Errors in WWDC 2018

Some errors in the translation example. WWDC 2018, Session 404: New Localization Workflows in Xcode 10, slide 34. Looks like additional words were added just to make EN->RU translation look more complicated :)

Catching nil as Error

Github gist.

I've posted this as an answer on stackoverflow before, and the information was highly appreciated by some people. The question was like: “How to catch any error, specially unexpectedly found nil in Swift?" Though the author was asking about catching system errors, I decided to post my super-handy Unwrap Snippet there.
struct UnwrapError: Error, CustomStringConvertible { let optional: T? public var description: String { return "Found nil while unwrapping \(String(describing: optional))!" } } public func unwrap(_ optional: T?) throws -> T { if let real = optional { return real } else { throw UnwrapError(optional: optional) } }
The idea of this approach is to replace multiple if let and guard let statements with a single do-try-catch block. You can:
do { // Parse JSON and assign variables which were defined somewhere above let dictionary = try unwrap(JSONSerialization.jsonObject( with: data, options: .allowFragments) as? [String: Any]) isAdsEnabled = try unwrap(dictionary["isAdsEnabled"] as? Bool) // While calling function which require a non-optional parameter in one line of code imageView.image = try UIImage(data: unwrap(receivedData)) // And also you can simplify the building of multipart data var data = Data() data += try unwrap(dispositionString.data(using: .utf8)) data += someContent data += try unwrap("\r\n".data(using: .utf8)) } catch error { // Handle error // ... // and exit return nil }
Those who make apps with web backend will definitely like.