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

Equality versus identity


Two instances are equal if they have the same value. Equality is used to determine the equality of two value types. For instance, two strings are equal if they have the same text value. The == operator is used to check for equality. The following example presents equality checking for two Int numbers (Int is a value type):

let firstNumber = 1 
let secondNumber = 1 

if firstNumber == secondNumber { 
    print("Two numbers are equal") // prints "Two numbers are equal\n" 
}

On the other hand, two instances are identical if they refer to the same instance of memory. Identity is used to determine whether two reference types are identical. The === operator is used to check for identity. The following example presents identity checking for two instances of the User class that we defined earlier:

let tarang = User(name: "Tarang") 
let sangeeth = User(name: "Sangeeth") 

if tarang === sangeeth { 
    print("Identical") 
} else { 
    print("Not identical") 
}

The preceding code...