Book Image

PHP 7 Programming Blueprints

By : Jose Palala, Martin Helmich
Book Image

PHP 7 Programming Blueprints

By: Jose Palala, Martin Helmich

Overview of this book

When it comes to modern web development, performance is everything. The latest version of PHP has been improvised and updated to make it easier to build for performance, improved engine execution, better memory usage, and a new and extended set of tools. If you’re a web developer, what’s not to love? This guide will show you how to make full use of PHP 7 with a range of practical projects that will not only teach you the principles, but also show you how to put them into practice. It will push and extend your skills, helping you to become a more confident and fluent PHP developer. You’ll find out how to build a social newsletter service, a simple blog with a search capability using Elasticsearch, as well as a chat application. We’ll also show you how to create a RESTful web service, a database class to manage a shopping cart on an e-commerce site and how to build an asynchronous microservice architecture. With further guidance on using reactive extensions in PHP, we’re sure that you’ll find everything you need to take full advantage of PHP 7. So dive in now!
Table of Contents (15 chapters)
PHP 7 Programming Blueprints
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Preface
4
Build a Simple Blog with Search Capability using Elasticsearch

Languages and grammars


In order for a parser to be able to understand a program, it needs a formal description of that language-a grammar. In this chapter, we will work with a so-called parsing expression grammar (PEG). A PEG is (relatively) easy to define and there are libraries that can generate a parser for a given grammar automatically.

A grammar consists of terminal symbols and non-terminal symbols. A non-terminal symbol is a symbol that maybe composed of several other symbols, following certain rules (production rules). For example, a grammar could contain a number as non-terminal symbol. Each number could be defined as an arbitrary-length sequence of digits. As a digit could then be any of the characters from 0 to 9 (with each of the actual digits being a terminal symbol).

Let's try to describe the structure of numbers (and then building on this mathematical expressions in general) formally. Let's start by describing how a number looks like. Each number consists of one or more digits...