abstract XML and bytes-on-the-wire interoperability

Last week I was asking whether CSS and XPath needed to be revised
to accomodate xml:id, and Norm pointed out that XPath was
defined in terms of the infoset datamodel, not serialized XML,
so it was, in a way, orthogonal. I pointed out that this doesn't
help with interoperability.

Noah said he could see both sides...

[[
NM: I think both views of this are right, there is a case to be said
that the infoset way is architecturally better
... OTOH, Dan is right as well and we need to provide [details missing]
]]
  -- http://www.w3.org/2001/tag/2005/04/19-minutes#item05

I think the [details missing] was something about interoperability
at the bytes-on-the-wire level.

I just happened to be looking at how URIs interact with XML
specifications, and I discovered (rediscovered?) that XML Schema
has conformance clauses at three levels:

  (1) the component level, where even the infoset representation
  of a schema is abstracted away

  (2) "conformance to the XML Representation of Schemas" which
  is actually at the infoset level

plus another that we didn't get into in the teleconference:

  (3) it has an explicit conformance clause for processors that
  aren't running on some disconnected LAN that has its own DNS root,
  but have access to to the captial-I Internet.

Interesting stuff.
 http://www.w3.org/TR/xmlschema-1/#concepts-conformance

I think the lack of a conformance level that ties the bytes-on-the-wire
to the infoset is less than ideal, since I think that's what a lot
of people rely on in practice. But I found the stuff that's there
pretty interesting. Hmm... the 3rd "fully conforming" level talks
about MIME types... that hints pretty strongly at bytes-on-the-wire
level interop.


-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E

Received on Friday, 22 April 2005 20:53:01 UTC