Re: Fixed base

James Clark wrote:
> It's undeniable that [absolutise++] treats URI references in namespace
> declarations differently from other URI references and I would accept
> that this is a minus point of the proposal (in fact the main minus
> point).
I agree; furthermore, it means you can't so easily use a single
piece of common code to handle the URI.

> However, I think there is motivation for it.  The primary
> function of URI references in namespace declaration is quite different
> from the normal function of URIs.
This is bigger problem as I see it.  Namespaces are using URIs in
a way we haven't seen elsewhere.

Where RDF makes statements about resources, and where both XML
and HTML (and XHTML) use a URI to refer to an object whose content
it to be used, XML Namespaces use a URI as an identifier for an
implicit schema and also as a hook to activate specific behaviour.

For example, a web browser might enable HTML anchor behaviour on
certain names associated with a particuar namespace.

We heard early on from people at Netscape and elsewhere that style
sheets were bad because the delay caused by the extra http fetch
would be unacceptable.

We heard early on that the delay caused by fetching a DTD would be
unacceptable.

We've seen requests for inline binary data in XML in order to avoid a
perceived delay in fetching separate images.

Now we see people saying it's unacceptable to fetch a schema or other
resource from a namespace URI, and coming up with all sorts of clearly
broken proposals to work around this.

The solution for the XML DTD was to make fetching it optional.
So there's a clear solution for Namespace Definitions (whatever
they may be): make fetching them optional.

There is then no problem with relative URIs, and people can then use
DOIs [1] for namespace identifiers if they want, by referencing them
in a namespace definition file.

If the fetching is optional, existing widely-used URIs can continue to
be recognised by XML processors.

Lee

-- 
Liam Quin - Barefoot in Toronto - liam@holoweb.net - http://www.holoweb.net/
Ankh on irc.sorcery.net http://valinor.sorcery.net/
Co-author, The XML Specification Guide, Wiley, 1999
Forthcoming: The Open Source XML Database Toolkit [July/August]

Received on Thursday, 22 June 2000 05:01:42 UTC