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

Intersection types

PHP 8 brought us union types, which is a feature where a parameter or return type can be one of a list of types, separated by the pipe (|) symbol. This is a hugely useful addition to the language and allows us to loosen the type strictness while being able to avoid using mixed as the type, or omit type hinting altogether. You can read all about union types in the RFC that was accepted into PHP 8:

PHP: rfc:union_types_v2

There is another scenario where we might want to list multiple types, and rather than allowing things to be looser, it is a scenario where we want things to be stricter.

An intersection type is one where the parameter, variable, or return must be all of the listed types. This is opposed to union types, where it can be any of the listed types. The syntax is very similar to a union type, however, the joining character is & instead of |. This corresponds neatly with the standard logical meaning...