John Paul Mueller - Functional Programming for Dummies

Functional Programming For Dummies

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Copyright 2019 by John Wiley & Sons, Inc., Hoboken, New Jersey

Published simultaneously in Canada

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Library of Congress Control Number: 2018965285

ISBN: 978-1-119-52750-3

ISBN 978-1-119-52751-0 (ebk); ISBN ePDF 978-1-119-52749-7 (ebk)

1. Chapter 11

1. Chapter 2
2. Chapter 3
3. Chapter 4
4. Chapter 6
5. Chapter 7
6. Chapter 8
7. Chapter 9
8. Chapter 10
9. Chapter 11
10. Chapter 12
11. Chapter 13
12. Chapter 14
13. Chapter 15
14. Chapter 16

The functional programming paradigm is a framework that expresses a particular set of assumptions, relies on particular ways of thinking through problems, and uses particular methodologies to solve those problems. Some people view this paradigm as being akin to performing mental gymnastics. Other people see functional programming as the most logical and easiest method for coding any particular problem ever invented. Where you appear in this rather broad range of perspectives depends partly on your programming background, partly on the manner in which you think through problems, and partly on the problem youre trying to solve.

Functional Programming For Dummies doesnt try to tell you that the functional programming paradigm will solve every problem, but it does help you understand that functional programming can solve a great many problems with fewer errors, less code, and a reduction in development time. Most important, it helps you understand the difference in the thought process that using the functional programming paradigm involves. Of course, the key is knowing when functional programming is the best option, and thats what you take away from this book. Not only do you see how to perform functional programming with both pure (Haskell) and impure (Python) languages, but you also gain insights into when functional programming is the best solution.

Functional Programming For Dummies begins by describing what a paradigm is and how the functional programming paradigm differs. Many developers today dont really understand that different paradigms can truly change the manner in which you view a problem domain, thereby making some problem domains considerably easier to deal with. As part of considering the functional programming paradigm, you install two languages: Haskell (a pure functional language) and Python (an impure functional language). Of course, part of this process is to see how pure and impure languages differ and determine the advantages and disadvantages of each.

Part of working in the functional programming environment is to understand and use lambda calculus, which is part of the basis on which functional programming it built. Imagine that youre in a room with some of the luminaries of computer science and theyre trying to decide how best to solve problems in computer science at a time when the term computer science doesnt even exist. For that matter, no one has even defined what it means to compute. Even though functional programming might seem new to many people, its based on real science created by the best minds the world has ever seen to address particularly difficult problems. This science uses lambda calculus as a basis, so an explanation of this particularly difficult topic is essential.

After you understand the basis of the functional programming paradigm and have installed tools that you can use to see it work, its time to create some example code. This book starts with some relatively simple examples that you might find in other books that use other programming paradigms so that you compare them and see how functional programming actually differs. You then move on to other sorts of programming problems that begin to emphasize the benefits of functional programming in a stronger way. To make absorbing the concepts of functional programming even easier, this book uses the following conventions:

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