One of my favorite things about Swift is just how so many of its language features that are implemented using its own type system. Take operators for example — they’re functions — which means that we can pass them, and call them, as functions/closures!

enum SortOrder {
    case ascending
    case descending
}

internal extension SortOrder {
    func makeComparator<T: Comparable>() -> (T, T) -> Bool {
        switch self {
        case .ascending:
            // Since Swift operators are implemented as
            // functions, we can both pass them as closures...
            return (<)
        case .descending:
            return (>)
        }
    }
}

internal extension Array {
    mutating func sort<T: Comparable>(by keyPath: KeyPath<Element, T>,
                                      order: SortOrder = .ascending) {
        sort { a, b in
            // ...and call them as closures!
            order.makeComparator()(
                a[keyPath: keyPath],
                b[keyPath: keyPath]
            )
        }
    }
}

For two weeks, many websites around the Swift community are featuring indie developers who have been financially impacted by the current pandemic. If you can, please help support these indies by downloading their apps. Today’s app is...

Working Copy: My favorite Git client for iOS. Working Copy lets me access all of my Git repositories while on the go, which lets me update my projects, check out files, and much more. Made by Anders Borum from Copenhagen.