Re: Query re XMLSpy XPath engine

> --- Elliotte Rusty Harold <elharo at metalab dot unc dot edu> wrote:
> 
> > 
> > At 1:23 PM +1000 7/22/02, Michael Leditschke wrote:
> > 
> > I have the following document
> > 
> > <root xmlns:html="http://www.w3.org/1999/xhtml";
> > xmlns="http://www.a.com";>
> >   <hr xmlns="http://www.w3.org/1999/xhtml"/>
> > </root>
> > 
> > Using the inbuilt XPath engine in XMLSpy 4.4, I
> > issue the following XPath query
> > 
> > //hr
> > 
> > It returns the hr element.
> > 
> > If I try
> > 
> > //html:hr
> > 
> > nothing is returned.
> > 
> > This seems the wrong way around to me. Have
> > I missed something?
> > 
> > 
>  Yes. Your hr element is in the http://www.a.com namespace, not the
>  http://www.w3.org/1999/xhtml namespace. So ion the second case
> XMLSpy
>  is correct.
>  
>  However, in the first case, XMLSpy is incorrect. //hr requests an hr
>  element in no namespace because the default namespace never applies
>  in
>  an XPath expression. Thus, //hr should return an empty node-set.
>  --
>  
> 
>
+-----------------------+------------------------+-------------------+
>  | Elliotte Rusty Harold | elharo@xxxxxxxxxxxxxxx | Writer/Programmer
>  |
> 
>
+-----------------------+------------------------+-------------------+
>  | XML in a Nutshell, 2nd Edition (O'Reilly, 2002) |
>  | http://www.cafeconleche.org/books/xian2/ |
>  | http://www.amazon.com/exec/obidos/ISBN%3D0596002920/cafeaulaitA/ |
> 
>
+----------------------------------+---------------------------------+
>  


XMLSpy is incorrect ***in both cases***.

   <hr xmlns="http://www.w3.org/1999/xhtml"/>

The above "hr" element is in the namespace
"http://www.w3.org/1999/xhtml", which overrides the previous default
namespace.

According to the spec 
(http://www.w3.org/TR/REC-xml-names/#scoping-defaulting):

"5.2 Namespace Defaulting
A default namespace is considered to apply to the element where it is
declared (if that element has no namespace prefix)"

As Jeni noted, the result of the evaluation of "//html:hr" will depend
on whether the "html" prefix has been declared at the current context
when the evaluation is performed.

As the "html" prefix is specified on the top element of the xml
docoment, the evaluation of "//html:hr" must be return the element:

<hr xmlns="http://www.w3.org/1999/xhtml"/>


Hope this helped.


=====
Cheers,

Dimitre Novatchev.
http://fxsl.sourceforge.net/ -- the home of FXSL

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