[NTG-context] parsing multi-valued parameters

Hello everyone, please can you give me pointers on how to easiest parse multi-valued \dummyparameter{...} like in \something[...,weather={sunshine, rain, hail},...] so that I can test for e.g.  rain, sunshine, wind, hail, mist, fog, storm etc, each if it is present or not? ...so I can keep my number of parameters down and my parameter list as simple as possible. I have no idea what to search for in the docs or (better) in the test cases / samples. Would be great if you could just let me know where to look or what to sarch for Thank you very much! Werner