《浅入浅出Swift》NestedTypes 嵌套类型

NestedTypes

struct BlackjackCard{
    //nested Suit enumeration 嵌套适合的枚举
    enum Suit: Character{//性格品质
        case Spades = "♠", Hearts = "♡", Diamonds = "♢", Clubs = "♣"
    }
    
    enum Rank: Int {
        case Two = 2, Three, Four, Five, Six, Seven, Eight, Nine, Ten
        case Jack, Queen, King, Ace
        
        struct Values {
            let first: Int, second: Int?
        }
        var values : Values{
            switch self{
            case .Ace:
                return Values(first: 1, second: 11)
            case .Jack, .Queen, .King:
                return Values(first: 10, second: nil)
            default:
                //使用toRaw 和fromRaw 两个函数，实现原始值和枚举值之间进行切换
                //定义原始枚举类型是Int型，只需要给第一个定义枚举赋值，后续会顺序分配；
                //你也可以使用浮点型和String类型作为枚举的原始类型
                return Values(first: self.toRaw(), second: nil)
            }
        }
    }

    
    //BlackjackCard properties and methods
    let rank: Rank , suit: Suit
    //描述
    var description: String {
        var output = "suit is \(suit.toRaw()),"//传入Spades
            output += "value is \(rank.values.second)"
            
            if let second = rank.values.second{
                output += " or \(second)"
            }
            return output
    }
    
}

let theAceOfSpades = BlackjackCard(rank: .Ace, suit: .Spades)
println("theAceOfSpades: \(theAceOfSpades.description)")
//theAceOfSpades : suit is ♠,value is lor 11

let heartsSymbol = BlackjackCard.Suit.Hearts.toRaw()//转化成实际值，
println("heartsSymbol = \(heartsSymbol)")

Reference

• The Swift Programming Language