> > Yet Another Noob Question.

> > What are the characteristics of each implementation?

> > How can I tell which I should be writing in what context...

> > (defun find-indicies (lst tst)
> >   (let ((li 0))
> >     (labels ((qpred (a)
> >                (incf li)
> >                (if (funcall tst a)
> >                    (1- li)
> >                    nil)))
> >       (remove nil (mapcar #'qpred lst)))))

> > (defun find-indices (lst tst)
> >   (loop
> >    for el in lst
> >    counting t into index
> >    if (funcall tst el)
> >    collect index))

> You are allergic to loop

> (defun find-indices (list test)
>    (loop for element in list
>          for index from 1
>          when (funcall test element) collect index))