Enums & pattern matching

One enum family

enum Color : u8 {
    Red;
    Green;
    Blue;
}

enum SocketRead {
    Data { Bytes: readonly byte[]; };
    WouldBlock;
    Closed;
    Failure { Code: i32; };
}

Payloadless and payload-carrying cases share one declaration family. Tagged values are inline; declaring an enum does not allocate.

Construction

let Red = Color.Red;
let Closed: SocketRead = .Closed;

Payloadless variants are values, without empty call parentheses. Payloads use named field initializers. Expected-type context permits a leading-dot variant spelling.

Matching

switch selects arms with case Pattern => ... and can bind named payload fields. Exhaustive enum matching makes the handled cases visible. See Result for a complete recoverable output example.

Native representation

A tagged enum is distinct from an untagged raw union. Do not assume the target-specific layout is a C ABI promise.