You seem to be listing ancestor-or-self rather than ancestor, I think
you only need to go up the ancestor axis once in each case, something
like
<xsl:stylesheet version="2.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>
<xsl:template match="/">
<xsl:apply-templates select="//p"/><!-- just for testing-->
</xsl:template>
<xsl:template match="*">
<xsl:copy>
<xsl:apply-templates select="." mode="a"/>
</xsl:copy>
</xsl:template>
<xsl:template match="*" mode="a">
<xsl:param name="trail" select="()"/>
<xsl:apply-templates select="parent::*" mode="a">
<xsl:with-param name="trail" select="name(),$trail"/>
</xsl:apply-templates>
</xsl:template>
<xsl:template match="*[@id]" mode="a">
<xsl:param name="trail" select="()"/>
<xsl:copy-of select="@id,'Ancestors:', name(), $trail"/>
</xsl:template>
</xsl:stylesheet>
which makes
<p id="x13">Ancestors: bar div p</p>
On 30 August 2017 at 19:49, Michael Müller-Hillebrand mmh(_at_)docufy(_dot_)de
<xsl-list-service(_at_)lists(_dot_)mulberrytech(_dot_)com> wrote:
Hi all,
I had an embarrassing moment today, when I found that the source of a severe
performance problem was sitting in front of the screen.
Using XSLT 2.0 I am transforming elements and at many points I have to look
up the ancestor axis, but only up to an element with an attribute "id".
Basically I have a deeply nested structure of topics and I want to analyze
ancestors inside the current topic.
The nearest topic is easy to find:
<xsl:variable name="topic" select="ancestor-or-self::*[@id][1]"
as="element()"/>
And then I was doing the following to find all ancestors that share the same
"topic ancestor":
<xsl:variable name="ancestors-in-topic"
select="ancestor-or-self::*[ancestor-or-self::* = $topic]" as="element()*"/>
This did not what I expected and also wasted a lot of resources because the
predicate was true for all or most elements. After some testing I went with
this:
<xsl:variable name="ancestors-in-topic"
select="ancestor-or-self::*[ancestor-or-self::*/generate-id() =
generate-id($topic)]" as="element()*"/>
Since that calculation is done very often I am wondering if xsl:key could be
used to speed things up?
Any pointers are very welcome, as always, thanks,
- Michael
PS: My sample XML and XSLT below.
<?xml version="1.0" encoding="UTF-8"?>
<bars id="x0">
<bar id="x1">
<bar id="x11">
<bar id="x12">
<div>
<bar id="x13">
<div>
<p/>
</div>
</bar>
</div>
</bar>
</bar>
</bar>
</bars>
<?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"; version="2.0">
<xsl:output method="xml" indent="yes" omit-xml-declaration="no"/>
<xsl:strip-space elements="*"/>
<xsl:template match="p">
<xsl:variable name="topic" select="ancestor-or-self::*[@id][1]"
as="element()"/>
<xsl:variable name="ancestors-in-topic"
select="ancestor-or-self::*[ancestor-or-self::*/generate-id() =
generate-id($topic)]" as="element()*"/>
<xsl:copy>
<xsl:attribute name="topic" select="$topic/@id"/>
<xsl:text>Ancestors: </xsl:text>
<xsl:sequence select="$ancestors-in-topic/name()"/>
</xsl:copy>
</xsl:template>
<xsl:template match="* | @*">
<xsl:copy>
<xsl:apply-templates select="@*, node()"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
Expected output for <p>: <p topic="x13">Ancestors: bar div p</p>
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