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Functional programming in Swift: Introduction

Before you dive in to the first article in this course, I want to give you a brief overview of our goals, how the content is structured, as well as a rough idea of what you can expect to find.

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Why functional?

There are lots of ways of thinking about programming, and you’ll often hear folks use terms such as imperative programming or declarative programming. Functional programming is one such approach, but it doesn’t really have a clear-cut definition – it’s a little bit fuzzy, so that the exact definition one person gives is unlikely to match the definition from someone else.

But that’s okay; definitions don’t really help much anyway, not unless you’re planning to sit an exam. Instead, I’m always much more interested in help you understand things in practice: I want you to see real functional Swift in action so the benefits are obvious to you, I want to give you hands-on examples even for the most advanced topics so you can get them into your own projects straightaway, and although I want to show you lots of “how” I also I want to give you as much why as I can – I want you to understand the underlying principles that are at play, so you feel confident in discussing and using functional programming at every level.

Lightweight encounters

I taught some functional programming in my book Pro Swift, and we’re going to use a similar approach here – at least to start with. That approach is based on something I was introduced to by Andy Matuschak, who used to work on the UIKit team at Apple.

The approach we’ll be starting with is called “lightweight encounters”, and it means we start by looking at functional programming purely in terms of practical benefits – we’ll pick off one small task, look at how we can solve it without functional programming, then upgrade our code to have a more functional approach. This “before and after” should mean you can see the benefits of functional programming for yourself, and also give you lots of places where you can get quick wins in your own code.

So, that’s a very similar approach to Pro Swift. However, here that’s just our starting point – as this course progresses we’re going to push further and further past lightweight encounters so you understand all the theory as well as the practice.

Now, that doesn’t mean we’re going to drift off into academia: everything we do will have a firm basis in Swift code you can try for yourself, and in fact I really do encourage you to try the code yourself so you can toy around with it and get a stronger grasp.

Stop when you’re ready

This course is structured so that it more or less gets steadily more complex as we progress. This means the whole first chunk of videos should be really useful to everyone, so you can just dive in and explore. As we progress you’ll feel the difficulty ramp up little by little and there might come a point where you think you’ve had enough – that you’ve already got enough benefit from the course, and are happy to move on to something else.

What I want to say is this: it’s okay to stop when you’re ready. Whenever that point is – whenever you think you’ve gained enough from this course to make a significant difference to your code – it’s okay to move on to something else. Obviously I hope you’ll continue get to the end and find value all the way, but if you’re sitting there thinking “this is hard” or – worse – “will I ever use this?” then chances are you’re not learning too much.

Don’t beat yourself up. Take a break, apply what you’ve learned, and reap the benefits of that – once you’re a bit further along you might find you can come back with fresh eyes and get a whole new round of benefits.

Releasing installments

This course is being published in installments, and although the exact release schedule will fluctuate a little depending on topic difficulty, you should be able to come and get new videos regularly.

However, if you are following along as videos are being published, this is a great chance for you to write in to ask for something specific. I’m happy to hear suggestions, as long as they align my goal of teaching theory and practice hand in hand.

Take your time

And finally, I want to remind you again that the most important thing you can do in this course is apply what you learn.

We all rely on muscle memory to make our jobs faster and easier, which means when it comes to solving a problem we naturally rely on approaches that worked previously. In this course we’ll be covering a huge range of techniques, and if you just fly through the material as fast as you can chances are you won’t retain much – it might be fun to learn, but it won’t really stick.

Instead, your goal should be to try to build new muscle memory: to slowly retrain your brain that there are newer, better ways of solving problems, so that over time you reach for functional programming techniques first and instinctively. The only way to do this is to apply, apply, and apply some more – as soon as you finish one part of this course, have a think about where you can try it out in your own projects, so that not only can you refer back to these articles in the future but you can also look at your own code.

Anyway, I hope you enjoy the course, and more importantly that you find lots of real-world success with functional programming!

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Using memoization to speed up slow functions