golang-channel-pipeline.go

// from https://yar999.gitbooks.io/gopl-zh/content/ch8/ch8-04.html
// gopl.io/ch8/pipeline3

package main

import (
	"fmt"
	//"sync"
)

func counter(out chan<- int) {
	for x := 0; x < 100; x++ {
		out <- x
		fmt.Println("A. counter sent", x)
	}
	close(out)
}

func squarer(in <-chan int, out chan<- int) {
	for v := range in {
		out <- v * v
		fmt.Println("B. squarer received", v)
	}
	close(out)
}

func printer(in <-chan int, outQuit chan<- int) {
	for v := range in {
		fmt.Println("C. printer received", v)
	}
	outQuit <- 0
}

func main() {
	naturals := make(chan int)
	squares := make(chan int)
	quit := make(chan int)

	// Counter
	go counter(naturals)

	// Squarer
	go squarer(naturals, squares)

	// Printer
	go printer(squares, quit)

	<-quit
	fmt.Println("main received quit")
}