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	<96c2e3be-41e5-49d5-b79e-36be2dd3c...@v5g2000yqn.googlegroups.com>
Date: Sat, 3 Dec 2011 18:59:56 +0100
Message-ID: <CAGqyAapRsm=xr2mLHo=jTB2CrzpkfUhDXwYWYUW8VUMk9b8...@mail.gmail.com>
Subject: Re: COND
From: Gary Verhaegen <Gary.Verhae...@ulb.ac.be>
To: land-of-lisp@googlegroups.com
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It's actually (cond (condition1 result1) (condition2 result2) ...), so
for example (illustrative of cond; highly suboptimal):
(defun fibo(n)
  (cond ((or (not (integerp n)) (< n 0)) (error "Arg must be a
positive integer"))
           ((=3D 0 n) 1)
           ((=3D 1 n) 1)
           ((=3D 2 n) 2)
           (t (+ (fibo (1- n)) (fibo (- n 2))))))

The conditions do not really need to be boolean operations, though. As
far as I can tell, Common Lisp does not even really have the notion of
a boolean: the empty list, written as either (), '() or nil, is
considered false in a boolean context, while any other value is
considered true. There is neither a separate "False" value, nor a
separate "True" value. t is juste the object at the top of the CLOS
hierarchy, which makes it the canonical "non-nil" value.

On Sat, Dec 3, 2011 at 18:11, Havvy <ryan.ha...@gmail.com> wrote:
> (cond condition1 result1 condition2 result2 ... conditionN resultN)
>
> conditionN just has to evaluate to a boolean. =C2=A0You can you boolean
> operators to conjunct (compose together) multiple simple conditions.
>
> (and (=3D 5 5) (!=3D 5 4))
>
> [Caveat: =C2=A0I haven't seen Common Lisp for about half a year, so check
> to see where brackets are necessary]
>
> On Dec 3, 5:00=C2=A0am, vikifor <viktorijastojko...@gmail.com> wrote:
>> Hi
>> I have one question.How can I put many condition in COND in some
>> function
>> Thanks