with Persistence_Types;  use Persistence_Types;
private with Ada.Streams;

package P is

   type T is limited private;

   function Persistence (O : not null access T)
     return not null access Persistence_Type'Class;

private

   use Ada.Streams;

   type Persistence_View (O : not null access T) is
     new Persistence_Type with null record;

   overriding
   procedure Write
     (Persistence : in Persistence_View;
      Stream      : not null access Root_Stream_Type'Class);

   overriding
   procedure Read
     (Persistence : in out Persistence_View;
      Stream      : not null access Root_Stream_Type'Class);


   type T is limited record
      Persistence : aliased Persistence_View (T'Access);
   end record;

end P;
with Persistence_Types2;  use Persistence_Types2;
with Ada.Streams;  use Ada.Streams;

package P2 is

   type T is limited new Persistence_Type with null record;

   overriding
   procedure Write
     (Persistence : in T;
      Stream      : not null access Root_Stream_Type'Class);
      
   overriding
   procedure Read
     (Persistence : in out T;
      Stream      : not null access Root_Stream_Type'Class);
      
end P2;
with Persistence_Types;  use Persistence_Types;

package Persistence_IO is
   pragma Elaborate_Body;

   procedure Init;
   procedure Save (Persistence : in Persistence_Type'Class);

end Persistence_IO;
with Persistence_Types2;  use Persistence_Types2;

package Persistence_IO2 is
   pragma Elaborate_Body;

   procedure Init;

   procedure Save (Persistence : in Persistence_Type'Class);
   
end Persistence_IO2;
with Ada.Streams;  use Ada.Streams;

package Persistence_Types is
   pragma Pure;

   type Persistence_Type is
     abstract tagged limited null record;

   procedure Write
     (Persistence : in Persistence_Type;
      Stream      : not null access Root_Stream_Type'Class) is abstract;

   procedure Read
     (Persistence : in out Persistence_Type;
      Stream      : not null access Root_Stream_Type'Class) is abstract;

end Persistence_Types;
with Ada.Streams;  use Ada.Streams;

package Persistence_Types2 is
   pragma Pure;

   type Persistence_Type is limited interface;

   procedure Write
     (Persistence : in Persistence_Type;
      Stream      : not null access Root_Stream_Type'Class) is abstract;

   procedure Read
     (Persistence : in out Persistence_Type;
      Stream      : not null access Root_Stream_Type'Class) is abstract;

end Persistence_Types2;
package body P is

   function Persistence (O : not null access T)
     return not null access Persistence_Type'Class
   is
   begin
      return O.Persistence'Access;
   end;

   procedure Write
     (Persistence : in Persistence_View;
      Stream      : not null access Root_Stream_Type'Class)
   is
   begin
      null;
   end;

   procedure Read
     (Persistence : in out Persistence_View;
      Stream      : not null access Root_Stream_Type'Class)
   is
   begin
      null;
   end;

end P;
package body P2 is

   procedure Write
     (Persistence : not null access T;
      Stream      : not null access Root_Stream_Type'Class)
   is
   begin
      null;
   end;

   procedure Read
     (Persistence : not null access T;
      Stream      : not null access Root_Stream_Type'Class)
   is
   begin
      null;
   end;

end P2;
with Ada.Streams.Stream_IO;

package body Persistence_IO is

   File : Ada.Streams.Stream_IO.File_Type;
   use Ada.Streams.Stream_IO;

   procedure Init is
   begin
      Create (File, Name => "test.dat");
   end;

   procedure Save (Persistence : in Persistence_Type'Class) is
   begin
      Persistence.Write (Stream (File));
   end Save;

end Persistence_IO;
with Ada.Streams.Stream_IO;

package body Persistence_IO2 is
   
   File : Ada.Streams.Stream_IO.File_Type;
   use Ada.Streams.Stream_IO;

   procedure Init is
   begin
      Create (File, Name => "test.dat");
   end;

   procedure Save
     (Persistence : in Persistence_Type'Class)
   is
   begin
      Persistence.Write (Stream (File));
   end Save;

end Persistence_IO2;
with P; use P;
with Persistence_Types;  use Persistence_Types;
with Persistence_IO;

procedure Test_Persistence is
   O : aliased T;
begin
   Persistence_IO.Init;
   Persistence_IO.Save (Persistence (O'Access).all);
end;
with P2; use P2;
with Persistence_Types2;  use Persistence_Types2;
with Persistence_IO2;

procedure Test_Persistence2 is
   O : T;
begin
   Persistence_IO2.Init;
   Persistence_IO2.Save (O);
end;