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Newsgroups: comp.lang.ada
Subject: Re: Specialization generic package parameters
References: <1996bbhvwjxcr$.1s16brw83713g$.dlg@40tude.net>
From: Stephen Leake <Stephe.Leake@nasa.gov>
Date: Sat, 24 May 2008 08:48:40 -0400
Message-ID: <ufxs7kguv.fsf@nasa.gov>
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Date: 2008-05-24T08:48:40-04:00
List-Id: <comp.lang.ada>

"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> writes:

> Recently I ran into the following problem with generic packages. Consider
>
>    type T is tagged null record;
>
> and a generic package that uses it:
>
>    generic
>       type Some_T is new T with private;
>    package P is
>       ...
>    private
>       ...
>    end P;

>
> Let there be some type S derived from T:
>
>    type S is new T with null record;
>
> Now the question is, how to derive another package Q from P, specialized
> for S, while keeping access to the private part of P?
>
Factor out the types and operations currently in the private part of P
into a helper child package P.Ops.

Access those operations from Q:

4. New package

    with P.Ops;
    generic
      type Some_S is new S with private;
    package Q is
    private
        -- Got access to P.Ops, and have specialization
    end P;

How would you do this in some other language?


-- 
-- Stephe