bowling.clj

(ns clj-bowling.core)

(defn last-frame? [rolls]
  (<= (count rolls) 3))

(defn strike? [rolls]
  (= 10 (first rolls)))

(defn spare? [rolls]
  (= 10 (sum (take 2 rolls))))

(defn sum [col]
  (reduce + col))

(defn score [rolls]
  (cond
    (last-frame? rolls) (sum rolls)
    (strike? rolls)     (+ (sum (take 3 rolls)) (recur (nthrest rolls 1)))
    (spare? rolls)      (+ (sum (take 3 rolls)) (recur (nthrest rolls 2)))
    :else               (+ (sum (take 2 rolls)) (recur (nthrest rolls 2)))))