merge-sort as a list generator

gistfile1.clj

(defn merge-step [seq1 seq2]
  (let [head1 (first seq1)
        head2 (first seq2)]
    (cond
      (nil? head1) seq2
      (nil? head2) seq1
      :else (if (< head1 head2)
              (cons head1 (merge-step (rest seq1) seq2))
              (cons head2 (merge-step seq1 (rest seq2)))))))

(defn divide-step [coll]
  (let [coll-length (count coll)]
    (if (> coll-length 1)
      (let [[seq1 seq2] (split-at (quot coll-length 2) coll)]
        (merge-step (divide-step seq1) (divide-step seq2)))
      coll)))