Re: Question on Controlled types

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Thu, 4 Jun 2009 07:34:43 -0700 (PDT), Hibou57 (Yannick Duch�ne) wrote:

> On 4 juin, 16:04, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
> wrote:
>>> So this means that if there was a second assignation of Delay1,
>>> Finalize would be invoked before the copy and the Adjust which will
>>> follow the copy ?
>>
>> Yes.
> 
> So this implies that at execution time, distinction can be made
> between the first and the next assignement.

No, initialization is not an assignment. This difference was subtle in Ada
95, but in Ada 2005 is more obvious. Consider a limited type T and the
function Create that "returns" T:

   X : T := Create; -- This is OK, because it is an initialization
begin
   X := Create; -- This is illegal, because it would be an assignment

Further within Create:

function Create return T is
begin
   return X : T [do ... end return]; -- This OK
end Create;

function Create return T is
   X : T;
begin
   return X;  -- This is not OK, because it returns a local
                -- limited object X, which is semantically equivalent
                -- to an assignment
end Create;

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de