anchor.diff:                          :if-exists :append)
       (log:info "Appending configuration form ~a to ~s." form (expand-path *auto-config-file-path*))
       (format file "~&~a~%" form)))
  -
  -(define-command describe-slot (&optional slot)
  -  "Inspect a slot and show it in a help buffer."
  -  (if slot
  -      (let ((input slot))
  -        (with-current-html-buffer (buffer
  -                                   (str:concat "*Help-" (symbol-name (name input)) "*")
  -                                   'nyxt/help-mode:help-mode)
  -          (str:concat (markup:markup (:style (style buffer)))
  -                      (describe-slot* (name input) (class-sym input)
  -                                      :mention-class-p t))))
  -      (prompt
  -       :prompt "Describe slot"
  -       :sources (make-instance 'slot-source))))
   
   (define-command common-settings ()
     "Configure a set of frequently used settings."
  
positive.code:                (list (markup:markup (:li "Default value: " (:code initform-string)))))))
         (when (getf props :documentation)
           ;; We use :pre for documentation so that code samples get formatted properly.
           ;; TODO: Parse docstrings and highlight code samples.
           (list (markup:markup (:li "Documentation: " (:pre (getf props :documentation))))))
         (unless (user-class-p class)
           (list (markup:markup
  
negative.code:        :sources (make-instance 'command-source
                                 :actions (list (make-unmapped-command describe-command))))))
  
  (define-command describe-slot (&optional slot)
    "Inspect a slot and show it in a help buffer."
    (if slot
        (let ((input slot))
          (with-current-html-buffer (buffer
                                     (str:concat "*Help-" (symbol-name (name input)) "*")
                                     'nyxt/help-mode:help-mode)
            (str:concat (markup:markup (:style (style buffer)))
                        (describe-slot* (name input) (class-sym input)
                                        :mention-class-p t))))
        (prompt
         :prompt "Describe slot"
         :sources (make-instance 'slot-source))))
  
  (defun describe-slot* (slot class &key mention-class-p)
    "Create the HTML that represents a slot."
    ;; TODO: Adapt HTML sections / lists to describe-slot and describe-class.
    ;; TODO: Parse docstrings and highlight code samples.
    (let ((props (mopu:slot-properties (find-class class) slot)))
      (markup:markup
       (:ul
  