(defconst nums [5 i32] [1 3 8 9 10])

(defn classify [n i32] string
  (cond
    (< n 0)  "negative"
    (= n 0)  "zero"
    :else    "positive"))

(defn countdown [n i32]
  (let [i n]
    (while (> i 0)
      (print i)
      (print " ")
      (set i (- i 1)))
    (println "")))

(defn first-even [s [i32]] (Option i32)
  (dotimes [i (len s)]
    (when (= 0 (% (at s i) 2))
      (return (Some (at s i)))))
  None)

(defn main []
  (println (classify -3))
  (countdown 4)
  (unless false
    (println "unless runs when the test is false"))
  (match (first-even (slice nums 0 (len nums)))
    (Some n) (do (print n) (println ""))
    None     (println "none")))