[BUG]: function looking-back (XEmacs incompatibility)

[Richard KLINDA <rklinda@gmail.com>]

XEmacs and older Emacs (22 and below) don't have the function LOOKING-BACK.

I've found a definiton of it here: http://moinmo.in/EmacsForMoinMoin

,----
| (or (fboundp 'looking-back)
| ; taken straight out of http://cvs.savannah.gnu.org/viewcvs/emacs/emacs/lisp/subr.el?rev=1.530&view=auto
|     (defun looking-back (regexp &optional limit greedy)
|       "Return non-nil if text before point matches regular expression REGEXP.
| Like `looking-at' except matches before point, and is slower.
| LIMIT if non-nil speeds up the search by specifying a minimum
| starting position, to avoid checking matches that would start
| before LIMIT.
| If GREEDY is non-nil, extend the match backwards as far as possible,
| stopping when a single additional previous character cannot be part
| of a match for REGEXP."
|       (let ((start (point))
|             (pos
|              (save-excursion
|                (and (re-search-backward (concat "\\(?:" regexp "\\)\\=") limit t)
|                     (point)))))
|         (if (and greedy pos)
|             (save-restriction
|               (narrow-to-region (point-min) start)
|               (while (and (> pos (point-min))
|                           (save-excursion
|                             (goto-char pos)
|                             (backward-char 1)
|                             (looking-at (concat "\\(?:"  regexp "\\)\\'"))))
|                 (setq pos (1- pos)))
|               (save-excursion
|                 (goto-char pos)
|                 (looking-at (concat "\\(?:"  regexp "\\)\\'")))))
|         (not (null pos)))))
`----

-- 
Richard