这是一个来自 clojure 的勇敢而真实的例子:
(time
(let [butter-promise (promise)]
(doseq [butter [yak-butter-international butter-than-nothing baby-got-yak]]
(future (if-let [satisfactory-butter (satisfactory? (mock-api-call butter))]
(deliver butter-promise satisfactory-butter))))
(println "And the winner is:" @butter-promise)))
如果没有黄油产品满足我们的标准怎么办？
最佳答案
(let [butter-promise (promise)]
;; ...
(if-let [winner (deref butter-promise 10000 nil)]
(println "And the winner is:" winner)
(println "Butter timed out."))
关于concurrency - 如何防止未交付的 promise 挂起？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/30382601/