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: about inheritance of subtypes and entities (such as constants) related to a type in the same package Date: Wed, 30 May 2018 10:13:57 +0200 Organization: Aioe.org NNTP Server Message-ID: References: NNTP-Posting-Host: MyFhHs417jM9AgzRpXn7yg.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/52.8.0 X-Notice: Filtered by postfilter v. 0.8.3 Content-Language: en-US Xref: reader02.eternal-september.org comp.lang.ada:52779 Date: 2018-05-30T10:13:57+02:00 List-Id: On 2018-05-30 12:12 AM, Randy Brukardt wrote: > Changing inheritance would be wildly incompatible, so I don't think there is > any chance of that. We can just add another method of inheritance as it has been successfully done with tagged types. We need interface inheritance from a concrete type with user-defined conversion operations to support substitution and class-wide values in the form (tag, value). BTW, the old inheritance has a very powerful and very useful mechanism of cloning types: type S is new T; There is much reason for both methods to coexist. Presently in order to be able to clone tagged type I must place its root type in a generic, which is huge overkill. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de