May 21, 2016 23:14 · May 21, 2016
diff --git a/Card.swift b/Card.swift
@@ -0,0 +1,17 @@
+enum Suit {}
+enum Rank: Int {}
+
+// In the example, let's say the Card is CustomStringConvertible so I can leverage all the external code
+// that prints stuff, and depends on using the var description
+struct Card : CustomStringConvertible {
+  var rank: Rank
+  var suit: Suit
+
+  var description : String {
+    return rank.simpleDescription() + suit.simpleDescription()
+  }
+}
+
+// Define a protocol for specializing Arrays of Cards
+protocol _CardType {}
+extension Card: _CardType {}
diff --git a/Deck.swift b/Deck.swift
@@ -0,0 +1,11 @@
+typealias Deck = [Card]
+
+// Using swift's constrained extensions
+extension Array where Element : _CardType {
+
+  // This is the method that would not compile if I try to use override
+	// override var description: String {
+	var description: String {
+    return "Deck: " + self.map { "\($0)" }.joinWithSeparator(",")
+  }
+}
diff --git a/DeckTests.swift b/DeckTests.swift
@@ -0,0 +1,15 @@
+class CardsTests: XCTestCase {
+
+  var deck : Deck!
+
+  override func setUp() {
+    super.setUp()
+    deck = Deck.standard() // Create a standard poker deck
+  }
+
+  func testBasicDeck() {
+    // Here you get the error Ambiguous use of description
+  	print(deck.description)
+  }
+
+}