grassroots thoughts on access types

[Mehdi Saada <00120260a@gmail.com>]

In my corrected exercices, I can read:

package P_Token.F is
   type T_Ptr_Token is access all T_Token'Class;
end P_Token.F;

package body  P_Token.Operateur.F is

   type T_Ptr_Token_Operateur is access all T_Token_Operateur;

   function Set_Ptr (Elem : in T_Operateur) return T_Ptr_Token is
      Ptr_Token : T_Ptr_Token_Operateur;
   begin
      Ptr_Token := new T_Token_Operateur;
      Initialisation(Ptr_Token.all,Elem);
      return Ptr_Token.all'access; -- @@@ HERE
   end Set_Ptr;

end P_Token.Operateur.F;

and

I understand the line marked (took me several minutes though ;-) ) but not the logic. Instead of
function Set_Ptr (Elem : in T_Operateur) return T_Ptr_Token is
      Ptr_Token : T_Ptr_Token_Operateur;
can we write:
 function Set_Ptr (Elem : in T_Operateur) return T_Ptr_Token is
      Ptr_Token : T_Ptr_Token;
? What's the difference regards to implementation, memory usage or anything ?
T_TOKEN is a null tagged record type, T_TOKEN_OPERATEUR has one more enumerative component.