gistfile1.clj

(ns bktree)

(defn root [distance-fn] {:distance-fn distance-fn :children {} :matches []})
(defn new-node [term] {:term term :children {} :matches []})

(defn insert
  ([element node]
    (insert element node (:distance-fn node)))

  ([element node distance-fn]
    (if (:term node)
      (let [dist (distance-fn (:term node) element)
            children (:children node)
            child (get children dist)]
        (if (= 0 dist)
          (assoc node :matches (cons element (:matches node)))
          (if child
            (assoc node :children (assoc children dist (insert element child distance-fn)))
            (assoc node :children (assoc children dist (new-node element))))))
      (assoc node :term element))))

(defn walk [a-fn node]
  (a-fn node)
  (doall (map (fn [n] (walk a-fn n)) (vals (:children node)))))