gistfile1.txt

(defun map-subseq (fn seq &optional start end from-end)
  "Helper function to map SEQ between START and END."
  (declare (type (or null array-index) start end)
           (optimize (debug 0) (safety 1)
                     (compilation-speed 0)))
  ;; (when (and start end)
  ;;   (assert (<= start end)))
  (let ((start (or start 0))
        (fn (ensure-function fn)))
    (fbind (fn)
      (seq-dispatch seq
        (if (null end)
            (if from-end
                (list-map-from-end/bordeaux fn seq :start start)
                (dolist (item (nthcdr start seq))
                  (fn item)))
            (if from-end
                (list-map-from-end/bordeaux fn seq :start start :end end)
                (loop for item in (nthcdr start seq)
                      for i below (- end start)
                      do (fn item))))
        (with-subtype-dispatch vector
            (simple-bit-vector
             bit-vector
             (simple-array character (*))
             simple-base-string)
            seq
          (let ((end (or end (length seq))))
            (if from-end
                (loop for i downfrom (1- end) to start
                      do (fn (vref seq i)))
                (loop for i from start below end
                      do (fn (vref seq i))))))
        (let ((end (or end (length seq))))
          (if from-end
              (loop for i downfrom (1- end) to start
                    do (fn (elt seq i)))
              (loop for i from start below end
                    do (fn (elt seq i)))))))))