Add example pyproject.toml using poetry instead of setuptools

[FedericoStra]

Take inspiration from:

• Add support for non pure python projects python-poetry/poetry#11
• Cython Extensions python-poetry/poetry#137
• Could not build wheels for XXX which use PEP 517 python-poetry/poetry#1516
• https://stackoverflow.com/a/63679316
• https://github.com/ADicksonLab/geomm/tree/v0.1.7 (example of build.py)
• https://github.com/zoj613/htnorm (more modern example of build.py)
• https://github.com/decred/tinydecred/ (example of build.py)
• https://github.com/iamishalkin/cyrtd (Cython + Sphinx + poetry example)

[FedericoStra]

The state of the art best practices for packaging python modules with compiled extensions is just a desolate land of pain and suffering.

The crucial detail to defeat python-poetry/poetry#1516 appears to be to require setuptools and Cython in the build system defined in pyproject.toml:

[build-system]
requires = ["poetry-core>=1.0.0", "setuptools>=57.0.0", "Cython>=0.29.27"]
build-backend = "poetry.core.masonry.api"

[FedericoStra]

There is an initial implementation in the branch poetry. One of the downsides is that installing with pip install . leads to the following folder structure

cypack/
├── answer.c
├── answer.cpython-310-x86_64-linux-gnu.so
├── answer.pyx
├── data
│   └── zen.txt
├── fibonacci.c
├── fibonacci.cpython-310-x86_64-linux-gnu.so
├── fibonacci.pyx
├── __init__.py
├── __pycache__
│   └── __init__.cpython-310.pyc
├── sub
│   ├── helper.c
│   ├── helper.h
│   ├── helper.pxd
│   ├── __init__.py
│   ├── __pycache__
│   │   └── __init__.cpython-310.pyc
│   ├── wrong.c
│   ├── wrong.cpython-310-x86_64-linux-gnu.so
│   └── wrong.pyx
├── utils.c
├── utils.cpython-310-x86_64-linux-gnu.so
├── utils.pxd
└── utils.pyx

instead of the cleaner and intended

cypack/
├── answer.cpython-310-x86_64-linux-gnu.so
├── data
│   └── zen.txt
├── fibonacci.cpython-310-x86_64-linux-gnu.so
├── __init__.py
├── __pycache__
│   └── __init__.cpython-310.pyc
├── sub
│   ├── helper.h
│   ├── helper.pxd
│   ├── __init__.py
│   ├── __pycache__
│   │   └── __init__.cpython-310.pyc
│   └── wrong.cpython-310-x86_64-linux-gnu.so
├── utils.cpython-310-x86_64-linux-gnu.so
└── utils.pxd

[rnestler]

I found this issue via search. I'm trying to cytonize parts of a package and also face the problem, that the resulting package will include the original Python, the C-source and the compiled binary.

My target is, that the wheel only contains the compiled binary.

[surya-sigtech]

@rnestler Any update to the issue you were facing (i.e, the resulting wheel also includes the original Python code)?