<li1>test1</li1>
<li3>test3</li3>

<ul level="1">
 <li tag="li1" pos="1">test1</li>
 <ul level="2">
    <ul level="3">
       <li tag="li3" pos="1">test3</li>
    </ul>
 </ul>
</ul>

   <xsl:template match="p" mode="new">
       <xsl:copy />
       <xsl:apply-templates select="following-sibling::*[1]" mode="new" />
   </xsl:template>

   <!-- true for a node of type <liX> where X is a number -->
   <xsl:function name="fn:is-li">
       <xsl:param name="node" />
       <xsl:sequence select="starts-with(local-name($node), 'li')" />
   </xsl:function>

Hello,

I have a working stylesheet, but it uses modes when I think it could be a bit slimmer and maybe more flexible.

The task is to create list containers (<ul>) around list elements in a flat element tree. I tried to follow Jeni Tennison's advice for constructing hierarchies <http://jenitennison.com/xslt/hierarchies-out.xml> and also evaluated xsl:for-each-group, but the latter seems not to work very well for a stylesheet in push mode (no changes to the element order).

To correctly group the <li1>s and <li2>s (even in the third case) in this example I successfully used the XSL below. I found no good enough example in the FAQs, so I dare to ask, whether there is a more elegant solution. (I simplified the case, in reality there are multiple elements that are either level 1 or level 2 list elements, and I do not use starts-with() to detect element names.)

Any advice is greatly appreciated!

- Michael M|ller-Hillebrand

<?xml version="1.0" encoding="UTF-8"?>
<levels>
<p/>
<li1>1</li1>
<li1>2</li1>
<li1>3</li1>
<li1>4</li1>
<p/>
<li1>5</li1>
<li1>6</li1>
<li2>7.1</li2>
<li2>7.2</li2>
<p/>
<li2>8.1</li2>
<li2>8.2</li2>
<li1>9</li1>
<li1>10</li1>
<p/>
</levels>

---------

<xsl:stylesheet version="2.0"
                xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:strip-space elements="*"/>
<xsl:output method="xml" indent="yes" />

<!-- Root element -->
<xsl:template match="levels">
  <xsl:copy>
    <xsl:apply-templates />
  </xsl:copy>
</xsl:template>

<!-- Keys to identify list elements after first element -->
<xsl:key name="list12-other"
  match="*[self::*[starts-with(name(), 'li')]
    and preceding-sibling::*[1][starts-with(name(), 'li')]]"
  use="generate-id(
    preceding-sibling::*[
      starts-with(name(), 'li')
      and not(preceding-sibling::*[1][starts-with(name(), 'li')])
    ][1])" />

<xsl:key name="list2-other"
  match="li2[preceding-sibling::*[1][self::li2]]"
  use="generate-id(
    preceding-sibling::li2[
      not(preceding-sibling::*[1][self::li2])
    ][1])" />

<!-- List 1 Container-->
<xsl:template match="*[starts-with(name(), 'li')
and not(preceding-sibling::*[1][starts-with(name(), 'li')])]" priority="1">
<ul level="1">
<xsl:apply-templates mode="list1"
select=". | key('list12-other', generate-id())" />
</ul>
</xsl:template>
<!-- List 1 elements -->
<xsl:template match="li1" mode="list1">
<li tag="{name()}" pos="{position()}">
<xsl:apply-templates />
</li>
</xsl:template>

<!-- or List 2 Container-->
<xsl:template match="li2[not(preceding-sibling::*[1][self::li2])]"
  mode="list1" priority="1">
  <ul level="2">
    <xsl:apply-templates mode="list2"
      select=". | key('list2-other', generate-id())" />
  </ul>
</xsl:template>
<!-- List 2 elements -->
<xsl:template match="li2" mode="list2">
  <li tag="{name()}" pos="{position()}">
    <xsl:apply-templates />
  </li>
</xsl:template>

<!-- skip list elements when matched outside list -->
<xsl:template match="li2" mode="list1"/>
<xsl:template match="*[starts-with(name(), 'li')]"/>

<!-- all other nodes -->
<xsl:template match="node()">
  <xsl:copy>
    <xsl:apply-templates />
  </xsl:copy>
</xsl:template>

</xsl:stylesheet>