Re: [xsl] NodeTest expected here - problem with creating xsl:key from document(url)

[Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>]

Malcolm,

At 06:02 PM 8/26/2002, you wrote:
> I'm trying to create a key based on the contents of an external 'lookup' 
> document, i.e. something like:
>
> <xsl:key name="keyedLookupTable" 
> match="document('LookupTable.xml')/LookupTable/Value" use="@key"/>
>
> Is this allowed? I get a 'NodeTest expected here' error. I've tried a few 
> alternatives (e.g. first assigning the external doc to a variable then 
> using match="msxsl:node-set($myVariable) etc).

Yes, from appearances it seems your processor is balking because it wants a 
pattern as the value of the declaration's match attribute, and your 
expression (with the document() function) doesn't follow the rules for a 
pattern. A pattern matches something, but it's a passive thing -- no nodes 
are fetched; rather, the pattern merely identifies which nodes *can* match 
the key (can be returned by the key function). (Patterns are restricted to 
a subset of XPath expressions that happens to exclude the document() 
function.) Which nodes actually are returned depends not only on the value 
supplied, but also the context of the call: the scope of the call being the 
document that contains the context node for the call (the spec reads the 
key() function "returns a node-set containing the nodes in the same 
document as the context node that have a value for the named key equal to 
[the argument]"). The trick here is *same document* since in your case the 
lookup table is a different document.

The solution is to match the element with a legal pattern, such as simple 
match="Value" or match="LookupTable/Value"; then when you call the key, you 
need to establish your lookup table document as the context for the call. 
So for example you could try something like:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>

<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>

<xsl:key name="keyedLookupTable" match="LookupTable/Value" use="@key"/>

<xsl:variable name="Lookup" select="document('LookupTable.xml')"/>

<xsl:template match="/">
  <Output>
    <xsl:for-each select="/Data/key">
      <xsl:variable name="currentKey" select="."/>
      <xsl:variable name="lookupValue">
        <xsl:for-each select="$Lookup">
        <!-- this for-each does nothing but change the context node for us -->
           <xsl:value-of select="key('keyedLookupTable' , $currentKey)"/>
        </xsl:for-each>
      </xsl:variable>
      <data>
        <xsl:value-of select="$lookupValue"/>
      </data>
    </xsl:for-each>
  </Output>
</xsl:template>

</xsl:stylesheet>

Post again if this doesn't work, if my explanation has only served to 
mystify you, or if I've totally bollixed up what you need.

Cheers,
Wendell


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Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
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