We can define some types within other types, just like this:
struct BlackjackCard {
// nested Suit enumeration
enum Suit: Character {
case spades = "?", hearts = "?", diamonds = "?", clubs = "?"
}
// nested Rank enumeration
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:
return Values(first: self.rawValue, second: nil)
}
}
}
// BlackjackCard properties and methods
let rank: Rank, suit: Suit
var description: String {
var output = "suit is \(suit.rawValue),"
output += " value is \(rank.values.first)"
if let second = rank.values.second {
output += " or \(second)"
}
return output
}
}
this is called Nested Types, which can be used inner and even outer.
But if we want to use it outside of its definition context, we need to prefix its name with the name of the type it’s nested within, just like this:
let heartsSymbol = BlackjackCard.Suit.hearts.rawValue
// heartsSymbol is "?"
Let’ think!
