一个匹配guard可以被添加到过滤手臂。
| fn main() { |
| let pair = (2, -2); |
| // TODO ^ Try different values for `pair` |
| println!("Tell me about {:?}", pair); |
| match pair { |
| (x, y) if x == y => println!("These are twins"), |
| // The ^ `if condition` part is a guard |
| (x, y) if x + y == 0 => println!("Antimatter, kaboom!"), |
| (x, _) if x % 2 == 1 => println!("The first one is odd"), |
| _ => println!("No correlation..."), |
| } |
| } |
