Raku Fundamentals

Gain the skills to begin developing Raku applications from the ground up in this hands-on compact book, which includes a foreword from Larry Wall, creator of Perl. You’ll learn enough to get started building with Raku, using Raku's gradual typing, handy object orientated features, powerful parsing capabilities, and human-usable concurrency. This book has been updated to include the latest version of Raku based upon the Perl 6.d major version which includes over 3,400 new commits in its specification.

After a short introduction, each chapter develops a small example project, explaining the Raku features used. When the example is done, you’ll explore another aspect, such as optimizing further for readability or testing the code. Along the way you’ll see Raku basics, such as variables and scoping; subroutines; classes and objects; regexes; and code testing.

When you’ve mastered the basics, Raku Fundamentals moves onto more advanced topics to give you a deeper understanding of the language. You’ll learn, amongst other things, how to work with persistent storage, how to generate good error messages, and how to write tricky applications such as a file and directory usage graph and a Unicode search tool.

WHAT YOU WILL LEARN

* Get coding with latest version of Raku
* Work on several hands-on examples and projects
Integrate Python libraries into your Raku-based programs * Parse INI files using regexes and grammars
* Build a date-time converter
* Carry out refactoring and other automated tests
WHO THIS BOOK IS FOR

If you already know one or more programming languages, and want to learn about Raku, then this book is for you. MORITZ LENZ is a Perl 6, now Raku, core developer. He has contributed significantly to the official test suite, the Rakudo Perl compiler, and is the initiator of the official Raku documentation project. He has also authored several modules, and runs infrastructure for the Raku community. In his day job, he develops Perl 5 and Python code, and maintains a continuous delivery system for his employer.

1. What is Raku?

1.1 Perl 5, the Older Sister

1.2 Library Availability

1.3 Why Should I Use Raku?

2. Running Rakudo Raku

2.1 Installers

2.2 Docker

2.3 Building from Source

2.4 Testing your Rakudo Star Installation

3. Formatting a Sudoku Puzzle

3.1 Making the Sudoku Playable

3.2 Shortcuts, Constants, and more Shortcuts

3.3 IO and other Tragedies

3.4 Get Creative!

4. Datetime Conversion for the Command Line

4.1 Libraries To The Rescue

4.2 DateTime Formatting

4.3 Looking the Other Way

4.4 Dealing With Time

4.5 Tighten Your Seat Belt

4.6 MAIN magic

4.7 Automatic Tests

4.8 Summary

5. Testing say()

5.1 Summary

6. Silent Cron, a Cron Wrapper

6.1 Running Commands Asynchronously

6.2 Implementing Timeouts

6.3 More on Promises

6.4 Possible Extensions

6.5 Refactoring and Automated Tests

Refactoring

Mocking and Testing

Improving Reliability and Timing

Installing a Module

6.6 Summary

7. Stateful Silent Cron

7.1 Persistent Storage

7.2 Developing the Storage Backend

7.3 Using the Storage Backend

7.4 Room for Expansion

7.5 Summary

8. Review of the Raku Basics

8.1 Variables and Scoping

8.2 Subroutines

8.3 Classes and Objects

8.4 Concurrency

8.5 Outlook

9. Parsing INI files using Regexes and Grammars

9.1 Regex Basics

Character Classes

Quantifiers

Alternatives

9.2 Parsing the INI primitives

9.3 Putting Things Together

9.4 Backtracking

9.5 Grammars

9.6 Extracting Data from the Match

9.7 Generating Good Error Messages

Failure is Normal

Detecting Harmful Failure

Providing Context

Shortcuts for Parsing Matching Pairs

9.8 Write Your Own Grammars

9.9 Summary

10. A File and Directory Usage Graph

10.1 Reading File Sizes

10.2 Generating a Tree Map

10.3 Flame Graphs

10.4 Functional Refactorings

10.5 More Language Support for Functional Programming

10.6 More Improvements

10.7 Explore!

10.8 Summary

11. A Unicode Search Tool

11.1 Code Points, Grapheme Clusters and Bytes

11.2 Numbers

11.3 Other Unicode Properties

11.4 Collation

11.5 Summary

12. Plotting Using Inline::Python and Matplotlib

13. What's Next?