Re: limited /non-limited tagged type

[Hacid <chadi.alkurdi@gmail.com>]

On 4 mar, 20:54, Edward Fish <edward.r.f...@gmail.com> wrote:
> On Mar 4, 11:56 am, Hacid <chadi.alku...@gmail.com> wrote:
>
>
>
> > Hi,
>
> > I haven't found an existing topic about this, so I ask my question :
>
> > I develop a package for colleagues. In this package I define a tagged
> > type. I want to prevent them from doing assignments on this type. But
> > I want to be able to do these assignments in my body.
>
> > I understand why I can't define my type limited in the public part and
> > not limited in the private part. But is there a way to do what I
> > want ?
>
> > Something like :
>
> > package Foo is
>
> >    type Object is tagged private;
>
> >    function ":=" (Left : out Object,; Right : in Object) is abstract;
> > -- I know this looks strange
>
> > end Foo;
>
> > Thanks.
>
> Yes, I think.
> You could add in an 'indirection step'.
>

--
package Whatever is

   type Public_Type is tagged limited private;

   --primitive functions.

private

  -- Base is the type that you will manipulate in the Body.
  type Base is tagged record
    -- fields
     null;
  end record;

  type Public_Type is new Base with null record;

end Whatever;
--
whatever.ads:15:08: completion of limited tagged type must be limited

This way seems to not work ... :o(