--- self == other
--- self > other
--- self >= other
--- self < other
--- self <= other

    ʸӡѿ $= ͤǤӤϥ
    ե٥åȤʸʸ̵뤷ƹԤޤ
    ($=ѿϤѻߤ뤳ȤˤʤäƤޤ obsolete 
    򻲾)

