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: 2003-09-11 15:38:34 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!logbridge.uoregon.edu!hammer.uoregon.edu!skates!not-for-mail From: Stephen Leake Newsgroups: comp.lang.ada Subject: Re: Is the Writing on the Wall for Ada? Date: 11 Sep 2003 18:01:32 -0400 Organization: NASA Goddard Space Flight Center (skates.gsfc.nasa.gov) Message-ID: References: <3F5F7FDC.30500@attbi.com> <3F6079A9.6080108@attbi.com> <3F60E380.4020307@attbi.com> NNTP-Posting-Host: anarres.gsfc.nasa.gov Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: skates.gsfc.nasa.gov 1063317839 24080 128.183.235.92 (11 Sep 2003 22:03:59 GMT) X-Complaints-To: usenet@news.gsfc.nasa.gov NNTP-Posting-Date: 11 Sep 2003 22:03:59 GMT User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 Xref: archiver1.google.com comp.lang.ada:42392 Date: 2003-09-11T22:03:59+00:00 List-Id: "Robert I. Eachus" writes: > Stephen Leake wrote: > > > I think to make this argument truly convincing, you need to show how > > it currently works in C++, and why that is bad. Showing that Ada is ok > > the way it is will not convince anyone who is sure it could be better > > if it was more like C++. > > No, someone arguing the other side needs to demonstrate what can be > done in language X that can't be done as well or better in Ada (with > or without interfaces added). Hmm. I'm talking to a mostly reasonable C++ advocate. She says "C++ has multiple inheritance, and it works fine. Why don't you just put that in Ada?". She doesn't know Ada. To be convincing, I need an example, _expressed in C++_, that shows that C++ multiple inheritance does _not_ "work fine". I think I remember seeing such an example once, and I could probably construct one from what you have been saying. It would be nice if there were such an example in the FAQ or on AdaIC, so we could all reference it; this comes up often. > The examples you say are needed have all been thoroughly discussed > by the ARG. (And are available on the web see: > http://www.ada-auth.org/cgi-bin/cvsweb.cgi/AIs/AI-00251.TXT) Well, there is no C++ there (I didn't really expect to see any). Maybe I'll find time to convert one of those Ada examples into C++. > We are adding interfaces to Ada because it allows a different style > of multiple inheritance than mix-ins, which of course are currently > well supported and used in Ada. I agree this is the best way to go. I'm just looking for a concise counter example for the C++ advocates. > But type inheritance cannot be from two concrete parents, no matter > what the language--one parent has to be abstract. You and I and many others understand this; still others do not. > So anyone who condemns Ada for not adding what cannot be done needs > to get a life. Or learn from a good example. They have all seen examples of how the C++ way does work. None of the C++ books say "here's how we do multiple inheritance, even though it really can't be done this way"! -- -- Stephe