W3C is pleased to receive the DDML submission from GMD and to provide archival storage for the product of the collaboration in the xml-dev forum.
This submission joins XML Data, DCD, and SOX as proposals in the XML Activity work on XML Schemas.
It is a rather straightforward adaptation of XML DTD functionality into XML element and attribute syntax. Translation from DDML to XML DTD syntax is an explicit design goal, and translation in the other direction is discussed.
An interesting aspect of the proposal is that translation is not 100% lossless in either direction (for example, comments, processing instructions, and parameter entities do not translate without some loss). The practical trade-offs in this area lead to interesting design choices.
Another interesting aspect of the proposal is the way it integrates XML Namespaces and suggests integrating XPointers and XML Linking. This demonstrates the benefit of unifying the XML Schema syntax with the syntax of XML elements and attributes.
As requested, the specification has been archived as a W3C NOTE. It will be brought to the attention of the W3C XML Activity, especially the XML Schema Working Group.