xml - Add namespace to root node when root node may have multiple types -

i using xlst 1.0 , want transform xml add 'nil' attributes empty elements. finding namespace being added each matching element e.g output looks like: <age xmlns:xsi="http://www.w3.org/2001/xmlschema-instance" xsi:nil="true" />

i know valid i'd rather added top-node. came across answer: how can add namespaces root element of xml using xslt?

however have multiple possible root nodes, thought this:

  <xsl:template match="animals | people | things">     <xsl:element name="{name()}">       <xsl:attribute name="xmlns:xsi">http://www.w3.org/2001/xmlschema-instance</xsl:attribute>       <xsl:apply-templates/>     </xsl:element>   </xsl:template> 

however error visual studio "prexix xmlns not defined" , i'm not sure this.

here total xlst file (it won't paste reason) tries few things:

1. transform different types of animal single type
2. add namespace root node
3. add xsi:nil = true empty elements (note must have no children not no text, or top-level node gets transformed)

first, namespace declaration not attribute, , cannot created using xsl:attribute instruction.

you can use xsl:copy-of insert namespace declaration "manually" @ desired location, example:

xslt 1.0

<xsl:stylesheet version="1.0"  xmlns:xsl="http://www.w3.org/1999/xsl/transform" xmlns:xsi="http://www.w3.org/2001/xmlschema-instance"> <xsl:output method="xml" version="1.0" encoding="utf-8" indent="yes"/> <xsl:strip-space elements="*"/>  <!-- identity transform --> <xsl:template match="@*|node()">     <xsl:copy>         <xsl:apply-templates select="@*|node()"/>     </xsl:copy> </xsl:template>  <xsl:template match="/*">     <xsl:copy>         <xsl:copy-of select="document('')/xsl:stylesheet/namespace::xsi"/>         <xsl:apply-templates/>     </xsl:copy> </xsl:template>  <xsl:template match="*[not(node())]">     <xsl:copy>         <xsl:attribute name="xsi:nil">true</xsl:attribute>         <xsl:apply-templates/>     </xsl:copy> </xsl:template>  </xsl:stylesheet> 

however, results rather processor- dependent. xalan, example, ignore instruction , repeat declaration @ every empty node outputs before. in general, have little no control on how xslt processor serializes output.

another option use namespace declaration @ root level, say:

<xsl:stylesheet version="1.0"  xmlns:xsl="http://www.w3.org/1999/xsl/transform" xmlns:xsi="http://www.w3.org/2001/xmlschema-instance"> <xsl:output method="xml" version="1.0" encoding="utf-8" indent="yes"/> <xsl:strip-space elements="*"/>  <!-- identity transform --> <xsl:template match="@*|node()">     <xsl:copy>         <xsl:apply-templates select="@*|node()"/>     </xsl:copy> </xsl:template>  <xsl:template match="/*">     <xsl:copy>         <xsl:attribute name="xsi:nil">false</xsl:attribute>         <xsl:apply-templates/>     </xsl:copy> </xsl:template>  <xsl:template match="*[not(node())]">     <xsl:copy>         <xsl:attribute name="xsi:nil">true</xsl:attribute>         <xsl:apply-templates/>     </xsl:copy> </xsl:template>  </xsl:stylesheet> 

this worked processors have tested (ymmv).

of course, best option nothing, since have noted, difference purely cosmetic.