Question

当预期返回5时，repl返回2.

(defn counter [] 
  (let [count 1]
    (fn [] 
      (+ count 1)
    )
  )
)

(defn test-counter []
  (let [increment (counter)]
    (increment)
    (increment)
    (increment)
    (increment)
  )
)

Answer 1

count不是可变变量，因此(+ count 1)不会更改其值。如果您想要变异，可以将计数存储在atom中并使用swap!进行更新：

(defn counter []
  (let [count (atom 0)]
    (fn [] (swap! count inc))))

Clojure闭合不符合预期？

1 个答案: