(defun quicksort (vec l r)
  (let ((i l)
	  (j r)
	(p (svref vec (round (+ l r) 2))))
    (while (<= i j)
      (while (< (svref vec i) p) (incf i))
      (while (> (svref vec j) p) (decf j))
      (when (<= i j)
	(rotatef (svref vec i) (svref vec j))
	(incf i)
	(decf j)))
    (if (> (- j l) 1) (quicksort vec l j))
    (if (> (- r i) 1) (quicksort vec i r)))
  vec)

;(defmacro while (test &rest body)
;  `(do ()
;       ((not ,test))
;     ,@body))

(deftest test-quicksort()
  (check
   (equal "#(1 2 4 6 7 9 8)" (format nil "~A" (quicksort (vector 8 9 4 2 6 7 1) 0 6)))
   (equal "#(0 1 2 4 3 5 6 7 8 9 10)" (format nil "~A" (quicksort (vector 10 9 8 7 6 5 3 4 2 1 0) 0 10)))
   ))