anchor.diff:  
   Spaces, tabs, any kind of line break, page breaks, and no-break spaces
   are considered whitespace."
  -  ;; Can't use CASE because chars may be repeated.
  -  (or (eql char #\Space)
  -      (eql char #\Tab)
  -      (eql char #\Newline)
  -      (eql char #\Linefeed)
  -      (eql char #\Return)
  -      (eql char #\Page)
  -      (eql char #\No-break_space)))
  +  (case char
  +    (#.(coerce whitespace 'list) t)))
   
   (defsubst trim-whitespace (string)
     "STRING without whitespace at ends."
  
positive.code:           words tokens lines
            fmt
            with-string
            downcase upcase capitalize
            escape
            ellipsize
            string^= string$= string~= string*=
  
negative.code:   (if (stringp control-string)
        `(fmt (formatter ,control-string) ,@args)
        decline))
  
  (defun escape (string table &key (start 0) end stream)
    "Write STRING to STREAM, escaping with TABLE.
  