Re: controlled initialization

[mheaney@on2.com (Matthew Heaney)]

Maxim Reznik <max1@mbank.com.ua> wrote in message news:<3DFD7B15.9050800@mbank.com.ua>...
> 
> I expected statement
>   return Statement'(Ada.Finalization.Controlled with C => 0);
> created object of type Statement,
> then Initialyze procedure would be called for it and
> Put_Line printed "Init".
> 
> May be it's bug of GNAT?

No, there is no bug.

> with Ada.Finalization;
> package Tests is
> 
>     type Statement is new Ada.Finalization.Controlled with record
>        C : Integer;
>     end record;
> 
>     procedure Initialize (Item : in out Statement);
> 
>     subtype Class is Ada.Finalization.Controlled'Class;
> 
>     function Create_Statement return Class;
> 
> end Tests;

In general, you should hide the fact of derivation from Controlled in
the private part of the spec, like this:

package Tests is

   type Statement_Type is private;

...
private

   type Statement_Type is new Controlled with record
     C : Integer;
   end record;

   procedure Initialize (Statement : in out Statement_Type);
...
end Tests;

Here, the partial view of the type can be tagged or non-tagged.  In my
example above, I have chosen not to make the partial view non-tagged.