Noarrowing in other indirect clone buffer

narrow.el

;; Narrow to the current buffer is somethimes weird because you loose
;; the ability to see other parts of the buffer.  One way is to first
;; create a clone of the current buffer. However, when this is
;; repeated, clones accumulate.

;; This hack just allows to kill clones when ending the narrowing,
;; allowing transparent workflow without manual buffer bookkeeping.


(defvar my-narrowed-buffers nil)
(defun my-kill-buffer-on-widen ()
  (when (member (current-buffer) my-narrowed-buffers)
    (setq my-narrowed-buffers
          (cl-remove-if (lambda (buf) (or (equal (current-buffer) buf)
                                          (not (buffer-live-p buf))))
                        my-narrowed-buffers))
    (kill-buffer)))
(advice-add 'widen :after #'my-kill-buffer-on-widen)

(defun my-narrow-to-sexp ()
  (interactive)
  (let ((start (point))
        (end (progn (forward-sexp) (point))))
    (goto-char start)
    (move-beginning-of-line 1)
    (let ((clone-buffer (clone-indirect-buffer nil nil))
          (narrow-start (point)))
      (with-current-buffer clone-buffer
        (goto-char start)
        (narrow-to-region narrow-start end)
        (push clone-buffer my-narrowed-buffers)
        (switch-to-buffer clone-buffer)))))