[xsl] Hierearchy navigation in XSL

[Scott Bronson <bronson@xxxxxxxxxxx>]

Hello.  I've solved most of this problem, but the last tiny bit has me
stumped.  I'm hoping someone can tell me how to fix this.

Here's some input:


<masterdoc>
  <class name="Object"       namespace="System"/>
  <class name="Array"        namespace="System"/>
  <class name="ArrayList"    namespace="System.Collections"/>
  <class name="Comparer"     namespace="System.Collections"/>
  <class name="Grimey"       namespace="System.Collections.Overkill"/>
  <class name="Formatter"    namespace="System.Runtime.Serialization"/>
  <class name="ObjectHandle" namespace="System.Runtime.Remoting"/>
  <class name="Garbage"      namespace="Other.SubAPI"/>
</masterdoc>


My script accepts a parameter that tells where it is in the hierarchy. 
It then outputs all immediate child nodes at that level in the
hierarchy.

Some examples: if we're at "System", the script should output
"Collections" and "Runtime".  If we're at "System.Collections", it
should output "Overkill".  If we're at "", it should output "System" and
"Other".  If at "Other", output "SubAPI".  Seems a fairly easy problem,
right?



Here's my script right now:


<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
version="1.0">
<xsl:output method="text"/>
<xsl:param name="ns"/>
<xsl:key name='uniq' match='class' use='@namespace'/>

<xsl:template match="/masterdoc">
  <xsl:for-each
select="class[generate-id()=generate-id(key('uniq',@namespace)[1])]">
    <xsl:sort select="@namespace"/>
    <xsl:choose>
      <xsl:when test="string-length($ns)=0">
        <xsl:value-of select="@namespace"/>
      </xsl:when>
      <xsl:when test="starts-with(@namespace,concat($ns,'.'))">
        <xsl:value-of
select="substring(@namespace,string-length($ns)+2)"/>
      </xsl:when>
    </xsl:choose>
<xsl:text>
</xsl:text>
  </xsl:for-each>
</xsl:template>

</xsl:stylesheet>



Here are some example runs of this script:

xalan -Q -XSL samp1.xsl -IN sample.xml -PARAM ns "'System.Collections'"
Overkill

xalan -Q -XSL samp1.xsl -IN sample.xml -PARAM ns "'System'"
Collections
Collections.Overkill
Runtime.Remoting
Runtime.Serialization


The last one illustrates the problem.  It should have output only
"Collections" and "Runtime".

I picture the algorithm being something like:
   if(not(already copied string-before("Runtime.Remoting", "."))
      then copy string-before("Runtime.Remoting", ".") to output

I've tried various combinations of preceding, preceding sibling, and
position to try to figure out what I've already output.  I even tried
key() and using IDs to navigate the parent.  All has resulted in
frustration.

Does anyone have any idea of what I can do?  I'm out of ideas.

Thank you!

    - Scott





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