转换器如何在 core.async 个通道中执行？

Question

将频道设为这样的频道时：

(chan 10 tx)

如果我像这样创建了 10 个通道，然后同时向所有通道发送一条消息，转换器将如何执行。他们会运行并发还是在一个线程上？

Answer 1

我认为现在换能器为运行时的行为未定义，但查看 ManyToManyChannel 的实现，换能器（即 add! 字段) 在通道写入和读取时都可以调用。

运行一个简单的测试好像是如果channel没满，写线程会执行transducer，但是如果channel满了，有时读线程运行s it.

具有小缓冲区的示例：

(defn thread-name []
  (.getName (Thread/currentThread)))

(require '[clojure.core.async :as async :refer [chan <! >! >!! go]])

(defn p [& args]
  (locking *out*
          (apply println (thread-name) ":" args)))

(defn log [v]
  (p "Transforming" v)
  v)

(def tx (map log))

(def c (chan 1 tx))
(def c2 (chan 1 tx))

(go
  (loop []
    (when-let [v (<! c)]
      (p "Getting from c1" v)
      (<! (async/timeout 100))
      (recur))))

(go
  (loop []
    (when-let [v (<! c2)]
      (p "Getting from c2" v)
      (<! (async/timeout 100))
      (recur))))

(dotimes [_ 5]
  (p "Putting in c1" 1)
  (>!! c 1)
  (p "Putting in c2" 100)
  (>!! c2 100))

产生输出：

nREPL-worker-20 : Transforming 1
nREPL-worker-20 : Putting in c2 100
async-dispatch-33 : Getting from c1 1
nREPL-worker-20 : Transforming 100
nREPL-worker-20 : Putting in c1 1
async-dispatch-31 : Getting from c2 100
nREPL-worker-20 : Transforming 1
nREPL-worker-20 : Putting in c2 100
nREPL-worker-20 : Transforming 100
nREPL-worker-20 : Putting in c1 1
async-dispatch-35 : Getting from c2 100
async-dispatch-34 : Transforming 1 <---- In this case is run in the reading side
async-dispatch-34 : Getting from c1 1
nREPL-worker-20 : Putting in c2 100
nREPL-worker-20 : Transforming 100
async-dispatch-37 : Getting from c2 100
async-dispatch-36 : Getting from c1 1
nREPL-worker-20 : Putting in c1 1

转换器如何在 core.async 个通道中执行？

How are transducers executed in core.async channels?

clojure

clojurescript

core.async