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

5 files changed, 191 insertions, 3 deletions

diff --git a/doc/progs/cat_rot13.go b/doc/progs/cat_rot13.go
index d5050155d..a8c570add 100644
--- a/doc/progs/cat_rot13.go
+++ b/doc/progs/cat_rot13.go
@@ -11,15 +11,14 @@ import (
 
 var rot13_flag = Flag.Bool("rot13", false, nil, "rot13 the input")
 
-func rot13(bb byte) byte {
-	var b int = int(bb)      /// BUG: until byte division is fixed
+func rot13(b byte) byte {
 	if 'a' <= b && b <= 'z' {
 	   b = 'a' + ((b - 'a') + 13) % 26;
 	}
 	if 'A' <= b && b <= 'Z' {
 	   b = 'A' + ((b - 'A') + 13) % 26
 	}
-	return byte(b)
+	return b
 }
 
 type Reader interface {
diff --git a/doc/progs/server.go b/doc/progs/server.go
new file mode 100644
index 000000000..3f64e9df0
--- /dev/null
+++ b/doc/progs/server.go
@@ -0,0 +1,49 @@
+// 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
+
+type BinOp (a, b int) int;
+
+type Request struct {
+	a, b	int;
+	replyc	*chan int;
+}
+
+func Run(op *BinOp, request *Request) {
+	result := op(request.a, request.b);
+	request.replyc -< result;
+}
+
+func Server(op *BinOp, service *chan *Request) {
+	for {
+		request := <-service;
+		go Run(op, request);  // don't wait for it
+	}
+}
+
+func StartServer(op *BinOp) *chan *Request {
+	req := new(chan *Request);
+	go Server(op, req);
+	return req;
+}
+
+func main() {
+	adder := StartServer(func(a, b int) int { return a + b });
+	const N = 100;
+	var reqs [N]Request;
+	for i := 0; i < N; i++ {
+		req := &reqs[i];
+		req.a = i;
+		req.b = i + N;
+		req.replyc = new(chan int);
+		adder -< req;
+	}
+	for i := N-1; i >= 0; i-- {   // doesn't matter what order
+		if <-reqs[i].replyc != N + 2*i {
+			print("fail at ", i, "\n");
+		}
+	}
+	print("done\n");
+}
diff --git a/doc/progs/server1.go b/doc/progs/server1.go
new file mode 100644
index 000000000..5d24d8a4a
--- /dev/null
+++ b/doc/progs/server1.go
@@ -0,0 +1,55 @@
+// 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
+
+type BinOp (a, b int) int;
+
+type Request struct {
+	a, b	int;
+	replyc	*chan int;
+}
+
+func Run(op *BinOp, request *Request) {
+	result := op(request.a, request.b);
+	request.replyc -< result;
+}
+
+func Server(op *BinOp, service *chan *Request, quit *chan bool) {
+	for {
+		var request *Request;
+		select {
+		case request <- service:      // can't say request := <-service here yet
+			go Run(op, request);  // don't wait for it
+		case <-quit:
+			return;
+		}
+	}
+}
+
+func StartServer(op *BinOp) (servch *chan *Request, quitch *chan bool) {
+	service := new(chan *Request);
+	quit := new(chan bool);
+	go Server(op, service, quit);
+	return service, quit;
+}
+
+func main() {
+	adder, quit := StartServer(func(a, b int) int { return a + b });
+	const N = 100;
+	var reqs [N]Request;
+	for i := 0; i < N; i++ {
+		req := &reqs[i];
+		req.a = i;
+		req.b = i + N;
+		req.replyc = new(chan int);
+		adder -< req;
+	}
+	for i := N-1; i >= 0; i-- {   // doesn't matter what order
+		if <-reqs[i].replyc != N + 2*i {
+			print("fail at ", i, "\n");
+		}
+	}
+	quit -< true;
+}
diff --git a/doc/progs/sieve.go b/doc/progs/sieve.go
new file mode 100644
index 000000000..60760cf4e
--- /dev/null
+++ b/doc/progs/sieve.go
@@ -0,0 +1,36 @@
+// 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 main() {
+	ch := new(chan int);  // Create a new channel.
+	go Generate(ch);  // Start Generate() as a goroutine.
+	for {
+		prime := <-ch;
+		print(prime, "\n");
+		ch1 := new(chan int);
+		go Filter(ch, ch1, prime);
+		ch = ch1
+	}
+}
diff --git a/doc/progs/sieve1.go b/doc/progs/sieve1.go
new file mode 100644
index 000000000..2cb90600b
--- /dev/null
+++ b/doc/progs/sieve1.go
@@ -0,0 +1,49 @@
+// 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");
+	}
+}