package main

import "fmt"

const max = 10000

// Send the sequence 2, 3, 4, ... to returned channel
func generate() chan int {
	ch := make(chan int)
	go func() {
		for i := 2; i < max; i++ {
			ch <- i
		}
		close(ch)
	}()
	return ch
}

// Filter out input values divisible by 'prime', send rest to returned channel
func filter(in chan int, prime int) chan int {
	out := make(chan int)
	go func() {
		for {
			i, open := <-in
			if !open {
				break
			}
			if i%prime != 0 {
				out <- i
			}

		}
		close(out)
	}()
	return out
}

func sieve() chan int {
	out := make(chan int)
	go func() {
		ch := generate()
		for {
			prime, open := <-ch
			if !open {
				break
			}
			ch = filter(ch, prime)
			out <- prime
		}
		close(out)
	}()
	return out
}

func main() {
	primes := sieve()
	for {
		val, open := <-primes
		if !open {
			break
		}
		fmt.Println(val)

	}
}