(ns tree-sample
  (:use [clojure.contrib str-utils map-utils]))

(def test-paths [
  "/usr/local/bin"
  "/var/www/data/stuff"
  "/var/www"
  "/var/www/data/misc"
  "/var/logs"
  "/var/logs/data"
  "/usr/fnord"
  ])

(defn split-path [p] (re-split #"/" p))

(defn path-to-map [p]
  (let [p-rev (reverse p)]
    (loop [hd (first p-rev) tl (rest p-rev) acc {}]
      (if (empty? tl)
        {hd acc}
        (recur (first tl) (rest tl) {hd acc})))))

(defn merge-trees [tl]
  (loop [hd (first tl) tl (rest tl) acc {}]
    (if (empty? tl)
      (deep-merge-with concat hd acc)
      (recur (first tl) (rest tl) (deep-merge-with concat hd acc)))))

(defn printTree 
  ([t] (printTree t 0))
  ([t indent]
    (let [prefix (apply str (repeat indent " "))
          dirs (sort (keys t))]
          (loop [curdir (first dirs) rd (rest dirs)]
            (println (if (zero? indent) "/" (str prefix "->")) curdir)
            (let [ch (get t curdir)]
              (when-not (empty? ch)
                (printTree ch (+ 2 indent))))
            (when-not (empty? rd)
              (recur (first rd) (rest rd)))))))

(println (str "test data:\n\t" (apply str (interpose "\n\t" test-paths
+))))

(println "tree:")
(printTree
  (merge-trees
    (map path-to-map
         (map split-path test-paths))))
[download]

Update: Tweaked to sort directory names.

Update 2: And yes, I have the Perl version (which came out about ~4 lines shorter). No, it's left as an exercise for the reader. :)

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