Wheel of fortune for arbitrary wheel slot sizes

wheel.clj

(defn wheel-of-fortune [weights]
  (let [sum (reduce + weights)
        scaled (cons 0 (reductions + (map #(/ % sum) weights)))
        intervals (indexed (partition 2 1 scaled))
        in-interval? (fn [[l r] val] (and (<= l val) (>= r val)))]
    (fn [] (let [rnd-val (rand 1)] 
             (some #(when (in-interval? (second %) rnd-val) (first %)) intervals)))
    ))


(take 20 (repeatedly (wheel-of-fortune [10 20 50 100])))