg@40tude.net> NNTP-Posting-Date: 09 Aug 2010 22:40:07 CEST NNTP-Posting-Host: 4ebaf617.newsspool2.arcor-online.net X-Trace: DXC=5JP[24^\CIh]l@YUW5NBknA9EHlD;3Ycb4Fo<]lROoRa8kFj`dQ]b X-Complaints-To: usenet-abuse@arcor.de Xref: g2news1.google.com comp.lang.ada:13018 Date: 2010-08-09T22:40:07+02:00 List-Id: On Mon, 09 Aug 2010 18:46:27 +0200, Georg Bauhaus wrote: > When good average programmers write programs, are they > structuring their data by conscious use of mathematical > structures like groups? I don't think so. They do it unconsciously. It is no matter if we do it willingly or not, there is only one right way. > It is these programmers that need to know the meaning > of "+". This seems vital. Example: C's "definition" of the data > type int and its "+" operation demonstrates what happens > if you are optimistic about mastery of C's "+" basics. I don't see your point. It is broken in C because it contradicts to the mathematical meaning of. So what do you propose? To keep it broken? Because people better understand broken stuff? They don't. > I think Bob's example involving "not" of a mod 3 variable > shows a related issue. (And will be included in a test of advanced > Ada knowledge? ;-P) Because *even* *though* there is a precise > mathematical definition (LRM) of what "not" should return, > referring to some overly complex set of rules explaining > the operation is hardly convincing? Consistency of the language > (with itself) is only an excuse, then. Nope, "not" is just broken for mod 3. It is a lattice operation, it has nothing to do with rings. The problem with modular types is that one tried to build a submarine which could fly. It sails like an aircraft and flies like a ship. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de