Enums

Enum is a special class that has a predefined and fixed set of instances, called enum constants.

The following example declares an enum to represent priority:

enum Priority {
    LOW,
    MEDIUM,
    HIGH,
}

All instances of enum are predefined. Trying to explicitly initiate enum leads to compilation error.

Just like class, enum supports constructor, fields and methods.

enum Priority(
    val level: int
) {

    LOW(1),
    MEDIUM(2),
    HIGH(3),

    ;

    fn isHigherThan(that: Priority) -> bool {
        return level > that.level
    }

}

Note that the semicolon separating enum constants from other other members is mandatory.