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From: Julian Day <julianday@geocities.com>
Subject: Re: friend classes in ada95
Date: 2000/04/14
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Newsgroups: comp.lang.ada
Date: 2000-04-14T00:00:00+00:00
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Stefan Folkesson wrote:

> In ADA95, is there a way to make the private part of one class
> accessable from another (see friend classes in C++)?
>

The technique to use is a hierarchical package structure.

package X is
    ...
private
    ...
end X;

package X.Y is
    -- Cannot see X's private part
private
    -- Can see X's private part
end X.Y;

package body X.Y is
    -- Can see X's private part
end X.Y;

>
> The reason I wonder this is because I want to apply the 'Iterator
> Pattern' in my design. This demands that the Iterator object can access
> the attributes of the Aggregate object.
>

Ah, maybe what you really want is the Iterator procedure in your ADT to be
generic, like this:
generic
    with Do_Something ( Item : in out Item_Type);
proceudre Iterator (ADT : in out ADT_Type);

Then you can just instantiate it in your client with what ever procedure
you want...

>
> Is this possible? Is there a pragma to supress the access check or do I
> have to declare the attributes of the Aggregate class in the public part
> of the specification.

Please don't go down that road.

HTH,

Julian

>
>
>
> /Stefan
>