OptionSet-Enum.swift

public enum Foo : OptionSet {
	
	case a
	case b
	case value(UInt8)
	
	public var rawValue: UInt8 {
		
		switch self {
		case .a:
			return 1
		case .b:
			return 2
		case .value(let value):
			return value
		}
	}
	
	public init(rawValue: UInt8) {
		
		switch rawValue {
		case 1:
			self = .a
		case 2:
			self = .b
		default:
			self = .value(rawValue)
		}
	}
	
	public static let all: Foo = [.a, .b]
}