swift-extensions

protocol Car { var wheels : Int { get set} init(wheels: Int) } extension Car { init(wheels: Int) { self.wheels = wheels } } on self.wheels = wheels i get the error Error: variable 'self' passed by reference before being initialized How can I define the initializer in the protocol extension? As you can see this doesn't work under these circumstances because when compiling, one has to make sure that all properties are initialized before using the struct/enum/class. You can make another initializer a requirement so the compiler knows that all properties are initialized: protocol Car { var wheels

This question already has an answer here: EXC_BAD_ACCESS Using IBInspectable 1 answer I want to have a default property of UIImageView , which would be isFlipped . I am able to do it by subclassing UIImageView and adding one property isFlipped . But I want to user protocol and extensions for this , but it is crashing after sometime. Below is my code. How can I use it in right way? Thanks import Foundation import UIKit protocol FlipImage { var isFlipped: Bool { get set } } extension UIImageView:FlipImage{ var isFlipped: Bool { get { return self.isFlipped } set { self.isFlipped = newValue } } }

Been having lots and lots of trouble with Swift protocols in combination with arrays, but I couldn't even reproduce my whole problem before things started to break in playground. Here's a minimal example. I have two protocols and a class Bus which declares conformance to one of the protocols. In addition, an empty extension of Bus declares conformance to the other protocol: import Foundation @objc protocol Displayable { var name: String {get} } @objc protocol Utterable { var utterance: String {get} } class Bus : Displayable { var name = "a bus"; var utterance = "this is a bus"} extension Bus :

I have a framework in my project that implements an extension on NSDate. The extension looks like this. extension NSDate { func isGreaterThanDate(otherDate: NSDate) -> Bool { //function implementation here } } I've imported this framework into an app project. Now if I copy and paste that same extension into a swift file in the app, the new copy in my app's code appears to override the copy in the framework's code. When I'm calling this function in my app, is there a way I can use namespacing to specify which implementation I want? The only answer I've found so far "No you can't use namespacing

Is there any existing function that looks for the index of a substring inside another string? A method like .indexOfSubstring thank does this: let word: String = "Hey there, how are you?" let indexOf: Int = word.indexOfSubstring("ere, how are") println("index = " + \(indexOf)) and prints: index = 6 You can use the rangeOfString method: import Foundation let word: String = "Hey there, how are you?" if let range = word.rangeOfString("ere, how are") { let index = distance(word.startIndex, range.startIndex) println("index = \(index)") } It returns a range, i.e. both sides of the searched string -

I am attempting to add an extension to the Array type in Swift limited to Arrays whose elements conform to the equatable protocol. I am attempting to define a function in the following manner: import Foundation extension Array where Iterator.Element: Equatable { func deletedIndicies<T: Equatable>(newArray: [T]) -> [Int] { var indicies = [Int]() for element in self { if newArray.index(of: element) == nil { indicies.append(self.index(of: element)!) } } return indicies } } } The purpose of the function is to return the indices of any items in the original array that do not appear in the newArray