anchor.diff:          (:register (:greedy-repetition 0 nil (:inverted-char-class #\})))
           #\}))
   
  +(define-parse-tree-synonym
  +  eval-in-code (:sequence
  +        #\{ #\{ 
  +        (:register (:greedy-repetition 0 nil (:inverted-char-class #\})))
  +        #\} #\}))
  +
   ;; should only happen once! (but need names to do this correctly)
   (eval-when (:load-toplevel :execute)
     #+(or)
  
positive.code:      :regex (create-scanner '(:sequence eval))
       :name 'eval
       :priority 1.5)
     :filter (lambda (key) (not (equal key '(code))))))
  
  (defmethod render-span-to-html ((code (eql 'eval)) body encoding-method)
    (declare (ignore encoding-method))
  
negative.code:    (lambda (key value)
       (when (funcall filter key)
         (insert-new-item value extension)))))
  
  #|
  (markdown "Hello {user-name :format :long}, how are you. Go {{here}}." :format :none)
  