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From: bds@mbunix.mitre.org (Barry D Smith)
Newsgroups: comp.lang.lisp
Subject: optional and key arguments
Message-ID: <64922@linus.UUCP>
Date: 22 Aug 89 19:36:48 GMT
Sender: news@linus.UUCP
Reply-To: bds@mbunix (Smith)
Distribution: comp.lang.lisp
Organization: The MITRE Corporation, Bedford, Mass.
Lines: 20

Since we were just burnt by this on a Symbolics, I wonder 
if anyone would comment:

Given the function:

(defun test (a b &optional (c 0) &key (d 1))
  (if (= d 1)
      (+ a b c d)
      (+ a b c)))

(test 5 4 :d 0) results in an error.  

Since optional arguments are evaluated first, c is bound to :d, and 0
isn't a key argument.  Is this the Common Lisp standard?  If so, does
it make sense?  In our case, we had 3 optional arguments, and we
wanted to use the default values, but to set the key argument to
something else.  It seems a violation of the notion of optional
arguments to have to specify them.

Barry Smith