go-tour: add defer slides
LGTM=adg
R=adg, campoy
CC=golang-codereviews
https://golang.org/cl/110520043
diff --git a/content/flowcontrol.article b/content/flowcontrol.article
index d910680..ef5fa59 100644
--- a/content/flowcontrol.article
+++ b/content/flowcontrol.article
@@ -108,6 +108,26 @@
.play prog/tour/switch-with-no-condition.go
+* Defer
+
+A defer statement defers the execution of a function until the surrounding
+function returns.
+
+The deferred call's arguments are evaluated immediately, but the function call
+is not executed until the surrounding function returns.
+
+.play prog/tour/defer.go
+
+* Stacking defers
+
+Deferred function calls are pushed onto a stack. When a function returns, its
+deferred calls are executed in last-in-first-out order.
+
+To learn more about defer statements read this
+[[http://blog.golang.org/defer-panic-and-recover][blog post]].
+
+.play prog/tour/defer-multi.go
+
* Congratulations!
You finished this lesson!
diff --git a/content/prog/tour/defer-multi.go b/content/prog/tour/defer-multi.go
new file mode 100644
index 0000000..30af534
--- /dev/null
+++ b/content/prog/tour/defer-multi.go
@@ -0,0 +1,13 @@
+package main
+
+import "fmt"
+
+func main() {
+ fmt.Println("counting")
+
+ for i := 0; i < 10; i++ {
+ defer fmt.Println(i)
+ }
+
+ fmt.Println("done")
+}
diff --git a/content/prog/tour/defer.go b/content/prog/tour/defer.go
new file mode 100644
index 0000000..92cac76
--- /dev/null
+++ b/content/prog/tour/defer.go
@@ -0,0 +1,9 @@
+package main
+
+import "fmt"
+
+func main() {
+ defer fmt.Println("world")
+
+ fmt.Println("hello")
+}
