the script is 'actually' a python script compressed, with a short header
(see the '#!/usr/bin/python' right at the front? I'm guessing that if you make
it executable, and run it, then it will either create a .py file that you can
edit, or just run the hdlmake function that you want.
This is not very well explained on the wiki page that you link to... you might
also try downloading the alternative distributions on the download page.