From c67921cb0edcc9761a800a8078886899aed6871c Mon Sep 17 00:00:00 2001 From: Niall Grant Date: Tue, 5 May 2020 17:09:39 +0100 Subject: [PATCH] Improve Channel Direction example --- .../channel-directions/channel-directions.go | 28 ++++++++------- .../channel-directions.hash | 4 +-- .../channel-directions/channel-directions.sh | 4 ++- public/channel-directions | 36 ++++++++++--------- 4 files changed, 40 insertions(+), 32 deletions(-) diff --git a/examples/channel-directions/channel-directions.go b/examples/channel-directions/channel-directions.go index 5f2786c..0636baa 100644 --- a/examples/channel-directions/channel-directions.go +++ b/examples/channel-directions/channel-directions.go @@ -7,24 +7,26 @@ package main import "fmt" -// This `ping` function only accepts a channel for sending +// This `send` function only accepts a channel for sending // values. It would be a compile-time error to try to // receive on this channel. -func ping(pings chan<- string, msg string) { - pings <- msg +func send(sendCh chan<- string, msg string) { + fmt.Println("send message:", msg) + sendCh <- msg } -// The `pong` function accepts one channel for receives -// (`pings`) and a second for sends (`pongs`). -func pong(pings <-chan string, pongs chan<- string) { - msg := <-pings - pongs <- msg +// The `fwd` function accepts one channel for receives +// (`sendCh`) and a second for sends (`forwardCh`). +func fwd(sendCh <-chan string, forwardCh chan<- string) { + msg := <-sendCh + fmt.Println("forwarding:", msg) + forwardCh <- msg } func main() { - pings := make(chan string, 1) - pongs := make(chan string, 1) - ping(pings, "passed message") - pong(pings, pongs) - fmt.Println(<-pongs) + sendCh := make(chan string, 1) + forwardCh := make(chan string, 1) + send(sendCh, "Hello, World!") + fwd(sendCh, forwardCh) + fmt.Println("reading messages: ", <-forwardCh) } diff --git a/examples/channel-directions/channel-directions.hash b/examples/channel-directions/channel-directions.hash index b848781..53b2309 100644 --- a/examples/channel-directions/channel-directions.hash +++ b/examples/channel-directions/channel-directions.hash @@ -1,2 +1,2 @@ -d1b1580f72c3c101ea46480e6c2361f4f96b049a -mjNJDHwUH4R +3c2151473e3a75fb2318566ad1d5528919cd47fa +tyxhbRAiXMa diff --git a/examples/channel-directions/channel-directions.sh b/examples/channel-directions/channel-directions.sh index 8db5cb6..4d42227 100644 --- a/examples/channel-directions/channel-directions.sh +++ b/examples/channel-directions/channel-directions.sh @@ -1,2 +1,4 @@ $ go run channel-directions.go -passed message +send message: Hello, World! +forwarding: Hello, World! +reading messages: Hello, World! diff --git a/public/channel-directions b/public/channel-directions index 2814e81..2c8b046 100644 --- a/public/channel-directions +++ b/public/channel-directions @@ -44,7 +44,7 @@ the program.

- + 
package main
@@ -65,15 +65,16 @@ the program.

-

This ping function only accepts a channel for sending +

This send function only accepts a channel for sending values. It would be a compile-time error to try to receive on this channel.

- 
func ping(pings chan<- string, msg string) {
-    pings <- msg
+          
func send(sendCh chan<- string, msg string) {
+    fmt.Println("send message:", msg)
+    sendCh <- msg
 }
 

 
@@ -82,15 +83,16 @@ receive on this channel.

         
         
           
-            
The pong function accepts one channel for receives
-(pings) and a second for sends (pongs).

+            
The fwd function accepts one channel for receives
+(sendCh) and a second for sends (forwardCh).

 
           
           
             
-          
func pong(pings <-chan string, pongs chan<- string) {
-    msg := <-pings
-    pongs <- msg
+          
func fwd(sendCh <-chan string, forwardCh chan<- string) {
+    msg := <-sendCh
+    fmt.Println("forwarding:", msg)
+    forwardCh <- msg
 }
 

 
@@ -104,11 +106,11 @@ receive on this channel.

           
             
           
func main() {
-    pings := make(chan string, 1)
-    pongs := make(chan string, 1)
-    ping(pings, "passed message")
-    pong(pings, pongs)
-    fmt.Println(<-pongs)
+    sendCh := make(chan string, 1)
+    forwardCh := make(chan string, 1)
+    send(sendCh, "Hello, World!")
+    fwd(sendCh, forwardCh)
+    fmt.Println("reading messages: ", <-forwardCh)
 }
 

 
@@ -126,7 +128,9 @@ receive on this channel.

           
             
           
$ go run channel-directions.go
-passed message
+send message: Hello, World!
+forwarding: Hello, World!
+reading messages:  Hello, World!
 

 
           
@@ -145,7 +149,7 @@ receive on this channel.