short version: you just need to add func "definitions" you want to share with reascripters in <sws-dev-root>/ReaScript.cpp, mother nature will do the rest (i.e. creating the sws_python.py function wrappers file)
..mother nature needs Perl at build time though
"Yes, that is a Perl script reading C++ to generate Python." <- schwa, who kindly shared some scripts with us and, well made this possible (see issue
432).