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)
1
Section 1: Fundamental Ruby Programming Principles
8
Section 2: Ruby Library Programming Principles
17
Section 3: Ruby Web Programming Principles

Learning when to use core classes

Let's consider the following Ruby code:

things = ["foo", "bar", "baz"]
things.each do |thing|
  puts thing
end

If you have come across this code, then you probably have an immediate understanding of what the code does. However, let's say you come across the following Ruby code:

things = ThingList.new("foo", "bar", " baz")
things.each do |thing|
  puts thing
end

You can probably guess what it does, but to be sure, you need to know about the ThingList class and how it is implemented. What does ThingList.new do? Does it use its arguments directly or does it wrap them in other objects? What does the ThingList#each method yield? Does it yield the same objects passed into the constructor, or other objects? When you come across code like this, your initial assumption may be that it would yield other objects and not the objects passed into the constructor, because why else would you have a class that duplicates the core Array class?

A good general principle is to only create custom classes when the benefits outweigh the costs. When deciding whether to use a core class or a custom class, you should understand the trade-off you are making. With core classes, your code is often more intuitive, and in general will perform better, since using core classes directly results in less indirection. With custom classes, you are able to encapsulate your logic, which can lead to more maintainable code in the long term, if you have to make changes. In many cases, you won't have to make changes in the future, and the benefits of encapsulation are not greater than the loss of intuition and performance. If you aren't sure whether to use a custom class or a core class, a good general principle is to start with the use of core classes, and only add a custom class when you see a clear advantage in doing so.