Subject: [xsl] Accessing input document from extension function loop (XSL 1.0) From: Michael Ludwig <mlu@xxxxxxxxxxxxx> Date: Fri, 15 Feb 2008 12:57:10 +0100 |
This question is related to content generated by extension functions and the context I'm in when using this content in a loop. The example requires EXSLT support, particularly support for the str:split function from "http://exslt.org/strings".
<Channels> <Ch ID="ard">ARD</Ch> <Ch ID="zdf">ZDF</Ch> </Channels>
<?xml version="1.0" encoding="UTF-8"?> <xsl:stylesheet version="1.0" xmlns:php="http://php.net/xsl" exclude-result-prefixes="php" xmlns:str="http://exslt.org/strings" extension-element-prefixes="str" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="Channels"> <Urmel> <U1> <xsl:for-each select="/Channels/Ch/@ID"> <xsl:call-template name="tests"/> </xsl:for-each> </U1> <!-- PHP example <U2> <xsl:for-each select="php:function('gen_nodes', 'ard zdf')/*"> <xsl:call-template name="tests"/> </xsl:for-each> </U2> --> <U3> <xsl:for-each select="str:split('ard zdf')"> <xsl:call-template name="tests"/> </xsl:for-each> </U3> </Urmel> </xsl:template>
<xsl:template name="tests"> <T1><xsl:copy-of select="."/></T1><!-- works as expected --> <T2><xsl:value-of select="."/></T2><!-- ditto --> <!-- T3 doesn't work for U2 and U3. --> <Cur><xsl:value-of select="current()"/></Cur> <T3><xsl:value-of select="/Channels/Ch[ @ID = current() ]"/></T3> <!-- Trying to use a variable in T4 doesn't work either. --> <xsl:variable name="current" select="."/> <Var><xsl:value-of select="$current"/></Var> <T4><xsl:value-of select="/Channels/Ch[ @ID = $current ]"/></T4> </xsl:template>
What am I trying to do here? I am doing a lookup using a string value, which is either 'ard' or 'zdf'. Of course, this lookup is trivial, but triviality here is for the sake of the example.
The interesting part is where I get this string value from. There are three cases: U1, U2 (requiring PHP, commented out) and U3 (requiring EXSLT).
In U2 (commented out) and U3, I get the string from an extension function, either EXSLT or PHP. And here's the problem, showing up in T3 and T4. (T1 and T2 work as expected and are there to show what's going on.) From inside the xsl:for-each loop using the content generated by the extension function, I don't seem to be able to access my original input document. Am I mistaken here or is this assumption correct?
And is there a remedy? What do I have to do to profit from extension functions in the way I'm trying to do while maintaining my ability to access the input document?
libxslt Version => 1.1.20 libxslt compiled against libxml Version => 2.6.27 libexslt Version => 1.1.20
Optionally, you may comment in the <U2> example and observe the same thing as in <U3> when processing the stylesheet using the following PHP program, "ef.php":
<?php function gen_nodes($str) { $doc = new DOMDocument; $root = $doc->appendChild($doc->createElement('Moin')); foreach (explode(' ', $str) as $s) $root->appendChild($doc->createElement('Tach')) ->appendChild($doc->createTextNode($s)); return $doc->documentElement; } $docstr = <<<EOS <Channels> <Ch ID="ard">ARD</Ch> <Ch ID="zdf">ZDF</Ch> </Channels> EOS; $Xsl = new XSLTProcessor(); $Xsl->registerPHPFunctions(); $Doc = new DOMDocument(); $Doc->loadXML($docstr); $xsldoc = new DOMDocument(); $xsldoc->load('extension-function.xsl'); $Xsl->importStyleSheet($xsldoc); echo $Xsl->transformToXML($Doc);
I have asked this question on the very low-traffic EXSLT list before but the answer hasn't clarified things for me.
[exslt] EXSLT str:split() and evaluation context http://lists.fourthought.com/pipermail/exslt/2007-September/001597.html http://lists.fourthought.com/pipermail/exslt/2007-October/001600.html
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