Re: controlled initialization

["Grein, Christoph" <christoph.grein@eurocopter.com>]

> 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;

Absolutely correct, MakeT is not elaborated when you call it here. So this code is not illegal, but will raise an exception.

And why would you want to call a function here? A record initialisation can 
easily be used because you have full visibility of all components.

In a contrived case like the following, you would have a point. But then simply 
define your complicated function in a child package, use an Elaborate_Body 
pragma and call the function to initilise O. Here you are - no problem.

package P is
   type T is private;
   O : constant T;
private
   type T is new Controlled with record
     Comp: Some_Type;
   end record;
   O : constant T := (Controlled with Comp => Some very complicated code here);
end P;