在对此question的答案中,响应者使用功能reduced
(defn state [t]
(reduce (fn [[s1 t1] [s2 t2]]
(if (>= t1 t) (**reduced** s1) [s2 (+ t1 t2)]))
(thomsons-lamp)))
我查看了文档和源,无法完全理解它。
(defn reduced
"Wraps x in a way such that a reduce will terminate with the value x"
{:added "1.5"}
[x]
(clojure.lang.Reduced. x))
在上面的示例中,我认为
(reduced s1)
应该结束缩减并返回s1。如果使用reduce + reduce等于假设的reduce-while或reduce-until函数(如果存在)?
最佳答案
减少提供了一种突破减少提供的值的方法。
例如将数字相加
(reduce (fn [acc x] (+ acc x)) (range 10))
返回45
(reduce (fn [acc x] (if (> acc 20) (reduced "I have seen enough") (+ acc x))) (range 10))
返回“我已经看够了”