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 Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!mx02.eternal-september.org!feeder.eternal-september.org!aioe.org!.POSTED!not-for-mail From: "Dmitry A. Kazakov" Newsgroups: comp.lang.ada Subject: Re: {Pre,Post}conditions and side effects Date: Sat, 9 May 2015 07:47:06 +0200 Organization: cbb software GmbH Message-ID: <11lbvusnpmkxa$.1wtukr2t396em$.dlg@40tude.net> References: <2430252d-52a1-4609-acef-684864e6ca0c@googlegroups.com> <0a718b39-ebd3-4ab5-912e-f1229679dacc@googlegroups.com> <9ee5e186-5aaa-4d07-9490-0f9fdbb5ca18@googlegroups.com> <87tww5296f.fsf@adaheads.sparre-andersen.dk> <871tj9dp5b.fsf@theworld.com> <121ytg16vbxsk$.18dxo1h7daxty.dlg@40tude.net> <12gipcoheoucz.15ckvrgi11h3a.dlg@40tude.net> Reply-To: mailbox@dmitry-kazakov.de NNTP-Posting-Host: evoS9sCOdnHjo0GRLLMU1Q.user.speranza.aioe.org Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Complaints-To: abuse@aioe.org User-Agent: 40tude_Dialog/2.0.15.1 X-Notice: Filtered by postfilter v. 0.8.2 Xref: news.eternal-september.org comp.lang.ada:25786 Date: 2015-05-09T07:47:06+02:00 List-Id: On Fri, 8 May 2015 18:24:28 -0500, Randy Brukardt wrote: > "Dmitry A. Kazakov" wrote in message > news:12gipcoheoucz.15ckvrgi11h3a.dlg@40tude.net... >> On Thu, 7 May 2015 14:01:34 -0500, Randy Brukardt wrote: > ... >> The point is that these are fundamentally different things. Correctness is >> outside. Behavior is inside. > > The only thing that matters is behavior. I care about correctness of the > behavior Everybody does. The issues are 1. what correctness is 2. how correctness can be addressed at the language level Effectively you say that you don't bother with #2. > (which for Ada, mainly boils down to how and when exceptions are > possible). Don't you care if 2+2 gives 4 in Ada? > There is no such thing as a correct program (or part of a program) outside > of its behavior. So long correctness is defined in terms of behavior, there is no problem to have correct programs. > It's madness to even talk about it. Programming languages > aren't defined well enough for the concept to be remotely meaningful. You don't need it well defined. A program can be correct even if written in C or Basic. Proving correct /= being correct. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de