<tschwartz@r...> wrote in message 
news:1167950447.064161.294510@1......
>I have an xml document in which elements are hierarchically related to
> eachother conceptually.  Unfortunately, the hierarchical relationship
> is not modelled in the schema (i.e., the elements are "flattened" in
> the document".  I have a case in which I want to remove a high level
> element using xslt and want all the related lower-level elements to be
> removed as well. Is there an easy way to do this in a template?
>
> For example, imagine a relationship of elements describing animals
> starting with "animal" at the top of the hierarchy and ending in "pets"
> at the bottom:
>
> animal => class => beastie => breed => pet
>
> Given the xml below, say I wanted to remove the class named "Aves" and
> wanted  to cause a cascading removal of all other elements related to
> "Aves".  Is there a simple way to do this using xsl that helps me avoid
> writing specific templates for each child node of "animals"?
>
> <?xml version="1.0" encoding="utf-8"?>
> <animals>
>
>   <classes>
>      <class name="Mammalia"/>
>      <class name="Aves"/>
>   </classes>
>
>   <beasties>
>      <beast type="cat" class="Mammalia"/>
>      <beast type="dog" class="Mammalia"/>
>      <beast type="bird" class="Aves"/>
>   </beasties>
>
>   <breeds>
>      <breed name="collie" type="dog"/>
>      <breed name="beagle" type="dog"/>
>      <breed name="persian" type="cat"/>
>      <breed name="siamese" type="cat"/>
>      <breed name="parakeet" type="bird"/>
>      <breed name="crow" type="bird"/>
>   </breeds>
>
>   <pets>
>      <pet name="rover" breed="collie"/>
>      <pet name="fluffy" breed="persian"/>
>      <pet name="tweety" breed="parakeet"/>
>   </pets>
>
> </animals>
>
> The desired xml output would be this:
>
> <?xml version="1.0" encoding="utf-8"?>
> <animals>
>
>   <classes>
>      <class name="Mammalia"/>
>   </classes>
>
>   <beasties>
>      <beast type="cat" class="Mammalia"/>
>      <beast type="dog" class="Mammalia"/>
>   </beasties>
>
>   <breeds>
>      <breed name="collie" type="dog"/>
>      <breed name="beagle" type="dog"/>
>      <breed name="persian" type="cat"/>
>      <breed name="siamese" type="cat"/>
>   </breeds>
>
>   <pets>
>      <pet name="rover" breed="collie"/>
>      <pet name="fluffy" breed="persian"/>
>   </pets>
>
> </animals>


XSLT 1.0 solution (49 lines):

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>
 <xsl:strip-space elements="*"/>

 <xsl:param name="pClassToDel" select="'Aves'"/>

 <xsl:key name="kBeastByType" match="beast"
    use="@type"/>

 <xsl:key name="kBreedByName" match="breed"
  use="@name"/>

  <xsl:template match="node()|@*" name="identity">
    <xsl:copy>
      <xsl:apply-templates select="node()|@*"/>
    </xsl:copy>
  </xsl:template>

  <xsl:template match="class">
    <xsl:if test="not(@name = $pClassToDel)">
      <xsl:call-template name="identity"/>
    </xsl:if>
  </xsl:template>

  <xsl:template match="beast">
    <xsl:if test="not(@class = $pClassToDel)">
      <xsl:call-template name="identity"/>
    </xsl:if>
  </xsl:template>

  <xsl:template match="breed">
    <xsl:if test=
      "not(key('kBeastByType', @type)/@class = $pClassToDel)">
      <xsl:call-template name="identity"/>
    </xsl:if>
  </xsl:template>

  <xsl:template match="pet">
    <xsl:if test=
      "not(key('kBeastByType',
                key('kBreedByName', @breed)/@type
                )/@class
          =
            $pClassToDel)">
      <xsl:call-template name="identity"/>
    </xsl:if>
  </xsl:template>

</xsl:stylesheet>

Output:

<animals>
  <classes>
    <class name="Mammalia" />
  </classes>
  <beasties>
    <beast type="cat" class="Mammalia" />
    <beast type="dog" class="Mammalia" />
  </beasties>
  <breeds>
    <breed name="collie" type="dog" />
    <breed name="beagle" type="dog" />
    <breed name="persian" type="cat" />
    <breed name="siamese" type="cat" />
  </breeds>
  <pets>
    <pet name="rover" breed="collie" />
    <pet name="fluffy" breed="persian" />
  </pets>
</animals>

XSLT 2.0 solution (40 lines):

<xsl:stylesheet version="2.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  exclude-result-prefixes="xs"
 >
 <xsl:output omit-xml-declaration="yes" indent="yes"/>
 <xsl:strip-space elements="*"/>

 <xsl:param name="pClassToDel" select="'Aves'"/>

 <xsl:key name="kDeleted" match="beast"
  use="string(@class = $pClassToDel)"/>

 <xsl:key name="kDeleted" match="class"
  use="string(@name = $pClassToDel)"/>

 <xsl:key name="kDeleted" match="breed"
  use="string(key('kBeastByType',@type)/@class = $pClassToDel)"/>

 <xsl:key name="kDeleted" match="pet"
  use="string(key('kBeastByType',
                   key('kBreedByName',@breed)/@type
                   )
                    /@class
             =
              $pClassToDel)"/>

 <xsl:key name="kBeastByType" match="beast"
    use="@type"/>

 <xsl:key name="kBreedByName" match="breed"
  use="@name"/>

  <xsl:template match="node()|@*" name="identity">
    <xsl:copy>
      <xsl:apply-templates select="node()|@*"/>
    </xsl:copy>
  </xsl:template>

  <xsl:template match="*[. intersect key('kDeleted', 'true')]"/>
</xsl:stylesheet>

Output:
<animals>
   <classes>
      <class name="Mammalia"/>
   </classes>
   <beasties>
      <beast type="cat" class="Mammalia"/>
      <beast type="dog" class="Mammalia"/>
   </beasties>
   <breeds>
      <breed name="collie" type="dog"/>
      <breed name="beagle" type="dog"/>
      <breed name="persian" type="cat"/>
      <breed name="siamese" type="cat"/>
   </breeds>
   <pets>
      <pet name="rover" breed="collie"/>
      <pet name="fluffy" breed="persian"/>
   </pets>
</animals>

Hope this helped.

Cheers,
Dimitre Novatchev