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From: koehnema@enuxsa.eas.asu.edu (Harry Koehnemann)
Subject: Re: Type extension questions
Message-ID: <D5wyp1.Fsv@ennews.eas.asu.edu>
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Reply-To: koehnema@enuxsa.eas.asu.edu (Harry Koehnemann)
Organization: Arizona State University
Date: Thu, 23 Mar 1995 22:05:25 GMT
References: <D5tFuE.1vx@ennews.eas.asu.edu> <1995Mar22.125057@di.epfl.ch>
Followup-To: comp.lang.ada
Date: 1995-03-23T22:05:25+00:00
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In article <1995Mar22.125057@di.epfl.ch> Robb.Nebbe@di.epfl.ch (Robb Nebbe) writes:
>In article <D5tFuE.1vx@ennews.eas.asu.edu>, koehnema@enuxsa.eas.asu.edu (Harry Koehnemann) writes:
>|> 
>|> 1) Is it possible to derive a type such that the parent operations are not
>|>    available to the user of the new type?  This question is equivalent to
>|>    the ability to do private inheritance ala C++ - class B: private A { ...};
>|>    I would assume the answer is yes, but haven't yet figured out how.
>
>Yes. For example when you need a type to be controlled typically you don't
>want to expose the finalize, initialize and adjust operations to the client
>so you write:
>
>	package P is
>
>	    type T is private;
>
>	private
>
>	    type T is new Ada.Finalization.Controlled with ...
>
>	    procedure Adjust( Object : in out T );

I don't think my request was clear enough.  This is close, but I'd
like P.T to be extensible.  The above approach hides the fact that P.T
is tagged and therefore extensions of P.T are not allowed.  What I
really want is private inheritance ala C++.

Thanks for the reply.  Any other suggestions?

--
Harry Koehnemann			Arizona State University
hek@asu.edu				Computer Science Department