Re: Dynamic Aggregation

From:
"Victor Bazarov" <v.Abazarov@comAcast.net>
Newsgroups:
comp.lang.c++
Date:
Wed, 25 Jul 2007 08:51:24 -0400
Message-ID:
<f87h0f$gee$1@news.datemas.de>
tony_in_da_uk@yahoo.co.uk wrote:

On Jul 25, 9:10 pm, c.gines...@imperial.ac.uk wrote:

I want to create classes that I could aggregate with each others
using operators. This would therefore take the form of a dynamic
aggregation.


I believe "c.ginestet" has a rather unconventional idea of what
"dynamic" means. For whatever reason I've always thought that in
C++ "dynamic" means either "driven by some data in the run-time"
or "having the lifetime not limited by scope". Maybe it's just me...

You might find it useful to search on "multiple inheritance",
basically:
 class dog_and_cat : public dog, public cat { };


How is that "dynamic"?

[..impossibility of dog_and_cat existense aside..]

Why do you specifically want to use "+" to do this? You can use
templates to do such things, [..]


Again, how would that be "dynamic"?

I don't question your suggestion of using templates. After all,
we can try writing

template<class T, class U> class from_two : public T, public U
{
    // ...
};

template<class T, class U>
    from_two<T,U>* operator+(T const& t, U const& u)
{
    return new from_two();
}

    ...
    mammal *dogcat = dog + cat; // requires 'mammal' to be
                                // a virtual base class in both

(or something similar). I am just questioning the use of the
term "dynamic" here. And I second the request to elaborate on the
problem the OP's solving.

V
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