As an iOS developer, I am forever shocked at how often I see fatalError(“This should never happen”) in production code. This usually arises in situations where an edge case is programatically possible, but logically impossible. The scenario Imagine a situation where I’d like an app to catalog the CDs and books on…

I’ve recently discovered Apple’s Natural Language framework and decided to have a play, test out some ideas and share my findings. This will be a short article about a few things the framework can do and potentially offer some inspiration for your own apps I started with UITextChecker. As the…

Background A very common pattern across programming languages is the use of callback functions. A callback function is a reference to executable code passed as an argument to other code, allowing it to be executed at a later time. In swift we encounter this patten often. One particularly common example is…

What Is Splatting? Argument splatting is the concept of extracting the parameters of an object to pass to a function automatically. In Swift this can be done using tuples. Suppose we had some data and a function that looked like this: We’d like to pass all our users through the makeGreeting function…

Background Recently I have been implementing a lot of analytics events in a client’s app. Tagging this application (which has a great deal of UI) was always going to a laborious task, so I was looking to architect an ergonomic API to interact with. Whilst deciding on the interface I remembered…

History For many years now, the go-to way of encoding and decoding Swift types to JSON has been the Codable protocol. This gave a more type safe way of handling json than its predecessor JSONSerialization, which spat out [String: Any] dictionaries. …

Recently I discovered that tuples can be used to easily and simply compare and equate multiple variables. Take for example the implementation of Date and Comparable taken from the Swift documentation: This compares the year, month and day in that order to determine which is greater (later). A simpler (and perhaps more readable) way of writing this same code is this: The tuple is compared in order of its variables so we achieve the same result.

One of the biggest downsides to UIGestureRecognizer is the inability to attach simple closures in-line. To use them, a target object must be specified alongside a Selector pointing to a function to call. One major disadvantage to this paradigm is that UIGestureRecognizer only passes the calling object to the called…

Background The Coordinator pattern has become increasingly popular recently in handling navigation through an iOS apps without tightly coupling different view controllers. There are a number of great articles that explain the various flavours of the pattern fantastically, so I’ll not rehash the same detail again. There is, however, one area…