Re: Emacs-devel Digest, Vol 69, Issue 108

[Richard Stallman]

    Could somebody give me an example in which adding properties to `t' and 
`nil' may be useful?

There have been Lisp programs that parse the user's input into
symbols and put properties on them.  In effect, these implement
other languages.  We don't want to rule out defining nil in those
languages.