11:10:02pjbThere were similar tools but for Lisp Machine.
11:11:48pjbFor lisp, I've been hacking Q&D thingies, generating class trees in ascii-art. cf. eg. https://gitlab.com/patchwork/patchwork/tree/master/doc
11:19:33pjbIIRC, there's a MCCLIM app to draw and manipulate graphs of objects. I don't remember the references, perhaps it was just a demo. If you find the sources, it could be used as a basis. Otherwise, MCLIM could be a good basis to do it.