Enums in Rust

#[derive(Debug)]
enum IpAddr {
    V4(u8, u8, u8, u8),
    V6(String),
}

#[derive(Debug)]
enum Event {
    KeyPress(char),
    MouseClick { x: f64, y: f64 },
    Resize(u32, u32),
    Quit,
}

impl Event {
    fn describe(&self) -> String {
        match self {
            Event::KeyPress(c) => format!("Key: {}", c),
            Event::MouseClick { x, y } => format!("Click at ({:.1}, {:.1})", x, y),
            Event::Resize(w, h) => format!("Resize to {}x{}", w, h),
            Event::Quit => String::from("Quit"),
        }
    }
}

fn main() {
    let events = vec![
        Event::KeyPress('a'),
        Event::MouseClick { x: 100.5, y: 200.0 },
        Event::Resize(1920, 1080),
        Event::Quit,
    ];
    for e in &events { println!("{}", e.describe()); }

    let home = IpAddr::V4(127, 0, 0, 1);
    let loopback = IpAddr::V6(String::from("::1"));
    println!("{:?} {:?}", home, loopback);
}

#[derive(Debug, PartialEq)]
enum OrderStatus {
    Pending,
    Processing { start: u64 },
    Shipped { tracking: String },
    Delivered,
    Cancelled(String),
}

impl OrderStatus {
    fn can_cancel(&self) -> bool {
        matches!(self, OrderStatus::Pending | OrderStatus::Processing { .. })
    }
    fn is_final(&self) -> bool {
        matches!(self, OrderStatus::Delivered | OrderStatus::Cancelled(_))
    }
}

fn main() {
    let mut order = OrderStatus::Pending;
    println!("{:?} can_cancel={}", order, order.can_cancel());

    order = OrderStatus::Processing { start: 1234567890 };
    println!("{:?} can_cancel={}", order, order.can_cancel());

    order = OrderStatus::Shipped { tracking: "1Z999AA1".to_string() };
    println!("{:?} final={}", order, order.is_final());

    order = OrderStatus::Delivered;
    println!("{:?} final={}", order, order.is_final());
}