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 autolearn=unavailable autolearn_force=no version=3.4.4 Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!feeder.eternal-september.org!nntp-feed.chiark.greenend.org.uk!ewrotcd!newsfeed.xs3.de!io.xs3.de!news.jacob-sparre.dk!franka.jacob-sparre.dk!pnx.dk!.POSTED.rrsoftware.com!not-for-mail From: "Randy Brukardt" Newsgroups: comp.lang.ada Subject: Re: some trivial questions? Date: Mon, 27 Nov 2017 18:19:53 -0600 Organization: JSA Research & Innovation Message-ID: References: <6a5368c5-f015-4dcb-9291-e77b40fa1bf1@googlegroups.com> Injection-Date: Tue, 28 Nov 2017 00:19:53 -0000 (UTC) Injection-Info: franka.jacob-sparre.dk; posting-host="rrsoftware.com:24.196.82.226"; logging-data="13428"; mail-complaints-to="news@jacob-sparre.dk" X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2900.5931 X-RFC2646: Format=Flowed; Response X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.7246 Xref: reader02.eternal-september.org comp.lang.ada:49199 Date: 2017-11-27T18:19:53-06:00 List-Id: "Dmitry A. Kazakov" wrote in message news:ov61c7$o80$1@gioia.aioe.org... > On 23/11/2017 01:19, Randy Brukardt wrote: > >> I agree with your points, but how do you prove compatibility of whatever >> model is adopted? Given that Ada is currently defined with English >> wording, >> it is very hard to prove if any change is compatible other than the most >> trivial ones. > > Is it really necessary? I mean it is not different from the promises each > compiler vendors gives. We trust that Ada standard is possible to > implement on a machine X. A more fundamental language core is kind of > machine Y. Nothing to prove, actually. It's necessary to have some sort of assurance of equivalence. Otherwise the forces of FUD (which includes pretty much everyone at some point or other) will have an open field and it is unlikely anything substantial would get adopted. The form of that assurance probably doesn't matter as much. For instance, if you had a trusted implementation of the existing language (which we can assume is true) and a trusted implementation of the revised language, one could compare what they do on a sufficiently large set of examples (the ACATS + additional source would certainly work). But the problem here is getting a trusted implementation of the revised rules -- that's either a lot of work or a lot of handwaving (neither of which is going to engender much confidence). There probably are other possibilities. But there's no chance of a change without some sort of assurance. Randy.