Enums And Match

Enums model tagged values. Variants can be empty, tuple-like, or record-like, and match gives scripts a controlled way to branch on those shapes.

Declaring Enums

Enum variants may carry fields and type hints. Vela does not use generic enum syntax, so Option and Result are ordinary dynamic enum families rather than Option<T> or Result<T, E>.

enum QuestState {
    NotStarted
    Active { step: i64 }
    Complete(reward: String)
}

Matching

Patterns include wildcards, bindings, literals, paths, tuple variants, and record variants. A guard can refine an arm.

fn next_step(state: QuestState) -> i64 {
    match state {
        QuestState::Active { step } if step < 10 => step + 1,
        QuestState::Active { step } => step,
        _ => 0,
    }
}

Variant Data

Record variants keep named fields. Tuple variants keep positional fields. Pattern bindings introduce local values for the arm body; updating an enum usually means constructing a new enum value.

Reload And Reflection

Variant names, field shapes, hints, and stable IDs participate in reflection and hot reload checks. Removing or reshaping a public variant can be rejected because existing callers or active frames may still depend on it.