On Mon, 12 May 2003, Barry Margolin wrote:

> >Using the loop macro you can find the maximum of some numerical function
> >f, applied
> >to each element of a list by
> >(loop for x in list maxmimize (funcall f x))
> >
> >But I want to return the x such that (funcall f x) is maximum
> >and I would like to write something like this:
> >
> >(loop for x in list argmaximize (funcall f x))
> >
> >Is there some loop keyword that would do this?
> >If there isn't such a keyword what's the most succinct way to
> >do this with the loop macro?
>
> There isn't a keyword for it.
>
> (loop with max-val = (car list)
> for x in (cdr list)
> when (> (funcall f x) max-val)
> do (setq max-val x))

That doesn't function correctly.

Gauche Scheme:

(reduce
(lambda (a b) (if (> (square a) (square b)) a b))
'list-was-empty
'(2 -8 4 6))

===>
-8

That calls the function more times than necessary.

(define lst '(2 -8 4 6))

(fold
(lambda (a b)
(define res (square a))
(if (or (null? b) (> res (car b))) (list res a) b))
'()
lst)

===>
(64 -8)