Compiling with pure setuptools

scikit-build-core can be recommended over this method.

An example of the following can be found here: https://github.com/Homomorpheus/Neo-ODE_interactive/tree/main/mass_spring_for_pyodide

The first step is to write the C++ code using pybind11 and compile it to an .so file for testing. After that, it has to be compiled to a wheel using setuptools. Wheels (.whl files) are python’s way of packaging libraries. See this article. To install setuptools, run:

pip install build

Let us say that our project and root directory are called foo, with the pybind code in foo/bind_foo.cc . The following also assumes that all the code is within the header files. The following should be in foo/conf.py :

from setuptools import setup
from pybind11.setup_helpers import Pybind11Extension

ext_modules = [
    Pybind11Extension(
        "foo",
        ["bind_foo.cc"],
    ),
]

headers = ["header_file_for_bind_foo.h",
           "another_header_file.h",
           "ode.h",
           "Newton.h"]

setup(
    name="foo",
    version="0.0.1",
    ext_modules=ext_modules,
    headers=headers,
)

In foo/pyproject.toml :

[build-system]
requires = [
    "setuptools>=42",
    "scikit-build>=0.13",
    "cmake>=3.18",
    "pybind11"
]
build-backend = "setuptools.build_meta"

You can also supply directories with header files, similar to CMake’s include_directory. Say we have two such folders, header_file_dir and another_header_file_dir. Create foo/Manifest.in with the following content:

graft header_file_dir
graft another_header_file_dir

The result can be compiled by executing

python -m build

within the foo directory. The compiled wheel can then be found in foo/dist and installed using pip. If this works, the next step is to compile a Web Assembly wheel. This is achieved using pyodide.