gobyexample/channels/channels.go

package channels

import (
	"fmt"
	"strings"
	"unicode/utf8"
)

func header(title string) {
	fmt.Println(strings.Repeat("-", utf8.RuneCountInString(title)))
	fmt.Println(title)
	fmt.Println(strings.Repeat("-", utf8.RuneCountInString(title)))
	fmt.Println()
}

func simpleChannels() {
	header("Simple channels")

	message := make(chan string)

	go func() {
		message <- "beep bop!"
	}()

	msg := <-message
	fmt.Println("Received secret message:", msg)
	fmt.Println("Done")
}

func bufferedChannels() {
	header("Buffered channels")

	message := make(chan string, 2)

	message <- "secret 1!"
	message <- "secret 2!"

	fmt.Println("First message:", <-message)
	fmt.Println("Second message:", <-message)
	fmt.Println("Done")
}

func ping(pingc chan<- string, msg string) {
	pingc <- msg
}

func pong(pingc <-chan string, pongc chan<- string) {
	fmt.Println("pong() received message:", <-pingc)
	pongc <- "pong!"
}

func pingPong() {
	header("Channel Directions")
	pingc, pongc := make(chan string, 1), make(chan string, 1)
	ping(pingc, "ping!")
	pong(pingc, pongc)
	fmt.Println("Received message in pingPong():", <-pongc)
}

func Channels() {
	simpleChannels()
	bufferedChannels()
	pingPong()
}