// cspbook 4.4 X2 UNPACK >> PACK

unpack.go

package main

import "fmt"

// cspbook 4.4 X2 UNPACK >> PACK

func unpack(in <-chan string, out chan<- rune) {
	for s := range in {
		for _, c := range s {
			out <- c
		}
	}
	close(out)
}

func pack(in <-chan rune, out chan<- string) {
	done := false
	for !done {
		s := ""
		for c := range in {
			s = s + string(c)
			if len(s) == 5 {
				break
			}
		}
		out <- s
		done = len(s) < 5
	}
	close(out)
}

func main() {
	c1 := make(chan string)
	c2 := make(chan rune)
	c3 := make(chan string)
	
	go unpack(c1, c2)
	go pack(c2, c3)
	
	go func() {
		c1 <- "1234"
		c1 <- "1234"
		c1 <- "1234"
		close(c1)
	} ()
	for c := range c3 {
		fmt.Printf("%q \n", c)
	}
}