RE: [xsl] Get XPath to Node from Node?

Subject: RE: [xsl] Get XPath to Node from Node?
From: Jeff Saylor <JSaylor@xxxxxxxxxxxxxxxxx>
Date: Mon, 8 Jan 2001 12:19:37 -0500
Dimitre,

That is an excellent piece of code - but it doesn't get me quite what I
need.  Unfortunately, it generates a path with indexes to elements:

    /root/nodeA[2]/nodeB[2]/namespace::*[local-name() = 'myNamespace']	

Unfortunately, this won't work in my application because the source document
could have elements inserted which would throw off the indexed references.
I'm fortunate in that I will be dealing with elements that have (within the
scope of their peers) unique attributes, like:

    <people>
        <person name='jeff'>
        <person name='jim'>
        <person name='joe'>
    </people>

If a user were to select person #2, I would need to be able to get 
    
    /people/person[@name='jim']

note that it's an absolute reference, not a relative one.

I will be looking at your code in some more detail to see if I can get it to
do what I need - I'm hoping to get it to sniff out the attributes of each
node up the tree and use those to build the XPath.

Any more ideas?

Cheers,

Jeff


-----Original Message-----
From: Dimitre Novatchev [mailto:dnovatchev@xxxxxxxxx]
Sent: Monday, January 08, 2001 11:37 AM
To: JSaylor@xxxxxxxxxxxxxxxxx
Cc: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
Subject: Re: [xsl] Get XPath to Node from Node? 


Jeff Saylor wrote:

> I need to be able to get the node's XPath.   Does anyone have an
> example for how to do this?  I am using MSXML 3.0.

Hi Jeff,

Below is a sample xml document and a stylesheet that takes a node-set
parameter and produces one valid XPath expression for every
member-node.

stylesheet (buildPath.xsl):
-------------------------
<xsl:stylesheet version='1.0'
xmlns:xsl='http://www.w3.org/1999/XSL/Transform'
xmlns:msxsl="urn:schemas-microsoft-com:xslt" 
>

<xsl:output method="text"/>
<xsl:variable name="theParmNodes" select="//namespace::*[local-name() =
'myNamespace']"/>
<xsl:template match="/">
  <xsl:variable name="theResult">
    <xsl:for-each select="$theParmNodes">
    <xsl:variable name="theNode" select="."/>
    <xsl:for-each select="$theNode |
$theNode/ancestor-or-self::node()[..]">
      <xsl:element name="slash">/</xsl:element>
      <xsl:choose>
        <xsl:when test="self::*">			
          <xsl:element name="nodeName">
            <xsl:value-of select="name()"/>
            <xsl:variable name="thisPosition" 
                select="count(preceding-sibling::*[name(current()) = 
                        name()])"/>
            <xsl:variable name="numFollowing" 
                select="count(following-sibling::*[name(current()) = 
                        name()])"/>
            <xsl:if test="$thisPosition + $numFollowing > 0">
              <xsl:value-of select="concat('[', $thisPosition +
                                                           1, ']')"/>
            </xsl:if>
          </xsl:element>
        </xsl:when>
        <xsl:otherwise> <!-- This node is not an element -->
          <xsl:choose>
            <xsl:when test="count(. | ../@*) = count(../@*)">	
            <!-- Attribute -->
              <xsl:element name="nodeName">
                <xsl:value-of select="concat('@',name())"/>
              </xsl:element>
            </xsl:when>		
            <xsl:when test="self::text()">	<!-- Text -->
              <xsl:element name="nodeName">
                <xsl:value-of select="'text()'"/>
                <xsl:variable name="thisPosition" 
                          select="count(preceding-sibling::text())"/>
                <xsl:variable name="numFollowing" 
                          select="count(following-sibling::text())"/>
                <xsl:if test="$thisPosition + $numFollowing > 0">
                  <xsl:value-of select="concat('[', $thisPosition + 
                                                           1, ']')"/>
                </xsl:if>
              </xsl:element>
            </xsl:when>		
            <xsl:when test="self::processing-instruction()">
            <!-- Processing Instruction -->
              <xsl:element name="nodeName">
                <xsl:value-of select="'processing-instruction()'"/>
                <xsl:variable name="thisPosition" 
                   
select="count(preceding-sibling::processing-instruction())"/>
                <xsl:variable name="numFollowing" 
                   
select="count(following-sibling::processing-instruction())"/>
                <xsl:if test="$thisPosition + $numFollowing > 0">
                  <xsl:value-of select="concat('[', $thisPosition + 
                                                            1, ']')"/>
                </xsl:if>
              </xsl:element>
            </xsl:when>		
            <xsl:when test="self::comment()">	<!-- Comment -->
              <xsl:element name="nodeName">
                <xsl:value-of select="'comment()'"/>
                <xsl:variable name="thisPosition" 
                         select="count(preceding-sibling::comment())"/>
                <xsl:variable name="numFollowing" 
                         select="count(following-sibling::comment())"/>
                <xsl:if test="$thisPosition + $numFollowing > 0">
                  <xsl:value-of select="concat('[', $thisPosition + 
                                                            1, ']')"/>
                </xsl:if>
              </xsl:element>
            </xsl:when>		
            <!-- Namespace: -->
            <xsl:when test="count(. | ../namespace::*) = 
                                               count(../namespace::*)">

              <xsl:variable name="apos">'</xsl:variable>
              <xsl:element name="nodeName">
                <xsl:value-of select="concat('namespace::*', 
                '[local-name() = ', $apos, local-name(), $apos, ']')"/>

              </xsl:element>
            </xsl:when>		
          </xsl:choose>
        </xsl:otherwise>			
      </xsl:choose>
    </xsl:for-each>
    <xsl:text>&#xA;</xsl:text>
  </xsl:for-each>
 </xsl:variable>
 <xsl:value-of select="msxsl:node-set($theResult)"/>
</xsl:template>
</xsl:stylesheet>

 
xml source (buildPath.xml):
-------------------------
<!-- top level Comment -->
<root>
    <nodeA>textA</nodeA>
 <nodeA id="nodeA-2">
  <?myProc ?>
        xxxxxxxx
  <nodeB/>
        <nodeB xmlns:myNamespace="myTestNamespace">
  <!-- Comment within /root/nodeA[2]/nodeB[2] -->
   <nodeC/>
  <!-- 2nd Comment within /root/nodeA[2]/nodeB[2] -->
        </nodeB>
        yyyyyyy
  <nodeB/>
  <?myProc2 ?>
    </nodeA>
</root>
<!-- top level Comment -->


Result:
-------
/root/nodeA[2]/nodeB[2]/namespace::*[local-name() = 'myNamespace']
/root/nodeA[2]/nodeB[2]/nodeC/namespace::*[local-name() =
'myNamespace']


Hope this helps,

Dimitre Novatchev.


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