Enums and Pattern Matching

NAME wyzer-enums - Enumerated types and exhaustive pattern matching

DESCRIPTION Enums define a type consisting of multiple variants. Variants can be tagged with explicit integral values via iota or contain complex data payloads.

SYNOPSIS: ENUMS AND IOTA

enum Flag {
    None = 0,
    Read = 1 << iota,
    Write = 1 << iota,
}

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

ENUM DETAILS

• iota: A built-in compile-time counter that automatically increments per variant.
• Data Variants: Variants can enclose structures (Move { x, y }) or tuples (Write(str)).

SYNOPSIS: PATTERN MATCHING

fn process(msg: Message) {
    match msg {
        Message::Quit => { /* ... */ },
        Message::Move { x, y } => { /* ... */ },
        Message::Write(text) => { /* ... */ },
    }
}

MATCH DETAILS

• match: Branches execution based on the enum variant.
• Exhaustiveness: The compiler strictly verifies that all possible variants are explicitly handled.