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Date: Wed, 26 Mar 2003 10:06:41 -0500
From: Hyman Rosen <hyrosen@mail.com>
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Subject: Re: Imitation is the sincerest form of flattery
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Date: 2003-03-26T10:06:41-05:00
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Dmitry A. Kazakov wrote:
> Wrong for what? There is no other way to specify a type set other than
> through closures of a subtyping relation. That's what inheritance is
> about.

Yes there is. We've been through all this before.
The other way is through use patterns.

> Let you declare:
>    void Foo (Element& X);
> then A[i] have to be of Element type to allow substitutability:
> 
>    Foo (A [i]);
> If A [i] is of some proxy class then you need ether to make the class
> a subtype of Element, or to write a wrapper for Foo.

No, you declare
     template <typename Element> void Foo(Element &X);
and you just call
     Foo(A[i]);
As long as the proxy class has all of the operations
that Foo uses, everything works fine. No inheritance
is used.

Please, let's not recapitulate the whole inheritance
vs. generics thread.