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: 103376,2ff5c149712ec0eb X-Google-Attributes: gid103376,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news2.google.com!border1.nntp.dca.giganews.com!nntp.giganews.com!newsfeed00.sul.t-online.de!newsfeed01.sul.t-online.de!t-online.de!newsfeed.arcor.de!newsspool2.arcor-online.net!news.arcor.de.POSTED!not-for-mail From: "Dmitry A. Kazakov" Subject: Re: Ada Interfaces and the Liskov Substitution Principle 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: <1179953657.839272.160320@a26g2000pre.googlegroups.com> <1179991769.376381.252010@m36g2000hse.googlegroups.com> <12h6mi42jcha0.7f9vfsnihjwr$.dlg@40tude.net> <1180003336.1163.29.camel@kartoffel> <83abvs7sa9.fsf@hod.lan.m-e-leypold.de> <465aa5ba$0$23147$9b4e6d93@newsspool1.arcor-online.net> <465b6606$0$10188$9b4e6d93@newsspool4.arcor-online.net> <1180445634.5664.23.camel@kartoffel> <39viqigjwhrb$.gz67xvpinyjr.dlg@40tude.net> <465c9077$0$23135$9b4e6d93@newsspool1.arcor-online.net> <1180531107.16197.30.camel@kartoffel> <1180611880.16197.59.camel@kartoffel> <46600538$0$6392$9b4e6d93@newsspool2.arcor-online.net> Date: Fri, 1 Jun 2007 15:07:20 +0200 Message-ID: NNTP-Posting-Date: 01 Jun 2007 15:05:01 CEST NNTP-Posting-Host: b7fd6a98.newsspool2.arcor-online.net X-Trace: DXC=S_J2V@jaWWO0YVY]kmLTlDA9EHlD;3YcB4Fo<]lROoRA8kFO0L;P>B@YflO X-Complaints-To: usenet-abuse@arcor.de Xref: g2news1.google.com comp.lang.ada:16025 Date: 2007-06-01T15:05:01+02:00 List-Id: On Fri, 01 Jun 2007 13:41:11 +0200, Georg Bauhaus wrote: > Dmitry A. Kazakov wrote: >> On Thu, 31 May 2007 13:44:40 +0200, Georg Bauhaus wrote: >> >>> When they write, >>> a := a + 1; >>> the may not be thinking about a commutative group of integers, >> >> It is no matter what they think, it matters what they write. > > This seems a contradiction to what you say below, about basing > solutions on technology/science. Why? This basing is about an ability to communicate the solution = using some formalism (like one of mathematics). > OTOH, when we started from LSP as a design principle, we started > from a guiding principle, I think. Which indicates the actual problem... > This means programmers who > do not accidentally write following the principle. So what are > the principles they have actually been following when > producing a solution that works even though the math behind it > is not known/mainstream/acceptable? LSP as a vague principle is just useless and confusing. It results in countless silly discussions about Circles and Ellipses. Similarly, one could discuss designs of a perpetual-motion machine. A minimal formalism would immediately clarify it. >>>> No, the point is that they cannot be mapped (implemented), this is why >>>> mathematics is necessary to describe what is going on, because no machine >>>> would be sufficient for that. >>> But what is actually going on in /dev/random? >> >> Realization of a random variable. > > What is realization in a machine if not an implementation? Implementation of a realization is a number (stored/computed). Note the difference between a number and a random variable, hence the implementations of. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de