emacs/lisp/acdw-org.el

;;; acdw-org.el -*- lexical-binding: t; coding: utf-8-unix -*-
;; Author: Various
;; URL: https://tildegit.org/acdw/emacs

;; This file is NOT part of GNU Emacs.

;;; License:
;; Everyone is permitted to do whatever with this software, without
;; limitation.  This software comes without any warranty whatsoever,
;; but with two pieces of advice:
;; - Don't hurt yourself.
;; - Make good choices.

;;; Commentary:
;; This file is for the weird little `org-mode' functions that just take up
;; space in my main init file.  I've tried to give credit where credit is due.

;;; Code:


;;; unpackaged.el: https://github.com/alphapapa/unpackaged.el

(defun acdw-org/element-descendant-of (type element)
  "Return non-nil if ELEMENT is a descendant of TYPE.
TYPE should be an element type, like `item' or `paragraph'.
ELEMENT should be a list like that returned by `org-element-context'."
  ;; MAYBE: Use `org-element-lineage'.
  (when-let* ((parent (org-element-property :parent element)))
    (or (eq type (car parent))
        (acdw-org/element-descendant-of type parent))))

(defun acdw-org/return-dwim (&optional default)
  "A helpful replacement for `org-return'.  With prefix, call `org-return'.

On headings, move point to position after entry content.  In
lists, insert a new item or end the list, with checkbox if
appropriate.  In tables, insert a new row or end the table."
  ;; Inspired by John Kitchin: http://kitchingroup.cheme.cmu.edu/blog/2017/04/09/A-better-return-in-org-mode/
  (interactive "P")
  ;; Auto-fill if enabled
  (when auto-fill-function
    (if (listp auto-fill-function)
        (dolist (func auto-fill-function)
          (funcall func))
      (funcall auto-fill-function)))
  (if default
      (org-return)
    (cond
     ;; Act depending on context around point.

     ;; NOTE: I prefer RET to not follow links, but by uncommenting this block, links will be
     ;; followed.

     ;; ((eq 'link (car (org-element-context)))
     ;;  ;; Link: Open it.
     ;;  (org-open-at-point-global))

     ((org-at-heading-p)
      ;; Heading: Move to position after entry content.
      ;; NOTE: This is probably the most interesting feature of this function.
      (let ((heading-start (org-entry-beginning-position)))
        (goto-char (org-entry-end-position))
        (cond ((and (org-at-heading-p)
                    (= heading-start (org-entry-beginning-position)))
               ;; Entry ends on its heading; add newline after
               (end-of-line)
               (insert "\n\n"))
              (t
               ;; Entry ends after its heading; back up
               (forward-line -1)
               (end-of-line)
               (when (org-at-heading-p)
                 ;; At the same heading
                 (forward-line)
                 (insert "\n")
                 (forward-line -1))
               ;; FIXME: looking-back is supposed to be called with more arguments.
               (while (not (looking-back (rx (repeat 3 (seq (optional blank) "\n")))))
                 (insert "\n"))
               (forward-line -1)))))

     ((org-at-item-checkbox-p)
      ;; Checkbox: Insert new item with checkbox.
      (org-insert-todo-heading nil))

     ((org-in-item-p)
      ;; Plain list
      (let* ((context (org-element-context))
             (first-item-p (eq 'plain-list (car context)))
             (itemp (eq 'item (car context)))
             (emptyp (eq (org-element-property :contents-begin context)
                         (org-element-property :contents-end context)))
             (item-child-p
              (acdw-org/element-descendant-of 'item context)))
        ;; The original function from unpackaged just tested the (or ...) test
        ;; in this cond, in an if.  However, that doesn't auto-end nested
        ;; lists.  So I made this form a cond and added the (and...) test in
        ;; the first position, which is clunky (the delete-region... stuff
        ;; comes twice) and might not be needed.  More testing, obviously, but
        ;; for now, it works well enough.
        (cond ((and itemp emptyp)
               (delete-region (line-beginning-position) (line-end-position))
               (insert "\n\n"))
              ((or first-item-p
                   (and itemp (not emptyp))
                   item-child-p)
               (org-insert-item))
              (t (delete-region (line-beginning-position) (line-end-position))
                 (insert "\n")))))

     ((when (fboundp 'org-inlinetask-in-task-p)
        (org-inlinetask-in-task-p))
      ;; Inline task: Don't insert a new heading.
      (org-return))

     ((org-at-table-p)
      (cond ((save-excursion
               (beginning-of-line)
               ;; See `org-table-next-field'.
               (cl-loop with end = (line-end-position)
                        for cell = (org-element-table-cell-parser)
                        always (equal (org-element-property :contents-begin cell)
                                      (org-element-property :contents-end cell))
                        while (re-search-forward "|" end t)))
             ;; Empty row: end the table.
             (delete-region (line-beginning-position) (line-end-position))
             (org-return))
            (t
             ;; Non-empty row: call `org-return'.
             (org-return))))
     (t
      ;; All other cases: call `org-return'.
      (org-return)))))

(defun acdw-org/fix-blank-lines (&optional prefix)
  "Ensure that blank lines exist between headings and
 between headings and their contents.  With prefix, operate on
 whole buffer. Ensures that blank lines exist after each
 headings's drawers."
  (interactive "P")
  (org-map-entries (lambda ()
                     (org-with-wide-buffer
                      ;; `org-map-entries' narrows the buffer, which
                      ;; prevents us from seeing newlines before the
                      ;; current heading, so we do this part widened.
                      (while (not (looking-back "\n\n" nil))
                        ;; Insert blank lines before heading.
                        (insert "\n")))
                     (let ((end (org-entry-end-position)))
                       ;; Insert blank lines before entry content
                       (forward-line)
                       (while (and (org-at-planning-p)
                                   (< (point) (point-max)))
                         ;; Skip planning lines
                         (forward-line))
                       (while (re-search-forward
                               org-drawer-regexp end t)
                         ;; Skip drawers. You might think that
                         ;; `org-at-drawer-p' would suffice, but for
                         ;; some reason it doesn't work correctly when
                         ;; operating on hidden text.  This works, taken
                         ;; from `org-agenda-get-some-entry-text'.
                         (re-search-forward "^[ \t]*:END:.*\n?" end t)
                         (goto-char (match-end 0)))
                       (unless (or (= (point) (point-max))
                                   (org-at-heading-p)
                                   (looking-at-p "\n"))
                         (insert "\n"))))
                   t (if prefix
                         nil
                       'tree)))

(defun acdw-org/fix-blank-lines-in-buffer ()
  (when (eq major-mode 'org-mode)
    (let ((current-prefix-arg 4))
      (call-interactively #'acdw-org/fix-blank-lines))))


;;; Generate custom IDs:
;; https://amitp.blogspot.com/2021/04/automatically-generate-ids-for-emacs.html

(defun acdw-org/generate-custom-ids ()
  "Generate CUSTOM_ID for any headings that are missing one."
  (let ((existing-ids (org-map-entries (lambda ()
                                         (org-entry-get nil "CUSTOM_ID")))))
    (org-map-entries
     (lambda ()
       (let* ((custom-id (org-entry-get nil "CUSTOM_ID"))
              (heading (org-heading-components))
              (level (nth 0 heading))
              (todo (nth 2 heading))
              (headline (nth 4 heading))
              (slug (acdw-org/title-to-filename headline))
              (duplicate-id (member slug existing-ids)))
         (when (and (not custom-id)
                    (< level 4)
                    (not todo)
                    (not duplicate-id))
           (message "Adding entry '%s' to '%s'" slug headline)
           (org-entry-put nil "CUSTOM_ID" slug)))))))

(defun acdw-org/title-to-filename (title)
  "Convert TITLE to a reasonable filename."
  ;; Based on the slug logic in `org-roam', but `org-roam' also uses a
  ;; timestamp, and I only use the slug.
  (setq title (s-downcase title))
  (setq title (s-replace-regexp "[^a-zA-Z0-9]+" "-" title))
  (setq title (s-replace-regexp "-+" "-" title))
  (setq title (s-replace-regexp "^-" "" title))
  (setq title (s-replace-regexp "-$" "" title))
  title)


;;; ADVICE AND TWEAKS

;; Correct `org-delete-backward-char' to use `backward-delete-char-untabify'
(defun acdw-org/delete-backward-char (N)
  "Like `delete-backward-char-untabify', insert whitespace at field end in tables.
When deleting backwards, in tables this function will insert
whitespace in front of the next \"|\" separator, to keep the
table aligned.  The table will still be marked for re-alignment
if the field did fill the entire column, because, in this case
the deletion might narrow the column."
  (interactive "p")
  (save-match-data
    (org-check-before-invisible-edit 'delete-backward)
    (if (and (= N 1)
             (not overwrite-mode)
             (not (org-region-active-p))
             (not (eq (char-before) ?|))
             (save-excursion (skip-chars-backward " \t") (not (bolp)))
             (looking-at-p ".*?|")
             (org-at-table-p))
        (progn (forward-char -1) (org-delete-char 1))
      (backward-delete-char-untabify N)
      (org-fix-tags-on-the-fly))))

(defun acdw-org/org-table-copy-down (n)
  "Like `org-table-copy-down', except instead of erroring when
  that command makes no sense, just call `org-return'."
  (interactive "p")
  (if (org-table-check-inside-data-field 'noerror)
      (org-table-copy-down n)
    (acdw-org/return-dwim n)))

;; This isn't the best code, but it'll do.
(defun acdw-org/count-words-stupidly (start end &optional limit)
  "Count words between START and END, ignoring a lot.

Since this function is, for some reason, pricy, the optional
parameter LIMIT sets a word limit at which to stop counting.
Once the function hits that number, it'll return -LIMIT
instead of the true count."
  (interactive (list nil nil))
  (cond ((not (called-interactively-p 'any))
         (let ((words 0)
               (continue t))
           (save-excursion
             (save-restriction
               (narrow-to-region start end)
               (goto-char (point-min))
               (while (and continue
                           (< (point) (point-max)))
                 (cond
                  ;; Ignore comments
                  ((or (org-at-comment-p)
                       (org-in-commented-heading-p))
                   (forward-line))
                  ;; Ignore headings
                  ((or (org-at-heading-p))
                   (forward-line))
                  ;; Ignore drawers
                  ((or (looking-at org-drawer-regexp)
                       (looking-at org-clock-drawer-re))
                   (search-forward ":END:" nil :noerror))
                  ;; Ignore tables
                  ((org-at-table-p) (forward-line))
                  ;; Ignore hyperlinks, but count the descriptions
                  ((looking-at org-bracket-link-analytic-regexp)
                   (when-let ((desc (match-string-no-properties 5)))
                     (save-match-data
                       (setq words (+ words
                                      (length (remove ""
                                                      (org-split-string
                                                       desc "\\W")))))))
                   (goto-char (match-end 0)))
                  ;; Ignore source blocks
                  ((org-in-src-block-p) (foreward-line))
                  ;; Count everything else
                  (t
                   ;; ... unless it's in a few weird contexts
                   (let ((contexts (org-context)))
                     (cond ((or (assoc :todo-keyword contexts)
                                (assoc :priority contexts)
                                (assoc :keyword contexts)
                                (assoc :checkbox contexts))
                            (forward-word-strictly))
                           
                           (t (setq words (1+ words))
                              (if (and limit
                                       (> words limit))
                                  (setq words (- limit)
                                        continue nil))
                              (forward-word-strictly)))))))))
           words))
        ((use-region-p)
         (message "%d words in region"
                  (acdw-org/count-words-stupidly (region-beginning)
                                                 (region-end))))
        (t
         (message "%d words in buffer"
                  (acdw-org/count-words-stupidly (point-min)
                                                 (point-max))))))


;;; Zero-width spaces
;; https://blog.tecosaur.com/tmio/2021-05-31-async.html#easy-zero-width

(defun insert-zero-width-space ()
  "Insert a zero-width space."
  (interactive)
  (insert "\u200b"))

(defun org-export-remove-zero-width-spaces (text _backend _info)
  "Remove zero-width spaces from TEXT."
  (unless (org-export-derived-backend-p 'org)
    (replace-regexp-in-string "\u200b" "" text)))


;;; Insert links .. DWIM
;; https://xenodium.com/emacs-dwim-do-what-i-mean/

(defun  org-insert-link-dwim ()
  "Like `org-insert-link' but with personal dwim preferences."
  (interactive)
  (let* ((point-in-link (org-in-regexp org-link-any-re 1))
         (clipboard-url (when (string-match-p
                               (rx (sequence bos
                                             (or "http"
                                                 "gemini"
                                                 "gopher")))
                               (current-kill 0))
                          (current-kill 0)))
         (region-content (when (region-active-p)
                           (buffer-substring-no-properties (region-beginning)
                                                           (region-end)))))
    (cond ((and region-content clipboard-url (not point-in-link))
           (delete-region (region-beginning) (region-end))
           (insert (org-make-link-string clipboard-url region-content)))
          ((and clipboard-url (not point-in-link))
           (insert (org-make-link-string
                    clipboard-url
                    (read-string  "title: "
                                  (with-current-buffer
                                      (url-retrieve-synchronously
                                       clipboard-url)
                                    (dom-text
                                     (car
                                      (dom-by-tag (libxml-parse-html-region
                                                   (point-min)
                                                   (point-max))
                                                  'title))))))))
          (t
           (call-interactively 'org-insert-link)))))


(provide 'acdw-org)
;; acdw-org.el ends here