generator-with-channel.go https://play.golang.org/p/xaKzUfd2sJ

generator-with-channel.go

package main

import (
	"fmt"
)

type IntGenerator struct {
	Chan chan int
	n    int
}

func NewIntGenerator() *IntGenerator {
	g := &IntGenerator{make(chan int), 0}
	go func() {
		for {
			select {
			case g.Chan <- g.n:
				g.n++
			}
		}
	}()
	return g
}

func (g *IntGenerator) Next() int {
	return <-g.Chan
}

func main() {
	g := NewIntGenerator()
	fmt.Println(g.Next())
	fmt.Println(g.Next())
	fmt.Println(g.Next())
}