8 comments

[ 0.17 ms ] story [ 2.9 ms ] thread
This is a nice party trick! I use it to provide easy installation of software that is written in rust, but is primarily used by Python users. (e.g.: Biology tools)
I was a bit nervous about this trend when it started picking up because I care about Pyodide (Python running via WebAssembly) and libraries that use PyO3 might not work in Pyodide.

Thankfully that's now been mostly solved - you can compile and publish WASM builds of Rust or C extensions on PyPI now and a Pyodide can then use them.

Here's the WASM build of the Rust-including Pydantic-core package for example: https://pypi.org/project/pydantic_core/#pydantic_core-2.49.0...

I'm kind of surprised to hear that was a concern because my perception is that PyO3 is more analogous to wrapping native C code in Python libraries (which is pretty well established since long before either Rust or WASM), and Pyodide seems more like something for use in browsers rather on the server-side. When I looked into this earlier this year, trying to run Python via WASM on the server side with Pyodide had a bunch of hoops I needed to jump through, and it ended up being a lot simpler to use a build of Python from one of the core Python contributors that directly targeted WASM.
Yes, Pyodide is almost entirely used in web browsers. I want to be able to run existing code that uses libraries like Pyodide-core in a browser.
> reach for, a Rust extension does the work

ai; dr, sorry

But does it work everywhere Python works? My main issue with this Rust move has always been compatibility. Python can be embedded and ran in a heck of a lot of places. What's the story when libraries that I may want to depend on are actually implemented in Rust and my target doesn't/can't handle the toolchain and there's no build target?
Why not just run C inside of Python?