locating a source directory

[Didier Verna]

  Hello,

I would like to find the source directory of an installed ASDF system
even if it's not loaded and even if some of its dependencies are not
installed (so it couldn't be loaded anyway). It seems that I can't use
SYSTEM-SOURCE-DIRECTORY in such a case. What should I do?

Thanks!

-- 
Resistance is futile. You will be jazzimilated.

Jazz site:   http://www.didierverna.com
Other sites: http://www.didierverna.info