From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on ip-172-31-65-14.ec2.internal X-Spam-Level: X-Spam-Status: No, score=-1.9 required=3.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.6 Path: eternal-september.org!reader02.eternal-september.org!aioe.org!esY63sJc+00ALEoUyxrwTg.user.46.165.242.91.POSTED!not-for-mail From: "Dmitry A. Kazakov" Newsgroups: comp.lang.ada Subject: Re: Discriminants or Constructor Function for Limited Types Date: Tue, 10 May 2022 08:18:21 +0200 Organization: Aioe.org NNTP Server Message-ID: References: <0b4ddd38-1f19-44fe-acd9-43a316ec9d29n@googlegroups.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Info: gioia.aioe.org; logging-data="54197"; posting-host="esY63sJc+00ALEoUyxrwTg.user.gioia.aioe.org"; mail-complaints-to="abuse@aioe.org"; User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 X-Notice: Filtered by postfilter v. 0.9.2 Content-Language: en-US Xref: reader02.eternal-september.org comp.lang.ada:63840 List-Id: On 2022-05-10 06:48, Randy Brukardt wrote: > "Dmitry A. Kazakov" wrote in message > news:t57vgs$4su$1@gioia.aioe.org... > ... >> No they do not. The goal is to eliminate non-functional states. Things >> like closed file, uninitialized variable, null pointer etc are artifacts >> of the design. There is nothing in the physical world that requires them. > > Most such things are artifacts of the target system. Closed files and closed > windows happen because of events that occur outside of your program. You > can't design them away. It is a totally unrealistic scenario. If there exist a way to close a handle from outside then only in the system kernel. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de