Mailman 3 June 2019 - cython-devel

Re: [Cython] Backport language_level=2 fix?
by Stefan Behnel June 29, 2019

June 29, 2019

Jeroen Demeyer schrieb am 27.06.19 um 12:44: > Since Cython 3.0 doesn't seem close to being released, is there any chance > to backport https://github.com/cython/cython/pull/2792 > > It's a fairly simple and reasonable bugfix. Done: https://github.com/cython/cython/commit/d019d9f3e057cae5f873280bf78bce639f2… Stefan

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Empty defines of Py_TPFLAGS_METHOD_DESCRIPTOR?
by Jeroen Demeyer June 23, 2019

June 23, 2019

Hello, What's the purpose of commit https://github.com/cython/cython/commit/8ac1a6a55fc44ff858cc367af556250a91f… I can't think of any reasonable scenario where Py_TPFLAGS_METHOD_DESCRIPTOR would be defined differently than in CPython (i.e. with value 1<<17). This is an honest question, I don't know what I'm missing. Jeroen.

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Working on METH_FASTCALL and vectorcall support
by Jeroen Demeyer June 17, 2019

June 17, 2019

Hello, this is just to let you know that I'm planning to add support for functions/methods defined with METH_FASTCALL instead of METH_VARARGS on CPython 3.7. Once this is implemented, it will be fairly easy to use vectorcall (PEP 590) for cython_function_or_method. Jeroen.

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Reason for __Pyx_PyObject_Call2Args, __Pyx_PyObject_Call3Args
by Jeroen Demeyer June 13, 2019

June 13, 2019

Is there any particular reason why Cython has specific code like __Pyx_PyObject_Call2Args, __Pyx_PyObject_Call3Args, ... And then there is even more complicated Python code in PyMethodCallNode generating something like __Pyx_PyObject_Call2Args for an arbitrary number of arguments. This could be simplified a lot by just writing code once to deal with n arguments and then letting the C compiler do the clever stuff: if you write a loop where the number of iterations is a small compile-time constant, the compiler should unroll it. I checked that GCC-6.4.0 is able to do this and the much simpler code with a for loop is as efficient as the current code. But maybe there are other compilers that don't do this (or there used to be such compilers when that code was written)? I stumbled on this while working on https://github.com/cython/cython/issues/2996

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