Snek: A Python-Inspired Language for Tiny Embedded Computers
By Keith Packard

Snek is a subset of Python which runs on Arduino hardware. It has been designed as part of a programming class for people ages 12-14 where the students build robots using Lego and program them in multiple languages. Learn how Python interpreters work, some unexpected challenges in Python semantics and what its like to teach kids Python while building Lego robots.

Tiny embedded computers, like the original Arduino, are great for automating simple tasks. What they are not great at is providing an easy-to-learn environment for new programmers.

As a part of a middle school robotics course based on Lego, I've developed a new language, Snek, which runs on these machines. Snek can run in as little as 32kB of ROM and 2kB of RAM. It provides a simpler, safer, easier to explore environment than C++. Snek is a subset of the Python language and comes with a host-based IDE written in Python that runs on Linux, Mac OS X and Windows.

This presentation will describe the Snek language along with a few of the interesting implementation details including:

  • A new parser generator, lola, that generates a parser 1/10 the size of bison

  • An in-place compacting garbage collector

  • A fine hack for representing values in 32 bits that includes 32-bit floats

  • Some challenges with Python syntax and semantics which make it difficult to fit into a small environment.

There will also be a demonstration of a few Snek-based Lego robots along with a description of how Snek has been integrated into the classroom environment. Comparisons with other embedded Python implementations will also be provided, including Micro Python, Circuit Python and full Python running on systems like the Raspberry PI.

Attendees will learn something about how interpreted Python implementations operate, how Python can be used in embedded systems and what teaching programming to middle school students (10-14 years old) is like.

Keith Packard

Keith Packard has been developing free software since 1986, working on the X Window System, Linux, and rocketry electronics. He is currently a Principle Engineer at SiFive and a consultant on Linux Graphics for Valve Corporation. Keith received a Usenix Lifetime Achievement award in 1999, an O'Reilly Open Source award in 2011 and sits on the X.org foundation board. He has spoken at numerous free software events around the world, including Linux Con, the Plumber's Conference, Linux Conf Australia, FOSDEM, FISL, Guadec, Akademy, OSCON and many others. Keith would appreciate being referred to with he, him and his pronouns.

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