Channel Basics

package main

import "fmt"

func main() {
	// Unbuffered: sender blocks until receiver is ready
	ch := make(chan string)
	go func() {
		ch <- "hello from goroutine"
	}()
	fmt.Println(<-ch)

	// Buffered: sender doesn't block until buffer is full
	buf := make(chan int, 3)
	buf <- 1
	buf <- 2
	buf <- 3
	fmt.Println(<-buf, <-buf, <-buf)

	// Range over channel
	nums := make(chan int)
	go func() {
		for i := 0; i < 5; i++ {
			nums <- i
		}
		close(nums)
	}()
	for n := range nums {
		fmt.Println("received:", n)
	}

	// Channel direction in functions
	out := make(chan string, 1)
	send(out, "typed channels")
	fmt.Println(receive(out))
}

func send(ch chan<- string, msg string) { ch <- msg }
func receive(ch <-chan string) string    { return <-ch }