note description: "Objects with an unique id." date: "$Date$" revision: "$Revision$" deferred class IDABLE feature -- Access id: INTEGER -- Unique id -- Can be used tp represent an object in a database deferred end feature -- Status Report has_id: BOOLEAN -- is there an id? do Result := id > 0 end feature -- Element Change set_id (a_id: INTEGER) -- Set `id' with `a_id'. require id_positive: a_id >= 0 deferred ensure id_set: id = a_id end end