Re: namespace usage as assertions

> In particular, if the user chose a namespace name beginning
> with http:, you can infer that a description of/representation of
> the resource identified by that URI is generally available on demand.

there is nothing in the namespace rec that leads anyone to infer
_anything_ about the namespace from the URI used as its name.
As you know this was backed up by countless clarifications from
memebrs of the WG at the time stressing this fact.

Apart from questions of whether you _should_ be able to infer that,
clearly you can't in practice as for example a large (perhaps largest)
class of namespaces using http URI do not have anything available on
demand. (eg xslt extensions).


>> there isn't necessarily a way to independently verify that there really
>> is such a namespace that includes the name "Title".  All you may be able
>> to know is that the user has made that assertion.
>
>True,

False. Title (like every other NCName) is in the namespace named by
any (and every) URI.



>For example, if userB writes
>
>	<html xmlns="http://www.w3.org/1999/xhtml">
>	<banana/>
>	</html>
>
>then userC can, independently, access http://www.w3.org/1999/xhtml 
>to get an HTML document that says that the use of that namespace
>name is governed by the XHTML 1.0 specification, look in that
>specification, and discover that there is no 'banana' element
>in the XHTML namespace at this time, and that every html element
>must contain a head and a body.
>

Not so. There is nothing wrong with your document. It is a well formed
XML document that conforms to the XML namespace recommendation and
includes elements with local names html and banana.

Of course it isn't schema valid, but we are not talking about schema
here.

One of the main insights in XML was that you could usefully formulate
a notion of well-formed but invalid documents. "invalid" doesn't mean
bad, (well actually in most cases that I use XML, it does, but the
principle of well-formed documents was sound). Unfortunately all the
good names have been used up so rather than "well formed" and "valid"
we have "conforming to the XML namespace recommendation" and "schema
valid" but the principle remains the same.


> In due course, an XML schema may become available from that URI,
> at which point the discovery that this document conflicts with
> the namespace name issuer's intended usage can be automated.

There are already several schema for that namespace, but even without
placing any of those schema at the URI, one would expect that any
schema validator would by default use one of the xhtml schema for
such a document. Having done that you would find the document was not
schema valid, but it would still be conforming to the namespace rec,
and banana would still be in the namespace.

David

Received on Wednesday, 21 June 2000 15:52:37 UTC