gistfile1.clj

(defn xconj [t v]
  (cond (nil? t) {:val v, :l nil, :r nil}
        (< v (:val t)) (cond
                        (nil? (:l t)) {:val (:val t), :l (xconj nil v), :r (:r t)}
                        :else {:val (:val t), :l (xconj (:l t) v), :r (:r t)})
        :else (cond (nil? (:r t)) {:val (:val t), :l (:l t), :r (xconj nil v)}
                    :else {:val (:val t), :l (:l t), :r (xconj (:r t) v)})))


(defn xseq [t]
  (when t
    (concat (xseq (:l t)) [(:val t)] (xseq (:r t)))))