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

Contains


Let's consider another common collection operation: contains.

In Go, lists of things are often stored in a slice. Wouldn't it be nice if Go provided a contains method to tell us whether the item we are looking for is contained in the slice? Since there is no generic contains method for working with lists of items in Go, let's implement one to iterate over a collection of car objects.

Iterating over a collection of cars

First, let's create a Car struct that we can use to define the Cars collection as a slice of Car. Later, we'll create a Contains() method to try out on our collection:

package main
type Car struct {
     Make string
     Model string
}
type Cars []*Car

Here's our Contains() implementation. Contains() is a method for Cars. It takes a modelName string, for example, Highlander, and returns true if it was found in the slice of Cars:

func (cars Cars) Contains(modelName string) bool {
     for _, a := range cars {
            if a.Model == modelName {
                   return...