Book Image

Polished Ruby Programming

By : Jeremy Evans
5 (1)
Book Image

Polished Ruby Programming

5 (1)
By: Jeremy Evans

Overview of this book

Anyone striving to become an expert Ruby programmer needs to be able to write maintainable applications. Polished Ruby Programming will help you get better at designing scalable and robust Ruby programs, so that no matter how big the codebase grows, maintaining it will be a breeze. This book takes you on a journey through implementation approaches for many common programming situations, the trade-offs inherent in each approach, and why you may choose to use different approaches in different situations. You'll start by refreshing Ruby fundamentals, such as correctly using core classes, class and method design, variable usage, error handling, and code formatting. Then you'll move on to higher-level programming principles, such as library design, use of metaprogramming and domain-specific languages, and refactoring. Finally, you'll learn principles specific to web application development, such as how to choose a database and web framework, and how to use advanced security features. By the end of this Ruby programming book, you’ll be a well rounded web developer with a deep understanding of Ruby. While most code examples and principles discussed in the book apply to all Ruby versions, some examples and principles are specific to Ruby 3.0, the latest release at the time of publication.
Table of Contents (23 chapters)
Section 1: Fundamental Ruby Programming Principles
Section 2: Ruby Library Programming Principles
Section 3: Ruby Web Programming Principles

Visiting objects

The visitor pattern is most commonly used when you have many objects of separate classes that you need to handle in some manner. You have a class called a visitor that processes, or visits, each object and does something with the object. Often when using the visitor pattern, you actually have multiple different types of operations that all need to deal with the same objects, so you have multiple visitor classes. However, you do not want to add methods for each visitor class to each of those separate classes. After all, while it is possible to define methods on any class in Ruby, it's generally considered bad practice to define methods on classes that are not part of your library, unless that is the sole purpose of your library.

The visitor pattern is a way around the problem of defining per-visitor methods in each class that is being visited. A classic approach to the visitor pattern results in a ton of complexity and still requires adding a method to the classes...