xset.clj

(defn xseq [t]
  (when t
    (concat (xseq (:l t)) [(:root t)] (xseq (:r t)))))
 
(defn xconj [t v]
  (cond
    (nil? t) {:root v :l nil :r nil}
    (< v (:root t)) {:root (:root t) :l (xconj (:l t) v) :r (:r t)}
    :else           {:root (:root t) :l (:l t) :r (xconj (:r t) v)}))

(let [t1 (-> nil (xconj 5) (xconj 8) (xconj 3)),
      t2 (xconj t1 4)]
  (println "t1:" (xseq t1))
  (println "t2:" (xseq t2))
  (println "Do they share?" (identical? (:r t1) (:r t2))))