英文:
Is there a purpose for "make"ing a one-directional channel?
问题
NB：这不是这个问题的重复，因为我理解何时使用单向通道。我一直这样做。我的问题是为什么这个程序是有效的：
func main() {
ch := make(chan<- int)
ch <- 5
fmt.Println("Hello, playground")
}
运行它，当然会导致死锁。如果你用%T检查类型，Go实际上会报告ch的类型是一个只发送的通道。在Go中，你可以使用make创建单向通道，但这没有太多意义，因为通过创建一个在初始时只能单向传输的通道，你确保至少一个读/写操作永远不会发生。
一个可能的解释是强制一个goroutine挂起，但是使用select {}同样容易实现。
我唯一的其他想法是强制一个goroutine只执行n次操作：
ch := make(chan<- int, 50)
// 做50次操作，因为缓冲区已满
for {
ch <- doSomething()
}
但是这更容易实现，而且更不容易引起混淆，可以使用许多不同的结构来实现。
这只是类型系统的一个怪癖/疏忽，还是我没有考虑到这种行为的用途？
英文:
NB: This is not a duplicate of this question, because I understand when you would use one-directional channels. I do so all the time. My question is why this program is valid:
func main() {
ch := make(chan<- int)
ch <- 5
fmt.Println("Hello, playground")
}
Running it, of course, gives a deadlock. If you check the type with %T, Go does in fact report that the type of ch is a send-only channel. In Go, you're allowed to make uni-directional channels, but it makes little sense because by making a channel that at its inception is one-way only, you're ensuring at least one of read/write will never occur.
A possible explanation would be to force a goroutine to hang but that's just as easily accomplished with select {}.
My only other idea is to force a goroutine to only do something n times,
ch := make(chan<- int, 50)
// do something 50 times, since then the buffer is full
for {
ch <- doSomething()
}
But that's more easily, not to mention less confusingly, accomplished with any number of different constructions.
Is this just a quirk/oversight of the type system, or is there use for this behavior I'm not thinking of?
答案1
得分: 4
你有一种语言：单词（标记）和语法。你总是可以写出有效的胡言乱语：蓝色不是一种颜色。
你写了一些有效的胡言乱语：
package main
func main() {
ch := make(chan<- int)
ch <- 5
}
这里还有一些有效的胡言乱语：
package main
func main() {
for {
}
}
英文:
You have a language: words (tokens) and a grammar. You can always write valid nonsense: blue is not a color.
You wrote some valid nonsense:
package main
func main() {
ch := make(chan<- int)
ch <- 5
}
Here's some more valid nonsense:
package main
func main() {
for {
}
}
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论