From: Thomas A. Russ
Subject: Re: loop ... until ... and then return this
Date: Mon, 06 Feb 2006 18:36:20 +0000
Message-ID: <ymislqwmj17.fsf@sevak.isi.edu>

···@zedat.fu-berlin.de (Stefan Ram) writes:

> ( defun noun-phrase-start()
>   ( loop until( setq result( append-a-random-noun-to( a-random-determiner ))))
>   result )
> 
>   The intention is to return the first result of
>   "append-a-random-noun-to" that is not nil. Just for curiosity,
>   is there a more idiomatic way to write this?

(defun noun-phrase-start ()
  (loop for result = (append-a-random-noun-to (a-random-determiner))
        when result return result))


Or using the loop anaphora reference:

(defun noun-phrase-start ()
  (loop when (append-a-random-noun-to (a-random-determiner)) return it))


And yes, the parentheses placement matters.

-- 
Thomas A. Russ,  USC/Information Sciences Institute