「不正確的參數標籤」當斯威夫特

Question

方法重載

我試圖做的方法斯威夫特重載用下面的代碼：

struct Game { 
    private let players: [UserProfile] //set in init() 
    private var scores: [Int] = [] 

    mutating func setScore(_ score: Int, playerIndex: Int) { 

     //... stuff happening ... 

     self.scores[playerIndex] = score 
    } 

    func setScore(_ score: Int, player: UserProfile) { 
     guard let playerIndex = self.players.index(of: player) else { 
      return 
     } 

     self.setScore(score, playerIndex: playerIndex) 
    } 
} 

我上self.setScore線得到一個錯誤：

Incorrect argument labels in call (have _:playerIndex:, expected _:player:)

我一直在看這段代碼一段時間，但不知道爲什麼這不起作用。任何提示？

Answer 1

感謝@Hamish指點我正確的方向。

原來，編譯器信息頗具誤導性。問題是每個調用mutating方法的方法本身都必須是mutating。因此，這解決了這個問題：

struct Game { 
    private let players: [UserProfile] //set in init() 
    private var scores: [Int] = [] 

    mutating func setScore(_ score: Int, playerIndex: Int) { 

     //... stuff happening ... 

     self.scores[playerIndex] = score 
    } 

    mutating func setScore(_ score: Int, player: UserProfile) { 
     guard let playerIndex = self.players.index(of: player) else { 
      return 
     } 

     self.setScore(score, playerIndex: playerIndex) 
    } 
} 

另見.sort in protocol extension is not working