Snakes and Ladders game built during code jugalbandhi at functional conf (http://confengine.com/functional-conf-2015/schedule#session-7464-info)

snl.clj

(ns snl.core
  (:require [clojure.string :as str]
            [clojure.pprint :as pp]))

(defonce game-state (atom {:players [] :board nil}))

(defn board! [] (:board @game-state))
(defn players! [] (:players @game-state))
(defn snakes! [] (:snakes (:board @game-state)))
(defn ladders! [] (:ladders (:board @game-state)))

(defn snake [size _]
  (let [sq1 (rand-int size)]
    [sq1 (inc (rand-int sq1))]))

(defn ladder [size _]
  (let [sq1 (rand-int size)
        sq2 (+ sq1 (rand-int (- size sq1)))]
    [sq1 sq2]))

(defn generate-board [n]
  (let [num-cells (* n n)
        snakes (into {} (map (partial snake num-cells) (range n)))
        ladders (into {} (map (partial ladder num-cells) (range n)))]
    {:num-cells num-cells :snakes snakes :ladders ladders}))

(defn next-pos [from num-cells]
  (let [new-pos (+ from (inc (rand-int 6)))]
    (if (< new-pos num-cells) new-pos from)))


(defn is-winning-move? [new-pos]
  (= new-pos (dec (:num-cells (:board @game-state)))))

(defn move! [from]
  (let [new-pos (next-pos from ((board!) :num-cells))
        ladder-pos (get (ladders!) new-pos)
        snake-pos (get (snakes!) new-pos)]
    (or snake-pos ladder-pos new-pos)))

(defn init-game! [board-size num-players]
  (let [players (into [] (repeat num-players 0))
        board (generate-board board-size)]
    (reset! game-state {:players players :board board})))

(defn play! []
  (while (not-any? is-winning-move? (players!))
    (let [positions (map move! (@game-state :players))]
      (swap! game-state assoc :players positions)
      (pp/pprint positions))))

(defn -main []
  (init-game! 20 5)
  (play!))