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From: =?iso-8859-1?Q?Correnson_Lo=EFc?= <Loic.Correnson@trusted-logic.fr>
To: "Ocaml" <caml-list@inria.fr>
References: <405EBD5D.1000406@baretta.com>
Subject: Re: [Caml-list] Delegation based OO
Date: Tue, 23 Mar 2004 09:56:39 +0100
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This is a very interesting way of OO-programming.
More over, it allows to fullly benefit from multi-inheritance:

Suppose we have:
class type a = object ... end
class type b = object ... end

Then:
class a_and_b = object
    delegates [classtype to] a ;
    delegates [classtype to] b ;
end

I mainly found the requirement for such a delegation mechanism while looking
at GUI system, where classes have in general a *lot* of methods that must be
delgated by hand.

>>From the compiler point of view, notice that such a delegation mechanism
would be  concistent with the one already existing for modules (and
functors) thanks to the "include" statement:

module type A = sig ... end
module type B = sig ... end
module A_and_B(mA : A)(mB : B) = struct
   include mA [ : A] ;
   include mB [ : B] ;
end

>>From an academic point of view, and looking for a beautiful symetry between
objects and modules, such an delegation-based OO system would be a nice
construction.

    Loic Correnson.

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