Towers of Hanoi in Clojure

towers_of_hanoi.clj

(defn hanoi [n left middle right]
  (cond
    (> n 5) (throw (Exception. "No way! This would run far too long!"))
    (= n 1) (println "Move disc" n "from" left "to" right)
    :else (do (hanoi (dec n) left right middle)
              (println "Move disc" n "from" left "to" right)
              (hanoi (dec n) middle left right))))

(hanoi 5 :left :middle :right)


(defn towers-of-hanoi-lazy [n from to via]
  (when (pos? n)
    (lazy-cat
     (towers-of-hanoi (dec n) from via to)
     (cons [from '-> to]
           (towers-of-hanoi (dec n) via to from)))))