Book Image

The Art of Modern PHP 8

By : Joseph Edmonds
5 (1)
Book Image

The Art of Modern PHP 8

5 (1)
By: Joseph Edmonds

Overview of this book

PHP has come a long way since its introduction. While the language has evolved with PHP 8, there are still a lot of websites running on a version of PHP that is no longer supported. If you are a PHP developer working with legacy PHP systems and want to discover the tenants of modern PHP, this is the book for you. The Art of Modern PHP 8 walks you through the latest PHP features and language concepts. The book helps you upgrade your knowledge of PHP programming and practices. Starting with object-oriented programming (OOP) in PHP and related language features, you'll work through modern programming techniques such as inheritance, understand how it contrasts with composition, and finally look at more advanced language features. You'll learn about the MVC pattern by developing your own MVC system and advance to understanding what a DI container does by building a toy DI container. The book gives you an overview of Composer and how to use it to create reusable PHP packages. You’ll also find techniques for deploying these packages to package libraries for other developers to explore. By the end of this PHP book, you'll have equipped yourself with modern server-side programming techniques using the latest versions of PHP.
Table of Contents (19 chapters)
Section 1 – PHP 8 OOP
Free Chapter
Chapter 1: Object-Oriented PHP
Section 2 – PHP Types
Chapter 5: Object Types, Interfaces, and Unions
Section 3 – Clean PHP 8 Patterns and Style
Section 4 – PHP 8 Composer Package Management (and PHP 8.1)
Section 5 – Bonus Section - PHP 8.1

Chapter 6: Parameter, Property, and Return Types

Hopefully, after reading the preceding chapters and topping up your knowledge gaps by hitting the official docs pages, you now have a good understanding of how PHP types work. What we are going to explore in this chapter is the way that those types can be checked and enforced in function or method parameters and return types. This is where types really gain their utility and so it is important that you have a clear understanding of how this works.

We will start off by looking at the difference between the default "coercive" mode and the recommended but optional "strict" mode. Then, we are going to try to get our heads around covariance and contravariance and understand how they limit what we can do when extending parent classes or implementing interfaces.

This chapter will cover the following topics:

  • Coercive and strict modes
  • Covariance and contravariance

As usual, you can find all the code...