Natools

   function Iterate (Container : in Constant_Map)
     return Map_Iterator_Interfaces.Reversible_Iterator'Class;

   function Iterate (Container : in Constant_Map; Start : in Cursor)
     return Map_Iterator_Interfaces.Reversible_Iterator'Class;

   function Iterate (Container : in Constant_Map; First, Last : in Cursor)
     return Map_Iterator_Interfaces.Reversible_Iterator'Class;


   type Constant_Reference_Type
     (Element : not null access constant Element_Type) is private
     with Implicit_Dereference => Element;

   function Constant_Reference
     (Container : aliased in Constant_Map;

     with Pre => Position.Is_Empty
        or else Backend_Refs."=" (Position.Backend, Object.Backend);

   overriding function Previous
     (Object   : Iterator;
      Position : Cursor) return Cursor
     is (Previous (Position))
     with Pre => Position.Is_Empty
        or else Backend_Refs."=" (Position.Backend, Object.Backend);


   type Range_Iterator is new Map_Iterator_Interfaces.Reversible_Iterator
   with record
      Backend : Backend_Refs.Immutable_Reference;
      First_Position : Cursor;
      Last_Position : Cursor;
   end record;
--   with Dynamic_Predicate => not Range_Iterator.Backend.Is_Empty
--      and then Has_Element (Range_Iterator.First_Position)
--      and then Has_Element (Range_Iterator.Last_Position)
--      and then not Range_Iterator.First_Position
--         > Range_Iterator.Last_Position;

   overriding function First (Object : Range_Iterator) return Cursor;

   overriding function Last  (Object : Range_Iterator) return Cursor;

   overriding function Next
     (Object   : Range_Iterator;
      Position : Cursor) return Cursor
     with Pre => Position.Is_Empty
        or else Backend_Refs."=" (Position.Backend, Object.Backend);

   overriding function Previous
     (Object   : Range_Iterator;
      Position : Cursor) return Cursor
     with Pre => Position.Is_Empty
        or else Backend_Refs."=" (Position.Backend, Object.Backend);


   No_Element : constant Cursor := (Is_Empty => True);

end Natools.Constant_Indefinite_Ordered_Maps;