Book Image

Swift Functional Programming - Second Edition

By : Dr. Fatih Nayebi
Book Image

Swift Functional Programming - Second Edition

By: Dr. Fatih Nayebi

Overview of this book

Swift is a multi-paradigm programming language enabling you to tackle different problems in various ways. Understanding each paradigm and knowing when and how to utilize and combine them can lead to a better code base. Functional programming (FP) is an important paradigm that empowers us with declarative development and makes applications more suitable for testing, as well as performant and elegant. This book aims to simplify the FP paradigms, making them easily understandable and usable, by showing you how to solve many of your day-to-day development problems using Swift FP. It starts with the basics of FP, and you will go through all the core concepts of Swift and the building blocks of FP. You will also go through important aspects, such as function composition and currying, custom operator definition, monads, functors, applicative functors,memoization, lenses, algebraic data types, type erasure, functional data structures, functional reactive programming (FRP), and protocol-oriented programming(POP). You will then learn to combine those techniques to develop a fully functional iOS application from scratch
Table of Contents (19 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Dedication
Preface

An example


We understand that there are cases where immutability makes our life harder. We barely touched the surface of these problems in a previous section. We will examine issues in more detail in the following chapters.

Let's redevelop our Product example with a FP style and compare the outcome to its OOP counterpart.

Let's use struct and make all properties in our Product example immutable and examine the outcome:

struct FunctionalProduct { 
    let name: String 
    let price: Double 
    let quantity: Int 
    let producer: Producer 
} 

Now we have struct instead of class and all properties are immutable. Also, we do not need an init method as struct provides it automatically.

We also need to modify our ProductTracker class:

struct FunctionalProductTracker { 
    let products: [FunctionalProduct] 
    let lastModified: Date 

    func addNewProduct(item: FunctionalProduct) -> (date: Date,    
    products: [FunctionalProduct]) { 
        let newProducts = self.products + [item] 
   ...