I am using XSLT to walk through an XML Schema to construct an Xforms
(output) instance.
In parallel I am scanning an (input) instance (of a document defined
by the schema) to
include default values in the form.

Scanning of the input instance is done by means of a variable that
keeps track of the
path. The variable is updated (renewed) each time a template is
(recursively) called with
the variable as parameter:

<xsl:with-param name="instance.path"
select="concat($instance.path,'/',$element.prefix,':',@name)" />

The template calls another template that writes the output instance.
In that template I
try to look up the default value in the input instance (an external document).

BUT:

<xsl:value-of select="document('file:/C:/dir/order.xml')/$instance.path" />
writes a path string to the output instance instead of the value of
the element, such as:
/rsm:PurchaseOrder/rsm:Identifier, so does copy-of select.

<xsl:value-of select="document('file:/C:/dir/order.xml')//rsm:DeliveryDate" />
writes correctly the content of the delivery date, but
<xsl:value-of select="document('file:/C:/dir/order.xml')//$deldate" />
(where $deldate contains the string "rsm:DeliveryDate") writes nothing.

Concluding the problem is node-format vs text format, I tried the
saxon evaluate
function, but:
<xsl:copy-of
select="saxon:evaluate(document('file:/C:/dir/order.xml')/$instance.path)"
/>
writes nothing, neither does value-of.

I am desperate. Does anyone have a clue how to solve this?

 <xsl:value-of select="document('file:/C:/dir/order.xml')/
                       key('myTable',$instance.path))"/>

T:\ftemp>type fred.xml
<a xmlns="urn:x-fred">
  <b>B1</b>
  <c>C1</c>
  <b>B2</b>
  <d>
    <e>E1</e>
  </d>
</a>
T:\ftemp>type fred-default.xml
<f:a xmlns:f="urn:x-fred">
  <f:b>def-B1</f:b>
  <f:c>def-C1</f:c>
  <f:b>def-B2</f:b>
  <f:d>
    <f:e>def-E1</f:e>
  </f:d>
</f:a>
T:\ftemp>call xslt2 fred.xml fred.xsl
<?xml version="1.0" encoding="UTF-8"?><a xmlns="urn:x-fred">
  <b>def-B1</b>
  <c>def-C1</c>
  <b>def-B2</b>
  <d>
    <e>def-E1</e>
  </d>
</a>
T:\ftemp>type fred.xsl
<?xml version="1.0" encoding="US-ASCII"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                xmlns:f="urn:x-fred"
                version="2.0">

<!--walk the element tree-->
<xsl:template match="*">
  <xsl:param name="path"/>
  <!--determine the path to this element-->
  <xsl:variable name="this-path"
                select="concat($path,f:make-step(.))"/>
  <!--preserve the element structure-->
  <xsl:copy>
    <!--preserve any attributes-->
    <xsl:apply-templates select="@*"/>
    <!--replace the value when there are no element children-->
    <xsl:choose>
      <xsl:when test="not(*)">
        <!--at a leaf element-->
        <xsl:value-of select="document('fred-default.xml')/
                              key('paths',$this-path)"/>
      </xsl:when>
      <xsl:otherwise>
        <!--at a branch element, keep going-->
        <xsl:apply-templates>
          <xsl:with-param name="path" select="$this-path"/>
        </xsl:apply-templates>
      </xsl:otherwise>
    </xsl:choose>
  </xsl:copy>
</xsl:template>

<!--identity for all other nodes-->
<xsl:template match="@*|comment()|processing-instruction()">
  <xsl:copy/>
</xsl:template>

<!--create a lookup key-->
<xsl:function name="f:make-path">
  <xsl:param name="element"/>
  <xsl:sequence select="string-join( for $e in $element/ancestor-or-self::*
                                     return f:make-step( $e ), '' )"/>
</xsl:function>

<xsl:function name="f:make-step">
  <xsl:param name="element"/>
  <xsl:for-each select="$element">
    <xsl:sequence select="concat('/{',namespace-uri(.),'}',local-name(.),
       '[',count(preceding-sibling::*[node-name(.)=node-name(current())])+1,
       ']')"/>
  </xsl:for-each>
</xsl:function>

--
XSLT/XSL-FO/XQuery training in Los Angeles (New dates!) 2009-06-08
Training tools: Comprehensive interactive XSLT/XPath 1.0/2.0 video
Video lesson:    http://www.youtube.com/watch?v=PrNjJCh7Ppg&fmt=18
Video overview:  http://www.youtube.com/watch?v=VTiodiij6gE&fmt=18
G. Ken Holman                 mailto:gkholman@xxxxxxxxxxxxxxxxxxxx
Crane Softwrights Ltd.          http://www.CraneSoftwrights.com/s/
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