anchor.diff:                                (:true "true")
                                 (:false "false")
                                 (:null "NULL")
  +                              (:size-t "size_t")
                                 (:string "string")
                                 (:wstring "wstring")
                                 (:scoped-ptr "scoped_ptr"))))
  
positive.code: 	'begin-block
  	(* <stmt>)
  	'end-block)
  
    (rule <class-member-fn-body> (naked) ::= (one-of <null-body>
                                                     (group 'begin-block <stmt> (* <stmt>) 'end-block)
  
negative.code: (def-grammar cpp
  
    (rule <definition> (naked) ::= (one-of <_> <//> <define> <ifndef> <std-include> <include> <define> <macro-call>
                                           <namespace> <using> <class-forward> <stmt>
                                           <class> <field> <method> <constructor> <destructor> <var>))
  
    (rule <_> ::= 'vertical-space)
    (rule <//> ::= "//" (* :comment-string) 'new-line)
  