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: 103376,1116ece181be1aea X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2003-09-09 06:13:58 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!nntp.cs.ubc.ca!nntp-relay.ihug.net!ihug.co.nz!news-out.nuthinbutnews.com!propagator2-sterling!news-in-sterling.nuthinbutnews.com!cyclone1.gnilink.net!spamkiller2.gnilink.net!nwrdny03.gnilink.net.POSTED!53ab2750!not-for-mail From: Ed Falis Newsgroups: comp.lang.ada Subject: Re: Is the Writing on the Wall for Ada? Message-ID: <20030909091326.03b02610.falis@verizon.net> In-Reply-To: References: X-Newsreader: Sylpheed version 0.9.4claws (GTK+ 1.2.10; i386-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Date: Tue, 09 Sep 2003 13:13:58 GMT NNTP-Posting-Host: 151.203.112.88 X-Complaints-To: abuse@verizon.net X-Trace: nwrdny03.gnilink.net 1063113238 151.203.112.88 (Tue, 09 Sep 2003 09:13:58 EDT) NNTP-Posting-Date: Tue, 09 Sep 2003 09:13:58 EDT Xref: archiver1.google.com comp.lang.ada:42316 Date: 2003-09-09T13:13:58+00:00 List-Id: On 09 Sep 2003 09:34:29 +0200 olehjalmar kristensen - Sun Microsystems - Trondheim Norway wrote: > >>>>> "HR" == Hyman Rosen writes: > > HR> Robert C. Leif wrote: > >> In particular adding interfaces to Ada allows derived types > >> where the type inherits one parent type and adds one or more > >interfaces. > > HR> Thereby exhibiting the simple lack of courage to add multiple > HR> inheritance. Why should we limit to inheriting from one type? > HR> What is it about one that makes it better than two or more? > > Beats me. In fact, one of the *nice* things about the C++ multiple > inheritance is that it allows me to express roles (a la Reenskaug) and > then combine different roles in the same object without jumping > through hoops. In Smalltalk you need an extra tool to do this, in C++ > all you need is a little care. I suppose it *could* be done in Ada > with generics, but I have not tried it, and it would certainly be more > obfuscated. I've done it in Ada using access discriminants to implement multiple inheritance - takes an awful lot of "plumbing" hanging around to do it. On the other hand, Eiffel lends itself quite nicely and cleanly to the role modelling approach, because it explicitly addresses the stickier issues in MI. - Ed