anchor.diff:      (let ((posts (sort *posts* #'string> :key #'post-date)))
         (loop for i from 1 then (1+ i)
            until (> (* (1- i) 20) (length posts))
  -         do (render-page (format nil "~d.html" i)
  -                         (funcall (theme-fn "INDEX")
  -                                  (list :taglinks (taglinks)
  -                                        :monthlinks (monthlinks)
  -                                        :posts (render-index (by-20 posts i))
  -                                        ; TODO: Populate prev and next with links.
  -                                        :prev nil
  -                                        :next nil)))))))
  +         do (write-index (by-20 posts i) (format nil "~d.html" i))))))
   
   (defun render-by-tag ()
     (let ((tags (remove-duplicates (mapcan #'post-tags *posts*) :test #'string=)))
  
positive.code:        collect (list :url (format nil "~a/month/~a.html" (domain *config*) month)
                       :name month))))
  
  (defun render-index (posts)
    (loop for post in posts
       collect (list :url (format nil "~a/posts/~a.html"
                                  (domain *config*) (post-slug post))
                     :title (post-title post)
                     :date (post-date post)
                     :contents (post-contents post))))
  
  (defun render-by-20 ()
    (flet ((by-20 (posts start)
  
negative.code:                                         (member tag x :test #'string=
                                                        :key #'post-tags))
                                        posts)))
              (write-index posts (format nil "tag/~a.html" tag))))))
  
  (defun render-by-month ()
    ;; TODO: Make this actually work. Add to render-indices.
    (let ((months (remove-duplicates (mapcar #'post-date *posts*) :test #'string=)))
      (loop for month in months
         do (let ((posts (remove-if-not (lambda (x)
                                          (from-month month x)
                                          posts))))
              (render-index posts)))))
  
  (defun render-indices ()
    (render-by-20)
    (render-by-tag))
  