Improve README

1 files changed, 5 insertions, 3 deletions

diff --git a/README.org b/README.org
index ee19a59..2a4fe4f 100644
--- a/README.org
+++ b/README.org
@@ -138,14 +138,16 @@ small example completion backend, which can be used with both
 
 (defun demo-backend (action &optional arg &rest _)
   (pcase action
-    ('prefix (and (memq (char-before) '(?: ?\;))
-                  (cons (string (char-before)) t)))
+    ('prefix
+     (when-let (beg (save-excursion
+                      (and (re-search-backward "[;:]" (pos-bol) t) (point))))
+       (cons (buffer-substring-no-properties beg (point)) t)))
     ('candidates (all-completions arg demo-alist))
     ('annotation (concat " " (cdr (assoc arg demo-alist))))
     ('post-completion
      (let ((str (buffer-substring (- (point) 3) (point))))
        (delete-region (- (point) 3) (point))
-     (insert (cdr (assoc str demo-alist)))))))
+       (insert (cdr (assoc str demo-alist)))))))
 
 ;; Register demo backend with `completion-at-point'
 (setq completion-at-point-functions