Book Image

Polished Ruby Programming

By : Jeremy Evans
Book Image

Polished Ruby Programming

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

Avoiding global variables, most of the time

Global variables are available in Ruby, but in general, their use is discouraged unless it is necessary. Some examples where it may make sense for you to use global variables are when you are modifying the load path:


Or when you are silencing warnings in a block (assuming you actually have a good reason to do that):

def no_warnings
  verbose = $VERBOSE
  $VERBOSE = nil
  $VERBOSE = verbose

Or lastly, when reading/writing to the standard input, output, or error:

$stdout.write($ rescue $stderr.puts($!.to_s)

These are all cases where you are using the existing global variables. It rarely makes sense to define and use your own global variables, even though Ruby does make it easy to use global variables since they are global and available everywhere.

The main issues with using global variables in Ruby are the same as...