Re: [xml-dev] namespaces redux (was: Re: [xml-dev] [XML Schema]Here's ho

[Liam R E Quin <liam@w3.org>]

On Tue, 2012-10-16 at 11:47 +0100, Andrew Welch wrote:

> xmlns:c="config"

This is still, of course, a URI, but now it is a relative URL.

Please don't do this.

Ah, for the reasons that John has said.

It looks nice but it does *not* have the meaning you seem to think it
does. Hmm, I should add that to the course notes I'm writing.

One problem is that you can create non-portable documents - software is
free (unfortunately) to resolve "config" as a relative URI reference
using the base URI of the containing resource, so that the actual
namespace URI in the document would vary depending on the document's
location.

Another is software that will go use that relative URI to fetch a schema
of some sort.

There was a large thread on the now-closed xml-lenary list in about A.D.
2000, with some 1500 postings in a short time, about relative URI
references as namespace names, and the only possible compromise was to
disallow it.

I was disappointed, as I'd always hoped we (the XMLers) would define a
catalog of some sort that could be located at a namespace URI and used
to locate schemas, DTDs, stylesheets, documentation, entity definitions,
code fragments and so forth. RDDL-style. But the consensus was that such
things are neither forbidden nor encouraged, and relative URIs should
not be used as a namespace name.

Liam

-- 
Liam Quin - XML Activity Lead, W3C, http://www.w3.org/People/Quin/
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Author, "Head First Namespaces", O'Grady Books, 1st April 2034