Re: True confessions RE:Multiple Inheritance

[Brian Rogoff <bpr@shellx.best.com>]

On Thu, 25 Sep 1997 Michael.P.Card@lmco.com wrote:
> Ingo Pakleppa (ingop@cts.com) wrote RE: absence of MI in Java:
> >
> >In my almost ten years of C++ programming, I have used multiple
> >inheritance maybe 10 times at the most, and 80% of that was for mix-in
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
<... snip ...>
> >So - when I started Java, I thought I was going to miss MI, but by now
> >find that I don't really need it in the first place.
> 
> The reason I thought this worthy of mention is that I have seen Ada
> bashed for not suppporting MI. The use of generics/tagged types for
> mixin inheritance has been described as a poor substitute for "the
> real thing", and the advocates for some other languages often crow
> about their support of "true MI." I have also seen many posts comp-
> laining about the complexity of using "true MI" on the newsgroups of
> these languages, however.

Which languages? The quote mentions C++, Eiffel programmers I've heard
acknowledge that MI in C++ is difficult, but claim that Eiffel makes it 
easy, and I'll grant that MI in Eiffel is better.

FWIW, I agree that MI is overrated, and that the Ada 95 designers were 
right to avoid adding some kind of MI. I don't find the Ada idioms for 
doing MI ugly or opaque at all, quite the opposite, whereas the Eiffel
workarounds for the lack of modules and binary functions are heinous in my
eyes. Thats not to say that there are no improvements to Ada OO that can
be made (that old withing thang) but MI is not one of them.

-- Brian