- (let* ((copy (%make-sequence-like sequence (- end start)))
- (setter (!find-data-vector-setter copy))
- (reffer (!find-data-vector-reffer data)))
- (declare (optimize (speed 3) (safety 0)))
- (do ((old-index start (1+ old-index))
- (new-index 0 (1+ new-index)))
- ((= old-index end) copy)
- (declare (index old-index new-index))
- (funcall setter copy new-index
- (funcall reffer data old-index))))))