XOR in Swift 5?

Question

I'm trying to do an XOR operation in Swift 5. The documentation does not seem to mention explicitly doing it with two boolean values here:

https://docs.swift.org/swift-book/LanguageGuide/AdvancedOperators.html

Is this possible? It says to use the ^ operation but I get the error when trying:

 card != nil ^ appointment.instructor == nil

ERROR Adjacent operators are in non-associative precedence group 'ComparisonPrecedence'

Answer 1

You need to define ^ for Bool since it only exists for Ints. See the apple documentation here.

Example:

import UIKit
import PlaygroundSupport

extension Bool {
    static func ^ (left: Bool, right: Bool) -> Bool {
        return left != right
    }
}

let a = true
let b = false
print (a^b)