I wrote a version of the position function that would work with circular
lists, since the other one will start an infinite loop if you give it a
circular list. I've included the function below, but it turns out that
infinite lists are only semi-supported -- calling length, or even
evaluating them in sawfish-client, causes an infinite loop. According
to the docs (where I should have looked first) only cons, car, cdr,
rplaca, rplacd, nth, and nthcdr can be used on circular lists.
In short: I don't know that it's worth it to fix it elsewhere, even if
we end up staying with rep, but if it's of any interest here's a version
of position that wont choke on infinite lists.
(define (position item l)
(let ((start l))
(let loop ((rest l)
(i 0))
(if (equal item (car rest))
i
(unless (or (null rest)
(and (/= 0 i)
(eq rest start)))
(loop (cdr rest) (1+ i)))))))
--
Jeremy Hankins <[email protected]>
