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: a07f3367d7,4ce5890331a5b529 X-Google-Attributes: gida07f3367d7,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news2.google.com!goblin1!goblin2!goblin.stu.neva.ru!newsfeed01.sul.t-online.de!t-online.de!newsfeed01.chello.at!newsfeed.arcor.de!newsspool2.arcor-online.net!news.arcor.de.POSTED!not-for-mail From: "Dmitry A. Kazakov" Subject: Re: Discriminants of tagged types Newsgroups: comp.lang.ada User-Agent: 40tude_Dialog/2.0.15.1 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Reply-To: mailbox@dmitry-kazakov.de Organization: cbb software GmbH References: <14314714-e92c-4036-9cbb-da8e72489261@h7g2000yqn.googlegroups.com> Date: Wed, 27 Oct 2010 15:19:46 +0200 Message-ID: <1bytu43t5bi8y.1t3tebqbls31j.dlg@40tude.net> NNTP-Posting-Date: 27 Oct 2010 15:19:46 CEST NNTP-Posting-Host: 2b22a1b7.newsspool2.arcor-online.net X-Trace: DXC=eN`jjD`Eff_PU8j_I0DN6_A9EHlD;3YcR4Fo<]lROoRQ8kF3fHA7eQ X-Complaints-To: usenet-abuse@arcor.de Xref: g2news1.google.com comp.lang.ada:14828 Date: 2010-10-27T15:19:46+02:00 List-Id: On Wed, 27 Oct 2010 05:34:26 -0700 (PDT), Ludovic Brenta wrote: > The tag has no default value and cannot have one, for that would > allow changing the type of an object at run time (through assignment > of an aggregate). No, it would not because you cannot assign a value of another type. > Therefore, *additional* discriminants cannot have default values either. I think there were concerns about implementation difficulties when the derived type adds new discriminants and/or defines some inherited ones. Anyway the limitation is indeed annoying. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de