Rust 语言学习手册

`match` 是强大的模式匹配工具，必须穷尽所有可能。 ```rust enum Coin { Penny, Nickel, Dime, Quarter } fn value_in_cents(coin: Coin) -> u8 { match coin { Coin::Penny => 1, Coin::Nickel => 5, Coin::Dime => 10, Coin::Quarter => 25, } } ``` **匹配 Option：** ```rust fn plus_one(x: Option) -> Option { match x { None => None, Some(i) => Some(i + 1), } } ``` **`_` 通配符**：处理剩余情况。 ```rust let some_u8_value = 0u8; match some_u8_value { 1 => println!("one"), 3 => println!("three"), _ => (), } ``` **if let**：简化只关心一种模式的场景。 ```rust if let Some(max) = some_value { println!("{}", max); } else { println!("nothing"); } ``` **while let** 循环匹配。