EnumerableFlag

For example, the Size enumeration declared here can be used as the type of a @Flag property:

enum Size: String, EnumerableFlag {
    case small, medium, large, extraLarge
}

struct Example: ParsableCommand {
    @Flag var sizes: [Size]

    mutating func run() {
        print(sizes)
    }
}

By default, each case name is converted to a flag by using the .long name specification, so a user can call example like this:

$ example --small --large
[.small, .large]

Provide alternative or additional name specifications for each case by implementing the name(for:) static method on your EnumerableFlag type.

extension Size {
    static func name(for value: Self) -> NameSpecification {
        switch value {
        case .extraLarge:
            return [.customShort("x"), .long]
        default:
            return .shortAndLong
        }
    }
}

With this extension, a user can use short or long versions of the flags:

$ example -s -l -x --medium
[.small, .large, .extraLarge, .medium]