gistfile1.clj

(ns tron.kekkonen)

(defn addv [a b] (mapv + a b))
(defn turn-left [[dx dy]] [dy (- dx)])
(defn turn-right [[dx dy]] [(- dy) dx])
(defn left? [old-dir new-dir] (= (turn-right new-dir) old-dir))

(defn president
  [turn & [primary-goal :as original-goals]]
  (fn [look {:keys [pos dir goals] :or {dir (or primary-goal [0 1])
                                        goals original-goals}}]
    (letfn
      [(ok? [new-dir & [dont-turn]]
         (let [new-pos (addv pos new-dir)]
           (when-not (look new-pos)
             {:pos new-pos :dir new-dir :goals (map (if dont-turn identity turn) goals)})))]
      (or
        (some ok? goals)
        (ok? dir true)
        (ok? (turn-left dir))
        (ok? (turn-right dir))))))

(def mannerheim (president identity [0 -1]))
(def kekkonen (president turn-left [0 -1]))