Closures

closes #35

guide/expressions.md

@@ -122,14 +122,35 @@ by `move`), but put a space between the second `|` and the expression of the
 closure. Between the `|`s, you should use function definition syntax, however,
 elide types where possible.
 
-Use closures without the enclosing `{}`, if possible. Add the `{}` when you
-have a return type, when there are statements before the final expression, or
-when you need to split it into multiple lines; examples:
+Use closures without the enclosing `{}`, if possible. Add the `{}` when you have
+a return type, when there are statements, there are comments in the body, or the
+body expression spans multiple lines and is a control-flow expression. If using
+braces, follow the rules above for blocks. Examples:
 
 ```rust
 |arg1, arg2| expr
 
-move |arg1: i32, arg2: i32| -> i32 { expr1; expr2 }
+move |arg1: i32, arg2: i32| -> i32 {
+ expr1;
+ expr2
+}
+
+|| Foo {
+ field1,
+ field2: 0,
+}
+
+|| {
+ if true {
+ blah
+ } else {
+ boo
+ }
+}
+
+|x| unsafe {
+ expr
+}
 ```
 
 ### Array literals