As in my sibling comment, pypy has already done all this work. CPython's struct module is just a shim importing the C implementations: https://github.com/pytho

As in my sibling comment, pypy has already done all this work. CPython's struct module is just a shim importing the C implementations: https://github.com/python/cpython/blob/main/Lib/struct.py https://github.com/python/cpython/blob/main/Lib/struct.py Pypy's is a Python(-ish) implementation, leveraging primitives from its own rlib and pypy.interpreter spaces: https://github.com/pypy/pypy/blob/main/pypy/module/struct/interp_struct.py https://github.com/pypy/pypy/blob/main/pypy/module/struct/in... The Python stdlib has enormous surface area, and of course it's also a moving target.