enum Direction {
    North,
    South,
    East,
    West,
}

fn compass(d: &Direction) -> &str {
    match d {
        Direction::North => "going up",
        Direction::South => "going down",
        Direction::East => "going right",
        Direction::West => "going left",
    }
}

fn main() {
    let d = Direction::North;
    println!("{}", compass(&d));

    // match with Option
    let x: Option<i32> = Some(42);
    match x {
        Some(n) if n > 100 => println!("big: {}", n),
        Some(n) => println!("small: {}", n),
        None => println!("none"),
    }
}