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,b78c363353551702 X-Google-NewGroupId: yes X-Google-Attributes: gida07f3367d7,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Received: by 10.68.228.227 with SMTP id sl3mr13153659pbc.5.1340630349126; Mon, 25 Jun 2012 06:19:09 -0700 (PDT) Path: l9ni18276pbj.0!nntp.google.com!news1.google.com!goblin1!goblin2!goblin.stu.neva.ru!aioe.org!.POSTED!not-for-mail From: "Dmitry A. Kazakov" Newsgroups: comp.lang.ada Subject: Re: about the new Ada 2012 pre/post conditions Date: Mon, 25 Jun 2012 15:19:11 +0200 Organization: cbb software GmbH Message-ID: <21wn0ooltm4q.fvk0lmtoro3f$.dlg@40tude.net> References: <1hgo6aks03zy.by4pq4xbjsgf$.dlg@40tude.net> <1jvy3elqtnd1j.1sjbk32evhp1f$.dlg@40tude.net> <1oih2rok18dmt.avbwrres5k12.dlg@40tude.net> <4fe59ea0$0$9502$9b4e6d93@newsspool1.arcor-online.net> <1mkp7fzlk1b0y.1ueinfjn48fcy$.dlg@40tude.net> <4fe72b6b$0$9504$9b4e6d93@newsspool1.arcor-online.net> <1bbvp3ghpjb5s.1go1s1qvcmagh$.dlg@40tude.net> <4fe76fad$0$9507$9b4e6d93@newsspool1.arcor-online.net> <1jt8vhzxfrv2i.eohce4d3rwx1$.dlg@40tude.net> <4fe83aaa$0$6624$9b4e6d93@newsspool2.arcor-online.net> <1pkfv0tiod3rn$.onx6dmaa3if9$.dlg@40tude.net> <4fe85beb$0$6638$9b4e6d93@newsspool2.arcor-online.net> Reply-To: mailbox@dmitry-kazakov.de NNTP-Posting-Host: FbOMkhMtVLVmu7IwBnt1tw.user.speranza.aioe.org Mime-Version: 1.0 X-Complaints-To: abuse@aioe.org User-Agent: 40tude_Dialog/2.0.15.1 X-Notice: Filtered by postfilter v. 0.8.2 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Date: 2012-06-25T15:19:11+02:00 List-Id: On Mon, 25 Jun 2012 14:39:06 +0200, Georg Bauhaus wrote: > On 25.06.12 13:54, Dmitry A. Kazakov wrote: > >>> Indeed, it helps to remember that logicians and mathematicians >>> have learned that logic and mathematics cannot justify themselves. >> >> No, they never ever did that. > > They tried, though. I didn't even say that they did. > > Frege thought, for some time, that he had done. > Russel sent a correction. Hilbert did not give up, though: Not at all. All three used axiomatic approach. None of them would ever seek to justify logic by means of logic. >>> We have to do something. DbC is something. Better than nothing. >> >> Is SPARK nothing? > > Try > > new Data'(Size => More_than_4k); How does this make SPARK null and void? >> Is strong typing nothing? > > Until Ada 2012, there was nothing in addition to the strong type > system of Ada 2005. And the point is? Some hidden Ada version between 2005 and 2012? >> But you seemingly did not read what I wrote earlier. There is either #1 or >> #2. > > I have tried to explain that neither #1 nor #2 are applicable > because they assume applicability of exhaustive formal analysis > to general program design (not programs). So #2 does not apply, I missed where you agreed with me on that. Ergo, Ada 2012 preconditions are not contract (not #2). Please confirm this, and we will proceed to #1 and whether (not #2 is equivalent to #1). >>> DbC is a best effort thing like every system building effort. >> >> How are you going to prove this, if "DbC" contradicts logic itself? > > A program that is known to be covered entirely by logic > is really an exception. Please, show this without logic. > Proving things in a DbC framework is similar to proving things > with the help of more than Ada, as is done when using SPARK. No. You claimed that what you call DbC does not obey laws of logic. I am eager to learn how are you going to "prove things" without these laws. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de