Grokking Functional Programming

There’s no need to fear going functional! This friendly, lively, and engaging guide is perfect for any perplexed programmer. It lays out the principles of functional programming in a simple and concise way that will help you grok what FP is really all about. In Grokking Functional Programming you will learn: Designing with functions and types instead of objects Programming with pure functions and immutable values Writing concurrent programs using the functional style Testing functional programs Multiple learning approaches to help you grok each new concept If you’ve ever found yourself rolling your eyes at functional programming, this is the book for you. Open up Grokking Functional Programming and you’ll find functional ideas mapped onto what you already know as an object-oriented programmer. The book focuses on practical aspects from page one. Hands-on examples apply functional principles to everyday programming tasks like concurrency, error handling, and improving readability. Plus, puzzles and exercises let you think and practice what you're learning. You’ll soon reach an amazing “aha” moment and start seeing code in a completely new way. About the technology Finally, there’s an easy way to learn functional programming! This unique book starts with the familiar ideas of OOP and introduces FP step-by-step using relevant examples, engaging exercises, and lots of illustrations. You’ll be amazed at how quickly you’ll start seeing software tasks from this valuable new perspective. About the book Grokking Functional Programming introduces functional programming to imperative developers. You’ll start with small, comfortable coding tasks that expose basic concepts like writing pure functions and working with immutable data. Along the way, you’ll learn how to write code that eliminates common bugs caused by complex distributed state. You’ll also explore the FP approach to IO, concurrency, and data streaming. By the time you finish, you’ll be writing clean functional code that’s easy to understand, test, and maintain. What's inside Designing with functions and types instead of objects Programming with pure functions and immutable values Writing concurrent programs using the functional style Testing functional programs About the reader For developers who know an object-oriented language. Examples in Java and Scala. About the author Michal Plachta is an experienced software developer who regularly speaks and writes about creating maintainable applications. Table of Contents Part 1 The functional toolkit 1 Learning functional programming 2 Pure functions 3 Immutable values 4 Functions as values Part 2 Functional programs 5 Sequential programs 6 Error handling 7 Requirements as types 8 IO as values 9 Streams as values 10 Concurrent programs Part 3 Applied functional programming 11 Designing functional programs 12 Testing functional programs

"An absolutely wonderful book for someone that has tried and failed to understand functional programming." - William E. Wheeler Grokking Functional Programming is a practical book written especially for object-oriented programmers. It will help you map familiar ideas like objects and composition to FP concepts such as programming with immutable data and higher-order functions. You will learn how to write concurrent programs, how to handle errors and how to design your solutions with modularity and readability in mind. And you'll be pleased to know that we skip the academic baggage of lambda calculus, category theory, and the mathematical foundations of FP in favor of applying functional programming to everyday programming tasks. At the end of the book, you'll be ready to pick a functional language and start writing useful and maintainable software. about the technologyFunctional programming is more than just writing the same old code in Scala, Clojure, or Haskell. To grok FP—to really get it—you need to rewire your brain to see the world differently. We're here to help you flip the switch. Grokking Functional Programming teaches you first to break down problems in a new way so you can approach them from a FP mindset. Following carefully-selected examples with thorough, carefully-paced explanations, you'll immerse yourself in FP concept by concept. Along the way, exercises, checks for understanding, and even the occasional puzzler give you opportunities to think and practice what you're learning. what's insideDesigning with functions and types instead of objectsMultiple learning approaches to help you grok each new conceptA practical programming-first teaching styleProgramming with pure functions & immutable valuesWriting concurrent programs with a functional styleTesting functional programs about the readerThe book assumes that the reader has at least one year of experience developing software using a mainstream object-oriented programming language like Java. While examples use Scala, this is not a Scala book. The concepts will apply to any FP language, and no prior knowledge of Scala or FP is required. about the authorMichał Płachta started using Scala commercially in 2014 and has been an active contributor to the Scala and JVM communities since. He regularly speaks at conferences, runs workshops, and organizes meetups to help others become better at functional programming. You can find his blog at michalplachta.com.