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Crystal Programming

You're reading from   Crystal Programming A project-based introduction to building efficient, safe, and readable web and CLI applications

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Product type Paperback
Published in May 2022
Publisher Packt
ISBN-13 9781801818674
Length 356 pages
Edition 1st Edition
Languages
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Authors (2):
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George Dietrich George Dietrich
Author Profile Icon George Dietrich
George Dietrich
Guilherme Bernal Guilherme Bernal
Author Profile Icon Guilherme Bernal
Guilherme Bernal
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Toc

Table of Contents (26) Chapters Close

Preface 1. Part 1: Getting Started
2. Chapter 1: An Introduction to Crystal FREE CHAPTER 3. Chapter 2: Basic Semantics and Features of Crystal 4. Chapter 3: Object-Oriented Programming 5. Part 2: Learning by Doing – CLI
6. Chapter 4: Exploring Crystal via Writing a Command-Line Interface 7. Chapter 5: Input/Output Operations 8. Chapter 6: Concurrency 9. Chapter 7: C Interoperability 10. Part 3: Learn by Doing – Web Application
11. Chapter 8: Using External Libraries 12. Chapter 9: Creating a Web Application with Athena 13. Part 4: Metaprogramming
14. Chapter 10: Working with Macros 15. Chapter 11: Introducing Annotations 16. Chapter 12: Leveraging Compile-Time Type Introspection 17. Chapter 13: Advanced Macro Usages 18. Part 5: Supporting Tools
19. Chapter 14: Testing 20. Chapter 15: Documenting Code 21. Chapter 16: Deploying Code 22. Chapter 17: Automation 23. Other Books You May Enjoy Appendix A: Tooling Setup 1. Appendix B: The Future of Crystal

Summary

And there you have it, a blog implementation that leverages some of the cooler Athena features that in turn made the implementation easy and highly flexible. We used param converters to handle both deserializing the request body, and also looking up and providing a value from the database. We created a custom annotation and format handler to support multiple format responses via content negotiation. And most importantly, we scratched the surface of the DI component by showing how it makes reusing objects easy as well as how the container per request concept can be used to prevent the bleeding of state between requests.

As you can imagine, Athena leverages quite a few metaprogramming concepts in order to implement its features. In the next chapter, we are going to be exploring a core metaprogramming feature, macros.

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