Enums

enum defines a nominal sum type with a fixed set of variants.

Currently, enums support:

• unit variants (E::A),
• tuple variants (E::B(x)),
• exhaustive match expressions over enum values (restricted subset; no guards),
• and statement-form ordinary enum match with qualified variant arms.

Full reference: enums.

Notes#

• Supported forms + representation: enums

Syntax#

enum Msg {
  Quit,
  Add(int),
}

Examples#

Example: construct + match#

enum Msg {
  Quit,
  Add(int),
}

fn main () -> int {
  let m: Msg = Msg::Add(5);
  return match m {
    Msg::Quit => 0,
    Msg::Add(n) => n,
  };
}

See also#

• Full reference: enums
• match expressions: flow match