anchor.diff:    `(with-connection (db)
        (retrieve-one
         (select :*
  -              (from :posts)
  -              ,@body)
  +        (from :posts)
  +        ,@body)
         :as 'post)))
   
   (defun latest-post ()
  
positive.code: 
  (defun post-by-id (id)
    (retrieve-post
     (where (:= id id))))
  
  (defun get-posts (post-limit &key (post-offset 0) (tag "%"))
    (if (< post-offset 0)
  
negative.code:   (with-connection (db)
      (retrieve-one
       (select :*
               (from :users)
               (where (:and (:= :username username)
                            (:= :password (:crypt password :password)))))
       :as 'user)))
  
  ;;
  