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=ham autolearn_force=no version=3.4.4 X-Google-Thread: 103376,5c89acd494ea9116 X-Google-Attributes: gid103376,public,usenet X-Google-Language: ENGLISH,UTF8 Path: g2news2.google.com!news4.google.com!proxad.net!feeder1-2.proxad.net!62.111.101.3.MISMATCH!news.germany.com!news.belwue.de!newsfeed.arcor.de!newsspool4.arcor-online.net!news.arcor.de.POSTED!not-for-mail Newsgroups: comp.lang.ada Subject: Re: Self pointer in limited record From: Georg Bauhaus In-Reply-To: <1mbajw59c3eir.jyl8bdp6qvj8.dlg@40tude.net> References: <1183577468.034566.57830@n60g2000hse.googlegroups.com> <1188578849.187422.280620@50g2000hsm.googlegroups.com> <9fy1xoukz1e3$.h574sqmiauri$.dlg@40tude.net> <46d968ee$0$30368$9b4e6d93@newsspool4.arcor-online.net> <137iu0lr82dtb$.wqy3zjz2vr9q.dlg@40tude.net> <46d972e8$0$30384$9b4e6d93@newsspool4.arcor-online.net> <1alyfwaig93sk$.99oy269uon$.dlg@40tude.net> <46d9c138$0$4531$9b4e6d93@newsspool3.arcor-online.net> <1rt8kdcrj6tf.1qgvycc6vh357$.dlg@40tude.net> <46db2bf4$0$7699$9b4e6d93@newsspool2.arcor-online.net> <1188816674.2630.25.camel@kartoffel.vocalweb.de> <9cdmw7k85sey.85sb2t1bjefy$.dlg@40tude.net> <1mbajw59c3eir.jyl8bdp6qvj8.dlg@40tude.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Message-Id: <1188850449.2630.60.camel@kartoffel.vocalweb.de> Mime-Version: 1.0 X-Mailer: Evolution 2.10.1 Date: Mon, 03 Sep 2007 22:14:09 +0200 Organization: Arcor NNTP-Posting-Date: 03 Sep 2007 22:13:30 CEST NNTP-Posting-Host: f2c9acb0.newsspool4.arcor-online.net X-Trace: DXC=J=kKZ>4P0hUHigV@eW57PQ4IUK On Mon, 2007-09-03 at 21:17 +0200, Dmitry A. Kazakov wrote: > On Mon, 03 Sep 2007 17:55:33 +0200, Jean-Pierre Rosen wrote: >=20 > > Dmitry A. Kazakov a =C3=A9crit : > >> It is difficult to see how an abstract state machine is not a type. Th= e > >> very word abstract assumes generalization, reuse and instances. It is = types > >> and generics, the tools to express the idea of instances. > >>=20 > > Sorry, but I beg to disagree here. > >=20 > > Abstraction is about the reduction of a real world objet to those=20 > > elements that are relevant for a given point of view. >=20 > Of just one object? I think that an abstraction always apply to a set of > things. What could be an abstraction of Spike, the dog? (Hope you don't mind be stepping in here.) The abstraction could be: Those elements of Spike that are relevant for the given point of view on Spike? (Guiding the abstraction process.) If you insist that abstraction as a word can only have the meaning "common to many things" and that what a Spike package will really do is a reduction of informational detail, well, apparently there are different frames of reference for "abstraction". I wonder, though, why then we can still talk about abstract data type and abstract state machine. > > A singleton is an abstraction of a single object, and does not need a=20 > > type. I don't see anything in the word abstract that assumes generaliza= tion. >=20 > There is little abstraction in being alone. This is actually the reason w= hy > no type is need for a singleton: no abstraction, no instances, no type. Is there little abstraction in being alone (hm, who said that being along is the source of the thing being an abstract?) or is there no abstraction? > In my view an abstract state machine has nothing to do with singletons. A > state machine might be a singleton, per chance. Could you say what you mean by "having nothing to do with"? (Sorry for being pedantic, but I think "nothing" and "per chance" (=3Dsomething) differ.) > But an *abstract* state > machine is definitely a type that generalizes many concrete state machine= s. By what definition of type is an ASM a type that generalizes many concrete state machines (=3Dwhat, in Ada terms?)?