Re: Type extension questions

[comar@cs.nyu.edu (Cyrille Comar)]

koehnema@enuxsa.eas.asu.edu (Harry Koehnemann) writes:
: I don't think my request was clear enough.  This is close, but I'd
: like P.T to be extensible.  The above approach hides the fact that P.T
: is tagged and therefore extensions of P.T are not allowed.  What I
: really want is private inheritance ala C++.
: 
: Thanks for the reply.  Any other suggestions?

(sorry for previous empty message, I try again)

Don't try to be too close to C++, this doesn't fit Ada's
model. "Private inheritance" is meaningless in Ada since "Private" is
a caracteristic of packages and inheritance a characteristic of types
but you can still do something very close from what you want :
package P is
   type T is tagged private;
   procedure Visible_Method (X : T);
private 
   procedure Private_Method (X : T);
   type T is ...
end P;

with P; use P;
package Q is 
  type T2 is new T with ....;
end Q;

a client of Q can use the inherited Visible_Method but not
Private_Method (unless the client happen to be child of P but this is
an other story... ;-)
-- 
------------------------------------------------------------------------
Cyrille Comar,                                  E-mail: comar@cs.nyu.edu
Gnat Project                                    US phone: (212) 998-3489