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

Handling errors with return values

In programming languages that do not support exceptions, errors are generally handled by using a return value that indicates failure. Ruby itself is written in C, and in C, functions that can fail will often use a return value that is zero on success, and non-zero on failure. While Ruby has exceptions, there are instances where methods can fail and this will occasionally return a value instead of raising an exception, even in cases where other programming languages raise an exception.

For example, in Python, if you have a hash (called a dictionary in Python), and you try to access a member in the hash that doesn't exist, you get an exception raised:

# Python code:
{'a': 2}['b']
# KeyError: 'b'

Ruby takes a different approach in this case, returning nil:

# => nil

This shows the two different philosophies between the languages. In Ruby, it is expected that when...