Looping through enum values in Swift

Question

Is it possible to loop through enum values in Swift? Or what is the alternative?

I'm working through Apple's Swift language guide, and I came across this example on enums.

//  EXPERIMENT
//
//  Add a method to Card that creates a full deck of cards, 
//  with one card of each combination of rank and suit.

struct Card {
    var rank: Rank
    var suit: Suit
    func simpleDescription() -> String {
        return "The \(rank.simpleDescription()) of \(suit.simpleDescription())"
    }
}
let threeOfSpades = Card(rank: .Three, suit: .Spades)
let threeOfSpadesDescription = threeOfSpades.simpleDescription()

enum Suit {
    case Spades, Hearts, Diamonds, Clubs
    func simpleDescription() -> String {
        switch self {
        case .Spades:
            return "spades"
        case .Hearts:
            return "hearts"
        case .Diamonds:
            return "diamonds"
        case .Clubs:
            return "clubs"
        }
    }
}

enum Rank: Int {
    case Ace = 1
    case Two, Three, Four, Five, Six, Seven, Eight, Nine, Ten
    case Jack, Queen, King
    func simpleDescription() -> String {
        switch self {
        case .Ace:
            return "ace"
        case .Jack:
            return "jack"
        case .Queen:
            return "queen"
        case .King:
            return "king"
        default:
            return String(self.toRaw())
        }
    }
}

Excerpt From: Apple Inc. “The Swift Programming Language.” iBooks. https://itun.es/us/jEUH0.l

I've tried the following, but the docs say enums in Swift are not assigned underlying integer values like in C, so I'm probably barking up the wrong tree.

Is there a better way solve this problem?

func deck() -> Card[]{
    var deck: Card[]
    for s in Suit {
        for r in Rank {
            deck += Card(rank: r, suit: s)
        }
    }
    return deck
}

func deck2() -> Card[]{
    var deck: Card[]
    for var s: Suit = .Spades; s <= .Clubs; s++ {
        for var r: Rank = .Ace; r <= .King; r++ {
            deck += Card(rank: r, suit: s)
        }
    }
    return deck
}

Solution

Is there another way? Sure. Is it better, that's for you to decide:

func generateDeck() -> Card[]
{
    let ranksPerSuit = 13
    var deck = Card[]()

    for index in 0..52
    {
        let suit = Suit.fromRaw(index / ranksPerSuit)
        let rank = Rank.fromRaw(index % ranksPerSuit + 1)

        let card = Card(rank: rank!, suit: suit!)
        deck.append(card)
    }

    return deck
}

let deck = generateDeck()

for card : Card in deck { println("\(card.description)") }

To use this, you will need to make sure that Rank and Suit enums both use Int for their type definitions (ex: enum Rank : Int).

Rank.Ace should equal 1 and the first Suit case should equal 0.

If you want to loop similar to your existing code, you should still make your enums Int types so you can use Rank.King.toRaw() and the like.

The Apple documentation states that enums are not restricted to being 'simply integer values', but certainly can be if you desire them to be.

UPDATE

Idea taken from comment by @jay-imerman, and applicable to Swift 5

extension Rank: CaseIterable {}
extension Suit: CaseIterable {}

func generateDeck() -> [Card] {
    var deck = [Card]();

    Rank.allCases.forEach {
        let rank = $0

        Suit.allCases.forEach {
            let suit = $0

            deck.append(Card(rank: rank, suit: suit))
        }
    }

    return deck;
}