In the following example, I would like to determine the "nesting level" of a node with an XPath (2.0) expression. This "nesting level" would be the number of consecutive descendants, e.g. if "span/span/span" exists, it would be 3. The expected nesting levels are given in comments:
<?xml version="1.0" encoding="UTF-8"?>
<text>
<div>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget
dolor. Aenean massa.
<span><!--nesting level:2-->Cum sociis natoque penatibus et magnis dis parturient montes,
nascetur ridiculus mus.
<span><!--nesting levels:1-->Donec quam felis, ultricies nec, pellentesque eu, pretium quis, sem.
<span><!--nesting levels:0-->Nulla consequat massa quis enim.</span>
</span>
<span><!--nesting levels:0-->Donec pede justo, fringilla vel, aliquet nec, vulputate eget, arcu.</span>
In enim justo, rhoncus ut, imperdiet a, venenatis vitae, justo.
</span>
<span><!--nesting levels:0-->Nullam dictum felis eu pede mollis pretium. Integer tincidunt. Cras dapibus. Vivamus
elementum semper nisi.
</span>
<span><!--nesting levels:0-->Aenean vulputate eleifend tellus. Aenean leo ligula,
porttitor eu, consequat vitae, eleifend ac, enim. Aliquam lorem ante, dapibus in, viverra
quis, feugiat a, tellus.
</span>
</div>
<div>Phasellus viverra nulla ut metus varius laoreet.
<span><!--nesting levels:0-->Quisque rutrum. Aenean imperdiet. Etiam ultricies nisi vel augue.
</span>
<span><!--nesting levels:2-->Curabitur ullamcorper ultricies nisi.
<span><!--nesting levels:0-->Nam eget dui.</span>
Etiam rhoncus.
<span><!--nesting levels:1-->Maecenas tempus, tellus eget condimentum rhoncus, sem quam semper libero, sit amet
adipiscing sem neque sed ipsum.
<span><!--nesting levels:0-->Nam quam nunc, blandit vel, luctus pulvinar, hendrerit id, lorem.</span>
<span><!--nesting levels:0-->Maecenas nec odio et ante tincidunt tempus.</span>
Donec vitae sapien ut libero venenatis faucibus.
<span><!--nesting levels:0-->Nullam quis ante.</span>
</span>
Etiam sit amet orci eget eros faucibus tincidunt. Duis leo. Sed fringilla mauris sit amet
nibh.
</span>
Donec sodales sagittis magna.
</div>
</text>
Now, I tried count(descendant::span)), but obviously, this will include also any siblings and produce a wrong result in many cases. I also tried count(descendant::span[1])) and count(descendant::span[position() = 1])), which also gave erraneous results. I could not yet figure out how to exclude the number of siblings from the total. Any hint is appreciated.
Within XSLT I get the right values with the expression
max(
for $leaf in descendant-or-self::span[not(span)]
return count($leaf/ancestor-or-self::span except ancestor-or-self::span)
)
for example with the stylesheet
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
exclude-result-prefixes="xs"
version="2.0">
<xsl:template match="@* | node()">
<xsl:copy>
<xsl:apply-templates select="@* | node()"/>
</xsl:copy>
</xsl:template>
<xsl:template match="span">
<xsl:copy>
<xsl:attribute name="nesting-level"
select="
max(
for $leaf in descendant-or-self::span[not(span)]
return count($leaf/ancestor-or-self::span except ancestor-or-self::span)
)"/>
<xsl:apply-templates select="@* | node()"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
I get the output
<?xml version="1.0" encoding="UTF-8"?><text>
<div>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget
dolor. Aenean massa.
<span nesting-level="2"><!--nesting level:2-->Cum sociis natoque penatibus et magnis dis parturient montes,
nascetur ridiculus mus.
<span nesting-level="1"><!--nesting levels:1-->Donec quam felis, ultricies nec, pellentesque eu, pretium quis, sem.
<span nesting-level="0"><!--nesting levels:0-->Nulla consequat massa quis enim.</span>
</span>
<span nesting-level="0"><!--nesting levels:0-->Donec pede justo, fringilla vel, aliquet nec, vulputate eget, arcu.</span>
In enim justo, rhoncus ut, imperdiet a, venenatis vitae, justo.
</span>
<span nesting-level="0"><!--nesting levels:0-->Nullam dictum felis eu pede mollis pretium. Integer tincidunt. Cras dapibus. Vivamus
elementum semper nisi.
</span>
<span nesting-level="0"><!--nesting levels:0-->Aenean vulputate eleifend tellus. Aenean leo ligula,
porttitor eu, consequat vitae, eleifend ac, enim. Aliquam lorem ante, dapibus in, viverra
quis, feugiat a, tellus.
</span>
</div>
<div>Phasellus viverra nulla ut metus varius laoreet.
<span nesting-level="0"><!--nesting levels:0-->Quisque rutrum. Aenean imperdiet. Etiam ultricies nisi vel augue.
</span>
<span nesting-level="2"><!--nesting levels:2-->Curabitur ullamcorper ultricies nisi.
<span nesting-level="0"><!--nesting levels:0-->Nam eget dui.</span>
Etiam rhoncus.
<span nesting-level="1"><!--nesting levels:1-->Maecenas tempus, tellus eget condimentum rhoncus, sem quam semper libero, sit amet
adipiscing sem neque sed ipsum.
<span nesting-level="0"><!--nesting levels:0-->Nam quam nunc, blandit vel, luctus pulvinar, hendrerit id, lorem.</span>
<span nesting-level="0"><!--nesting levels:0-->Maecenas nec odio et ante tincidunt tempus.</span>
Donec vitae sapien ut libero venenatis faucibus.
<span nesting-level="0"><!--nesting levels:0-->Nullam quis ante.</span>
</span>
Etiam sit amet orci eget eros faucibus tincidunt. Duis leo. Sed fringilla mauris sit amet
nibh.
</span>
Donec sodales sagittis magna.
</div>
</text>