Make M-up and M-down transpose paragraphs in org buffers

[Paul Sexton <psexton@xnet.co.nz>]

By default, if used within ordinary paragraphs in org mode, M-up and M-down 
transpose *lines* (not sentences). This was not useful to me. The following 
code makes these keys transpose paragraphs, keeping the point at the start
of the moved paragraph. Behaviour in tables and headings is unaffected. It
would be easy to modify this to transpose sentences.


(defun org-transpose-paragraphs (arg)
  (interactive)
  (when (and (not (or (org-at-table-p) (org-on-heading-p) (org-at-item-p)))
             (thing-at-point 'sentence))
    (transpose-paragraphs arg)
    (backward-paragraph)
    (re-search-forward "[[:graph:]]")
    (goto-char (match-beginning 0))
    t))

(add-to-list 'org-metaup-hook 
  (lambda () (interactive) (org-transpose-paragraphs -1)))
(add-to-list 'org-metadown-hook 
  (lambda () (interactive) (org-transpose-paragraphs 1)))