clojure datafy and nav to explore an open-ended state space

array_game.clj

(defn nav-> [x p]
  (nav x p (get x p)))

(defn array-game-inc [x k v]
  (with-meta
   (assoc x k (inc v))
   (meta x)))

(defn array-game []
  (with-meta
   [0 0 0 0]
   {`clojure.core.protocols/datafy #'identity
    `clojure.core.protocols/nav #'array-game-inc}))


(-> (array-game) ;[0 0 0 0]
    (nav-> 0)    ;[1 0 0 0]
    datafy
    (nav-> 0)    ;[2 0 0 0]
    datafy
    (nav-> 0)    ;[3 0 0 0]
    datafy
    (nav-> 1)    ;[3 1 0 0]
    )