如何在匹配表达式中进行多重绑定或模式？

Question

有没有办法绑定同名的一堆或匹配项？

因此，例如在下面的代码中，我希望 n 是任何匹配项，1、2 或 3.

fn main() {
    match 2 {
        n @ 1 | 2 | 3 => {
            println!("{}", n);
        }
        _ => {},
    }
}

Playground

它抱怨：

error[E0408]: variable `n` is not bound in all patterns
 --> src/main.rs:3:17
  |
3 |         n @ 1 | 2 | 3 => {
  |         -       ^   ^ pattern doesn't bind `n`
  |         |       |
  |         |       pattern doesn't bind `n`
  |         variable not in all patterns

Answer 1

用 ()（括号）将 or 匹配包围起来就可以正确绑定：

fn main() {
    match 2 {
        n @ (1 | 2 | 3) => {
            println!("{}", n);
        }
        _ => {},
    }
}

Playground

如何在匹配表达式中进行多重绑定或模式？

How to multibind or patterns in match expressions?

match

rust