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From: Martin Dowie <martin.dowie@btopenworld.com>
Newsgroups: comp.lang.ada
Subject: Re: Possible Ada deficiency?
Date: Fri, 31 Dec 2004 19:16:22 +0000 (UTC)
Organization: BT Openworld
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Date: 2004-12-31T19:16:22+00:00
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danmcleran@hotmail.com wrote:
> In C++ and Java, no private data can be seen by child classes. I think
> that Ada would benefit from extending its information hiding
> capabilities by allowing a package writer to conceal type information
> from child packages.

...but "protected" data can? E.g.

package C_Plus_Plus is

    type Public_Type is tagged record
       I : Integer;  -- Anyone can see
    end record;

    type Protected_Type is new Public_Type with private;

private

    type Protected_Type is new Public_Type with record
       F : Float;  -- Any derived class can see
    end record;

end C_Plus_Plus;

package body C_Plus_Plus is

    type Private_Type is new Protected_Type with record
       B : Boolean;  -- Only "parent namespace" can see
    end record;

end C_Plus_Plus;