"有些"是什么意思？

Question

Swift调试器打印输出中的'Some'是什么意思？
......这是默认的"类"值吗？如果是这样......它将如何改变？

注意: 'Some'似乎指向默认类.

(lldb) po rootNode
Some
 {
  nodeValue = 10
  leftNode = Some {
    nodeValue = 1
    leftNode = nil
    rightNode = Some {
      nodeValue = 2
      leftNode = nil
      rightNode = Some {
        nodeValue = 3
        leftNode = nil
        rightNode = Some {
          nodeValue = 4
          leftNode = nil
          rightNode = Some {
            nodeValue = 5
            leftNode = nil
            rightNode = nil
          }
        }
      }
    }
  }
  rightNode = nil
}

Answer 1

Some是以下两种情况之一Optional:

enum Optional<T> : Reflectable, NilLiteralConvertible {
    case None
    case Some(T)
    init()
    init(_ some: T)
    var hasValue: Bool { get }

    /// Haskell's fmap, which was mis-named
    func map<U>(f: (T) -> U) -> U?
    func getMirror() -> MirrorType
    static func convertFromNilLiteral() -> T?
}

您可以通过展开可选项来提取值rootNode!.