The Python Podcast.__init__

The Python Podcast.__init__

The podcast about Python and the people who make it great

15 April 2019

Exploring Python's Internals By Rewriting Them In Rust - E207

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The CPython interpreter has been the primary implementation of the Python runtime for over 20 years. In that time other options have been made available for different use cases. The most recent entry to that list is RustPython, written in the memory safe language Rust. One of the added benefits is the option to compile to WebAssembly, offering a browser-native Python runtime. In this episode core maintainers Windel Bouwman and Adam Kelly explain how the project got started, their experience working on it, and the plans for the future. Definitely worth a listen if you are curious about the inner workings of Python and how you can get involved in a relatively new project that is contributing to new options for running your code.


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  • Your host is Tobias Macey and today I’m interviewing Adam Kelly and Windel Bouwman about RusPython, a project to implement a new Python interpreter in Rust


  • Introduction
  • How did you get introduced to Python?
  • Can you start by explaining what Rust is for anyone who isn’t familiar with it?
  • How did RustPython got started and what are your goals for the project?
  • Can you discuss what is involved in implementing a fully compliant Python interpreter?
  • What are some of the challenges that you face in replicating the capabilities of the CPython interpreter?
    • Are you attempting to maintain bug parity?
    • How much of the stdlib needs to be reimplemented?
    • Can you compare and contrast the benefits of Rust vs C?
    • Will the end result be compatible with libraries that rely on C extensions such as NumPy?
  • What is the current state of the project?
    • What are some of the notable missing features?
  • Can you talk through your vision of how the WebAssembly support will manifest and the types of applications that it will enable?
    • How much effort have you put into size optimization for the webassembly target to reduce client-side load time?
    • Are there any existing options for minification of Python code so that it can be delivered to users with less bandwidth?
  • What have been some of the most interesting/challenging/unexpected aspects of implementing a Python runtime?
  • What do you have planned for the future of the project?
  • What are the risks that you anticipate which could derail the project before it becomes production ready?

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The intro and outro music is from The Hug by The Freak Fandango Orchestra / CC BY-SA

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