Swift-多类型封装

enum IntOrString {
    case IntValue(Int)
    case StringValue(String)
}

 func mixedType() {
        let mixed = [IntOrString.IntValue(1),
                     IntOrString.StringValue("string"),
                     IntOrString.StringValue("Int")]
        
        for value in mixed {
            switch value {
            case var .IntValue(i):
                i += 1
                print("i: \(i)")
            case let .StringValue(s):
                print(s)
            }
        }
    }