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=unavailable autolearn_force=no version=3.4.4 X-Received: by 10.224.172.68 with SMTP id k4mr13652766qaz.1.1376080240639; Fri, 09 Aug 2013 13:30:40 -0700 (PDT) X-Received: by 10.50.62.20 with SMTP id u20mr305870igr.11.1376080240577; Fri, 09 Aug 2013 13:30:40 -0700 (PDT) Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!news.eternal-september.org!news.eternal-september.org!feeder.eternal-september.org!v102.xanadu-bbs.net!xanadu-bbs.net!news.glorb.com!f7no1741461qan.0!news-out.google.com!he10ni1155qab.0!nntp.google.com!fx3no1827306qab.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Fri, 9 Aug 2013 13:30:40 -0700 (PDT) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=66.126.103.122; posting-account=RxNzCgoAAACA5KmgtFQuaU-WaH7rjnAO NNTP-Posting-Host: 66.126.103.122 References: <19fr4wmxmen$.gjbias2fj461$.dlg@40tude.net> <72539e4c-dddd-40e4-82e8-14c4f2016ccc@googlegroups.com> <1656c260-4488-42d8-8d31-0fde538470ee@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: <6ee1653b-7232-4a32-940d-25bb556a19d4@googlegroups.com> Subject: Re: GNAT GPL 2013 bug? From: Adam Beneschan Injection-Date: Fri, 09 Aug 2013 20:30:40 +0000 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Xref: news.eternal-september.org comp.lang.ada:16741 Date: 2013-08-09T13:30:40-07:00 List-Id: On Friday, August 9, 2013 1:05:54 PM UTC-7, Robert A Duff wrote: > Adam Beneschan writes: >=20 > > It was probably OK, though, if the only effect was that a call to P > > might actually call some other P in some other package. >=20 > For clients outside the package? I don't think that would be OK. > But I don't see how it can happen, since you can't do 'Class on > the private view. Yes, that's a good point. It doesn't seem particularly useful to declare an untagged private type who= se full type is something that only the package, or a child package, could = derive types from. Unfortunately, Ada doesn't have the concept of a "tagge= d type from which nothing can be derived". That concept would be useful so= that one could declare a type derived from Ada.Finalization.Controlled or = some other tagged type, but declare that no other types may be derived from= it, so that *new* operations declared for the type wouldn't have to be dis= patching. Then the language could decree that an untagged private type cou= ldn't be completed by a tagged type unless it were underivable, and then th= e dispatching issue wouldn't arise at all. (And one could declare operatio= ns of more than one such type, since they wouldn't be dispatching operation= s; this is what led to the original AI95-183 issue.) I wish I or someone e= lse had thought of that back in 1997. -- Adam