empty nil true empty cons x l false head cons x l x tail nil nil tail cons x l l rev nil nil rev cons x l cons rev1 x l rev2 x l last x l if empty l x l if true x l x if false x l last head l tail l rev2 x nil nil rev2 x cons y l rev cons x rev2 y l empty 1 nil 0 true 0 cons 2 false 0 head 1 tail 1 rev 1 rev1 2 rev2 2 last 2 if 3 FULL ./TRS/SchneiderKamp/trs/thiemann08.trs