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,FREEMAIL_FROM autolearn=ham autolearn_force=no version=3.4.4 X-Google-Thread: a07f3367d7,73cb216d191f0fef X-Google-Attributes: gida07f3367d7,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,UTF8 X-Received: by 10.224.189.78 with SMTP id dd14mr1197784qab.0.1363993548420; Fri, 22 Mar 2013 16:05:48 -0700 (PDT) X-Received: by 10.50.236.40 with SMTP id ur8mr423728igc.6.1363993548164; Fri, 22 Mar 2013 16:05:48 -0700 (PDT) Path: k8ni11100qas.0!nntp.google.com!ca1no2143031qab.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Fri, 22 Mar 2013 16:05:47 -0700 (PDT) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=69.20.190.126; posting-account=lJ3JNwoAAAAQfH3VV9vttJLkThaxtTfC NNTP-Posting-Host: 69.20.190.126 References: <18r2kop6fyozu.tctrjnghfxqs.dlg@40tude.net> <1wv3p3nrtejfk$.bwebhg9agt0l.dlg@40tude.net> <514874d3$0$6628$9b4e6d93@newsspool2.arcor-online.net> <1o60gooo8xvba$.1ei9cebb07zek$.dlg@40tude.net> <514897bd$0$6641$9b4e6d93@newsspool2.arcor-online.net> <1oqwvcemo8dha$.hevuedtz8eze.dlg@40tude.net> <14aijp8ckzahf$.1ilfm1nw6qgyt$.dlg@40tude.net> <1xg9wka6slgit.1q0leacagdeuv.dlg@40tude.net> <10cliooad0uk.1prxobehp9yr0.dlg@40tude.net> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: Subject: Re: Is this expected behavior or not From: Shark8 Injection-Date: Fri, 22 Mar 2013 23:05:48 +0000 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Date: 2013-03-22T16:05:47-07:00 List-Id: On Friday, March 22, 2013 4:18:02 PM UTC-6, J-P. Rosen wrote: > Le 22/03/2013 15:54, Dmitry A. Kazakov a =EF=BF=BDcrit : >=20 > >> > Therefore, > >> > you can't translate Ada's subtypes into the terms of ADT. > > I just did it. >=20 > And that's where everybody (including those who designed/maintain the > language) thinks you are wrong. I think I can see Dmitry's point but, like you said earlier, it's a matter = of definitions if you'll allow me a stab at Dmitry->everybody-else translat= ion it's like this: The notion of TYPE is two sets: {v | values of the type} & {o | operations = on that type} Given that a "subtype" may have different valid values 'v' than its parent = type (e.g. Positive has restricted valid-values than Integer) then he wishe= s to call it a TYPE. Everyone else is saying that Ada's notion of "subtype" contains a third set= , a subset of of v {valid | the valid values}, and that v /=3D valid is not= reason to panic and call "subtype" a true type simply because there are [p= ossibly] values contained in its parent's v that are not present in the sub= type's valid. So the problem is in the conflation of "values" and "valid values" of some = [sub]type. ---------------------------------------------------------------- That all is, IMO, a problem exacerbated in CS by the overpowering prevalenc= e of "extension" in the "Object Oriented" paradigm; this even to the point = that some of the new CS graduates [superficially] seem utterly unable to gr= asp the usefulness/utility of excluding values. {Though the attitude is sur= prising given the math/logic background/history of CS: where one routinely = excludes things as a premise.} -- It's so odd that the idea of subtyping is= so rare that it becomes difficult to explain the usefulness thereof to oth= er programmers {like trying to explain that a "plow" is a good/useful thing= to [other] farmers...} simply because the idea is so _obvious_.