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conditional loop

3 posts · 2082 views

mparsa

#1 Wed Jun 27, 2012 2:41 pm

How we can have a conditional loop in lisp ?
I know that we can dotimes for having loop but I want to have a condition : until var is not equal to "test" continue and when it equals to "test" do not continue.

Goheeca

#2 Wed Jun 27, 2012 4:03 pm

Re: conditional loop

Check out loop macro (http://www.unixuser.org/~euske/doc/cl/loop.html, http://www.gigamonkeys.com/book/loop-fo ... belts.html)

Solution for your issue is:

(loop until condition do form)

where condition and form are code not loop keywords.

cl-2dsyntax is my attempt to create a Python-like reader. My mirror of CLHS (and the dark themed version). Temporary mirrors of aferomentioned: CLHS and a dark version.

pjstirling

#3 Thu Jun 28, 2012 10:24 am

Re: conditional loop

(defmacro until (test &body body)
  `(do ()
       (,test)
     ,@body))
;; and its companion
(defmacro while (test &body body)
  `(until (not ,test)
     ,@body))