Versioning MicroXML (Was: MicroXML)

I really like the idea of MicroXML.  My only slight fear is that it might be 
too light!

I wonder if it's possible to include a light-weight versioning scheme in the 
proposal.

Taking ideas from various internet protocol negotiation schemes, can we 
include a uxmldecl that includes a "require" attribute that lists features 
the uXML parser must support.

For example:

<?uxml require="ns pi"?>

would indicate that a particular namespace scheme was required and PIs need 
to be handled.

No uxmldecl would indicate that the MicroXML is a pure subset of XML as per 
James' original proposal.

You could design MicroXML so that the most basic of parsers would report an 
error when encountering "<?", thus the implementation burden is minimal.  In 
fact there need be no difference in implementation between a parser 
implemented according to James' original proposal and a proposal 
incorporating this feature.  At this stage it's more of an issue of 
specification.

BTW - I think its important to agree that we are only looking for 3 or 4 
widely implemented features, rather than 3 or 4 million!  If we have too 
many then we lose interoperability.  Things analogous to XML namespaces and 
xml:id that were added to XML after the initial release of XML are the sorts 
of things we should be looking for.

Thanks,

Pete Cordell
Codalogic Ltd
Interface XML to C++ the easy way using C++ XML
data binding to convert XSD schemas to C++ classes.
Visit http://codalogic.com/lmx/ or http://www.xml2cpp.com
for more info