Re: controlled initialization

[Bill Findlay <yaldnifw@blueyonder.co.uk>]

On 17/12/02 01:50, in article DpvL9.30910$4W1.11730@nwrddc02.gnilink.net,
"Hyman Rosen" <hyrosen@mail.com> wrote:


> 
> Interesting. So (remembering that I don't know Ada) the following
> would be illegal as well? If it is, is there a way to do what the
> code obviously intends? Do I understand the issue correctly, that
> is that MakeT could use O?
> 
> package P is
>  type T is private;
>  O : constant T;
> private
>  type T is new Controlled with null record;
>  function MakeT return T;
>  O : constant T := MakeT;
> end P;
> 

We don�t need O to be deferred, or T to derive from Controlled,
for that sort of construction to fail, unfortunately.

All that's necessary is to call a function defined in the body of P
during the elaboration of P's spec.

This makes hiding the manufacture of exported ADT constants somewhat
problematic.

-- 
Bill-Findlay chez blue-yonder.co.uk ("-" => "")