Re: [xsl] questions regd namespaces

[Jeni Tennison <jeni at jenitennison dot com>]

Hi Subbu,

> 1. Is xmlns treated different from a normal attribute??

Yes. 'xmlns' attributes don't count as attributes as far as the XSLT
processor is concerned (either on input or output). The XSLT processor
automatically adds namespace declarations to the output that you
create based on the namespaces of and the namespace nodes on the
elements in the result tree.

> 2. In my case how do i output the value of xmlns??

Well, the simplest way is to make sure that your all-centres element
in the result is in the namespace
'http://www.nda-centres.com/namespaces'. The simplest way of doing
that is to include a namespace declaration on the literal result
element. For example:

<xsl:template match="/">
  <all-centres xmlns="http://www.nda-centres.com/namespaces"; />
</xsl:template>

But more usually you should declare the namespace on the
xsl:stylesheet element as the default namespace for the stylesheet:

<xsl:stylesheet version="1.0"
                xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
                xmlns="http://www.nda-centres.com/namespaces";>

<xsl:template match="/">
  <all-centres />
</xsl:template>

</xsl:stylesheet>

> 3. How will someone benifit from using a namespace declaration??

That's a hard question to answer. The namespace of an element is an
essential part of an element, so it's like asking "How will someone
benefit from naming an element?" They'll benefit because the element
will be recognised properly by applications that are built to process
elements in that namespace. The point of namespaces in general is to
enable you to have documents that mix elements from lots of different
markup languages without getting confused about what a particular
element means.

> 4. In the xsl:stylesheet instruction,
> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>
> the above namespace allows some XSL functions where as the older version 
> <xsl:stylesheet xmlns:xsl="http://www.w3.org/TR/WD-xsl";> does not allow some 
> methods..
> so where are these methods?? how does the processor know that the perticular 
> namespace doesnt contain the method or does contain the method??where does it 
> look for this information?

The XSLT processor has the methods (I assume you mean functions and
elements) built into it. The XSLT processor knows which elements and
functions it needs to use based on the namespace URI, which is
hard-coded into the processor. The XSLT processor doesn't need to look
anywhere to find this information -- it is programmed in by the
implementer; the implementer found out what functions and elements
need to be supported by reading the spec.

Cheers,

Jeni

---
Jeni Tennison
http://www.jenitennison.com/


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