Book Image

Functional Kotlin

Book Image

Functional Kotlin

Overview of this book

Functional programming makes your application faster, improves performance, and increases your productivity. Kotlin supports many of the popular and advanced functional features of functional languages. This book will cover the A-Z of functional programming in Kotlin. This book bridges the language gap for Kotlin developers by showing you how to create and consume functional constructs in Kotlin. We also bridge the domain gap by showing how functional constructs can be applied in business scenarios. We’ll take you through lambdas, pattern matching, immutability, and help you develop a deep understanding of the concepts and practices of functional programming. If you want learn to address problems using Recursion, Koltin has support for it as well. You’ll also learn how to use the funKtionale library to perform currying and lazy programming and more. Finally, you’ll learn functional design patterns and techniques that will make you a better programmer.By the end of the book, you will be more confident in your functional programming skills and will be able to apply them while programming in Kotlin.
Table of Contents (22 chapters)
Title Page
Copyright and Credits
Dedication
Packt Upsell
Contributors
Preface
Index

Chapter 4. Functions, Function Types, and Side Effects

Functional programming revolves around the concepts of immutability and functions. We learned about immutability in the last chapter; we also got a glimpse of pure functions while discussing immutability. Pure functions are basically one of the many types (but probably the most important one) that functional programming has to offer.

This chapter will revolve around functions. To go into depth on functional programming, you need a strong base in functions. To get your concepts clear, we will start with ordinary Kotlin functions and then gradually move on to discuss abstract concepts on functions that functional programming defines. We will also see their implementation in Kotlin.

In this chapter, we are going to cover the following topics:

  • Functions in Kotlin
  • Function types
  • Lambda
  • High order functions
  • Understanding side effects and pure functions

So, let's get started by defining functions.