Match

• Match is exhaustive
• _ Placeholder can be used as a catch-all
• Functions with specific return types can be specified

Enums

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,
    }
}

Option<T>

fn plus_one(x: Option<i32>) -> Option<i32> {
        match x {
            None => None,
            Some(i) => Some(i + 1),
        }
    }

    let five = Some(5);
    let six = plus_one(five);
    let none = plus_one(None);

If-let

The if let syntax lets you combine if and let into a less verbose way to handle values that match one pattern while ignoring the rest

let config_max = Some(3u8);

match config_max {
    Some(max) => println!("The maximum is configured to be {}", max),
    _ => (),
}

Estas son expresiones equivalentes

let config_max = Some(3u8);

if let Some(max) = config_max {
    println!("The maximum is configured to be {}", max);
}

We can use max in the body of the if let block in the same way we used max in the corresponding match arm.