Re: [xsl] Does <xsl:copy> use a lot of memory? Is there an alternative that is more efficient?

Subject: Re: [xsl] Does <xsl:copy> use a lot of memory? Is there an alternative that is more efficient?
From: David Carlisle <davidc@xxxxxxxxx>
Date: Mon, 03 Sep 2012 17:58:30 +0200
I suspect Michael just posted something equivalent or better or whatever but

<x>
   <b id="i1">aaa</b>
   <b idref="i1"/>
   <b id="i2">kkk <c idref="i3"/></b>
   <b> aaa <c idref="i2"/></b>
   <b id="i3"> aaa <c idref="i2"/></b>
</x>

processed with

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>

<xsl:key name="id" match="*[@id]" use="@id"/>

<xsl:template match="*">
<xsl:copy>
<xsl:copy-of select="@* except @idref"/>
<xsl:apply-templates select="@idref,node()"/>
</xsl:copy>
</xsl:template>

<xsl:template match="@idref">
<xsl:param name="seen" tunnel="yes"/>
<xsl:choose>
<xsl:when test=".=$seen"><xsl:copy-of select="."/>
</xsl:when>
<xsl:otherwise>
<xsl:apply-templates select="key('id',.)">
<xsl:with-param name="seen" select="$seen,string(.)" tunnel="yes"/>
</xsl:apply-templates>
</xsl:otherwise>
</xsl:choose>
</xsl:template>


</xsl:stylesheet>



produces





$ saxon9 aaa.xml aaa.xsl
<?xml version="1.0" encoding="UTF-8"?><x>
<b id="i1">aaa</b>
<b><b id="i1">aaa</b></b>
<b id="i2">kkk <c><b id="i3"> aaa <c><b id="i2">kkk <c idref="i3"/></b></c></b></c></b>
<b> aaa <c><b id="i2">kkk <c><b id="i3"> aaa <c idref="i2"/></b></c></b></c></b>
<b id="i3"> aaa <c><b id="i2">kkk <c><b id="i3"> aaa <c idref="i2"/></b></c></b></c></b>
</x>




where idrefs have been expanded out unless you are already in the the descendants of its expansion in which case it is left as a ref.

David


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