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// $G $F.go && $L $F.$A # don't run it - goes forever
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
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'.
}
}
}
// 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()
}
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