Question

I use XSLT as a “code generator” for various components, including other XSLT. For example, I have a query that produces an XML output of MSSQL sys.columns rows for a table, and wish to produce an XSLT that includes a table with a column for each row.

So I want to produce the following XSLT:

<xsl:stylesheet version="1.0" xmlns:format="urn:qbo3-formatting" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  ...
</xsl:stylesheet>

I generate the XSLT above with something like this ‘generator’ XSLT:

<xsl:element name="xsl:stylesheet">
  <xsl:attribute name="version">1.0</xsl:attribute>
  <xsl:attribute name="format" namespace="http://www.w3.org/XML/1998/namespace" >urn:qbo3-formatting</xsl:attribute>
  ...
</xsl:element>

The problem is that this ‘generator’ XSLT produces:

<xsl:stylesheet version="1.0" xml:format="urn:qbo3-formatting" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  ...
</xsl:stylesheet>

Note the xml:format instead of the desired xmlns:format.

According to W3C, ‘xmlns’ is reserved and bound to ‘http://www.w3.org/2000/xmlns/’. If I attempt to create the format attribute above using this namespace, I get an error:

Elements and attributes cannot belong to the reserved namespace 'http://www.w3.org/2000/xmlns/'.

Any suggestions on a work-around?

Thanks in advance,

Eric

Answer 1

This is exactly the main usecase for the <xsl:namespace-alias> instruction:

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
 xmlns:format="some:format"
 xmlns:xxx="xxx">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>

 <xsl:namespace-alias stylesheet-prefix="xxx"
                      result-prefix="xsl"/>

 <xsl:template match="/">
    <xxx:stylesheet version="1.0"
         xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
         xmlns:format="some:format"
     >

      <xxx:template match="node()|@*">
        <xxx:copy>
          <xxx:apply-templates select="node()|@*"/>
         </xxx:copy>
      </xxx:template>
    </xxx:stylesheet>

 </xsl:template>
</xsl:stylesheet>

When this transformation is applied on any XML document (not used), the wanted result (a new stylesheet with all wanted attributes and namespaces) is produced:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                xmlns:format="some:format">
  <xsl:template match="node()|@*">
    <xsl:copy>
      <xsl:apply-templates select="node()|@*" />
    </xsl:copy>
  </xsl:template>
</xsl:stylesheet>

Do note: Avoid using xsl:element and prefer xsl:namespace-alias whenever the transformation should generate another XSLT stylesheet.