Effective Ruby: 48 Specific Ways to Write Better Ruby

If you’re an experienced Ruby programmer, Effective Ruby will help you harness Ruby’s full power to write more robust, efficient, maintainable, and well-performing code. Drawing on nearly a decade of Ruby experience, Peter J. Jones brings together 48 Ruby best practices, expert tips, and shortcuts—all supported by realistic code examples.   Jones offers practical advice for each major area of Ruby development, from modules to memory to metaprogramming. Throughout, he uncovers little-known idioms, quirks, pitfalls, and intricacies that powerfully impact code behavior and performance. Each item contains specific, actionable, clearly organized guidelines; careful advice; detailed technical arguments; and illuminating code examples. When multiple options exist, Jones shows you how to choose the one that will work best in your situation.   Effective Ruby will help you systematically improve your code—not by blindly following rules, but by thoroughly understanding Ruby programming techniques.   Key features of this concise guide include How to avoid pitfalls associated with Ruby’s sometimes surprising idiosyncrasies What you should know about inheritance hierarchies to successfully use Rails (and other large frameworks) How to use misunderstood methods to do amazingly useful things with collections Better ways to use exceptions to improve code reliability Powerful metaprogramming approaches (and techniques to avoid) Practical, efficient testing solutions, including MiniTest Unit and Spec Testing How to reliably manage RubyGem dependencies How to make the most of Ruby’s memory management and profiling tools How to improve code efficiency by understanding the Ruby interpreter’s internals

Table of Contents:
Foreword xi Preface xiii Acknowledgments xvii About the Author xix   Chapter 1: Accustoming Yourself to Ruby 1 Item 1: Understand What Ruby Considers to Be True 1 Item 2: Treat All Objects as If They Could Be nil 3 Item 3: Avoid Ruby’s Cryptic Perlisms 6 Item 4: Be Aware That Constants Are Mutable 9 Item 5: Pay Attention to Run-Time Warnings 12   Chapter 2: Classes, Objects, and Modules 17 Item 6: Know How Ruby Builds Inheritance Hierarchies 17 Item 7: Be Aware of the Different Behaviors of super 24 Item 8: Invoke super When Initializing Subclasses 28 Item 9: Be Alert for Ruby’s Most Vexing Parse 31 Item 10: Prefer Struct to Hash for Structured Data 35 Item 11: Create Namespaces by Nesting Code in Modules 38 Item 12: Understand the Different Flavors of Equality 43 Item 13: Implement Comparison via “<=>” and the Comparable Module 49 Item 14: Share Private State through Protected Methods 53 Item 15: Prefer Class Instance Variables to Class Variables 55   Chapter 3: Collections 59 Item 16: Duplicate Collections Passed as Arguments before Mutating Them 59 Item 17: Use the Array Method to Convert nil and Scalar Objects into Arrays 63 Item 18: Consider Set for Efficient Element Inclusion Checking 66 Item 19: Know How to Fold Collections with reduce 70 Item 20: Consider Using a Default Hash Value 74 Item 21: Prefer Delegation to Inheriting from Collection Classes 79   Chapter 4: Exceptions 85 Item 22: Prefer Custom Exceptions to Raising Strings 85 Item 23: Rescue the Most Specific Exception Possible 90 Item 24: Manage Resources with Blocks and ensure 94 Item 25: Exit ensure Clauses by Flowing Off the End 97 Item 26: Bound retry Attempts, Vary Their Frequency, and Keep an Audit Trail 100 Item 27: Prefer throw to raise for Jumping Out of Scope 104   Chapter 5: Metaprogramming 107 Item 28: Familiarize Yourself with Module and Class Hooks 107 Item 29: Invoke super from within Class Hooks 114 Item 30: Prefer define_method to method_missing 115 Item 31: Know the Difference between the Variants of eval 122 Item 32: Consider Alternatives to Monkey Patching 127 Item 33: Invoke Modified Methods with Alias Chaining 133 Item 34: Consider Supporting Differences in Proc Arity 136 Item 35: Think Carefully Before Using Module Prepending 141   Chapter 6: Testing 145 Item 36: Familiarize Yourself with MiniTest Unit Testing 145 Item 37: Familiarize Yourself with MiniTest Spec Testing 149 Item 38: Simulate Determinism with Mock Objects 152 Item 39: Strive for Effectively Tested Code 156   Chapter 7: Tools and Libraries 163 Item 40: Know How to Work with Ruby Documentation 163 Item 41: Be Aware of IRB’s Advanced Features 166 Item 42: Manage Gem Dependencies with Bundler 170 Item 43: Specify an Upper Bound for Gem Dependencies 175   Chapter 8: Memory Management and Performance 179 Item 44: Familiarize Yourself with Ruby’s Garbage Collector 179 Item 45: Create Resource Safety Nets with Finalizers 185 Item 46: Be Aware of Ruby Profiling Tools 189 Item 47: Avoid Object Literals in Loops 195 Item 48: Consider Memoizing Expensive Computations 197   Epilogue 201   Index 203

About the Author :
Peter J. Jones is a freelance software developer and a senior instructor for programming workshops taught by Devalot.com. He has been programming in Ruby since 2005, and has written and taught several development workshops, including an 11-week Ruby class for beginners.