Preface

The purpose of this book is to teach useful principles for intermediate to advanced Ruby programmers to follow. The focus is not generally on how to implement solutions, but on different implementation approaches, the trade-offs between them, and why some approaches are better in certain situations. While the main focus of the book is teaching principles, in some cases this book also teaches advanced Ruby programming techniques.

This book starts by teaching some fundamental principles, such as how best to use the core classes, when and how best to use each variable type, and how best to use the different types of method arguments. After building on the fundamental principles, the book teaches principles for better library design, such as how best to design extensible plugin systems, trade-offs when using metaprogramming and DSLs, and how best to approach testing, refactoring, and optimization. This book concludes with a few small chapters that are focused on principles specific to web programming in Ruby, with a separate chapter each on database design, application design, and web application security.