关于clojure：为什么我只能拿一包！ 从这个频道？


Why am I only getting one take! from this channel?

试图了解渠道如何运作； 我不明白为什么我的take!在此REPL序列中只能运行一次，即使我尝试了多次推子：

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cplay.core> (def h (chan))
#'cplay.core/h
cplay.core> (go (put! h"hello"))
#<ManyToManyChannel clojure.core.async.impl.channels.ManyToManyChannel@4afdd6ba>
cplay.core> (go (take! h (fn [x] (println x))))
#<ManyToManyChannel clojure.core.async.impl.channels.ManyToManyChannel@9fe39a1>
cplay.core> hello

cplay.core> (go (take! h (fn [x] (println x))))
#<ManyToManyChannel clojure.core.async.impl.channels.ManyToManyChannel@206564e9>
cplay.core> (go (put! h"hello"))
#<ManyToManyChannel clojure.core.async.impl.channels.ManyToManyChannel@6c0ec468>
cplay.core> (go (take! h (fn [x] (println x))))
#<ManyToManyChannel clojure.core.async.impl.channels.ManyToManyChannel@60c85184>
cplay.core> (go (take! h (fn [x] (println x))))
#<ManyToManyChannel clojure.core.async.impl.channels.ManyToManyChannel@3edc08c3>
cplay.core> (go (take! h (fn [x] (println x))))
#<ManyToManyChannel clojure.core.async.impl.channels.ManyToManyChannel@6a7b295f>
cplay.core> (go (put! h"hello"))
#<ManyToManyChannel clojure.core.async.impl.channels.ManyToManyChannel@60331d8b>
cplay.core> (go (take! h (fn [x] (println x))))
#<ManyToManyChannel clojure.core.async.impl.channels.ManyToManyChannel@557c3bce>
cplay.core> (go (put! h"hello"))
#<ManyToManyChannel clojure.core.async.impl.channels.ManyToManyChannel@203fdcfb>
cplay.core> (go (put! h"hello"))
#<ManyToManyChannel clojure.core.async.impl.channels.ManyToManyChannel@ed11c1>
cplay.core> (go (take! h (fn [x] (println x))))
#<ManyToManyChannel clojure.core.async.impl.channels.ManyToManyChannel@6c7ea146>
cplay.core>

是否是因为当通道上什么都没有时，我随后连续几次从通道中取出，从而留下了"空洞"，这些空洞被后续的看跌期权所填充，直到通道以某种方式恢复到甚至是看跌期权的数量为止？

相关讨论

在这种异步情况下，println行为很奇怪。
如果您最后一次调用是"接管！" fn然后，您将最终获得打印结果，但最后四个调用是" put！"。 fn然后您必须在nrepl-server终端上找到打印结果。

这种行为和必要的工作空间是在core.async的Timothy Baldridge视频的开头介绍的

这是我在emacs中的两帧的一个屏幕截图，一个用于nrepl，另一个用于nrepl-server输出

相关讨论

不要用go包装put!和take!。 想要或!>进入内部：

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user=> (require '[clojure.core.async :refer (chan put! take! <! >!)])
nil
user=> (def h (chan))
#'user/h
user=> (put! h"hello")
true
user=> (take! h println)
hello
nil
user=> (put! h"hello")
true
user=> (take! h println)
hello
nil
user=> (put! h"hello")
true
user=> (take! h println)
hello
nil
user=> (put! h"hello")
true
user=> (take! h println)
hello
nil
user=> (take! h println)
nil
user=> (put! h"hello")
hello
true
相关讨论