close_channel.go

package main

import (
	"fmt"
	"time"
)

type sender struct {
	ch chan string
}

func (s *sender) send(msg string) {
	s.ch <- msg
}

type receiver struct {
	ch chan string
}

func (r *receiver) recv() {
	for {
		msg := <-r.ch
		fmt.Println("received:", msg)
	}
}

func connect(s *sender, r *receiver) {
	ch := make(chan string)
	s.ch, r.ch = ch, ch
}

func disconnect(s *sender, r *receiver) {
	// What to do here?
	// close channel? this panics
	// close(s.ch)
	// or set channel to nil? this doesn't
	s.ch, r.ch = nil, nil
}

func main() {
	s := &sender{}
	r := &receiver{}
	connect(s, r)
	go r.recv()
	go func() {
		for {
			s.send("Hi there!")
			time.Sleep(time.Second * 1)
		}
	}()
	time.Sleep(time.Second * 3)
	disconnect(s, r)
	// wait for user input
	var input string
	fmt.Scanln(&input)
}