fn main() {
    let x = 5;
    let y = &x;

    match y {
        &val => println!("matched ref: {}", val),
    }

    match *y {
        val => println!("dereferenced: {}", val),
    }

    // ref pattern to borrow from a match
    let name = String::from("Alice");
    match name {
        ref s => println!("borrowed: {}", s),
    }
    // name is still usable
    println!("name: {}", name);

    // ref mut
    let mut data = vec![1, 2, 3];
    match data[0] {
        ref mut val => *val *= 10,
    }
    println!("data: {:?}", data);
}