Simon Willison’s Weblog

The Python Language Summit 2023: Making the Global Interpreter Lock Optional. Extremely informative update covering Sam Gross’s python-nogil proposal from this year’s language summit at PyCon.

Sam has been working hard on his fork for the past year, and now has it rebased for Python 3.12. If his PEP is accepted it could end up as an optional compile-time build in time for Python 3.13.

“The plan for nogil remains that it would be enabled via a compile-time flag, named --disable-gil. Third-party C extensions would need to provide separate wheels for GIL-disabled Python.” # 31st May 2023, 12:04 am

Trogon (via) The latest project from the Textualize/Rich crew, Trogon provides a Python decorator—@tui—which, when applied to a Click CLI application, adds a new interactive TUI mode which introspects the available subcommands and their options and creates a full Text User Interface—with keyboard and mouse support—for assembling invocations of those various commands.

I just shipped sqlite-utils 3.32 with support for this—it uses an optional dependency, so you’ll need to run “sqlite-utils install trogon” and then “sqlite-utils tui” to try it out. # 21st May 2023, 9:39 pm

Writing Python like it’s Rust (via) Fascinating article by Jakub Beránek describing in detail patterns for using type annotations in Python inspired by working in Rust. I learned new tricks about both languages from reading this. # 21st May 2023, 12:18 am

Real Multithreading is Coming to Python—Learn How You Can Use It Now (via) Martin Heinz provides a detailed tutorial on trying out the new Per-Interpreter GIL feature that’s landing in Python 3.12, which allows Python code to run concurrently in multiple threads by spawning separate sub-interpreters, each with their own dedicated GIL.

It’s not an easy feature to play with yet! First you need to compile Python yourself, and then use APIs that are generally only available to C code (but should hopefully become available to Python code itself in Python 3.13).

Martin’s workaround for this is ingenious: it turns out the Python test.support package provides utility functions to help write tests against interpreters, and Martin shows how to abuse this module to launch, run and cleanup interpreters using regular Python code.

He also demonstrates test.support.interpreters.create_channel(), which can be used to create channels with receiver and sender ends, somewhat similar to Go. # 15th May 2023, 7:42 pm

Implement DNS in a weekend (via) Fantastically clear and useful guide to implementing DNS lookups, from scratch, using Python’s struct, socket and dataclass modules—Julia Evans plans to follow this up with one for TLS which I am very much looking forward to. # 12th May 2023, 6:14 pm

Mojo may be the biggest programming advance in decades (via) Jeremy Howard makes a very convincing argument for why the new programming language Mojo is a big deal.

Mojo is a superset of Python designed by a team lead by Chris Lattner, who previously created LLVM, Clang and and Swift.

Existing Python code should work unmodified, but it also adds features that enable performant low-level programming—like “fn” for creating typed, compiled functions and “struct” for memory-optimized alternatives to classes.

It’s worth watching Jeremy’s video where he uses these features to get more than a 2000x speed up implementing matrix multiplication, while still keeping the code readable and easy to follow.

Mojo isn’t available yet outside of a playground preview environment, but it does look like an intriguing new project. # 4th May 2023, 4:41 am