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: 103376,585fd78267abd80c X-Google-Attributes: gid103376,domainid0,public,usenet X-Google-Language: ENGLISH,UTF8 Path: g2news2.google.com!news4.google.com!feeder.news-service.com!feeder.news-service.com!newsfeed-fusi2.netcologne.de!newsreader2.netcologne.de!news.netcologne.de!newsfeed-hp2.netcologne.de!newsfeed.arcor.de!newsspool1.arcor-online.net!news.arcor.de.POSTED!not-for-mail From: "Dmitry A. Kazakov" Subject: Re: On pragma Precondition etc. Newsgroups: comp.lang.ada User-Agent: 40tude_Dialog/2.0.15.1 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Reply-To: mailbox@dmitry-kazakov.de Organization: cbb software GmbH References: <4889886d$0$18827$9b4e6d93@newsspool2.arcor-online.net> <6etsi6F8mbmbU2@mid.individual.net> <488efc8d$1@news.post.ch> <488f26e8$0$20705$9b4e6d93@newsspool4.arcor-online.net> <1668bcqbkwlun$.mzzrx5m5ug2t$.dlg@40tude.net> <488f3d67$0$20703$9b4e6d93@newsspool4.arcor-online.net> <13nqxvysv2w75.bpxxsup39g9u$.dlg@40tude.net> <489032df$0$1076$9b4e6d93@newsspool3.arcor-online.net> Date: Wed, 30 Jul 2008 15:56:14 +0200 Message-ID: NNTP-Posting-Date: 30 Jul 2008 15:56:14 CEST NNTP-Posting-Host: 07e33552.newsspool4.arcor-online.net X-Trace: DXC=6Q;mf7mOTR\YI9]OHn9o5^4IUK\BH3YRdg`:chfkgR4L[8_b@^i?T X-Complaints-To: usenet-abuse@arcor.de Xref: g2news2.google.com comp.lang.ada:7112 Date: 2008-07-30T15:56:14+02:00 List-Id: On Wed, 30 Jul 2008 11:22:38 +0200, Georg Bauhaus wrote: > Dmitry A. Kazakov schrieb: >> On Tue, 29 Jul 2008 17:55:18 +0200, Georg Bauhaus wrote: > >>> What if one precondition states a relation between two suprogram >>> parameters, or between properties of two suprogram parameters? >> >> This case is equivalent to full multiple dispatch. Ada does not have it. If >> it had multiple dispatch then it would clearer how to deal with the >> corresponding contracts (=conditions). > > Design by Contract™ has been made to be a *design* tool. This applies to everything. > It starts from the simple truth that we will likely think > about pre/post of subprograms once the language suggests we > can. The checking mechanism supports us by checking our > assumptions as good as it possibly can do this. > > DbC is not meant to be reduced to a static proof tool. OK, that is another discussion. No, correctness is a property of a given program. As such it is static per the definition of <=> correctness of P may not depend on any of the run-time states of P <=> P cannot be correct in one of its states and incorrect in another <=> a correct P traverses only the states where P is correct, etc. Contracts *when* thought as statements about the correctness are static. I don't care about the meaning of DbC™ as a registered trademark. I care about Ada. (:-)) -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de