Bubble sort em lisp utilizando recursividade!

bubble-sort.lisp

(defun change(lat x)
    (setq Aux (nth x lat))
    (setf (nth x lat) (nth (+ 1 x) lat))
    (setf (nth (+ 1 x) lat) Aux))

(defun bubble(lat x y)
    (if(= x (length lat))
        (print lat)
        (cond((< y (length lat))
                        (cond((not (null (nth (+ 1 y) lat)))
                                        (if (> (nth y lat) (nth (+ 1 y) lat))
                                            (change lat y))))
                        (bubble lat x (+ 1 y)))
                        ((= y (length lat))
                        (bubble lat (+ 1 x) 0)))))

(bubble '(3 1 8 2 32 12 98 73 111 623 5 35) 0 0)
(bubble '() 0 0)
(bubble '(1) 0 0)