> > implementation, how would you expect
> >
> > (loop for i from 5 downto 2
> > for x = (loop for j below i collect j)
> > for y in x
> > collect y)
> >
> > to behave? I think the Lisp you're using is broken.
>
> Mine surely is, the above snippet results in NIL in SBCL. And (0 1 2 3)
> in Clisp. Given that the result I expected was (0 1 2 3 4 0 1 2 3 0 1 2 0
> 1), it seems that both are broken, albeit in different ways. And adapting
> the testcases to ITERATE uncovered some bugs in the same vein as well.
> Fun times, bugreports ahoy.

(use srfi-42) ;; list-ec for Gauche Scheme
or
(require srfi/42) ;; list-ec for Racket

(list-ec (:range x 5 1 -1) (:range y x) y)
===>
(0 1 2 3 4 0 1 2 3 0 1 2 0 1)