An improbable transformation example

to illustrate the DOM-like XSLT construct <xsl element name="... ">

1. Basic

   • Source document (RDF list of names)
     

     ---

     <?xml version="1.0"?>
<rdf:RDF
  xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'
  xmlns:vcard='http://www.w3.org/2001/vcard-rdf/3.0#'
  xml:base='http://somewhere/'
 >

  <rdf:Description rdf:about='#JohnSmith'>
    <vcard:FN>John Smith</vcard:FN>
  </rdf:Description>
  <rdf:Description rdf:about='#SarahJones'>
    <vcard:FN>Sarah Jones</vcard:FN>
  </rdf:Description>
.....
</rdf:RDF>
     

     ---

     
     
   • Target (list of names-as tags...)
     

     ---

     <?xml version="1.0"?>
<list>
  <JohnSmith xml:id="1">
    <fullName>John Smith</fullName>
  </JohnSmith>
  <SarahJones xml:id="2">
    <fullName>Sarah Jones</fullName>
  </SarahJones>
 ....
</list>
     

     ---

     
     
   • Stylesheet
     

     ---

     <?xml version='1.0'?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version='1.0'
  xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'
  xmlns:vcard='http://www.w3.org/2001/vcard-rdf/3.0#'
>
<xsl:output method="xml" indent="yes"/>

<xsl:template match="/">
    <list>
        <xsl:apply-templates select="rdf:RDF/rdf:Description" />
    </list>
</xsl:template>

<xsl:template match="rdf:Description">
    <xsl:element name="{substring-after(@rdf:about, '#')}">
        <xsl:attribute name="xml:id">
            <xsl:value-of select="position()" />
        </xsl:attribute>
        <fullName>
            <xsl:value-of select="vcard:FN" />
        </fullName>
    </xsl:element>
</xsl:template>

</xsl:stylesheet>
     

     ---

     
     

2. Advanced

   • Source (a more detailed RDF list of names)
     

     ---

     <?xml version="1.0"?>
<rdf:RDF
  xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'
  xmlns:vcard='http://www.w3.org/2001/vcard-rdf/3.0#'
  xml:base='http://somewhere/'
 >
 
  <rdf:Description rdf:about='#JohnSmith'>
    <vcard:FN>John Smith</vcard:FN>
    <vcard:N rdf:nodeID="A0"/>
  </rdf:Description>
 <rdf:Description rdf:nodeID="A0">
    <vcard:Family>Smith</vcard:Family>
    <vcard:Given>John</vcard:Given>
  </rdf:Description>
....
</rdf:RDF>
     

     ---

     
     
   • Target (names-as-tags with additional detail)
     

     ---

     <?xml version="1.0"?>
<list>
  <JohnSmith xml:id="1">
    <fullName>John Smith</fullName>
    <familyName>Smith</familyName>
    <personalName>John</personalName>
  </JohnSmith>
...
</list>
     

     ---

     
     
   • Stylesheet
     

     ---

     <?xml version='1.0'?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version='1.0'
  xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'
  xmlns:vcard='http://www.w3.org/2001/vcard-rdf/3.0#'
>
<xsl:output method="xml" indent="yes"/>

<xsl:template match="/">
    <list>
        <xsl:apply-templates select="rdf:RDF/rdf:Description[@rdf:about]" />
    </list>
</xsl:template>

<xsl:template match="rdf:Description[@rdf:about]">
    <xsl:variable name="VN" select="vcard:N/@rdf:nodeID" />
    <xsl:element name="{substring-after(@rdf:about, '#')}">
        <xsl:attribute name="xml:id">
            <xsl:value-of select="position()" />
        </xsl:attribute>
        <fullName>
            <xsl:value-of select="vcard:FN" />
        </fullName>
        <xsl:apply-templates select="//rdf:Description[@rdf:nodeID=$VN]" />
    </xsl:element>
</xsl:template>

<xsl:template match="rdf:Description[@rdf:nodeID]">
    <familyName>
        <xsl:value-of select="vcard:Family" />
    </familyName>
    <personalName>
        <xsl:value-of select="vcard:Given" />
    </personalName>
</xsl:template>

</xsl:stylesheet>
     

     ---

     
     Tech. Notes
     
     • "rdf:Description[@rdf:about]" and "rdf:Description[@rdf:nodeID]"
       simply naming the attribute in the predicate (instead of comparing its value) means "selecting those Desc. that have such an attr.
       
       
     • Use of an <xsl:variable>
       This is not a variable in the ususal sense of  (imperative) programming : its value cannot change !
       It is more like the "let var=expr in { sequence }" construct of functional languages.
       
       In our example, it is necessary to remember the value of the XPath expr. "vcard:N/@rdf:nodeID" in the orignal Description node
       in order to test the value of "@rdf:nodeID" in other Description nodes.