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: a07f3367d7,735c710b5e547bad X-Google-Attributes: gida07f3367d7,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,ASCII-7-bit Received: by 10.180.96.42 with SMTP id dp10mr1297224wib.2.1343313821277; Thu, 26 Jul 2012 07:43:41 -0700 (PDT) Path: q11ni75688256wiw.1!nntp.google.com!volia.net!news2.volia.net!feed-A.news.volia.net!npeer.de.kpn-eurorings.net!npeer-ng0.de.kpn-eurorings.net!newsfeed.straub-nv.de!newsfeed.x-privat.org!aioe.org!.POSTED!not-for-mail From: "Dmitry A. Kazakov" Newsgroups: comp.lang.ada Subject: Re: Ada 2005 puzzle Date: Fri, 20 Jul 2012 09:20:10 +0200 Organization: cbb software GmbH Message-ID: <1agfifqlayl3y.1bp09z5i37ewk$.dlg@40tude.net> References: <1arp60wtxes8h$.1qs6bt732ztgp.dlg@40tude.net> <030cde76-7435-405d-9f12-ac7f730ecab8@googlegroups.com> <1f9q6vk5z2r3t$.1hayo9rmxfwu7$.dlg@40tude.net> Reply-To: mailbox@dmitry-kazakov.de NNTP-Posting-Host: 9A8bJrx4NhDLcSmbrb6AdA.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: 2012-07-20T09:20:10+02:00 List-Id: On Thu, 19 Jul 2012 21:22:27 -0500, Randy Brukardt wrote: > "Dmitry A. Kazakov" wrote in message > news:wd9m63dfb4hn.1feik6xrauuel$.dlg@40tude.net... >> On Thu, 19 Jul 2012 01:53:35 -0500, Randy Brukardt wrote: > ... >>> My personal feeling always was that this restriction was not acceptable, but >>> I couldn't explain why. Thus, I think it would be a good idea to send your >>> problem to Ada-Comment, so that the ARG can consider the problem. I'm pretty >>> sure that your example is reasonable in all respects, and I can't figure out >>> any good reason that you shouldn't be able to do it. >> >> ARG should concentrate on the real problem instead. Which is: >> >> It shall be possible to write a constructing function for any type derived >> from a type having a constructing function. > > The ARG isn't going to do anything unless real users (like yourself) report > reasonable examples that don't appear to be possible with the current rules. > Generally, we're not interested in *solutions* from the public (we're happy > to figure out the best solution for the language as a whole), but we are > interested in *problems*. The problem is just same it was when ARG invented limited aggregates and function returns. > So far as (most) of the ARG is aware, there is no problem with this feature, > and in the absence of reports of real problems I doubt that anything will > change. You could simply say that you agree/disagree with the principle. >> Why not to fix that too? Objects with the no-copies semantics are >> everywhere. Larger/complex the object become, less likely anybody would >> copy it. Clearly, Ada as a language for *large* projects shall support >> this. > > It can't be fixed; you almost always need copying in some circumstances. No, you never need copying except for scalar objects and marshaling. Remember that Ada is used for systems programming where all objects are strictly referential, some allocated at dedicated memory addresses. > (Claw could not work sanely with limited windows, and the implementation > effort to provide non-limited windows was insane. So neither option really > works -- I don't see a way to eliminate this.) It is clearly a very worrying language problem when GUI elements could not be made limited. But as you say, when nobody reports, you included, everything is fine. > And if you expect me to take your problems to the ARG, let me say that they > will have a lot more weight if they come from real Ada users and not just me > (or Adam, or Bob, all of whom are "tainted" as implementors). You mean ARG is unaware that constructing functions cannot be written in the cases like presented? Or that they would not believe you or Bob telling so? -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de