Improve requires clause parsing

[KangarooKoala]

This makes the requires clause parsing more accurate to the C++ standard. Notably, this allows having operators on parenthesized expressions. (Previously, something like requires (mp::m == Distance) || (mp::rad == Distance) would fail because the parser would only consume the first parenthesized expression, leaving || (mp::rad == Distance) to be unsuccessfully parsed as part of the declaration.)

Relevant pages:

• Requires clause description
• Primary expression description

The parenthesized parameter list is optional in a requires expression (See https://en.cppreference.com/w/cpp/language/requires.html), but for now I left it as mandatory. I could make that optional too if you want, though.

Also, what should be done for tests? I'm having trouble building locally (running uvx --from build pyproject-build --installer uv emits Error: You need to create a tag for this repo to use the builder), which appears to be necessary to run the tests. I also don't know if we want to add tests (and if so, where).

[virtuald]

If you find an bug, we encourage you to submit a pull request! New changes will only be accepted if there are tests to cover the change you made (and if they don’t break existing tests).

In the tests directory, every test is generated via python -m cxxheaderparser.gentest. It takes a header file as an input, and prints out the testcase. Take the cases that don't currently work, put them in the header, and generate test cases.

I think uvx doesn't like my custom setuptools stuff. Just comment out the version stuff at the beginning of setup.py and it'll probably be happier. I've been meaning to migrate over to hatchling, so maybe I should do that.

I usually just do pip install -e . in the repository, followed by pip install pytest. Then you can run the tests using python -m pytest tests.

[virtuald]

If you rebase on main, I migrated to hatchling. I haven't tested it, but I bet that uvx will be happier with that.

[KangarooKoala]

Thanks, rebasing on main fixed the uvx issues!

[virtuald]

This looks simpler, thanks. One potential improvement?

[virtuald]

Thanks!