[O] New org-count-words function

[Adam Porter]

Hi friends,

Here's a new function that counts lines, words, and characters in the
region or the subtree at point.  It prints a message like `count-words`
does, like:

    Subtree "Heading" has 7 line, 5 words, and 28 characters.

Note that it does *not* count words in heading lines, planning lines,
and drawers, so it gives a more useful count for the "prose" in the
subtree.

Here's the code:

#+BEGIN_SRC elisp
(defun ap/org-count-words ()
  "If region is active, count words in it; otherwise count words in current 
subtree."
  (interactive)
  (if (use-region-p)
      (funcall-interactively #'count-words-region (region-beginning) 
(region-end))
    (org-with-wide-buffer
     (cl-loop for (lines words characters)
              in (org-map-entries
                  (lambda ()
                    (ap/org-forward-to-entry-content 'unsafe)
                    (let ((end (org-entry-end-position)))
                      (list (count-lines (point) end)
                            (count-words (point) end)
                            (- end (point)))))
                  nil 'tree)
              sum lines into total-lines
              sum words into total-words
              sum characters into total-characters
              finally do (message "Subtree \"%s\" has %s lines, %s words, and 
%s characters."
                                  (org-get-heading t t)
                                  total-lines total-words
                                  total-characters)))))
#+END_SRC

It requires this supporting function:

#+BEGIN_SRC elisp
(defun ap/org-forward-to-entry-content (&optional unsafe)
  "Skip headline, planning line, and all drawers in current entry.
    If UNSAFE is non-nil, assume point is on headline."
  (unless unsafe
    ;; To improve performance in loops (e.g. with `org-map-entries')
    (org-back-to-heading))
  (cl-loop for element = (org-element-at-point)
           for pos = (pcase element
                       (`(headline . ,_)
                        (org-element-property :contents-begin element))
                       (`(,(or 'planning 'property-drawer 'drawer) . ,_)
                        (org-element-property :end element)))
           while pos
           do (goto-char pos)))
#+END_SRC

I think it's an improvement over the functions I've seen that do this.
Hope someone finds it useful.