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Polished Ruby Programming

You're reading from   Polished Ruby Programming Build better software with more intuitive, maintainable, scalable, and high-performance Ruby code

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Product type Paperback
Published in Jul 2021
Publisher Packt
ISBN-13 9781801072724
Length 434 pages
Edition 1st Edition
Languages
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Author (1):
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Jeremy Evans Jeremy Evans
Author Profile Icon Jeremy Evans
Jeremy Evans
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Table of Contents (23) Chapters Close

Preface 1. Section 1: Fundamental Ruby Programming Principles
2. Chapter 1: Getting the Most out of Core Classes FREE CHAPTER 3. Chapter 2: Designing Useful Custom Classes 4. Chapter 3: Proper Variable Usage 5. Chapter 4: Methods and Their Arguments 6. Chapter 5: Handling Errors 7. Chapter 6: Formatting Code for Easy Reading 8. Section 2: Ruby Library Programming Principles
9. Chapter 7: Designing Your Library 10. Chapter 8: Designing for Extensibility 11. Chapter 9: Metaprogramming and When to Use It 12. Chapter 10: Designing Useful Domain-Specific Languages 13. Chapter 11: Testing to Ensure Your Code Works 14. Chapter 12: Handling Change 15. Chapter 13: Using Common Design Patterns 16. Chapter 14: Optimizing Your Library 17. Section 3: Ruby Web Programming Principles
18. Chapter 15: The Database Is Key 19. Chapter 16: Web Application Design Principles 20. Chapter 17: Robust Web Application Security 21. Assessments 22. Other Books You May Enjoy

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:

$LOAD_PATH.unshift("../lib")

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
  yield
ensure
  $VERBOSE = verbose
end

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

$stdout.write($stdin.read) 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...

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