Creates a clojure bimap from an map atom

gistfile1.txt

(defn bimap [map-atom]
  (let [inv-atom (atom {})]
    (add-watch map-atom :bimap
      (fn [k r old cur]
        (let [o (set (keys old))
              n (set (keys cur))]
          (doseq [removed (difference o n)]
            (swap! inv-atom dissoc (old removed)))
          (doseq [added (difference n o)]
            (swap! inv-atom assoc (cur added) added)))))
    inv-atom))