Getting to Know Swift

Native iOS and macOS development

November 4, 2017
Swift

For the last several years I’ve primarily been a backend developer using C# and occasionally doing work on the frontend with JavaScript. I’ve dabbled in learning Rust as well but I wanted to try my hand at writing native iOS and macOS applications for a change.

After doing some research on where to begin, I started reading the book App Development with Swift by Apple. This book has been a great guide for learning Swift through developing iOS applications. The book is broken up into distinct sections where they teach you features of Swift and then show you how to use them when writing many iOS applications. Apple wrote this book to be used in classrooms but I’ve been following along on my own time during the evenings.

The book has you do bunches of small projects in XCode which has been extremely helpful in learning XCode. Since I’m a Vim person I’ve found it extremely difficult – but worth it – to learn the native keyboard shortcuts on the Mac as well as in XCode itself. Having to do so many different projects has already gotten me much more comfortable using XCode and Interface builder.

What about Xamarin

Xamarin looks like a great option for C# developers who want to keep using C# or share code with Android and iOS applications. This is not the problem I am trying to solve. I enjoy learning new things and since I use C# daily at work, I wanted to give native app development a chance. The concepts I learn writing iOS and macOS applications in Swift will help me if my company ever needs a native app written. Even though they’d likely use Xamarin (we are a C# heavy office after all) I will learn a great deal about the underlying platform. That knowledge will be useful whether or not I am writing code in Swift or C#.

What do I like about Swift right now

So far Swift has been a lot of fun to learn. I’m getting to try out a new language as well as two different native paradigms of iOS and macOS development. I found Objective-C’s syntax to be hard to follow and I was always a bit afraid of managing my own memory. So far this is what I have liked about Swift as well as what I’ve found confusing.

Optionals

Handling optionals in Swift is pretty easy. this syntax is pretty similar to what I learned from Rust. It is something that I’d love to see C# take a cue from.

1let someOptional: OptionalType?
2if let someOptional = someOptional {
3    // use the now unwrapped someOptional
4} else {
5    // some optional was nil
6}

Guard statements

Guard statements have been awesome, they combine a lot of what I like about how swift handles optionals and lets me invert the check so my code doesn’t get to be an arrowhead. I also like that you can do additional checks and have your function return.

1func someFunction(some nullableParameter: SomeParameter) {
2    guard let parameter = nullableParameter else { return }
3
4    // use parameter here
5}

One thing I’ll eventually want to figure out with guard statements, is what the general suggestions for formatting a guard statement are. I’m writing them like this for now:

1guard let symbol = aDecoder.decodeObject(forKey: PropertyKey.symbol) as? String,
2      let name = aDecoder.decodeObject(forKey: PropertyKey.name) as? String,
3      let detailDescription = aDecoder.decodeObject(forKey: PropertyKey.detailDescription) as? String,
4      let usage = aDecoder.decodeObject(forKey: PropertyKey.usage) as? String
5else { return nil }

Generics

I haven’t gotten too far into using Generics in Swift yet but they feel pretty similar to what I’ve gotten used to in C# and Rust.

What confuses me about Swift so far

I’ve run into a few things in Swift that I’ve found confusing. Either from suggestions on how you should organize your code using Extensions or more historical aspects of iOS and macOS.

Extensions

I’m used to C# where extension methods currently are static methods that operate on a type. In Swift, that doesn’t seem to be the case, you can extend most classes it looks like including adding interface implementations or mutating functions. It also seems like some style guides prefer you to break up a class or struct by having interface implementations go into extensions. I’ll have to dig into extensions a little more to understand them.

iOS and macOS differences

This isn’t really specifically about Swift but more the platforms I’m using swift on. Either way, it is confusing that it looks like iOS and macOS have similar APIs in Swift but there seems to be a version of the same objects across the platforms. On macOS everything is NSSomething where in iOS it looks like there is always a UISomething. It hasn’t been extremely confusing but I have had to do some translating when trying to write code for the Mac when the examples I’ve been looking at have been for iOS.

What about Objective-C

As I’ve tried to learn about writing apps for macOS, I’ve noticed that a large number of examples are written in Objective-C. This isn’t a bad thing but I avoided learning iOS and macOS development for a long time because of Objective-C. So what about Objective-C now? Ultimately, it isn’t that bad and I’ve been able to understand most API examples even if they are written in Objective-C.

The release of Swift 4 has made large strides in the API surface area it also seems. Many of the APIs had a decidedly C or Objective-C feel to them but there seems to be a big effort by Apple to make more APIs feel natural in Swift.

Ultimately, I’ll teach myself at least some Objective-C. If I want to do anything significant in Swift I likely am going to have to deal with some Objective-C code for a long time to come. For now though, I’ll try to stick to just Swift.

Goals learning Swift

I decided to learn Swift because I wanted to learn a new programming paradigm I’ve never used before. At my job right now, I do almost exclusively backed web development using C#. I don’t get much time to work on UIs or native app development. To that end, I thought I’d give macOS development a try and have been working on a simple Pomodoro timer for the Mac.

I want to eventually have enough skills with Swift (and probably a little Objective-C) that I could be a passable native iOS or macOS developer. I don’t know what the job opportunities look like there but it doesn’t really matter that much. Perhaps I’ll try to release an app or two on the App Store, either way, I’ll have learned a new skill that I would enjoy.