From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.5-pre1 (2020-06-20) on ip-172-31-74-118.ec2.internal X-Spam-Level: X-Spam-Status: No, score=-1.9 required=3.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.5-pre1 Path: eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail From: "J-P. Rosen" Newsgroups: comp.lang.ada Subject: Re: Question on variant/discriminated records Date: Thu, 31 Dec 2020 11:52:23 +0100 Organization: Adalog Message-ID: References: <3c1a2fe9-e8f2-401f-870d-aecd9e0f9c69n@googlegroups.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Date: Thu, 31 Dec 2020 10:52:24 -0000 (UTC) Injection-Info: reader02.eternal-september.org; posting-host="f14b7380425b11c1cdd1c897d16d7b15"; logging-data="8371"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19gKjINj1n9Yo7zCFxxJdKS" User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 Cancel-Lock: sha1:w/N6WVKWVg8xFY/nCAvA004EnUA= In-Reply-To: <3c1a2fe9-e8f2-401f-870d-aecd9e0f9c69n@googlegroups.com> Content-Language: fr Xref: reader02.eternal-september.org comp.lang.ada:60983 List-Id: Le 31/12/2020 à 11:38, reinert a écrit : > Assume the following program and change "y1" to "y". > > procedure test3 is > type options1_Type is (a,b,c); > type rec1_Type(option1 : options1_Type) is > record > x : Float; > case option1 is > when a => null; > when b => y : float; > when c => y1,z : float; > end case; > end record; > begin > null; > end test3; > > My compiler does not like this change. I find it not natural to invent > a new name "y1" instead of "y". What should I do? > Yes, it is a rule that identifiers in parallel branches cannot be identical. And there is a good reason for this: in Ada, when you access a component, the compiler checks that the component exists, according to the value of the discriminant. Assume that you write (if V is of type rec1_type): V.Y := 1.0; If both components are named Y, should the discriminant be B or C? -- J-P. Rosen Adalog 2 rue du Docteur Lombard, 92441 Issy-les-Moulineaux CEDEX Tel: +33 1 45 29 21 52, Fax: +33 1 45 29 25 00 http://www.adalog.fr