go/doc/progs/sieve1.go
Rob Pike db9002f152 replace 235 with sieve - less problematic
add programs, not yet described, to demonstrate servers.

R=gri
DELTA=279  (177 added, 16 deleted, 86 changed)
OCL=15380
CL=15389
2008-09-16 11:00:11 -07:00

50 lines
928 B
Go

// 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 returned channel
func Generate() *chan int {
ch := new(chan int);
go func(ch *chan int){
for i := 2; ; i++ {
ch -< i
}
}(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 := new(chan int);
go func(in *chan int, out *chan int, prime int) {
for {
if i := <-in; i % prime != 0 {
out -< i
}
}
}(in, out, prime);
return out;
}
func Sieve() *chan int {
out := new(chan int);
go func(out *chan int) {
ch := Generate();
for {
prime := <-ch;
out -< prime;
ch = Filter(ch, prime);
}
}(out);
return out;
}
func main() {
primes := Sieve();
for {
print(<-primes, "\n");
}
}