A few weeks ago, after Apple announced their new programming language Swift, it became very clear to me that we had to write a book on Functional Programming in Swift. Once the idea was there, I just couldn't stop thinking about it anymore. After getting Wouter and Florian on board, I knew we had a killer team for writing this book.
We decided to do give people early access, so they can read along and comment as we proceed with the writing. So far, the response has been really great, and I'm really happy that we chose to do this. It works like this: after people buy the early access version, we immediately grant them access to a GitHub repository where they can read and comment on the chapters we've written so far.
One of the things I only realized after we started: if we do this right, we might write a book that is still relevant in 5 or 10 years. The book is not about any specific frameworks, it's about doing functional programming. Frameworks might change a lot, the principles of functional programming have been the same for a really long time. Because we write our chapters using literate programming it's very easy for us to update them later on as the language evolves.
After we brainstormed a lot of ideas (way more than we could possibly fit into one book) we picked the best ones, and starting writing chapter outlines and example code. I'm so excited about some of the examples we'll show you: they make things that were previously complex now very simple. Functional programming can be like that: making certain programs smaller by a huge factor.
What I love about Swift is that it allows us to mix functional and object-oriented programming. We can keep doing all the great stuff that we know, we can keep using all of Apple's great APIs, but at the same time we can write parts of our program in a functional style. This book will hopefully show you examples where the functional style is way more powerful.