Swift 1.2 redeclares Objective-C method

Question

I just updated from swift 1.1 to swift 1.2 and get compiler Error:

Method \'setVacation\' redeclares Objective-C method \'setVacation:\'

Here

Answer 1

This is cause by the change stated in Xcode 6.3beta release notes:

Swift now detects discrepancies between overloading and overriding in the Swift type system and the effective behavior seen via the Objective-C runtime. (18391046, 18383574) For example, the following conflict between the Objective-C setter for “property” in a class and the method “setProperty” in its extension is now diagnosed:

 class A : NSObject {
     var property: String = "Hello" // note: Objective-C method 'setProperty:’
                                    // previously declared by setter for
                                    // 'property’ here
 }
 extension A {
     func setProperty(str: String) { } // error: method ‘setProperty’
                                       // redeclares Objective-C method
                                       //'setProperty:’
 }

To fix this you need to make all you method signatures unique (as Objective-C does not provide method overload)

Or don't inherit from NSObject if you need Swift only class.

Answer 2

Cappy: For the Standford problem I used simply this, because it looks like the Xcode Beta simply says that the operation: (Double, Double) -> Double is the same as operation: Double -> Double, I don't know if it is a bug or not...

But the code below works, but is NOT clean :(

func performOperation(r:String? = "2", 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()
    }
}

Answer 3

As noted by @Kirsteins, Swift now detects conflicting symbols between Swift and Obj-C, and swift symbols that would cause Obj-C grief. In addition to the answer given, you can avoid this in general by specifying a required label for the additional types, thus changing the call signature:

import Foundation

extension NSObject {
    func foo(d:Double, i:Int) { println("\(d), \(i)") }
    func foo(withInt d:Int, i:Int) { println("\(d), \(i)") }
}

let no = NSObject()
no.foo(withInt:1, i: 2)

Beyond that though, and to answer your immediate question, you are trying to apply Obj-C idioms to Swift. What you really want, is to either implement didSet (most likely), or possibly set:

class WhatIDidLastSummer {

    var vacation:Bool = false {
        didSet {
            // do something
        }
    }

    var staycation:Bool {
        get { return true }
        set {
            // do something
        }
    }

}