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From: "Gerd" <GerdM.O@t-online.de>
Newsgroups: comp.lang.ada
Subject: How to hide type internals
Date: 30 Jun 2006 03:50:36 -0700
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Date: 2006-06-30T03:50:36-07:00
List-Id: <comp.lang.ada>

Hi,

I would like to write a package that exports functions using a special
type, without showing the details in the spec (even not in the private
part).
In Modula-2 one can declare opaque types (which mostly are pointers but
also can be any type of word size).

Like this:

package keys is
  type key;
  function GetKey return key;
  procedure FetchElement (k : key);
-- implementation of key not visible here
end keys;

package body keys
 ...
  type Data is record
                     ...
                    end record;
  type key is access Data;
...
end keys;