Re: A few questions

[Simon Wright <simon@pushface.org>]

"Randy Brukardt" <randy@rrsoftware.com> writes:

> Since 'Unrestricted_Access is GNAT junk, it's doesn't have any value
> for a sample implementation (if you really need 'Unrestricted_Access,
> then the interface can't be implemented in Ada, and that would be a
> major problem.)  So far as I know, you might need to use
> 'Unchecked_Access, but that's necessary anytime one needs to get a
> pointer to save the evaluated version of something.

I can't of course speak for AdaCore, but I think that the problem is
to do with obtaining a writable view of an in parameter; for example, in
the Bounded Hashed Map (GCC 5) there is

   function Iterate
     (Container : Map) return Map_Iterator_Interfaces.Forward_Iterator'Class
   is
      B  : Natural renames Container'Unrestricted_Access.all.Busy;
   begin
      return It : constant Iterator :=
        (Limited_Controlled with
           Container => Container'Unrestricted_Access)
      do
         B := B + 1;
      end return;
   end Iterate;

I dare say something could be done with 'Address and Address To Access
Conversions.