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-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,103b407e8b68350b X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2003-01-31 08:27:45 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!headwall.stanford.edu!fu-berlin.de!uni-berlin.de!tar-alcarin.cbb-automation.DE!not-for-mail From: Dmitry A. Kazakov Newsgroups: comp.lang.ada Subject: Re: Anybody in US using ADA ? One silly idea.. Date: Fri, 31 Jan 2003 17:27:43 +0100 Message-ID: References: <1043680098.61106@master.nyc.kbcfp.com> <3afc3v4uur2kvd53v4ul18b5npjfm188o3@4ax.com> <1043773909.385612@master.nyc.kbcfp.com> <1043855067.848326@master.nyc.kbcfp.com> <1043938878.313737@master.nyc.kbcfp.com> <1043949677.919365@master.nyc.kbcfp.com> <1044025904.464559@master.nyc.kbcfp.com> NNTP-Posting-Host: tar-alcarin.cbb-automation.de (212.79.194.111) Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: fu-berlin.de 1044030463 35858188 212.79.194.111 (16 [77047]) X-Newsreader: Forte Agent 1.8/32.548 Xref: archiver1.google.com comp.lang.ada:33647 Date: 2003-01-31T17:27:43+01:00 List-Id: On Fri, 31 Jan 2003 10:11:44 -0500, Hyman Rosen wrote: >Dmitry A. Kazakov wrote: >> In the spirit of this definition int is an in-subtype of double > >No, it is not, assuming the universe of allowed operations on >doubles. The compiler converts the int to a double, but the int >itself is not a double. Do you know, an integer is definitely a real number. So you should clarify whether you are talking about mathematical objects or their computer models. Note also that the same mathematical (or any other object) can be modelled by many different ways in the same program. This why the representation of a particular type should be no issue, when subtyping is considered. >As I have been saying in my other messages, >in the conventional OO view, a subtype is simultaneously its own >type and all of its base types, and no conversion is required when >viewing it as a base type. This is manifestly not the case for int >and double. There is no conventional view on this issue. But if you want to see objects with several types, OK, substitute everywhere "most specific type" for "type". And you will again have *different* [most specific] types. >You persist in using your own definitions for these terms, >which will cause confusion for people who are not immersed >in this thread. Most importantly, Ada, C++, and Java don't >share your view, so people familiar with those languages >and unfamiliar with you will not kknow what's going on. ARM: 3.2 Types and Subtypes: "A type is characterized by a set of values, and a set of primitive operations which implement the fundamental aspects of its semantics. An object of a given type is a run-time entity that contains (has) a value of the type." However I see no sense in appealing to authority. If in your view to say that an object has a type is not feasible, then please, show why. --- Regards, Dmitry Kazakov www.dmitry-kazakov.de