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From: dommo1234@my-deja.com
Subject: Generic type parameters
Date: 1999/06/14
Message-ID: <7k3ae5$stk$1@nnrp1.deja.com>#1/1
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Date: 1999-06-14T00:00:00+00:00
List-Id: <comp.lang.ada>

This query regards generic packages, and their instantiation with some
actual type.

OK, I have a generic package that requires to be instantiated with a
number of different types. The generic has a number of primative methods
that need to return either the type that the generic package was
instantiated with, an access to the type, or a constant access to the
type, as in the example below :-

generic
    type TypeX is private;
package Example is
    function One(..) return TypeX;
    function Two(..) return TypeX_A;
    function Three(..) return TypeX_AC;
end Example;

... where 'TypeX_A' needs to be "access all TypeX"
    and   'TypeX_AC' needs to be "access constant TypeX".

The problem is that if I delcare the two types 'TypeX_A' and 'TypeX_AC'
inside the generic, then any code containing variables that catch the
values of functions 'Two' and 'Threee' inside my generic must be of type
<generic inst>.Type_A etc. This is not very readable or convenient!

The only (not so sensible) solution I can think of is provide the
generic with 3 formal parameters, ie. TypeX, TypeX_A and TypeX_AC ....

Does anyone have a neater solution to this??

Thanks,
Dom.



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