seqpat2.clj

gistfile1.clj

(let [x 1 y 2 z 4]
    (match [x y z]
           [1 2 b] b
           [a 2 4] a))

;; =>

(cond
 (= x 1) (cond
          (= y 2) (let [b z] b)
          :else (throw (java.lang.Exception. "Found FailNode")))
 :else (cond
        (= y 2) (cond
                 (= z 4) (let [a x] a)
                 :else (throw
                        (java.lang.Exception. "Found FailNode")))
        :else (throw (java.lang.Exception. "Found FailNode"))))

;; perf

;;  170ms
(let [x '(1 2 nil nil nil)]
  (dotimes [_ 10]
    (time
     (dotimes [_ 1e6]
       (match [x]
              [(1)]     :a0
              [(1 2)]   :a1
              [(1 2 nil nil nil)] :a2)))))

;; 750ms
(let [x '(1 2 nil nil nil)]
  (dotimes [_ 10]
    (time
     (dotimes [_ 1e6]
       (let [[a b c d e] x])))))