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Re: locally scoped element decls and namespaces

From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
Date: 04 Jan 2000 17:44:24 +0000
To: James.Anderson@mecomnet.de
Cc: XML List <xml-dev@ic.ac.uk>, xml-schema-comments <www-xml-schema-comments@w3c.org>
Message-ID: <f5bpuvhn347.fsf@cogsci.ed.ac.uk>
james anderson <James.Anderson@mecomnet.de> writes:

> Henry S. Thompson wrote:
> > 
> > [...]
> > 
> > We don't yet have a concrete syntax for indicating an association
> > between "no namespace" and a schema in xsi:schemaLocation.
> Wait. Is this really saying that one is looking for a way to encode the
> specification, that a symbol, so encoded as to denote that it is in no
> namespace, is really to be taken to be identical with another symbol, so
> encoded as to denote that it is in another, definite namespace?
> Isn't this impossible by definition?

I think you've misunderstood my (admittedly obscure) point.  Suppose I
have an XML instance document with no namespace declarations of any
kind governing some or all of the GIs therein.  These GIs are not in
any namespace at all.  The Namespace REC even gives us a way of
EXPLICITLY indicating that names in a certain scope are in no
namespace, namely "xmlns=''".  But I may perfectly well want to
identify a schema to use for schema-validating such an instance
document.  How do I do so?  xsi:schemaLocation uses PAIRS of URIs to
accomplish this, with the first member of each pair being a namespace
URI.  But _ex hypothesi_ the GIs of the elements in question are not
in a namespace, hence there is no namespace URI I can use in
xsi:schemaLocation.  If we stay with the admittedly rather clunky
syntax of xsi:schemaLocation as it stands, I expect we'll nominate
something such as ##noNamespace for this purpose. . .

  Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
     2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
	    Fax: (44) 131 650-4587, e-mail: ht@cogsci.ed.ac.uk
		     URL: http://www.ltg.ed.ac.uk/~ht/
Received on Tuesday, 4 January 2000 12:44:28 UTC

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