swift 20 - Nested Types

Nested Types 只是为了方便类型的整合和使用

1. struct BlackjackCard {
3. // nested Suit enumeration
4. enum Suit: Character {
5. case spades = "?", hearts = "?", diamonds = "?", clubs = "?"
6. }
8. // nested Rank enumeration
9. enum Rank: Int {
10. case two = 2, three, four, five, six, seven, eight, nine, ten
11. case jack, queen, king, ace
12. struct Values {
13. let first: Int, second: Int?
14. }
15. var values: Values {
16. switch self {
17. case .ace:
18. return Values(first: 1, second: 11)
19. case .jack, .queen, .king:
20. return Values(first: 10, second: nil)
21. default:
22. return Values(first: self.rawValue, second: nil)
23. }
24. }
25. }
27. // BlackjackCard properties and methods
28. let rank: Rank, suit: Suit
29. var description: String {
30. var output = "suit is \(suit.rawValue),"
31. output += " value is \(rank.values.first)"
32. if let second = rank.values.second {
33. output += " or \(second)"
34. }
35. return output
36. }
37. }

1. let theAceOfSpades = BlackjackCard(rank: .ace, suit: .spades)
2. print("theAceOfSpades: \(theAceOfSpades.description)")
3. // Prints "theAceOfSpades: suit is ?, value is 1 or 11"