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 10.36.200.2 with SMTP id w2mr13012162itf.6.1473714726811; Mon, 12 Sep 2016 14:12:06 -0700 (PDT) X-Received: by 10.157.4.137 with SMTP id 9mr1070366otm.3.1473714726776; Mon, 12 Sep 2016 14:12:06 -0700 (PDT) Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!news.eternal-september.org!feeder.eternal-september.org!news.glorb.com!x192no819849itb.0!news-out.google.com!b4ni17378iti.0!nntp.google.com!u18no659775ita.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Mon, 12 Sep 2016 14:12:06 -0700 (PDT) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=2601:191:8302:3f70:5985:2c17:9409:aa9c; posting-account=fdRd8woAAADTIlxCu9FgvDrUK4wPzvy3 NNTP-Posting-Host: 2601:191:8302:3f70:5985:2c17:9409:aa9c References: User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: Subject: Re: Class-wide types algebra From: rieachus@comcast.net Injection-Date: Mon, 12 Sep 2016 21:12:06 +0000 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Xref: news.eternal-september.org comp.lang.ada:31757 Date: 2016-09-12T14:12:06-07:00 List-Id: On Monday, September 12, 2016 at 4:26:24 PM UTC-4, Dmitry A. Kazakov wrote: > Presently class-wide types are singletons. I would propose to extend=20 > that to call-wide expressions, namely conjunction in all places where=20 > T'Class is expected. e.g. >=20 The problem may be worth solving, but I dread the number of cases that woul= d have to be considered to come up with workable rules. A more restricted = case, which should deal with the issue would be to allow "T'Class is in R'C= lass;" where R is an interface, or an ancestor of T'Class. Why the second case? The real issue seems to be visibility. You have an i= nterface, and a type which could/should be a member, but the declaration is= more deeply nested. (There would still need to be some magic so that the = lifetime of T'Class is the same as R'Class. Or better, just a rule that re= quires them to have the same lifetime from other rules.)