Enums

  • Rust supports regular enums:
    enum IpAddr {
  V4,
  V6
}

IpAddr::V4
  • Each enum entry can also have “associated data” that is not necessarily consistent:
    enum IpAddr {
  V4(String),
  V6(String)
}

IpAddr::V6(String::from("::1"))

enum Message {
  Quit,
  Move { x: i32, y: i32},
  Write(String),
  ChangeColor(i32, i32, i32)
}

Message::Move { x: 5, y: 6 };
Message::ChangeColor(255, 255, 0);
  • This is almost like each enum variant is a struct-like thing on its own, but it’s also a Message, and so can be passed to anything that expects a Message.
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