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=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM autolearn=ham autolearn_force=no version=3.4.4 X-Google-Thread: a07f3367d7,39579ad87542da0e X-Google-Attributes: gida07f3367d7,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,UTF8 X-Received: by 10.180.85.5 with SMTP id d5mr1647071wiz.0.1368583637538; Tue, 14 May 2013 19:07:17 -0700 (PDT) Path: p18ni110084wiv.0!nntp.google.com!feeder1.cambriumusenet.nl!feed.tweaknews.nl!194.109.133.86.MISMATCH!newsfeed.xs4all.nl!newsfeed3.news.xs4all.nl!xs4all!border4.nntp.ams.giganews.com!border2.nntp.ams.giganews.com!border2.nntp.dca.giganews.com!nntp.giganews.com!newsfeed.news.ucla.edu!nrc-news.nrc.ca!News.Dal.Ca!news.litech.org!news.stack.nl!aioe.org!.POSTED!not-for-mail From: =?utf-8?Q?Yannick_Duch=C3=AAne_=28Hibou57?= =?utf-8?Q?=29?= Newsgroups: comp.lang.ada Subject: Re: Seeking for papers about tagged types vs access to subprograms Date: Fri, 10 May 2013 14:40:00 +0200 Organization: Ada @ Home Message-ID: References: <1vrhb7oc4qbob$.q02vuouyovp5$.dlg@40tude.net> <19lrzzbgm77v6.1dzpgqckptaj6.dlg@40tude.net> <1bfhq7jo34xpi.p8n2vq6yjsea.dlg@40tude.net> <12gn9wvv1gwfk.10ikfju4rzmnj.dlg@40tude.net> <1cir6d72wemw.qxx9mozot7hl.dlg@40tude.net> NNTP-Posting-Host: uGUognJZXpdb++Da0QvCqg.user.speranza.aioe.org Mime-Version: 1.0 X-Complaints-To: abuse@aioe.org User-Agent: Opera Mail/12.15 (Linux) X-Notice: Filtered by postfilter v. 0.8.2 Content-Type: text/plain; charset=utf-8; format=flowed; delsp=yes Content-Transfer-Encoding: Quoted-Printable Date: 2013-05-10T14:40:00+02:00 List-Id: Le Fri, 10 May 2013 14:15:35 +0200, Dmitry A. Kazakov = a =C3=A9crit: >> If so, that's indeed be true, as the program can then >> be derived, but there is not a single possible derivation, there are >> typically multiple solutions, so the program still requires human >> intervention to be generated. > > Human intervention is needed to handle the semantics, not because of > multiplicity of implementations. You could choose them randomly. You can't choose randomly, the program must have runtime properties as = well. Another case, is with what in the domain is known as shallow embedding; = = this means you model the target language (or a subset of it or some = constructs of it) in the terms of the formal language, then write the = program in the target language indirectly writing proof involving these = = constructs (I mean, the ones representing the target language). Then, yo= u = ends with a program in the target language with syntactic transformation= s. = There is another way to do, which is named deep embedding, but I don't = really know it and don't like it anyway. In all cases (either one of the three), the target language is always = there, it just appears at different stage, sometime immediately from the= = start, sometime only at the final stage. >> With this kind of formal system, you typically go from a specificatio= n = >> and >> derives a program. > > That won't work. If you can derive the program (in the object language= ) = > you don't need the object language anymore. You really can't say =E2=80=9Cit won't work=E2=80=9D, since there are pe= ople who already = do this, and that works, and that's not restricted to =E2=80=9Cacademic = = experiments=E2=80=9D. The object language is still needed, as further mo= re, Ada = had even been famously involved as a target language with the B formal = method (whose target languages may be either Ada or C). I know it was us= ed = in france for the software of some subway lines in Paris (they used B an= d = Ada 95 if I'm not wrong). This was from specification to Ada, and not fr= om = Ada to proof (as SPARK do). -- = =E2=80=9CSyntactic sugar causes cancer of the semi-colons.=E2=80=9D [1] =E2=80=9CStructured Programming supports the law of the excluded muddle.= =E2=80=9D [1] [1]: Epigrams on Programming =E2=80=94 Alan J. =E2=80=94 P. Yale Univers= ity