I did something somewhat like this about 10 years ago, at http://www.dalkescientific.com/writings/diary/archive/2008/0... :

  for line in open("python_yacc.py"):
      if line =~ m/def (?P<name>\w+) *(?P<args>\(.*\)) *:/:
          print repr($1), repr($args)

I did not use import hooks, like this project does.

It got appreciative hisses when I did a lightning talk about it at a PyCon.