anchor.diff:           (posts (get-posts 20 :post-offset (* 20 (1- page))))
            (previous-page (unless (< (1- page) 1) (1- page)))
            (next-page (when (get-posts 1 :post-offset (* 20 page)) (1+ page))))
  -    (if (eq posts nil)
  +    (if (null posts)
           (throw-code 404)
           (render (absolute-path "blog_index.html")
                   (list :posts posts :previous previous-page :next next-page)))))
   
   (defroute ("/blog/post/([\\d]+)" :regexp t) (&key captures)
     (let ((id (parse-integer (first captures))))
  -    (if (eq (post-by-id id) nil)
  +    (if (null (post-by-id id))
           (throw-code 404)
           (render-post (post-by-id id)))))
   
  
positive.code: 
  (defroute ("/login" :method :POST) (&key |username| |password|)
    (let ((current-user (get-user |username| |password|)))
      (when (eq current-user nil)
        (redirect "/login?error=t"))  
      (unless (eq current-user nil)
        (setf (gethash :username *session*) |username|)
        (setf (gethash :groups *session*) (user-groups current-user))
        (redirect "/blog/new"))))
  
negative.code:          (posts (get-posts 20 :post-offset (* 10 (1- page)) :tag tag))
           (previous-page (unless (< (1- page) 1) (1- page)))
           (next-page (when (get-posts 1 :post-offset (* 20 page) :tag tag) (1+ page))))
      (if (null (car posts))
          (throw-code 404)
          (render (absolute-path "blog_index.html")
                  (list :posts posts :previous previous-page :next next-page)))))
  