Re: Abstract realizations can't be inherited??

[dennison@telepath.com]

In article <EyDBJB.6JH.0.-s@inmet.camb.inmet.com>,
  stt@houdini.camb.inmet.com (Tucker Taft) wrote:
> This is not the intent of 3.9.3(6).  It is only talking about the
> type from which the subprograms are inherited.  For a record
> extension, it is the direct parent.  For a private extension,
> it is whatever ancestor is specified.

Good. That's the way I'd expect it to work.

> It would be helpful if you included the relevant source code.  It may
> either be that there is a compiler bug, or that the description above
> lacks some critical detail.

I had to move on, so that code isn't around in that form any more. However, I
rigged up a dummy example, and I think I see my problem. ...My problem with
the code anyway :-).

package Thingamabob is
   type Instance is abstract tagged null record;

   procedure Foo (On : in out Instance) is abstract;

end Thingamabob;

package Thingamabob.Big is
   type Instance is new Thingamabob.Instance with private;

private
   procedure Foo (On : in out Instance);

   type Instance is new Thingamabob.Instance with null record;
end Thingamabob.Big;

with Thingamabob.Big;
package Big_And_Hairy_Thingamabob is
   type Instance is new Thingamabob.Big.Instance with private;

private

   type Instance is new Thingamabob.Big.Instance with null record;
end Big_And_Hairy_Thingamabob;

This gives me the error. But if I move the declartion of Thingamabob.Big.Foo
out of the private section, it works ok. So it looks like the real problem is
that I can't inherit a routine declared in the private section. That seems a
little more sensible.

The thing that makes that a little odd is that I can directly call
Thingamabob.Big.Foo, even though its declared in the private section. So for
the purposes of calling it isn't really "private", but for the purposes of
inheritance it is. %-(

--
T.E.D.

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