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From: "Ehud Lamm" <mslamm@huji.ac.il>
Newsgroups: comp.lang.ada
Subject: Re: class wide object in generic package
Date: Tue, 11 Jun 2002 22:57:11 +0200
Organization: Ehud Lamm
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References: <3D045767.8020102@rcs.ei.tum.de> <wkelffffuy.fsf@acm.org>
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Date: 2002-06-11T22:57:11+02:00
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"Stephen Leake" <stephen_leake@acm.org> wrote in message
news:wkelffffuy.fsf@acm.org...
> Thomas Maier-Komor <maierkom@rcs.ei.tum.de> writes:
>
>
> If you want dispatching, you'll have to use a generic formal package
> parameter:
>
> generic
>    package Object_Package is new Generic_Obj_Package (...);
> package generic_pac ...
>

It seems to me you want as a generic paramter any type that has the Eval
operation.
So you can define a parent type having this operation (say an abstract type
called Evalable).
Now you can define the generic

with Evalable_Pak;
generic
    type My_Evalable is new Evalable_Pak.Evalable with private;
....

My_Evalable will have a primitive Eval operation.

(Hope I am not making a fool of myself here. I confess not compiling a real
example.)

Ehud Lamm
(Stay tuned to the results of the Ada-Europe'2002 Workshop on a Standard
Container Library for Ada!)