anchor.diff:  
   ;;
   (defun js-string? (o)
  -  (or (stringp o)
  -      (stringp (value o))))
  +  (typecase o
  +    (string t)
  +    (t (eq (prototype o) string.prototype))))
   
   (defparameter string.ctor
     (js-function (obj)
  
positive.code: 
  ;;
  (defun js-number? (o)
    (flet ((num? (o)
  	   (or (numberp o)
  	       (eq o :NaN)
  	       (eq o :Inf)
  	       (eq o :-Inf))))
      (or (num? o) (num? (value o)))))
  
  (deftype js.number ()
    `(satisfies js-number?))
  
negative.code: (defgeneric to-string (obj)
    (:method (obj) (format nil "~A" obj)))
  
  (defgeneric prototype (obj)
    (:method (obj) nil))
  ;;
  (defparameter value-of nil) ;;function.prototype is not defined yet
  (defparameter to-string nil)
  