Tried to write merge sort in Clojure. Nearly killed me.

gistfile1.clj

(mergesort [6 4 2 3 5 1])

(defn mergesort [x]
  (if (< (count x) 2) x
    (let [half (quot (count x) 2)]
    (merge (mergesort (take half x)) (mergesort (drop half x))))))

(defn merge[a, b]
  (if (empty? a) b
    (if (empty? b) a
      (if (< (first a) (first b)) (cons (first a) (merge (rest a) b))
        (cons (first b) (merge a (rest b)))))))