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From: olehjalmar kristensen - Sun Microsystems - Trondheim Norway
 <ok145024@sun.com>
Newsgroups: comp.lang.ada
Subject: Re: Is the Writing on the Wall for Ada?
Date: 15 Sep 2003 10:33:56 +0200
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Date: 2003-09-15T08:33:57+00:00
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>>>>> "RIE" == Robert I Eachus <rieachus@attbi.com> writes:

    RIE> Hyman Rosen wrote:
    >> Robert I. Eachus wrote:
    >> 

    >>> You inherit from two virtual  classes, then use concrete mix-ins to
    >>> implement the classes.

    >> I still  feel like we're talking  past each other. I  am showing you
    >> why

    >> one might want to inherit from two different concrete classes. In my
    >> example, you want an object which is Colorable and Resizable, and you
    >> want to reuse the concrete implementations of the adapter classes.

    RIE> There is  no problem inheriting  from two concrete classes.  I showed
    RIE> how it is done in Ada.  What I have been saying is that you can't have
    RIE> direct  inheritance (with  the  isa relationship)  from two  unrelated
    RIE> classes.       This        paper       by       Bertrand       Meyer:
    RIE> http://archive.eiffel.com/doc/manuals/technology/bmarticles/joop/multiple.html

Of course you can, provided that you don't expect them to magically
react to form something entirely new, like apple pie. To do that, you
would probably use mixins.