indexing
	description: "The location within the DESIGN_ROOM that may hold"
    "foreground and background design pieces."

class DESIGN_CELL

inherit

  ROOM_CELL
  rename
    occupy as set_foreground_piece, 
    occupied as foreground_piece_exists,
    occupant as foreground_piece,
    vacate as remove_foreground_piece
  redefine
    room, foreground_piece
  end


creation

feature{NONE}

feature

  room : DESIGN_ROOM

  foreground_piece : DESIGN_PIECE
  -- require foreground_piece_exists

  background_piece : DESIGN_PIECE
  -- require background_piece_exists

  background_piece_exists : BOOLEAN

  set_background_piece( bg : like background_piece ) is
  require
    not background_piece_exists
  do
    background_piece := bg
    background_piece_exists := True
  ensure
    new_piece : background_piece = bg
    bg_exists : background_piece_exists
  end

  remove_background_piece is
  require
    background_piece_exists
  do
    background_piece_exists := False
  ensure
    not background_piece_exists
  end

--  spoor : INTEGER
  -- Track left by some Mobile piece.

--  set_spoor( s : INTEGER ) is
  -- Change my `spoor' to `s'
--  do
--    spoor := s
--  ensure
--    spoor = s
--  end

end