-slice for dash

slice-dash.el

(defun -slice (list &optional from to)
  "Return copy of LIST, starting from index FROM to index TO.
FROM or TO may be negative"
  (setq from (or from 0))
  (setq to (or to 0))
  (let ((from-list list)
        (result-list nil)
        (index 0)
        (len 0))
    (cond
     ((and (>= from 0) (>= to 0))
      (--dotimes from (!cdr from-list))
      (if (= to 0)
          from-list
        (--dotimes (- to from -1) 
          (when from-list
            (!cons (car from-list) result-list)
            (!cdr from-list)))
        (nreverse result-list)))
     ((and (>= from 0) (< to 0))
      (--dotimes from (!cdr from-list))
      (while from-list
        (!cons (car from-list) result-list)
        (!cdr from-list))
      (--dotimes (abs to) (!cdr result-list))
      (nreverse result-list))
     ((and (< from 0) (>= to 0))
      (while from-list
        (!cons (car from-list) result-list)
        (!cdr from-list)
        (setq len (1+ len)))
      (--dotimes (- len to 1) (!cdr result-list))
      (--dotimes (- (abs from) (- len to 1))
        (!cons (car result-list) from-list)
        (!cdr result-list))
      from-list)
     ((and (< from 0) (< to 0))
      (while from-list
        (!cons (car from-list) result-list)
        (!cdr from-list)
        (setq len (1+ len)))
      (--dotimes (abs to) (!cdr result-list))
      (--dotimes (- (abs from) (abs to))
        (!cons (car result-list) from-list)
        (!cdr result-list))
      from-list)
     )
    ))