new(go): Add video "Google I/O 2012 - Go Concurrency Patterns" and some code from it.

diff --git a/go-concurrency-patterns/.gitignore b/go-concurrency-patterns/.gitignore
new file mode 100644 (file)
index 0000000..e9e5b3f
--- /dev/null
+++ b/go-concurrency-patterns/.gitignore
@@ -0,0 +1 @@
+conc1

diff --git a/go-concurrency-patterns/Google_IO_2012_-_Go_Concurrency_Patterns-Rob_Pike-f6kdp27TYZs.webm b/go-concurrency-patterns/Google_IO_2012_-_Go_Concurrency_Patterns-Rob_Pike-f6kdp27TYZs.webm
new file mode 120000 (symlink)
index 0000000..1b3a1a0
--- /dev/null
+++ b/go-concurrency-patterns/Google_IO_2012_-_Go_Concurrency_Patterns-Rob_Pike-f6kdp27TYZs.webm
@@ -0,0 +1 @@
+../.git/annex/objects/zW/j0/SHA256E-s427452422--4a49f19882b027b5db671084c06a574a6a05f41b8a9e285856fb3f1f76e00a8b.webm/SHA256E-s427452422--4a49f19882b027b5db671084c06a574a6a05f41b8a9e285856fb3f1f76e00a8b.webm
\ No newline at end of file

diff --git a/go-concurrency-patterns/conc1.go b/go-concurrency-patterns/conc1.go
new file mode 100644 (file)
index 0000000..82f4a73
--- /dev/null
+++ b/go-concurrency-patterns/conc1.go
@@ -0,0 +1,59 @@
+
+package main
+
+import (
+    "fmt"
+    "time"
+    "math/rand"
+)
+
+func boring(msg string) <- chan string {
+    c := make(chan string)
+    go func() {
+        for i := 0; ; i++ {
+            r := rand.Intn(3e3)
+            c <- fmt.Sprintf("%s %d (%d)", msg, i, r)
+            time.Sleep(time.Duration(r) * time.Millisecond)
+        }
+    }()
+    return c
+}
+
+func main1() {
+    c := boring("boring!")
+    for i := 0; i< 5; i++ {
+        fmt.Printf("You say: %q\n", <-c)
+    }
+    fmt.Println("You're boring. I'm leaving.")
+}
+
+func main2() {
+    joe := boring("Joe")
+    ann := boring("Ann")
+    for i := 0; i < 5; i++ {
+        fmt.Println(<-joe)
+        fmt.Println(<-ann)
+    }
+    fmt.Println("You're both boring. I'm leaving.")
+}
+
+func fanIn(input1, input2 <- chan string) <-chan string {
+    c := make(chan string)
+    go func() { for { c <- <-input1 } }()
+    go func() { for { c <- <-input2 } }()
+    return c
+}
+
+func main3() {
+    c := fanIn(boring("Joe"), boring("Ann"))
+    for i := 0; i < 10; i++ {
+        fmt.Printf("%q\n", <-c)
+    }
+    fmt.Println("You're boring. I'm leaving.")
+}
+
+func main() {
+    rand.Seed(time.Now().Unix())
+
+    main3()
+}