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sergei zh
2,687 Pointscrash of playground
This was my initial code: //---------
import UIKit
class Product { let title: String let price: Double
init(title: String, price: Double) {
self.title = title
self.price = price
}
func discountedPrice(persentage: Double) -> Double {
return price - (price * persentage / 100)
}
}
enum Size { case Small, Medium, Large init(){ self = .Small } }
//----
When I've add this at the bottom:
class Clothing: Product { var size = Size()
override func discountedPrice(_ persentage: Double = 10) -> Double {
return price - (price * persentage / 100)
}
}
system say "Extraneus '_' in parameter: 'persentage' has no keyword argument name
and then I get message "communication with playground service was interrupted"
I've try this on two different computers, same result. What it can be?
4 Answers
Brian Patterson
19,588 PointsI would like to know the answer to this. As this must be specific to Swift 2.0. I am getting the same error.
sergei zh
2,687 PointsIt is a bug in xcode 7. Download Xcode 6.4 from Apple site
Brian Patterson
19,588 PointsI think I will wait for a update and look forward to the new videos that are coming next week. Will proceed to the next video.
Steve Hunter
57,712 PointsNow Xcode 7 is on general release, this still persists.
There must be a change in how overridden methods are declared as I can't get the video's code to work. It doesn't throw an error - it just crashes.
I can work around it but I will do some digging in the documentation to see if how we should be defaulting parameters has changed. Certainly, the underscore upsets the compiler and as soon as you add a default value to the parameter, the crash occurs.
Christian Carey
15,445 PointsThe documentation of Swift 2.1 says :
"If a default value is defined, you can omit that parameter when calling the function."
So that explains the error message, because the underscore is no longer needed.
As for the crashing, I guess we'll have to wait for an update.
Christian Carey
15,445 PointsHere's another thing that may help you work around this for now.
If you have a default value for the original method AND for the one you're using to override, the crash does not occur. It only occurs if just one of them has a default value.