go by example part 3

5-go-by-example/27-channel-directions.go

@@ -0,0 +1,23 @@
+// specify if a channel is meant to only send or receive values
+package main
+
+import "fmt"
+
+// ping function only accepts a channel for sending values
+func ping(pings chan<- string, msg string) {
+	pings <- msg
+}
+
+// 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
+}
+
+func main() {
+	pings := make(chan string, 1)
+	pongs := make(chan string, 1)
+	ping(pings, "passed message")
+	pong(pings, pongs)
+	fmt.Println(<-pongs)
+}