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

Nullable, void, and uninitialized

There are three special types in PHP that represent no value at all. The first is null; it is something that is expected as a valid value for your properties and return types, though it is something that you need to account for.

Another one is void and it really does mean nothing. It is only used as a return type and it defines that the function or method does not return anything at all.

The final one is uninitialised, which is a special limbo state that has been introduced along with PHP 8 constructor property promotion. We will explore how all of these work.

Null and nullable

First, let's have a look at null. null behaves like a scalar value in that you can assign it, check for it, and return it as an option on any other type.

Have a look at this code:



namespace Book\Part2\Chapter4;
// assigning null as a value
$foo = null;
// short...