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Re: CSS Namespaces: Need multiple namespaces!

From: Chris Lilley <chris@w3.org>
Date: Sun, 10 Oct 1999 23:06:47 +0200
Message-ID: <3800FFE7.2A5175B9@w3.org>
To: jelks@jelks.nu
CC: Peter Linss <peterl@netscape.com>, www-style <www-style@w3.org>


Jelks Cabaniss wrote:
> 
> Peter Linss wrote:
> 
> > The real issue here is how namespaces are really going to
> > be used in the real world. My takeaway from reading the
> > Namespace Rec is that a namespace is *just a name*, the
> > URL doesn't actually point to anything and shouldn't be
> > overloaded to point to a schema or DTD or anything (except
> > perhaps someday some information about the *namespace* not
> > the document where it is used).
> 
> That was *last* month. :)  But then you have this (TimBL):
> 
>         http://www.lists.ic.ac.uk/hypermail-archive/xml-dev/xml-dev-Sep-1999/1251.html

Where Tim asserts several things

a) that it isn't clear
b) that there are some useful references anyway, in particular [1]
c) that RDF assumes that there is something obtained by deferencencing
the namespace URI of an RDF schema

All of these are true, and none of them contradict that the Namespcaes
Eec says thatit is not an error for a namespace URI to resolve to
something.

It is also clearly true, from the laws of physics, that as time flows
forwards, once cannot define content models for every possible other
namespace that might be invented later; and also from extensibiklity and
modularity, that the definitionof a namespace should concern itself only
withthat namespace, not with everything ele that it might ever be
combined with; and thus namespace URIs might be used in an XSchema which
is defining one particular way of combining these said namespaces into
asingle, validatable document, but cannot themselves point off to
Schemas. Otherwise, you can't validate the whole document, or else you
can't declare content models any more, which would make Xschema be DTD--
instead of DTD++

> > If you presume that languages identified by namespace are going
> > to have one and only one namespace for all schemas/DTD and all
> > versions (as I believe the namespace was meant to be used),

That is my presumption also.


[1] http://www.w3.org/DesignIssues/Extensible.html
where we read
"The resource defining a namespace may be generic and allow definitions
of the namespace in varying present or future languages."

Note "may". Note that it doesn't say "by dereferencing it". It might be
"by usingit as a database key".

--
Chris
Received on Sunday, 10 October 1999 17:07:07 GMT

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