anchor.diff:    (when (| a b)
       (| a (= a (make-hash-table :test b.__tre-test)))
       (? (defined? b.__tre-keys)
  -       (= a.__tre-keys (*Object.create b.__tre-keys)))
  +       (= a.__tre-keys (*object.create b.__tre-keys)))
       (%= nil (%%native
                   "for (var k in " b ") "
                       "if (k != \"" '__tre-object-id "\" && k != \"" '__tre-test "\" && k != \"" '__tre-keys "\") "
  
positive.code:       (%%%=-aref value hash key)))
  
  (defun %href-user (hash key)
    (adolist ((hashkeys hash))
      (& (funcall hash.__tre-test ! key)
         (return (%%%aref hash (%href-key hash !))))))
  
  (defun href (hash key)
    (!? (%htest hash)
  
negative.code:   (%%%string+ "~~N" x))
  
  (defun hashkeys (hash)
    (invoke-debugger)
    (? (& (hash-table? hash)
          (defined? hash.__tre-keys))
       (cdrlist (%property-list hash.__tre-keys))
  