覆盖Swift中的func

Question

我正在学习Swift,我正在学习Paul Hegarty关于如何使用波兰语反向表示法构建计算器的教程.代码如下所示:

@IBAction func operate(sender: UIButton) {
    let operation = sender.currentTitle!
    if userIsEnteringData{
        enter()
    }
    switch operation {
    case "×": performOperation {$0 * $1}
    case "÷": performOperation {$1 / $0}
    case "+": performOperation {$0 + $1}
    case "?": performOperation {$1 - $0}
    case "?": performOperation {sqrt($0)}
    case "sin": performOperation {sin($0)}
    case "cos": performOperation {cos($0)}
    case "?": performOperation{$0 * M_PI}
    default: break
    }

}

func performOperation (operation : ( Double, Double ) -> Double){

    if operandStack.count >= 2 {
        displayValue = operation(operandStack.removeLast(), operandStack.removeLast())
        enter()

    }
}

func performOperation (operation : Double -> Double){

    if operandStack.count >= 1 {
        displayValue = operation(operandStack.removeLast())
        enter()

    }
}

xCode编译器不喜欢performOperation函数的第二个实例,并报告它之前已经定义过.它报告的错误是:

Method 'performOperation' with Objective-C selector 'performOperation:' conflicts with previous declaration with the same Objective-C selector

我的代码出了什么问题？

Answer 1

我不知道你的类声明,但在这种情况下最可能的问题是你继承了一个@objc类.Objective-C不支持方法重载,但Swift确实如此.所以要么你不应该继承am @objcclass,要么你可以使用不同的方法名称.

作为参考,您可以阅读这篇文章