Currently, version and revision use Optional[Non_empty_XML_serializable_string] and check their types in the invariants (matches_version_type()). In order to avoid confusion, it would be clearer, to add seperate types, inheriting from Non_empty_XML_serializable_string, similar to how it's done in Name_type.
Currently,
versionandrevisionuseOptional[Non_empty_XML_serializable_string]and check their types in the invariants (matches_version_type()). In order to avoid confusion, it would be clearer, to add seperate types, inheriting fromNon_empty_XML_serializable_string, similar to how it's done inName_type.