Book Image

Functional Programming in Go

By : Dylan Meeus
Book Image

Functional Programming in Go

By: Dylan Meeus

Overview of this book

While Go is a multi-paradigm language that gives you the option to choose whichever paradigm works best for the particular problem you aim to solve, it supports features that enable you to apply functional principles in your code. In this book, you’ll learn about concepts central to the functional programming paradigm and how and when to apply functional programming techniques in Go. Starting with the basic concepts of functional programming, this Golang book will help you develop a deeper understanding of first-class functions. In the subsequent chapters, you’ll gain a more comprehensive view of the techniques and methods used in functional languages, such as function currying, partial application, and higher-order functions. You’ll then be able to apply functional design patterns for solving common programming challenges and explore how to apply concurrency mechanisms to functional programming. By the end of this book, you’ll be ready to improve your code bases by applying functional programming techniques in Go to write cleaner, safer, and bug-free code.
Table of Contents (17 chapters)
1
Part 1: Functional Programming Paradigm Essentials
7
Part 2: Using Functional Programming Techniques
11
Part 3: Design Patterns and Functional Programming Libraries

Predicate-based functions

The first type of functions that we will explore is predicate-based functions. A predicate is a statement that can be evaluated as either true or false. Typically, in a language without a higher-order function, this would be achieved by using if statements inside the body of a function. A common use case is to filter a set of data into a subset that matches a specific condition – for example, given a list of people, return all of those who are older than 18 years old.

To start, we can introduce a type alias for a function that defines the type signature of a predicate:

type Predicate[A any] func(A) bool

This type alias tells us that the function takes an input with a type of A, which can represent the any type in our program, but needs to return a bool value. This type uses generics, which were introduced in Go 1.18. We can now use this type in every place at which a predicate is expected. The first function that works using predicates is the...