ruststep takes a similar approach to STEPcode but is written in Rust and produces Rust code. I wonder why nobody has a repo of the various STEP specs run through stepcode to produce usable C++ read/writer.

I think working on Open CASCADE may be worth peoples efforts, but I've opted to work on Solvespace instead. The core NURBS code is only about 8000 lines, while OCCT is absolutely huge.