last nil 0 last cons x nil x last cons x cons y xs last cons y xs del x nil nil del x cons y xs if eq x y x y xs if true x y xs xs if false x y xs cons y del x xs eq 0 0 true eq 0 s y false eq s x 0 false eq s x s y eq x y reverse nil nil reverse cons x xs cons last cons x xs reverse del last cons x xs cons x xs last 1 nil 0 0 0 cons 2 del 2 if 4 eq 2 true 0 false 0 s 1 reverse 1 FULL ./TRS/aprove08/parting01_reverse.trs