[O] [RFC] org-style

[Marco Wahl]

Hi all,

For some time now I enforce a simple "style" for my org-mode files on
save.  Concretely the style is just assuring the number of blank lines
immediately before a heading and the number of blank lines after the
meta section, e.g. a property-drawer, in each subtree.

This unifies my org files and I don't change blank lines by hand very
often any more.

What do you think about this?  Is this worth to merge into org mode?


Ciao,  Marco


P.S.: I have the code below in my init.el.

#v+
(defcustom org-style-blanklines-num-before-heading 1
"Number of blank lines before each heading.")

(defcustom org-style-blanklines-num-after-meta 1
"Number of blank lines after the heading meta section.
If this happens to be a section before a heading the value of
`num-blanklines-before-heading' is taken.")

(defun org-style-blanklines-assure (num)
  "Assure exactly NUM blanklines and set point to the end of those.
The buffer remains unchanged when the blanklines are already there."
  (skip-chars-backward "\t \n")
  (let ((numplusone-newlines (make-string (1+ num) ?\n)))
    (if (looking-at (concat numplusone-newlines  "[^\n]"))
        (goto-char (1- (match-end 0)))
      (delete-region (point) (progn (skip-chars-forward "\t \n") (point)))
      (insert numplusone-newlines))))

(defun org-style-blanklines-at-headings ()
"Apply blank lines style.
This is the number of blank lines:

. before a heading`org-style-num-blanklines-before-heading' and

. after the org meta data `org-style-num-blanklines-after-meta'."
  (goto-char (point-min))
  (unless (org-at-heading-p)
    (outline-next-heading))
  (while (and (not (eobp)) (< (point) (point-max)))
    (cl-assert (org-at-heading-p) "programming logic error.  shoot a 
programmer, but not me")
    (org-style-blanklines-assure org-style-blanklines-num-before-heading)
    (org-style-blanklines-after-next-meta-data 
org-style-blanklines-num-after-meta)
    (unless (org-at-heading-p)
      (outline-next-heading))))

(defun org-style-blanklines-after-next-meta-data (num)
  "Assure exactly NUM blanklines after next meta data.
When end of meta data is a headline, then leave point there and
do nothing else."
  (org-end-of-meta-data t)
  (unless (org-at-heading-p)
    (org-style-blanklines-assure num)))

;; style the org-mode buffer before save.
(add-hook 'before-save-hook
          (lambda () (when (equal 'org-mode major-mode)
                  (save-excursion
                    (org-style-blanklines-at-headings)))))
#v-