Re: [xml-dev] Re: determining ID-ness in XML

[Rick Jelliffe <ricko@allette.com.au>]

 From: "James Clark" <jjc@jclark.com>

> The problem that xml:id is not completely solving the problem, at least as 
> I see it. 

Why do we need a complete solution?  We need to have broad solutions
apppropriate for different classes of users.

> Overall xml:id is pretty intrusive.

If it were couple with the rule that unknown entity references are resolved
against the ISO standard entity sets (i.e. build the ISO sets into XML),
then it would allow DTD-less documents, suitable for lightweight, well-known
and informal systems.

That would let us move to three forms of XML:

 1) Instance-only XML  (=WF XML - DTD + xml:id + xmlns + ISO entities + xml:base + xml:include + xlink)
 2) Classic XML (= Valid XML + namespaces) 
 3) PSVI-convertable XML (e.g. XML + XML Schemas)
 
I think that would be a pretty healthy split.  I believe most users of XML would 
head towards Instance-only XML, especially since it still could be validated (by RELAX, 
by XML Schema, by Schematron).    The database and tools-making companies 
would continue to take the PSVI-based XML track, I would guess.
 
> An alternative would be to have an attribute that declares the name of the 
> attribute that is an ID attribute, say xml:idatt. To make this useable, 
> xml:idatt would be inherited.  

By the time we factor in inheritence, we may as well have a schema language.

I think the answer to the "problem" should come architecturally, rather than solving
small problems.  The architectural solution is IMHO to have a clear roadmap
for different kinds of XML, and to avoid one-size-fits-all-ism. 

Cheers
Rick Jelliffe