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points by 0xpgm 2 days ago | 0 comments

For a long time Guido wanted CPython to remain simple, as the reference implementation.

Probably also during the 2 to 3 migration, but that goal appears to have now been abandoned.

I wonder how the authors of other implementations like pypy will be able to keep up as the reference implementation becomes more and more complex.

[–] Pxtl 2 days ago

> the reference implementation.

The problem was he exposed too much of the implementation into the language itself, destroying its ability to be a simple reference implementation that others could re-implement.

[–] mohamedkoubaa 2 days ago

This is slowly being addressed now, each version of Python sees the c API become more opaque.

[–] jsmith45 2 days ago

That's at best a partial fix for the API side. Python side CPython sill exposes a LOT of implementation details, and as a result occasionally projects will choose to rely on some of these details. Then other implementations need to decide whether to also pick the same implementations details and expose them, or use different details, and lack compatibility with any library that depended upon them.

The python documentation has historically also not been especially clear at distinguishing between what the language guarantees, vs what is just implementation details of the cPython implementation. So even if libraries wanted to try to avoid depending on implementation specifics, it isn't always clear what those are.

The net result is that for the end user python the language is effectively: whatever cpython does. This really, really discourages creating alternate implementations, as the only way to be an alternative implementation with good compatibility is to be a living fork of cpython, constantly merging in all the changes from it, while also maintaining your improvements.

[–] mohamedkoubaa 2 days ago

This is also slowly being addressed

[–] twoodfin 2 days ago

Are there any PEPs that describe this work?

[–] mohamedkoubaa 2 days ago

See the stable ABI for Python 3.15 and PEP 793, 803, 820 for recent movements in this general direction and the following draft: https://github.com/py-ni/peps/blob/main/peps/pep-08xx.rst (the py-ni project is pushing for this)

[–] iqbal1980 2 days ago

They reference this one in the article https://peps.python.org/pep-0836/

[–] twoodfin 2 days ago

I meant the trend of making the C interop more opaque.

[–] seabrookmx 2 days ago

That question is already answered. pypy only supports 3.11 today and is largely unmaintained.

[–] t43562 2 days ago

https://pypy.org/posts/2026/10/pypy-v801-release.html

Last release on Oct 14. Beta support for 3.12. It's not that bad really and 1/10 of the people who complain about it did something then the situation would be better.