swift - 是否可以在 switch 运算符中解构对象？

Question

今天发现了一段笨拙的代码:

if segue.identifier == "settings" {
  if let settingsController = segue.destination as? SettingsController 
  {
    //...setup settings controller here
  }
} else if segue.identifier == "mocks" {
  if let mocksController = segue.destination as? MocksController 
  {
    //...setup mocks controller here controller here
  }
}
//... and a lot of if-elses

我真的很讨厌在我的代码中使用 if-else-if 并决定用 switch 重构这一部分。不幸的是，我对快速模式匹配的了解非常有限，所以我能做的最好的事情是:

switch segue.identifier! {
  case "mocks" where segue.destination is MocksController:
    let mocksController = segue.destination as! MocksController
    // do corresponding staff here
  break

  case "settings" where segue.destination is SettingsController:
    let settingsController = segue.destination as! SettingsController
    // do corresponding staff here
  break
}

我想知道是否可以像下面的伪代码一样使用模式匹配从 segue 对象中提取 identifier 和 destination 属性:

switch segue {
  case let destination, let identifier where destination is ... && identifier == "...": 
  //do somthing 
  break
}

Answer 1

是的，这完全有可能。Swift 很强​​大 ;)

switch (segue.identifier, segue.destination) {
    case let ("mocks"?, mocksController as MocksController):
             // do corresponding stuff here
  ...
}