EnumWithAssociatedTypeAndRawRepresentable.swift

enum MyEnum {
    case IntCase(value: Int)
    case StringCase(value: String)
    case IntStringCase(intValue: Int, stringValue: String)
}

extension MyEnum: RawRepresentable {

    init?(rawValue: Any) {
        switch rawValue {
        case let value as Int:
            self = .IntCase(value: value)

        case let value as String:
            self = .StringCase(value: value)

        case let value as (Int, String):
            self = .IntStringCase(intValue: value.0, stringValue: value.1)

        default:
            return nil
        }
    }

    var rawValue: Any {
        switch self {
        case .IntCase(let value):
            return value

        case .StringCase(let value):
            return value

        case .IntStringCase(let intValue, let stringValue):
            return (intValue, stringValue)
        }
    }

}


let foo = MyEnum(rawValue: 42)
let bar = MyEnum(rawValue: "Hello")
let baz = MyEnum(rawValue: (123, "World"))