Overloaded functions in swift error

Question

I am new to swift and have an error in the following code. I have one function with two different parameters. Xcode(version 6) is giving an error on the second definition with a parameter as a function which takes one value.Here is the code:

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()
    }

}

show the error because this overload is legal and nothing wrong with it — Daniel Krom, Aug 13 '15 at 15:42
method performOperation with objective-C selector 'performOperator:' conflicts with previous declaration — sanjiv soni, Aug 13 '15 at 15:47

score 1 · Answer 1 · edited May 23 '17 at 10:26

Update:
Another solution is add private before method definition (Source):

private func performOperation(operation: (Double, Double) -> Double) {
    if(operandStack.count >= 2){
        displayValue = operation(operandStack.removeLast(), operandStack.removeLast())
        enter()
    }
}

private func performOperation(operation: Double -> Double){
    if(operandStack.count >= 1){
        displayValue = operation(operandStack.removeLast())
        enter()
    }

}

Original Answer:
Looks like your methods are defined in class that is inherited from some Objective-C class, for example:

class TestClass : NSObject {  
    func test(a : String) {}
    func test(a : UInt) {}
}

Compiler will produce such error:

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

To fix that you need avoid inheritance from Objective-C class:

class TestClass {  
    func test(a : String) {}
    func test(a : UInt) {}
}

This variant will work correct.

The problem is that Objective-C doesn't support methods overloading, but Swift does. That's why you need create pure Swift class.

This function is defined in class ViewController: UIViewController — sanjiv soni, Aug 13 '15 at 16:02
@sanjivsoni UIViewController is ObjC class. Consider create separate Swift class and define these functions there. Then you will be able to use that class in ViewController: UIViewController class. — Vlad Papko, Aug 13 '15 at 16:05

Overloaded functions in swift error

1 Answers1