Re: [xsl] xsl:namespace

["G. Ken Holman" <gkholman@xxxxxxxxxxxxxxxxxxxx>]

At 2009-02-20 18:32 +0100, Jesper Tverskov wrote:
> So wee still need some good examples of why xsl:namespace can be
> necessary.

How about when creating an XSLT stylesheet from a ISO/IEC 19757-3 
Schematron schema?

Schematron has an element-based namespace declaration, and here is an 
example of use:

<schema xmlns="http://purl.oclc.org/dsdl/schematron";
        defaultPhase="only-phase">
  <title>Business rules for maximum total value</title>
  <ns prefix="cbc"
      uri="urn:oasis:names:draft:ubl:schema:xsd:CommonBasicComponents-2"/>
  <ns prefix="cac"
      uri="urn:oasis:names:draft:ubl:schema:xsd:CommonAggregateComponents-2"/>
  <phase id="only-phase">
    <active pattern="code-list-rules"/>
    <active pattern="total-limit"/>
  </phase>
  <include href="total-limit-constraint.sch"/>
  <include href="order-constraints.sch"/>
</schema>

Since the namespaces are only ever used in XPath expressions in 
attributes, there is no way result tree serialization will detect the 
need to create a namespace declaration.  This isn't cosmetic ... it 
is absolutely required that the stylesheet creating the XSLT from the 
Schematron schema dynamically create a namespace declaration.

When using XSLT 1.0 one creates dummy attributes on the document 
element that trigger the need for a namespace declaration, which then 
has scope through the entire stylesheet.  The dummy attribute is 
ignored.  With access to a node-set() extension, one can create the 
dummy attribute in a result tree fragment and then copy that one node 
to the document element.  But without such an extension you have to 
create the dummy attribute to trigger the declaration on the document element.

When using XSLT 2.0 one can use <xsl:namespace> on the generated 
stylesheet's document element to have scope through the entire stylesheet.

To me that makes <xsl:namespace> a very valuable instruction, and not 
only cosmetic.

I hope this helps.

. . . . . . . . . .. Ken

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