*gist 332731*

(defn map-keys
  "Applies f to all keys of m recursively."
  [f m]
  (cond
   (map? m) (into {} (map (fn [[key value]]
                            [(f key) (map-keys f value)])
                          m))
   (coll? m) (map (partial map-keys f) m)
   :default m))

(comment (map-keys keyword {"a" 1 "b" [{"c" 1}]}))
; => {:a 1, :b ({:c 1})}