declare
local
   SetSelf={NewName}
   class DelegateMixin
      attr this Delegate:none
      meth !SetSelf(S) this:=S end
      meth set(A X) A:=X end
      meth get(A ?X) X=@A end
      meth setDelegate(D) Delegate:=D end
      meth Del(M S) SS in
         SS=@this this:=S
         try {self M} finally this:=SS end
      end
      meth call(M) SS in
         SS=@this this:=self
         try {self M} finally this:=SS end
      end
      meth otherwise(M)
         if @Delegate==none then
            raise undefinedMethod end
         else
            {@Delegate Del(M @this)}
         end
      end
   end
in
   fun {NewD Class Init}
      Obj={New class $ from Class DelegateMixin end Init}
   in
      {Obj SetSelf(Obj)}
      Obj
   end
end