Chris Eidhof is one of the objc.io co-founders. He has spent the last years exclusively on Apple's platforms, but was a Haskell programmer before that.

Florian Kugler is one of the objc.io co-founders. He’s been at home in the OOP paradigm for quite a while, and he makes sure to keep the monads and endofunctors in check.

Wouter Swierstra has more than 15 years of experience with functional programming. He has worked in industry, taught courses, and published research articles — all using functional programming.

This book will teach you how to use Swift to apply functional programming techniques to your iOS or OS X projects. These techniques complement object-oriented programming that most Objective-C developers will already be familiar with, providing you with a valuable new tool in your developer's toolbox. We will start by taking a look at Swift's new language features, such as higher-order functions, generics, optionals, enumerations, and pattern matching. Mastering these new features will enable you to write functional code effectively. After that, we will provide several examples of how to use functional programming patterns to solve real-world problems. These examples include a compositional and type-safe API around Core Image, a library for diagrams built on Core Graphics, and a small spreadsheet application built from scratch.