From child elements to attributes

Still working on XSLT with Saxon, here we'll have a look at the xsl:copy element that copies just a bare node from the input xml to the resulting file, without considering descendant node or attribute, if any.

An usage for such a stripped down copy is showed here, where we want to transform an xml swapping the child nodes as attributes. This is the input:

<?xml version="1.0" encoding="UTF-8"?>
<People>
  <Person>
    <FirstName>Tom</FirstName>
    <LastName>Smith</LastName>
  </Person>
  <Person>
    <FirstName>Bill</FirstName>
    <LastName>Krill</LastName>
  </Person>
  <Person>
    <FirstName>Phil</FirstName>
    <LastName>Delphi</LastName>
  </Person>
</People>

We want to get this as output:

<?xml version="1.0" encoding="UTF-8"?>
<People>
  <Person FirstName="Tom" LastName="Smith"/>
  <Person FirstName="Bill" LastName="Krill"/>
  <Person FirstName="Phil" LastName="Delphi"/>
</People>

Here is the XSLT we use:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0">

  <xsl:template match="/">
    <People>
      <xsl:apply-templates select="/People/Person"/> <!-- 1 -->
    </People>
  </xsl:template>
  
  <xsl:template match="Person">  <!-- 2 -->
    <xsl:copy>  <!-- 3 -->
      <xsl:attribute name="FirstName">  <!-- 4 -->
        <xsl:value-of select="FirstName"/>  <!-- 5 -->
      </xsl:attribute>
      <xsl:attribute name="LastName">
        <xsl:value-of select="LastName"/>
      </xsl:attribute>
    </xsl:copy>
  </xsl:template>

</xsl:stylesheet>

1. we use apply-templates on each person
2. here is the called template relative to (1)
3. copy the current element (a Person, actually)
4. generate a FirstName attribute in the copied (stripped down) node
5. set as value-of the output FirstName attribute the value of the input FirstName child
And then the same for a second attribute.

And here how I called Saxon:

java -jar c:\dev\saxon\saxon9he.jar in.xml change.xslt -o:out.xml

More information on XSLT and Saxon in chapter eight of Beginning XML by David Hunter et al. (Wrox).