snake.clj

(ns main (:gen-class))

;; Snake :: [[int int]…]
;;  vector of x,y tuples
;;  head is first, tail is last

;; out-of-bounds? :: (int int int) -> bool
;;  grid-size is 1-indexed, x+y are 0-indexed
(defn out-of-bounds? [grid-size x y]
  (or (neg? x) (neg? y) (>= x grid-size) (>= y grid-size)))

;; intersects-snake :: (Snake [int int]) -> bool
(defn intersects-snake [snake [x y]]
  (some
    #(and (= x (first %)) (= y (second %)) true)
    snake))

;; move-snake :: (int char Snake) -> Snake
(defn move-snake [grid-size direction snake]
  (let [
    [x y] (first snake)
    head (cond
      (= direction \E) [(+ x 1) y]
      (= direction \S) [x (+ y 1)]
      (= direction \W) [(- x 1) y]
      (= direction \N) [x (- y 1)])
  ] (butlast (cons head snake))))

;; random-xy :: int -> [int int]
(defn random-xy [size]
  [(rand-int size) (rand-int size)])

;; random-food :: (fn int Snake) -> [int int]
(defn random-food [random-xy size snake]
  (let [xy (atom (random-xy size))]
    (while (intersects-snake snake @xy)
      (swap! xy (fn [& xs] (random-xy size))))
    @xy))

(defn -main
  [& args]
  (println "Hello, World!"))