Re: Language lawyer question: task activation

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

On Thu, 19 Feb 2009 09:37:31 -0800 (PST), Adam Beneschan wrote:

> with Text_IO;
> procedure Test is
> 
>     task type TType is
>         entry E1;
>     end TType;
> 
>     task body TType is
>     begin
>          accept E1 do
>             Text_IO.Put_Line ("E1 accepted");
>          end E1;
>     end TType;
> 
>     function Func return TType is
>     begin
>         return X : TType;
>     end Func;
> 
>     procedure Do_It (X : TType) is
>     begin
>         X.E1;
>     end Do_It;
> 
> begin
>     Do_It (Func);
> end Test;

Cool! I am not a language lawyer but I think it is a bug. Even more funny
it becomes with:

   function Func return TType is
   begin
      return X : TType do
         X.E1; -- Communicating with not yet returned object!
      end return;
   end Func;

I guess that GNAT does not fire the task until its "construction," which
happens too late in these cases. I cannot tell if this behavior is correct.
Anyway is nicely illustrates why 2005 return statements and Pickwickian
functions are bogus.

Let's see what others say.

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