Re: Declaration of private type Containers

[Matthew Heaney <mheaney@on2.com>]

On May 30, 7:49 am, alexander.kle...@web.de wrote:
> The only thing I want to do is to  declare a list package, whose
> Element_Type is of a private record type:
>
> package A is
>
> type My_Type is private
>
> package My_Type_Lists is new Ada.Containers.Doubly_Linked_List
>      (Element_Type      => My_Type);
>
> private
>
> type My_Type is
> record
> ...
> end record;
>
> end A;

It's unlikely you need all of the features supported by the standard
linked list container.  If so, one alternative for you would be to
create a more high level container:

package A is
  type T is private;

  type Container is tagged limited private;

  procedure Insert
   (C : in out Container;
    Obj : T);

  procedure Remove
    (C : in out Container;
     Obj : T);

  procedure Iterate
    (C : Container;
     P : not null access procedure (Obj : T));

private
   type T is ...;

   package T_Lists is new Ada.C.DLLists (T);

   type Container is tagged limited record
     L : T_Lists.List;
   end Container;

end A;