Swift Equatable Protocol

Question

I was folling this tutorial for Swift: https://www.raywenderlich.com/125311/make-game-like-candy-crush-spritekit-swift-part-1 and came across this code:

func          


        

Answer 1

Move this function

func == (lhs: Cookie, rhs: Cookie) -> Bool {
    return lhs.column == rhs.column && lhs.row == rhs.row
}

Outside of the cookie class. It makes sense this way since it's overriding the == operator at the global scope when it is used on two Cookies.

Answer 2

making the class an NSObject solved the equatable problems for me...

class Cookie: NSObject {
...
}

(got the tip from the iOS apprentice tutorials)

Answer 3

SWIFT 2:

As in swift 2 NSObject already conforms to Equatable.You don't need conformance at the top so it's like

class Cookie: NSObject {
    ...

}

And you need to override isEqual method as

class Cookie:NSObject{
    var column: Int
    var row: Int

    //..........

    override func isEqual(object: AnyObject?) -> Bool {
        guard let rhs = object as? Cookie else {
            return false
        }
        let lhs = self

        return lhs.column == rhs.column
    }

}

This time isEqual method is inside the class. :)

EDIT for SWIFT 3: Change this method as

override func isEqual(_ object: AnyObject?) -> Bool {
        guard let rhs = object as? Cookie else {
            return false
        }
        let lhs = self

        return lhs.column == rhs.column
    }