Date: Mon, 09 Nov 2020 22:00:00 -0500
<div class="wp-block-jetpack-markdown"><h3>Summary</h3> <p>The CPython implementation has grown and evolved significantly over the past ~25 years. In that time there have been many other projects to create compatible runtimes for your Python code. One of the challenges for these other projects is the lack of a fully documented specification of how and why everything works the way that it does. In the most recent Python language summit Mark Shannon proposed implementing a formal specification for CPython, and in this episode he shares his reasoning for why that would be helpful and what is involved in making it a reality.</p> <h3>Announcements</h3> <ul> <li>Hello and welcome to Podcast.__init__, the podcast about Python and the people who make it great.</li> <li>When you’re ready to launch your next app or want to try a project you hear about on the show, you’ll need somewhere to deploy it, so take a look at our friends over at Linode. 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It’s like the first year of computer science that you never took compressed into 10 fun hours of Python coding and problem solving. Go to <a href="https://www.pythonpodcast.com/talkpython?utm_source=rss&utm_medium=rss">pythonpodcast.com/talkpython</a> today and get 10% off the course that will help you find your next level. That’s <a href="https://www.pythonpodcast.com/talkpython?utm_source=rss&utm_medium=rss">pythonpodcast.com/talkpython</a>, and don’t forget to thank them for supporting the show.</li> <li>Your host as usual is Tobias Macey and today I’m interviewing Mark Shannon about his efforts to create a formal specification for the CPython interpreter</li> </ul> <h3>Interview</h3> <ul> <li>Introductions</li> <li>How did you get introduced to Python?</li> <li>Can you start by describing the current state of how the Python language and the CPython runtime are defined?</li> <li>What is your motivation in advocating for a specification? <ul> <li>After ~25 years of the language, why is now the time to pursue this effort?</li> <li>How does the history of the language and the scope of the ecosystem and community impact the effort required to make this a reality?</li> </ul> </li> <li>What is involved in creating the specification and where would it be located once complete? <ul> <li>What are some examples of languages that are formally specified?</li> </ul> </li> <li>What are the possible benefits of creating a specification for the CPython virtual machine? <ul> <li>What is the distinction between a specification for the VM as opposed to a specification for the language?</li> </ul> </li> <li>What are some potential downsides to having a (semi-)formal specification become part of the definition of the interpreter?</li> <li>Can you describe the process of doing the work to create the specification?</li> <li>How are you approaching the actual definition of the specification (e.g. prose vs programmatic)? <ul> <li>What are the tradeoffs of prose vs. an executable specification (e.g. TLA+, Alloy)?</li> </ul> </li> <li>How does this work tie into your goals of improving the speed of the CPython interpreter?</li> <li>What are some of the most interesting, unexpected, or challenging aspects of your efforts to bring this specification to CPython?</li> <li>How can the community contribute to this effort?</li> </ul> <h3>Keep In Touch</h3> <ul> <li><a href="https://github.com/markshannon?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">markshannon</a> on GitHub</li> <li><a href="https://sites.google.com/site/makingcpythonfast/?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">Website</a></li> </ul> <h3>Picks</h3> <ul> <li>Tobias <ul> <li>American Gods <a href="https://www.neilgaiman.com/works/Books/American+Gods/?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">book</a> and <a href="https://www.imdb.com/title/tt1898069/?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">TV series</a></li> </ul> </li> <li>Mark <ul> <li><a href="https://en.wikipedia.org/wiki/Roadside_Picnic?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">Roadside Picnic</a></li> <li><a href="https://www.oculus.com/experiences/quest/2334376869949242/?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">In Death (VR game)</a> –<a href="https://store.steampowered.com/app/605450/In_Death/?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">On Steam</a></li> </ul> </li> </ul> <h3>Closing Announcements</h3> <ul> <li>Thank you for listening! Don’t forget to check out our other show, the <a href="https://feeds.fireside.fm/pythonpodcast/rss">Data Engineering Podcast</a> for the latest on modern data management.</li> <li>Visit the <a href="https://www.pythonpodcast.com?utm_source=rss&utm_medium=rss">site</a> to subscribe to the show, sign up for the mailing list, and read the show notes.</li> <li>If you’ve learned something or tried out a project from the show then tell us about it! Email <a href="mailto:hosts@podcastinit.com">hosts@podcastinit.com</a>) with your story.</li> <li>To help other people find the show please leave a review on <a href="https://itunes.apple.com/us/podcast/podcast.-init/id981834425?mt=2&uo=6&at=&ct=&utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">iTunes</a> and tell your friends and co-workers</li> <li>Join the community in the new Zulip chat workspace at <a href="https://www.pythonpodcast.com/chat?utm_source=rss&utm_medium=rss">pythonpodcast.com/chat</a></li> </ul> <h3>Links</h3> <ul> <li><a href="https://en.wikipedia.org/wiki/CPython?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">CPython</a></li> <li><a href="https://www.pypy.org/?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">PyPy</a></li> <li><a href="https://www.python.org/dev/peps/pep-0380/?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">PEP 380</a> yield from</li> <li><a href="https://us.pycon.org/2020/events/languagesummit/?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">Language Summit</a></li> <li><a href="https://rustpython.github.io/?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">RustPython</a></li> <li><a href="https://www.jython.org/?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">Jython</a></li> <li><a href="https://en.wikipedia.org/wiki/C%2B%2B?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">C++</a></li> <li><a href="https://en.wikipedia.org/wiki/ML_(programming_language)?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">ML</a> programming language</li> <li><a href="https://en.wikipedia.org/wiki/Java_(programming_language)?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">Java</a></li> <li><a href="https://github.com/markshannon/python_formal_semantics?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">Python Formal Semantics git repository</a></li> <li><a href="https://www.pythonpodcast.com/cpython-parser-replacement-episode-285/?utm_source=rss&utm_medium=rss">CPython PEG Parser Episode</a> with Pablo Galindo and Lysandros Nikolaou</li> <li><a href="https://www.ietf.org/standards/rfcs/?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">IETF RFCs</a></li> </ul> <p>The intro and outro music is from Requiem for a Fish <a href="http://freemusicarchive.org/music/The_Freak_Fandango_Orchestra/?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">The Freak Fandango Orchestra</a> / <a href="http://creativecommons.org/licenses/by-sa/3.0/?utm_source=rss&utm_medium=rss" rel="noopener" target="_blank">CC BY-SA</a></p> </div> <img alt="" height="0" src="https://analytics.boundlessnotions.com/piwik.php?idsite=1&rec=1&url=https%3A%2F%2Fwww.pythonpodcast.com%2Fcpython-formal-specification-episode-288%2F&action_name=Making+The+Case+For+A+%28Semi%29+Formal+Specification+Of+CPython+-+Episode+288&urlref=https%3A%2F%2Fwww.pythonpodcast.com%2Ffeed%2F&utm_source=rss&utm_medium=rss" style="border: 0; width: 0; height: 0;" width="0" />