phantom type dummy code

phantom_type.swift

// ref http://qiita.com/taketo1024/items/71e3272211f08d7e0cde

class Status {}
class Status_NORMAL : Status {}
class Status_HIGH : Status {}

class Car<T: Status> {
  static func createNormalCar() -> Car<Status_NORMAL> {
    return Car<Status_NORMAL>()
  }
  static func createHighCar() -> Car<Status_HIGH> {
    return Car<Status_HIGH>()
  }
}

extension Car where T: Status_HIGH {
  func setHighSpeedMode() {
    print("High Speed Mode On")
  }
}

/*
let high_car = Car.createHighCar()
let normal_car = Car.createNormalCar()

high_car.setHighSpeedMode()  ok
normal_car.setHighSpeedMode() compile error
*/