[Bese-devel] Re: more feedback

[Andreas Fuchs]

On 2004-04-13, Jan Rychter <jan at rychter.com> wrote:
> Ok. Having played with UCW during some airplane trips, I now know
> where it gets stuck. It was looping forever in (defmethod find-frame
> ((s standard-session) (frame-id string)) ...). Possibly because of
> some problem with ITERATE. I have rewritten the iterate using loop:
>
> (defmethod find-frame ((s standard-session) (frame-id string))
> "Returns the frame whose id is STEP-ID and eliminates any
> frames in the stack in the session after the frame. If no frame
> with that id exists the session's stack is left untouched and
> an error of type inexistent-frame-id is signaled."
> (loop with stack = (session.stack s)
> 	while stack
> 	when (string= (frame.id (car stack)) frame-id)
> 	do (progn (setf (session.stack s) stack)
> 		  (return-from find-frame (car stack)))
> 	else do (pop stack)
> 	finally (return-from find-frame nil)))

perhaps it would make sense to use a more iterate-y variant of the
code (which looks like a literal translation of the WHILE form (-:

let's see...

(iterate
    (for stack on (session.stack s))
    (finding stack such-that (string= (frame.id (car stack)) frame-id)
                   into found-session-stack)
    (finally (when found-session-stack
	       (setf (session.stack s) found-session-stack)
	       (return (car found-session-stack)))))

should look better (and work, too). I'm looking forward to your
comments.

Cheers,
-- 
Andreas Fuchs, <asf at boinkor.net>, asf at jabber.at, antifuchs