Nested grouping based on parent field using XSLT

Question

This is a sample of the raw XML I'm working with:

<dsQueryResponse>
  <Rows>
    <Row Title="Animal" Parent="" />
    <Row Title="Mammal" Parent="Animal" />
    <Row Title="Lion" Parent="Mammal" />
    <Row Title="Plant" Parent="" />
    <Row Title="Elephant" Parent="Mammal" />
  </Rows>
</dsQueryResponse>

Using XSLT, how do I get the output to be a nested UL like:

<ul>
  <li>
    Animal
    <ul>
      <li>
        Mammal
        <ul>
          <li>Elephant</li>
          <li>Lion</li>
        </ul>
      </li>
    </ul>
  </li>
  <li>Plant</li>
</ul>

_{I'm only "okay" with XSLT and can only do simple sorting, and I know I can do this easily through JavaScript/jQuery, but I'd rather use XSLT for this.}

Answer 1

Try this XSLT:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="xml" indent="yes"/>

  <xsl:template match="/">
    <ul>
      <xsl:apply-templates select="//Row[@Parent = '']"/>
    </ul>
  </xsl:template>

  <xsl:template match="Row">
    <li>
      <xsl:value-of select="@Title"/>

      <xsl:if test="../Row[@Parent = current()/@Title]">
        <ul>
          <xsl:apply-templates select="../Row[@Parent = current()/@Title]"/>
        </ul>
      </xsl:if>
    </li>
  </xsl:template>
</xsl:stylesheet>

Output:

<ul>
  <li>
    Animal<ul>
      <li>
        Mammal<ul>
          <li>Lion</li>
          <li>Elephant</li>
        </ul>
      </li>
    </ul>
  </li>
  <li>Plant</li>
</ul>