【Go语言并发之道】第四章 repeat生成器

记录了书上的错误…

先直接上代码吧。

package main

import (
	"fmt"
)

func main() {

	repeat := func(
		done <-chan interface{},
		values ...interface{},
	) <-chan interface{} {
		valueStream := make(chan interface{})
		go func() {
			defer close(valueStream)
			for {
				for _, v := range values {
					select {
					case <-done:
						return
					case valueStream <- v:
					}
				}
			}
		}()
		return valueStream
	}

	take := func(
		done <-chan interface{},
		valueStream <-chan interface{},
		num int,
	) <-chan interface{} {
		takeStream := make(chan interface{})
		go func() {
			defer close(takeStream)
			for i := 0; i < num; i++ {
				select {
				case <-done:
					return
				case takeStream <- <- valueStream:
				}
			}
		}()
		return takeStream
	}

	done := make(chan interface{})
	defer close(done)

	for num := range take(done, repeat(done, 1, 2, 3), 10) {
		fmt.Printf("%v ", num)
	}
	fmt.Println()
}

package main

import (

"fmt"

)

func main() {

repeat := func(

done <-chan interface{},

values ...interface{},

) <-chan interface{} {

valueStream := make(chan interface{})

go func() {

defer close(valueStream)

for {

for _, v := range values {

select {

case <-done:

return

case valueStream <- v:

}

}()

return valueStream

}

take := func(

done <-chan interface{},

valueStream <-chan interface{},

num int,

) <-chan interface{} {

takeStream := make(chan interface{})

go func() {

defer close(takeStream)

for i := 0; i < num; i++ {

select {

case <-done:

return

case takeStream <- <- valueStream:

}

}()

return takeStream

}

done := make(chan interface{})

defer close(done)

for num := range take(done, repeat(done, 1, 2, 3), 10) {

fmt.Printf("%v ", num)

}

fmt.Println()

}

这里注意 case takeStream <- <- valueStream: (line 41)这一行，书中原文是一个箭头，但是实际上要两个。

原因是我们需要将 valueStream内容取出来然后塞进takeStream里面去。

但是因为类型是 interface，然后原文只有一个箭头： case takeStream <- valueStream:

意义就变成了将 valueStream直接塞到了takeStream里面去了。

【Go语言并发之道】第四章 repeat生成器

Tagged on: Go