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RE: Question about the sytax of namespace declarations

• To: "Tim Bray" <tbray@t...>,<xml-dev@l...>
• Subject: RE: Question about the sytax of namespace declarations
• From: "Julian Reschke" <julian.reschke@g...>
• Date: Thu, 28 Feb 2002 20:06:59 +0100
• Importance: Normal
• In-reply-to: <5.1.0.14.2.20020227140834.0232d830@p...>

> From: Tim Bray [mailto:tbray@t...]
> Sent: Wednesday, February 27, 2002 11:12 PM
> To: xml-dev@l...
> Subject: Re:  Question about the sytax of namespace
> declarations
>
>
> At 12:41 PM 27/02/02 -0800, Wayne Steele wrote:
> >Question:
> >
> >Is the below document "conforming" with regard to the XML-Namespaces rec?
> >
> ><root xmlns:a="" />
>
> It's not, but this is probably a bug BTW.  You can "undeclare" the
> default namespace like so:
>
> <root xmlns="foo" >
>  <child xmlns="" />
>  </root>
>
> so why shouldn't you be able to undeclare other prefixes, e.g.
>
> <root xmlns:foo="bar" >
>   <child xmlns:foo="" />
>   </root>
>
> James Clark was the first to notice this, but that was after
> namespaces had been out for a year.
>
> BTW, *nobody* thinks it's a good idea to allow a namespace name
> to be an empty string - if the abovec were allowed, it would
> strictly be in the interests of undeclaring prefixes; which
> would break no existing namespace semantics.  Who knows,
> it might even get done someday. -Tim

Wait-a-minute.

Why would you want to undeclare a namespace prefix???

In the case of

	<a:root xmlns:a="" />

we would have a qualified name "a:root", with a prefix of "a".

http://www.w3.org/TR/1999/REC-xml-names-19990114/#ns-qualnames says:

"The Prefix provides the namespace prefix part of the qualified name, and
must be associated with a namespace URI reference in a namespace
declaration. [Definition:] The LocalPart provides the local part of the
qualified name. "

I don't see what this would be good for.

If you want to write an element which has no namespace and are unsure about
the context in which it appears, write

	<root xmlns="" />

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