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 X-Google-Thread: 103376,aae01e0853bff01c X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2003-09-16 20:12:26 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!in.100proofnews.com!in.100proofnews.com!cycny01.gnilink.net!cyclone1.gnilink.net!wn14feed!wn13feed!wn11feed!worldnet.att.net!204.127.198.203!attbi_feed3!attbi_feed4!attbi.com!rwcrnsc53.POSTED!not-for-mail Message-ID: <3F67D0FA.9020506@attbi.com> From: "Robert I. Eachus" User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.0.2) Gecko/20021120 Netscape/7.01 X-Accept-Language: en-us, en MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: Should MI be supported (was: Can MI be supported?) References: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit NNTP-Posting-Host: 24.34.139.183 X-Complaints-To: abuse@comcast.net X-Trace: rwcrnsc53 1063768345 24.34.139.183 (Wed, 17 Sep 2003 03:12:25 GMT) NNTP-Posting-Date: Wed, 17 Sep 2003 03:12:25 GMT Organization: Comcast Online Date: Wed, 17 Sep 2003 03:12:25 GMT Xref: archiver1.google.com comp.lang.ada:42594 Date: 2003-09-17T03:12:25+00:00 List-Id: Matthew Heaney wrote: > Bob Eachus showed how to use generic mixins to translate Hyman's example > into Ada95, but the classes in the C++ example didn't strike me as being > proper "mixin" classes. Usually it's pretty obvious when a class is a > mixin. > > So can you use generic mixins to effect MI in Ada95? Probably, yes. > Did I think Bob's translation was very natural? Not really, no. I guess we just have to agree to disagree on this. I personally find the mixin idiom to be more natural than the view conversion approach. But Ada allows both, and in fact several other ways to code the same example, and we are talking about adding one more. But this is how it should be. Ada should allow you to express a model using whatever patterns are most appropriate. If we disagree on which patterns to use, well that is a style issue, not something where there is a definite right or wrong. Of course, the other discussion in this thread is one of right and wrong. If you insist on "true" isa multiple inheritance, it has to be inconsistant. For those who haven't studied such fun Theory of Computation topics as G�del's Proof, the Halting problem, and Post's correspondence problem, If you have one inconsistant axiom you can prove anything. G�del's Proof basically says that any programming language must be either incomplete or inconsistant. Problems like the Halting problem and Post's correspondence problem cannot be solved in general in any consistant language. Ada is incomplete, and it will stay that way, thank you very much. -- Robert I. Eachus "As far as I'm concerned, war always means failure." -- Jacques Chirac, President of France "As far as France is concerned, you're right." -- Rush Limbaugh