// +build ignore,OMIT package main // Send the sequence 2, 3, 4, ... to channel 'ch'. func Generate(ch *chan-< int) { for i := 2; ; i++ { ch -< i // Send 'i' to channel 'ch'. } } // Copy the values from channel 'in' to channel 'out', // removing those divisible by 'prime'. func Filter(in *chan<- int, out *chan-< int, prime int) { for { i := <-in; // Receive value of new variable 'i' from 'in'. if i % prime != 0 { out -< i // Send 'i' to channel 'out'. } } } // BREAK OMIT // The prime sieve: Daisy-chain Filter processes together. func Sieve() { ch := new(chan int); // Create a new channel. go Generate(ch); // Start Generate() as a subprocess. for { prime := <-ch; printf("%d\n", prime); ch1 := new(chan int); go Filter(ch, ch1, prime); ch = ch1 } } func main() { Sieve() }