namespace string shortener

a.clj

(defn ns-str-shortener
  ([ns-str] ns-str)
  ([ns-str number]
   (let [length (.length ns-str)]
     (if (< number length)
       (let [splitted (.split #"\." ns-str)
             endi     (dec (alength splitted))
             short    (volatile! false)]
         (areduce splitted i ret ""
                  (let [j      (- endi i)
                        comp   (aget splitted j)
                        length (+ (.length ret) (.length comp) 1)
                        comp   (cond
                                 @short (subs comp 0 1)
                                 (== i 0) comp
                                 (< number length) (do (vreset! short true)
                                                       (subs comp 0 1))
                                 :else comp)]
                    (str (when-not (== j 0) ".") comp ret))))
       ns-str))))
       
(ns-str-shortener "namespace.somewhat.long.example" 16)
;; => "n.s.long.example"