limited /non-limited tagged type

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

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.