-- This file is  free  software, which  comes  along  with  SmartEiffel. This
-- software  is  distributed  in the hope that it will be useful, but WITHOUT
-- ANY  WARRANTY;  without  even  the  implied warranty of MERCHANTABILITY or
-- FITNESS  FOR A PARTICULAR PURPOSE. You can modify it as you want, provided
-- this header is kept unaltered, and a notification of the changes is added.
-- You  are  allowed  to  redistribute  it and sell it, alone or as a part of
-- another product.
--       Copyright (C) 1994-2002 LORIA - INRIA - U.H.P. Nancy 1 - FRANCE
--          Dominique COLNET and Suzanne COLLIN - SmartEiffel@loria.fr
--                       http://SmartEiffel.loria.fr
--
class ITERATOR_ON_TWO_WAY_LINKED_LIST[E]

inherit ITERATOR[E]

creation make

feature {NONE}

   linked_list: TWO_WAY_LINKED_LIST[E]
	 -- The one to be traversed.

   item_link: LINK2[E]
	 --  Memorize the current position.

feature

   make(twll: TWO_WAY_LINKED_LIST[E]) is
      require
	 twll /= Void
      do
	 linked_list := twll
	 item_link := linked_list.first_link
      ensure
	 linked_list = twll
      end

   start is
      do
	 item_link := linked_list.first_link
      end

   is_off: BOOLEAN is
      do
	 Result := item_link = Void
      end

   item: E is
      do
	 Result := item_link.item
      end

   next is
      do
	 item_link := item_link.next
      end

end