Following up – I think I need to look into this a bit more. JRubyArt, for example, is listed on some pages as a library under Ruby, and it appears to be both a subcategory of Processing and its own category.
They don’t work in the same way, of course – Processing.py is not a Python library, and you can’t import it into Python 2 or 3 – but how to frame it for wiki users seems like there are several options.