Convert "jun" -> 06 and vice versa

gistfile1.clj

(require '[clj-time.format :as tf])


(defn format-month [month]
  (let [letter-fmt (tf/formatter "MMM")
        num-fmt (tf/formatter "MM")
        converter (fn [month from-fmt to-fmt]
                    (->> month
                         (tf/parse from-fmt)
                         (tf/unparse to-fmt)
                         str/lower-case))]
    (if (re-matches #"\d{2}" month)
      (converter month num-fmt letter-fmt)
      (converter month letter-fmt num-fmt))))