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From: d-yang@cs.columbia.edu (David Yang)
Newsgroups: comp.lang.lisp
Subject: Re: Problem with (apply #'or <list>)? (cl 3.0.1)
Message-ID: <1991Feb15.192603.12714@cs.columbia.edu>
Date: 15 Feb 91 19:26:03 GMT
References: <1991Feb15.065508.28609@cs.columbia.edu>
Reply-To: d-yang@cs.columbia.edu (David Yang)
Followup-To: comp.lang.lisp
Organization: Columbia University Department of Computer Science
Lines: 36

Thanks for all the helpful and patient answers;
here's one with an alternative.

David

From: Andrew Philpot <philpot@ptolemy.arc.nasa.gov>
;  
;  As someone has no doubt already told you (but hey what's another
;  redundant message):
;  
;  OR is usually a macro, (or I think sometimes a special form) and thus
;  cannot be applied.
;  
;  If you want to map across a list of (assumed) boolean values,
;  returning the first one which is not NIL, or NIL if they all are NIL,
;  try:
;  
;  (some #'identity <list of booleans>)
;  
;  for example
;  
;  > (some #'identity '(t nil t nil))
;  T
;  
;  > (some #'identity '(nil nil () 5 t nil))
;  5
;  
;  > (some #'identity '(nil nil nil nil))
;  NIL
;  
;  etc.
;  
;  Also see EVERY, NOTANY, NOTEVERY.
;  
;  << Andrew >>
;