Have you tried out what you propose as equivalent below?
No XSLT processor is doing what you say, xsltproc, saxon, DataPower, ...
$ saxon Graydon.1.xsl Graydon.xml ; echo
<?xml version="1.0" encoding="UTF-8"?><B/>
$
$ saxon Graydon.2.xsl Graydon.xml ; echo
<?xml version="1.0" encoding="UTF-8"?>
$
$ cat Graydon.xml
<A><a><b><c><B/></c></b></a></A>
$
$ cat Graydon.1.xsl
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
<xsl:output method="xml"/>
<xsl:template match="/">
<xsl:copy-of select="/A//B"/>
</xsl:template>
</xsl:stylesheet>
$
$ cat Graydon.2.xsl
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
<xsl:output method="xml"/>
<xsl:template match="/">
<xsl:copy-of select="B[/A]"/>
</xsl:template>
</xsl:stylesheet>
$
Mit besten Gruessen / Best wishes,
Hermann Stamm-Wilbrandt
Level 3 support for XML Compiler team, Fixpack team lead
WebSphere DataPower SOA Appliances
https://www.ibm.com/developerworks/mydeveloperworks/blogs/HermannSW/
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From: Graydon <graydon(_at_)marost(_dot_)ca>
To: xsl-list(_at_)lists(_dot_)mulberrytech(_dot_)com,
Date: 12/01/2011 12:50 AM
Subject: [xsl] XPath equivalence question
Sent by: <graydon(_at_)marost(_dot_)ca>
Does
<xsl:template match="/A//B">
match exactly the same thing as
<xsl:template match="B[/A]">?
My presumption is that the second form is preferable on efficiency
grounds -- on simple table lookup versus whatever tree-structure the
descendant axis search produces -- but I don't actually know.
-- Graydon
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