Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!decwrl!shelby!csli!johnson
From: johnson@csli.STANFORD.EDU (Mark Johnson)
Newsgroups: comp.lang.lisp
Subject: Re: Self-referencing Closures
Message-ID: <7931@csli.STANFORD.EDU>
Date: 7 Mar 89 16:46:59 GMT
References: <6859@phoenix.Princeton.EDU> <52880@yale-celray.yale.UUCP>
Sender: johnson@csli.Stanford.EDU (Mark Johnson)
Reply-To: johnson@csli.stanford.edu (Mark Johnson)
Organization: Center for the Study of Language and Information, Stanford U.
Lines: 20

Bruce Krulwich is quite correct - the LABELS form is what you need
to make these self-referencing closures.  His example contains
a minor bug, however: he forgot to use #' in front of the final -self-
form.  The corrected version is:

(defun make-closure ()
  (labels ((self ()
                 (print 'hello)))
    #'self))

Too much Scheme!  Someone else just sent a message on the net asking
why CommonLisp uses different name spaces for variable and function
definitions.  Personally, I think that this is one of the worst
features of CommonLisp.  It makes my programs look like fields of #'
symbols and funcalls.  It is also one of the hardest things for
students to learn - they get continually confused between the use of
LIST as a function and a variable.  (I know it's bad programming
style, but people do do it).

Mark Johnson