We have fixed this problem as part of the resolution of this bug:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=27051
Sorry, but the discussion contains a number of links to member-only email
archives.
Abel pointed out in the bug report that we had made unintentional changes with
the consequence that <xsl:apply-templates select="@*"/> was no longer
streamable. The fix we adopted changes the posture of the expression @* from
climbing to striding. Saxon 9.6 implements the "unintentional changes".
Of course, in XSLT 3.0 you no longer need the identity template. You can
instead write
<xsl:mode on-no-match="shallow-copy"/>
A workaround for Saxon 9.6 is to apply-templates to copies of attributes made
using copy-of().
Michael Kay
Saxonica
mike(_at_)saxonica(_dot_)com
+44 (0) 118 946 5893
On 25 Jan 2015, at 15:14, Martin Honnen martin(_dot_)honnen(_at_)gmx(_dot_)de
<xsl-list-service(_at_)lists(_dot_)mulberrytech(_dot_)com> wrote:
I am wondering how one would write the identity transformation template
<xsl:template match="@* | node()">
<xsl:copy>
<xsl:apply-templates select="@* | node()"/>
</xsl:copy>
</xsl:template>
in an XSLT 3.0 stylesheet supposed to work with streaming. The section
http://www.w3.org/TR/xslt-30/#built-in-templates-shallow-copy in the XSLT 3.0
specification has a template
<xsl:template match="." mode="M">
<xsl:copy validation="preserve">
<xsl:apply-templates select="@*" mode="M"/>
<xsl:apply-templates select="node()" mode="M"/>
</xsl:copy>
</xsl:template>
and explains "A further reason for choosing this form is for streamability:
this formulation is guaranteed-streamable".
However, when I try
<xsl:stylesheet version="3.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
exclude-result-prefixes="xs">
<xsl:mode streamable="yes"/>
<xsl:template match=".">
<xsl:copy validation="preserve">
<xsl:apply-templates select="@*"/>
<xsl:apply-templates select="node()"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
with Saxon 9.6 EE I get a compilation error saying:
Error at xsl:template on line 8 column 25 of test2015012505.xsl:
XTSE3430: Template rule is declared streamable but it does not satisfy the
streamability rules.
* In a streaming apply-templates instruction, the select expression cannot
select
ancestors or attributes (that is, it must not have climbing posture)
So how would one write a template doing a shallow copy and then processing
any attribute and child nodes in a streaming way?
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