>
> True. I thought about that and concluded that it would be a lot harder
> to look for more than one words, matching a certain expansion. It will
> be especially tricky, I think, if the words the user types and which
> match an extension, spans more than one line. Of course not impossible but
> I thought I would start with the easy and probably quite common use
> case.
>

Okay, so... Turns out it was not that hard... :)

With two helper functions I could rewrite the suggest function quite nicely:

(defun asug-count-words (expansion)
  (length (split-string expansion " " t)))

(defun asug-get-previous-words (n)
  (let ((end (point))
        words)
    (save-excursion
      (backward-word n)
      (replace-regexp-in-string
       "[\n\r]" " "
       (buffer-substring-no-properties (point) end)))))

(defun absug-maybe-suggest ()
  "Suggest an abbrev to the user based on the word(s) before point."
  (let ((expansions (absug-get-active-abbrev-expansions))
         words found expansion word-count)
    (while (and expansions
                (not found))
      (setq expansion (pop expansions))
      (when expansion
        (setq word-count (asug-count-words (car expansion))
              words (asug-get-previous-words word-count))
        (when (and (> word-count 0)
                   (string= words (car expansion)))
          (setq found t)
          (message "You can write `%s' using the abbrev `%s'."
                   (car expansion) (cdr expansion)))))))

It works for abbrevs that has an expansion with multiple words and
it also works across lines.

Now I will clean this up a bit and checkdoc it...