-- 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 MEMO[E]
   -- This strange tiny class is useful to share a common volatile
   -- expanded value between different objects or as the result of 
   -- a once function.
   -- So in most cases the E type is expanded and the reference to the
   -- MEMO[E] container object is shared.
   -- Other name for `MEMO' is sometimes `CELL'

feature

   item: E

   set_item(i: like item) is
      do
         item := i
      ensure
         item = i
      end

   clear is
         -- Reset `item' with the default value.
      local
         default_item: like item
      do
         item := default_item
      end

end -- MEMO[E]