Book Image

Learning Functional Programming in Go

By : Lex Sheehan
Book Image

Learning Functional Programming in Go

By: Lex Sheehan

Overview of this book

Lex Sheehan begins slowly, using easy-to-understand illustrations and working Go code to teach core functional programming (FP) principles such as referential transparency, laziness, recursion, currying, and chaining continuations. This book is a tutorial for programmers looking to learn FP and apply it to write better code. Lex guides readers from basic techniques to advanced topics in a logical, concise, and clear progression. The book is divided into four modules. The first module explains the functional style of programming: pure functional programming, manipulating collections, and using higher-order functions. In the second module, you will learn design patterns that you can use to build FP-style applications. In the next module, you will learn FP techniques that you can use to improve your API signatures, increase performance, and build better cloud-native applications. The last module covers Category Theory, Functors, Monoids, Monads, Type classes and Generics. By the end of the book, you will be adept at building applications the FP way.
Table of Contents (21 chapters)
Title Page
Credits
About the Author
Acknowledgments
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
Index

The importance of Type systems to FP


The purpose of a type system is to reduce bugs by defining the interfaces between the different functions in a program and verifying that those functions can be reliably connected. Types can be a simple as strings, ints, and booleans or can be a complex data structure with embedded fields and interfaces. Types can be checked at compile time or runtime.

The Lambda Calculus was originally untyped, but Alonzo Church found that that though it was more expressive, it caused inconsistencies. So, Church introduced a typed version to simplify computation. We use type systems for similar reasons, that is, to improve determinism and to help prevent bugs.

Since in FP a function is a data type, we need to define our functions' type for the type system.

A type system can also increase our programs' runtime performance. Go is a statically compiled language, so the data types are known at compile time. This makes type erasure possible. So, Go does not have to require our...