void update(T d) { vi->Data() = sae::serialization::convert_to_string<T>(d); }
vertex_data_type& data() { return *((vertex_data_type *) vi->Data()); }
T parse() { T ret = sae::serialization::convert_from_string<T>(vi->Data()); return ret; }
const vertex_data_type& data() const { return *((vertex_data_type *) vi->Data()); }