On 30/11/2018, Steve Dower email@example.com wrote:
On 29Nov2018 2206, Armin Rigo wrote:
On Thu, 29 Nov 2018 at 18:19, Steve Dower firstname.lastname@example.org wrote:
quo. We continue to not be able to change CPython internals at all, since that will break people using option B.
No? That will only break users if they only have an option-B ``foo.cpython-318m-x86_64-linux-gnu.so``, no option-A .so and no source code, and want to run it elsewhere than CPython 3.18. That's the same as today. If you want option-B .so for N versions of CPython, recompile the source code N times.
Just to be clear, if done correctly there should be no need for #ifdefs in the source code of the extension module.
The problem is that if option B remains as compatible as it is today, we can't make option A faster enough to be attractive. The marketing pitch for this looks like: "rewrite all your existing code to be slower but works with PyPy, or don't rewrite your existing code and it'll be fastest with CPython and won't break in the future". This is status quo (where option A today is something like CFFI or Cython), and we can already see how many people have made the switch (FWIW, I totally prefer Cython over pure C for my own projects :) ).
My proposed marketing pitch is: "rewrite your existing code to be forward-compatible today and faster in the future without more work, or be prepared to rewrite/update your source code for each CPython release to remain compatible with the low level API". (...)
Discussing marketing pitches on python-dev is not one of my favorite past-times, so I'll excuse myself out of this conversation. Instead, I might try to implement the basics, check out the performance on CPython and on PyPy, and seek out interest---I'm thinking about Cython, for example, which might relatively easily be adapted to generate that kind of code. This might be a solution for the poor performance of Cython on PyPy... If everything works out, maybe I'll come back here at some point, with the argument "the CPython C API is blocking CPython from evolution more and more? Here's one possible path forward."