Since the GNU project is celebrating its anniversary, and the initial announcement for GNU is linked to (http://www.gnu.org/gnu/initial-announcement.en.html) all over the place, I reread it and I stumbled upon the plan for a lisp-based window system:
and eventually a Lisp-based window system through which several Lisp programs and ordinary Unix programs can share a screen.
It is well known that Stallman had a lisp background and has launched lisp-based projects (Emacs, Guile). As I understand, Stallman's preferred desktop environment for the GNU system is nowadays GNUstep (which seems to be a little dormant).
So I wonder: What happened to this plan of a Lisp-based window system? Has it been actually pursued once?