Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!RIVERSIDE.SCRC.SYMBOLICS.COM!stever
From: stever@RIVERSIDE.SCRC.SYMBOLICS.COM
Newsgroups: comp.lang.scheme
Subject: self reproducing code
Message-ID: <19881007210401.2.LISP-MACHINE@HALEAKALA.S4CC.Symbolics.COM>
Date: 7 Oct 88 21:04:00 GMT
References: <8810071930.AA25143@car.utah.edu>
Sender: daemon@bloom-beacon.MIT.EDU
Organization: The Internet
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    Date: Fri, 7 Oct 88 13:30:30 MDT
    From: carr%car@cs.utah.edu (Harold Carr)

    It was an anonymous lambda application which, when evaluated in Common
    Lisp, would return the exact same for, which could then be evaluated
    again, always returning the same anonymous application.

((LAMBDA (TEMPLATE)
   (SETF (SECOND (SECOND TEMPLATE)) (COPY-TREE TEMPLATE))
   TEMPLATE)
 '((LAMBDA (TEMPLATE)
     (SETF (SECOND (SECOND TEMPLATE)) (COPY-TREE TEMPLATE))
     TEMPLATE)
   (QUOTE *PLACEHOLDER*)))

This will work.  I'm pretty sure there's a more elegant way to do it.
If anyone send you one, I'd appreciate a copy.

Thanks,

Stephen