anchor.diff:  
        (initial-suggestions '()
                             :reader initial-suggestions
  +                          :export t
                             :documentation
                             "Suggestions used on initialization, before any
   user input is processed.
  
positive.code: display and match against, see `active-properties'.")
  
       (filter #'fuzzy-match
               :type function
               :documentation
               "Takes `input' and a `suggestion' and return a new suggestion, or
  nil if the suggestion is discarded.")
  
negative.code:                  (preprocessed-suggestions (mapcar #'copy-object
                                                     (initial-suggestions source))))
               (setf preprocessed-suggestions
                     (if (filter-preprocessor source)
                         (maybe-funcall (filter-preprocessor source)
                                        preprocessed-suggestions source input)
                         (list (make-instance 'suggestion
                                              :value input
                                              :properties (maybe-funcall (suggestion-property-function source)
                                                                         input)
                                              :match-data ""))))
               ;; TODO: Should we really reset the suggestions here?
               (setf (slot-value source 'suggestions) '())
               (if (or (str:empty? input)
  