Question

I’ve been trying to transform some simple XML into another simple XML using XSLT. I am new to XSLT, so if someone could give me an example I will expand on it.

I have arbitrary XML files: e.g

<element>
 <child_element>
  <grandchild_element>
     only one
  </grandchild_element>
 </child_element>
 <child_element>
  <grandchild_element>
     one
  </grandchild_element>
  <grandchild_element>
     two
  </grandchild_element>
 </child_element>
</element>

From which I want to produce:

<tree>
 <item class="element" id="1">
  <item class="child_element" id="11">
   <item class="grandchild_element" id="111" value="only one"/>
  </item>
  <item class="child_element" id="12">
   <item class="grandchild_element" id="121" value="only one"/>
   <item class="grandchild_element" id="122" value="only one"/>
  </item>
 </item>
</tree>

Thanks!

Answer 1

One of the simplest/shortest solutions (only 3 templates no modes, no axes, no count(), only a single xsl:attribute) that is at the same time most generic (works with any element names):

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>
 <xsl:strip-space elements="*"/>

 <xsl:template match="/">
  <tree>
   <xsl:apply-templates/>
  </tree>
 </xsl:template>

 <xsl:template match="*">
  <xsl:variable name="vNumber">
   <xsl:number count="*" level="multiple"/>
  </xsl:variable>

  <item class="{name()}"
        id="{translate($vNumber, '.', '')}">
   <xsl:apply-templates/>
  </item>
 </xsl:template>

 <xsl:template match="text()">
  <xsl:attribute name="value">
   <xsl:value-of select="normalize-space()"/>
  </xsl:attribute>
 </xsl:template>
</xsl:stylesheet>

when this transformation is applied on the provided XML document:

<element>
 <child_element>
  <grandchild_element>
     only one
  </grandchild_element>
 </child_element>
 <child_element>
  <grandchild_element>
     one
  </grandchild_element>
  <grandchild_element>
     two
  </grandchild_element>
 </child_element>
</element>

the wanted, correct result is produced:

<tree>
   <item class="element" id="1">
      <item class="child_element" id="11">
         <item class="grandchild_element" id="111" value="only one"/>
      </item>
      <item class="child_element" id="12">
         <item class="grandchild_element" id="121" value="one"/>
         <item class="grandchild_element" id="122" value="two"/>
      </item>
   </item>
</tree>