A simple qsort implementation in Clojure

gistfile1.clj

(defn %remove-first [val seq]
  (loop [h seq
         t []]
    (if (empty? h) 
      t
      (if (= (first h) val)
        (concat t (rest h))
        (recur  (rest h) (conj t (first h)))))))

(defn qsort [seq]
  (if (empty? seq) [] 
      (let [pivot (rand-nth seq)
            seq   (%remove-first pivot seq)
            left  (filter #(> pivot %1) seq)
            right (filter #(<= pivot %1) seq)]
        (concat (qsort left) [pivot] (qsort right)))))