rust-by-practice/solutions/pattern-match/patterns.md

fn main() {}
fn match_number(n: i32) {
    match n {
        // match a single value
        1 => println!("One!"),
        // fill in the blank with `|`, DON'T use `..` ofr `..=`
        2 | 3 | 4 | 5 => println!("match 2 -> 5"),
        // match an inclusive range
        6..=10 => {
            println!("match 6 -> 10")
        },
        _ => {
            println!("match 11 -> +infinite")
        }
    }
}

struct Point {
    x: i32,
    y: i32,
}

fn main() {
    // fill in the blank to let p match the second arm
    let p = Point { x: 2, y: 20 }; // x can be [0, 5], y can be 10 20 or 30

    match p {
        Point { x, y: 0 } => println!("On the x axis at {}", x),
        // second arm
        Point { x: 0..=5, y: y@ (10 | 20 | 30) } => println!("On the y axis at {}", y),
        Point { x, y } => println!("On neither axis: ({}, {})", x, y),
    }
}

enum Message {
    Hello { id: i32 },
}

fn main() {
    let msg = Message::Hello { id: 5 };

    match msg {
        Message::Hello {
            id:  id@3..=7,
        } => println!("Found an id in range [3, 7]: {}", id),
        Message::Hello { id: newid@(10 | 11 | 12) } => {
            println!("Found an id in another range [10, 12]: {}", newid)
        }
        Message::Hello { id } => println!("Found some other id: {}", id),
    }
}

fn main() {
    let num = Some(4);
    let split = 5;
    match num {
        Some(x) if x < split => assert!(x < split),
        Some(x) => assert!(x >= split),
        None => (),
    }
}

fn main() {
    let numbers = (2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048);

    match numbers {
        (first,..,last) => {
           assert_eq!(first, 2);
           assert_eq!(last, 2048);
        }
    }
}

fn main() {
    let mut v = String::from("hello,");
    let r = &mut v;

    match r {
        // The type of value is &mut String
       value => value.push_str(" world!") 
    }
}