anchor.diff:                           (return nil))
                           ((not parsed-input)
                            (if if-invalid
  -                             (funcall if-invalid)
  +                             (funcall (parse-if-invalid if-invalid))
                                (say "Invalid value" :color error-color)))
                           (parsed-input
                            (return parsed-input)))))))
  
positive.code:           :parser #'chronicity:parse
            :default default
            :required-p required-p
            :if-invalid (or if-invalid
                            (lambda () (say "Error. Invalid timestamp"
                                            :color error-color)))
            :color color
  
negative.code:             (prompt msg :default default
                          :required-p required-p
                          :validator (clavier:valid-url)
                          :if-invalid (or (parse-if-invalid if-invalid)
                                          (lambda (&optional value)
                                            (say "Invalid url" :color error-color)))
                          :color color
  