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From: gat@robotics.Jpl.Nasa.Gov (Erann Gat)
Newsgroups: comp.lang.lisp
Subject: Re: STRUCTUREP
Message-ID: <758@forsight.Jpl.Nasa.Gov>
Date: 10 Oct 90 23:31:54 GMT
References: <753@forsight.Jpl.Nasa.Gov> <1990Oct10.091722.4495@hellgate.utah.edu> <1990Oct10.165312.29838@hellgate.utah.edu>
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 13

In article <1990Oct10.165312.29838@hellgate.utah.edu>, moore%cdr.utah.edu@cs.utah.edu (Tim Moore) writes:
> You could print the object to a string and
> strip the #S...

That's actually not a bad solution to the puzzle:

(defun structurep (thing)
  (equal "#S" (subseq (format nil "~S" thing) 0 2)))

This would work for any structure which did not have a :print-function
defined.  (What a horrible hack, though!)

E.