-- File:	PCollection_Compare.cdl
-- Created:	Tue May 14 18:07:48 1991
-- Author:	Annick PANCHER
--		<apc@topsn2>
-- Revised:     Mireille MERCIEN
--              <mip@sdsun3>           	 
--           	Copyright:	 Matra Datavision 1992


deferred generic class Compare from PCollection ( Item as Storable)
inherits Storable

	---Purpose: Defines a comparison operator which can be used by
	-- any ordered structure.   The  way to compare items
	-- has  to be described  in  subclasses, which inherit
	-- from instantiations of Compare.

is

    IsLower (me; Left, Right: Item)
	---Purpose: Returns True if <Left> is lower than <Right>
    	returns Boolean is virtual;
    ---Level: Public
    
    IsGreater (me; Left, Right: Item)
	---Purpose: Returns True if <Left> is greater than <Right>
    	returns Boolean is virtual;
    ---Level: Public

    IsEqual(me; Left, Right: Item)
	---Purpose: Returns True when <Right> and <Left> are equal.
	returns Boolean;
    ---Level: Public
end;