---

yaml
---
r: 216990
b: refs/heads/stable
c: f59f41e
h: refs/heads/master
v: v3

Author: geofft

[refs]

@@ -29,5 +29,5 @@ refs/heads/tmp: 378a370ff2057afeb1eae86eb6e78c476866a4a6
 refs/tags/1.0.0-alpha.2: 4c705f6bc559886632d3871b04f58aab093bfa2f
 refs/tags/homu-tmp: a5286998df566e736b32f6795bfc3803bdaf453d
 refs/tags/1.0.0-beta: 8cbb92b53468ee2b0c2d3eeb8567005953d40828
-refs/heads/stable: 8d50216e9dfb055d28abf9da35f91542c2e9fe90
+refs/heads/stable: f59f41e04c044f322285f80d17916bd207d8ed04
 refs/tags/1.0.0: 55bd4f8ff2b323f317ae89e254ce87162d52a375

branches/stable/src/doc/trpl/match.md

@@ -61,3 +61,40 @@ let number = match x {
 ```
 
 Sometimes it’s a nice way of converting something from one type to another.
+
+# Matching on enums
+
+Another important use of the `match` keyword is to process the possible
+variants of an enum:
+
+```rust
+enum Message {
+    Quit,
+    ChangeColor(i32, i32, i32),
+    Move { x: i32, y: i32 },
+    Write(String),
+}
+
+fn quit() { /* ... */ }
+fn change_color(r: i32, g: i32, b: i32) { /* ... */ }
+fn move_cursor(x: i32, y: i32) { /* ... */ }
+
+fn process_message(msg: Message) {
+    match msg {
+        Message::Quit => quit(),
+        Message::ChangeColor(r, g, b) => change_color(r, g, b),
+        Message::Move { x: x, y: y } => move_cursor(x, y),
+        Message::Write(s) => println!("{}", s),
+    };
+}
+```
+
+Again, the Rust compiler checks exhaustiveness, so it demands that you
+have a match arm for every variant of the enum. If you leave one off, it
+will give you a compile-time error unless you use `_`.
+
+Unlike the previous uses of `match`, you can’t use the normal `if`
+statement to do this. You can use the [`if let`][if-let] statement,
+which can be seen as an abbreviated form of `match`.
+
+[if-let][if-let.html]