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!aioe.org!.POSTED!not-for-mail From: "Dmitry A. Kazakov" Newsgroups: comp.lang.ada Subject: Re: [Newbie] doubly constrained array, dumb question Date: Tue, 27 Feb 2018 18:37:46 +0100 Organization: Aioe.org NNTP Server Message-ID: References: <62f83fe5-15d6-41cf-952f-bc3cb077d42f@googlegroups.com> <473f9b1a-6466-4745-9041-107f54062cf2@googlegroups.com> NNTP-Posting-Host: yZRtMzZmKCYxZ5GHo5ZYiA.user.gioia.aioe.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Complaints-To: abuse@aioe.org User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 Content-Language: en-US X-Notice: Filtered by postfilter v. 0.8.3 Xref: reader02.eternal-september.org comp.lang.ada:50688 Date: 2018-02-27T18:37:46+01:00 List-Id: On 2018-02-27 18:08, G. B. wrote: > Dmitry A. Kazakov wrote: >> On 27/02/2018 02:29, Mehdi Saada wrote: >> >>> For 8: a class has any sense at all only if there's no dispatching to an >>> inexistent method, and your forbidding some methods would do the same, raise an exception. >> >> Not in the case of subtypes. For example, the "class" Integer of which >> Positive is a "member" > > Or a subset, rather? All x in Positive are such that > x in Integer, but Positive is not an element of Integer. Subsetting is an "implementation" to subclassing. The latter also inherits operations as Positive does. Subsetting is silent about operations. Note that even unary minus is inherited and kind of works, because Constraint_Error is a part of the contract. That is a way around LSP ... -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de