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Hijacking Ruby Syntax in Ruby

Satoshi "moris" Tagomori and Tomohiro Hashidate • November 13, 2018 • Los Angeles, CA

This talk, presented by Tomohiro Hashidate and Satoshi Tagomori at RubyConf 2018, delves into the fascinating world of hijacking Ruby syntax through various metaprogramming techniques. The speakers emphasize Ruby's flexibility and power by demonstrating how developers can extend Ruby's capabilities by employing lesser-known features and methods.

Key points discussed throughout the talk include:

  • Introduction of Speakers: Tomohiro Hashidate shares his background as a data engineer and introduces his co-speaker, Satoshi Tagomori, an open-source software developer with experience in IoT services. Their collaboration stems from their engagement with the Ruby community in Tokyo.

  • Binding: The concept of Binding is outlined as a context object encapsulating local and instance variables. The speakers present examples showing how binding allows access to these variables and how it can be manipulated through the 'binding-proxy' method. They emphasize the controlled management of variables in their respective contexts.

  • TracePoint: They explain how TracePoint can trace events within the Ruby Virtual Machine. By hooking into various events, they demonstrate how to gather information about method calls and class definitions, as well as to manipulate the behavior of methods based on their context.

  • Refinements: The presentation elaborates on refinements as a means to create local extensions of classes, emphasizing safety and method visibility. The speakers highlight how refinements can help in better code organization and refactoring.

  • Method Hooks and Modifiers: The possibility of tracking method definitions using hooks is introduced. The speakers draw parallels to Java by introducing method modifiers like 'final', 'override', and 'abstract', showing how these concepts can make transitioning from Java to Ruby easier for developers. They caution that improper use of hooks can lead to complex debugging scenarios.

  • Safe Resource Allocation: Discussing resource management in Ruby, they propose a syntax to allocate and deallocate resources efficiently, drawing parallels with familiar constructs from languages like Java. This allows for cleaner code while managing resources effectively.

  • Conclusions and Takeaways: The speakers wrap up by reinforcing the versatility that these metaprogramming techniques offer to Ruby developers. They encourage the audience to leverage these advanced features creatively in their projects. They invite questions, indicating their enthusiasm for sharing the wonders of Ruby programming.

Overall, this talk aims to enrich Ruby developers' understanding of how to push the boundaries of Ruby's syntax and behavior using innovative techniques, thus enhancing their coding practices and toolsets.

Hijacking Ruby Syntax in Ruby
Satoshi "moris" Tagomori and Tomohiro Hashidate • November 13, 2018 • Los Angeles, CA

RubyConf 2018 - Hijacking Ruby Syntax in Ruby by Satoshi Tagomori & Tomohiro Hashidate

This talk shows how to introduce new syntax-ish stuffs using meta programming techniques and some more Ruby features not known well by many Rubyists. Have fun with magical code!

Show Ruby features to hack Ruby syntax (including Binding, TracePoint, Refinements, etc)
Describe stuffs introduced by these techniques
method modifiers (final, abstract, override)
Table-like syntax for testing DSL
Safe resource allocation/collection (with, defer)

RubyConf 2018

00:00:15.379 Hello everyone! I think that Ruby is one of the most amazing programming communities, and today we will explore the fun of hijacking Ruby syntax.
00:00:27.750 We will discuss how to hijack Ruby syntax and showcase the power of Ruby metaprogramming.
00:00:39.260 First, let me introduce myself: my name is Tomohiro Hashidate, and I come from Japan. My friends call me Joker, due to my personality.
00:00:55.649 I work as a data engineer and have experience in web application engineering, which has made me quite familiar with Ruby and Ruby on Rails.
00:01:10.290 This is my first trip to the United States, and it is also my first time giving a talk like this. I am a bit nervous, but I am very happy to be here.
00:01:30.869 Next, I'd like to introduce my partner, Satoshi Tagomori, who will be joining me. I am an open-source software developer and manage several projects, including Groovy and others.
00:01:54.149 I'm currently working at a tech company as a software developer in the IoT services division, providing enterprise data analytics platforms.
00:02:18.490 Satoshi and I work at different companies, but we come together through the great Ruby community in Tokyo, where we discuss interesting programming techniques.
00:02:31.470 In this talk, we will introduce some Ruby features and share our own code that utilizes these metaprogramming techniques.
00:02:47.620 First, I want to talk about 'Binding.' Binding is a context object that includes local variables and instance variables. It is often used in template engines.
00:03:05.660 This sample code shows how to retrieve a binding object from context or method, using 'get_binding' to access the values of local variables and instance variables.
00:03:32.229 Notably, binding allows us to access values like local variable 'n' or instance variable 'secret,' demonstrating its flexibility.
00:03:50.770 The code shows how to obtain a binding object through the 'binding-proxy' method, enabling us to access variables defined as 'a', 'b', and 'c'.
00:04:16.950 Though this binding object can be utilized to set new local variables, it's important to note that these new variables only exist in the context of that binding.
00:04:40.750 For example, setting 'D' in one context does not allow it to persist in another. This behavior of Binding allows for flexible yet controlled variable management.
00:05:06.190 Next, let's explore 'TracePoint.' This Ruby feature allows the tracing of events within the Ruby Virtual Machine and enables hooks for various events.
00:05:32.970 We can hook into many events, such as method calls, class definition beginnings, and method returns. It allows us to gather information for various purposes, including exception handling.
00:05:52.900 The sample code demonstrates a simple method definition that takes an argument and returns a string, showcasing how TracePoint can interact with local variables.
00:06:24.090 Interestingly, when TracePoint is enabled, the behavior of method calls can change based on the method's context, allowing us to manipulate and observe variable states.
00:06:47.970 Next, I will talk about refinements, a method of extending classes locally to improve safety. Most Rubyists are not fully aware of this feature.
00:07:28.470 Refinements can create super-private methods, allowing our defined methods to be used within this file only, aiding in refactoring and controlling visibility.
00:08:07.800 I also want to talk about method hooks, which are not very popular but can provide a lot of potential for Ruby methods.
00:08:39.020 These hooks allow us to track method definitions and provide ways to implement method modifiers like 'final', 'override', and others.
00:09:12.800 These method modifiers also suggest similarities to methods in Java, which might make them easier to understand for users transitioning from Java.
00:09:50.380 By using these techniques, we can redefine behaviors in Ruby, effectively allowing modifications similar to what can be achieved through hooks.
00:10:33.480 However, caution must be exercised; misusing or forgetting to disable hooks can result in unintended consequences, making debugging more difficult.
00:11:06.240 For instance, combining these techniques with threading and execution flow may introduce complex bugs that are hard to trace.
00:11:26.220 It's essential to understand when to leverage binding and TracePoint to control which variables are accessed, manipulated, and released during execution.
00:12:02.560 As we continue with our presentation, we aim to illustrate how utilizing these advanced features can enhance Ruby applications, from memory management to robust error handling.
00:12:50.510 Finally, we'll discuss safe resource allocation, referencing the existing syntax of languages like Java, which readily provides resource management techniques.
00:13:57.840 In Ruby, we can achieve this through a simplified syntax, utilizing features like 'with' in conjunction with top-level scope definitions to manage resources intelligently.
00:15:10.690 The implementation allows for block-level resource assignment, ensuring that resources can be allocated and deallocated seamlessly, promoting better memory management.
00:15:50.560 Furthermore, the adjustments made around resource handling not only streamline operations but also facilitate cleaner, more readable code structures.
00:16:21.440 This transition to more advanced resource management structures aligns with our ongoing efforts to make Ruby an even more powerful and efficient programming language.
00:16:56.240 As we wrap up our talk, we hope to leave you with a better understanding of how to utilize these metaprogramming techniques creatively and effectively in your Ruby projects.
00:18:00.680 Thank you for your time, and we are happy to take any questions you might have as we embark on this exciting journey through Ruby.
Explore all talks recorded at RubyConf 2018
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