How do lisp gurus truncate?

[Lennart Borgman <lennart.borgman@gmail.com>]

I want to truncate an ordered list if the rest of the values are
bigger than some limit. I just wrote some code like this one to do
that, but there must be some more standard way of doing that, or?

          (when nxml-where-first-change-pos
            (setq nxml-where-path 'dummy nxml-where-path)
            (let ((path nxml-where-path))
              (while (cdr path)
                (when (> (nth 1 (nth 1 path)) nxml-where-first-change-pos)
                  (setcdr path nil))
                (setq path (cdr path))))
            (setq nxml-where-path (cdr nxml-where-path)))