Scope of variables in XSL templates (Cocoon, Xalan, ...)

[Frank Olsen <fo...@acm.org>]

Hi,

I wonder if anyone could please help me with an XSLT problem. For
reference: I use Cocoon 1.7.4 (with the versions of Xalan, Xerces, etc.
furnished with Cocoon ) under WebSphere 3.0.2.1.

I'm trying to find a way to navigate in a result set from a DB query;
i.e., I want to present the results to the user in packets of, say, 10.
I use a Cocoon custom producer to send the query and to send the XML
result set to an XSL stylesheet, the relevant portion of which is given
here:

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

  <xsl:import href="common.xsl"/>

  <xsl:template match="QueryResults">
    <xsl:variable name="numToDisplay"><xsl:value-of
select="../parameters/numToDisplay" /></xsl:variable>
    <xsl:variable name="lastNumDisplayed"><xsl:value-of
select="../parameters/lastNumDisplayed" /></xsl:variable>
    <xsl:variable name="direction"><xsl:value-of
select="../parameters/direction" /></xsl:variable>

    <!-- some HTML -->

    <table>
    <!-- table header -->

    <xsl:choose>
      <!-- 2 when clauses for the direction of navigation -->
      <xsl:otherwise>
        <xsl:apply-templates select="child::ResultVector[position()
&gt;= 1 and position() &lt; $numToDisplay]" />
      </xsl:otherwise>
    </xsl:choose>

    </table>

  </xsl:template>

  <xsl:template match="ResultVector">
  <!-- fill in the records from the vector -->
  </xsl:template>

I've focussed on the xsl:otherwise clause, since it is the first to be
invoked (I don't set the 'direction' parameter the first time.

The problem is that $numToDisplay is out of scope (or...?):

  pattern = 'child::SearchCustomerVector[position() >= 1 and position()
< $numToDisplay]'
      VariableReference given for variable out of context or without
definition!  Name = numToDisplay
              at org.apache.xalan.xslt.XSLTEngineImpl.error
(XSLTEngineImpl.java:1630)

I'm able to use $numToDisplay to set another variable on the same level
as the <xsl:apply-templates ... /> and to print it to the HTML output.

Do you have any idea what causes this? Have I misunderstood the scoping
rules for variables?

There are probably other ways of doing what I want -- since I'm new to
XML, XSL, ... I tried this way...

In advance, thanks a lot!!!

Regards,

Frank Olsen