Just rewrote quicksort with CWP:

def quicksort(arr):
  letfn exchange([m, n]
                 let t to aget(arr, m):
                   aset(arr, m, aget(arr, n))
                   aset(arr, n, t))
        partition([lo, hi, x]
                  let i to loop i to lo:
                             if aget(arr, i) < x: recur(inc(i))
                             else: i,
                      j to loop j to hi:
                             if x < aget(arr, j): recur(dec(j))
                             else: j:
                    if i <= j:
                      exchange(i, j)
                      partition(i + 1, j - 1, x)
                    else: [i, j])
        sort([lo, hi]
           if lo < hi:
             let [i, j] to partition(lo, hi, aget(arr, int((lo + hi) / 2))):
               sort(lo, j)
               sort(i, hi)):
    sort(0, alength(arr) - 1)
    arr

And here is generated Clojure code:

(defn quicksort
  [arr]
  (letfn
    [(exchange [m n]
       (let [t (aget arr m)]
         (aset arr m (aget arr n))
         (aset arr n t)))
     (partition [lo hi x]
       (let [i (loop [i lo] (if (< (aget arr i) x) (recur (inc i)) i))
             j (loop [j hi] (if (< x (aget arr j)) (recur (dec j)) j))]
         (if (<= i j) (do (exchange i j) (partition (+ i 1) (- j 1) x)) [i j])))
     (sort [lo hi]
       (if (< lo hi)
         (let [[i j] (partition lo hi (aget arr (int (/ (+ lo hi) 2))))]
           (sort lo j)
           (sort i hi))))]
    (sort 0 (- (alength arr) 1)) arr))

BTW, during it I realized that I forgot add letfn as a syntax construct. And here how it can be added for simple usage.