anchor.diff:      :   TAG_START_VERSION
           NAME_NUM ATTR_EQ ATTR_VALUE_START v=INT ATTR_VALUE_END
           TAG_CLOSE
  -        doc=SHORTDOC*
  +        (doc=SHORTDOC)*
           TAG_END_VERSION SHORTDOC*
   /*
   <version num="1.2.3">Game Name</version>
  
positive.code:         | attr_expression_ver2
          | anyattribute
          )* TAG_CLOSE
          doc=SHORTDOC*
          enum_option+
          TAG_END_ENUM SHORTDOC*
          -> ^(ENUMDEF ^(DOC $doc?) $name $type enum_option+)
      ;
  
  enum_option
  
negative.code:         | anyattribute
          )*
          ( TAG_CLOSE
            (doc+=SHORTDOC)*
            TAG_END_ADD
          | TAG_END
          )
  