A simple msort implementation in Clojure

gistfile1.clj

(defmacro recurse [v]
  (if (= v :left)
    `(recur ~'l (rest ~'r) (conj ~'res (first ~'r)))
    `(recur (rest ~'l) ~'r (conj ~'res (first ~'l)))))

(defn %merge [l r]
  (loop [l l
         r r
         res []]
    (if (every? empty? [l r])
      res
      (cond
       (empty? l)               (recurse :left)
       (empty? r)               (recurse :right)
       (>= (first l) (first r)) (recurse :left)
       (< (first l) (first r))  (recurse :right)))))

(defn msort [seq]
  (let [count (/ (count seq) 2)
        left  (take count seq)
        right (drop count seq)]
    (println left right)
    (if (empty? right) 
      left
      (%merge (msort left) (msort right)))))