To add to this,



At 04:22 PM 3/1/2005, David wrote:
Still I'll avoid answering that (because explaining the 2 pass version
is easier:-)first do an identity template

<xsl:template match="*">
<xsl:copy>
<xsl:copy-of select="@*"/>
<xsl:apply-templates/>
</xsl:copy>
</xsl:template>

Then add a template to work out your sorting key which is, I think



<xsl:template match"b">
<xsl:copy-of select="@*"/>
<xsl:variable name="x">
<xsl:copy-of select=".//desc"/>
</xsl:variable>
<b sort="$x">
<xsl:apply-templates/>
</b>
</xsl:template>

that's all you need the first transform, now you have an intermediate
file that's like your original except every b has a sort attribute.
Now you can just sort/group on that as usual as described in
www.jenitennison.com/xslt/grouping.
You are in a better situation now as your grouping key is just a singke
Xpath @sort.

If you are doing this from java you should be able to avoid the costs of
writing out the intermediate document as a file and parsing it back
again and just pass it as an in memory object from the first transform
to the next. The details of that depend on the API you are using (and
anyway there are others who can tell you a lot more about java.

I'll fill in a bit by adding that two passes can be accomplished in a 
single run of a stylesheet, if you use either XSLT version 2.0, or a very 
popular extension function in XSLT 1.0, usually called node-set().



The node-set() extension is popular enough almost to be official, and for 
an extension, it's very portable: see http://www.exslt.org. The idea here 
is that you would bind the results of the first pass to a variable, use the 
extension function to convert it from a result tree (which, in XSLT 1.0, 
you cannot process further as such, merely copy it or process it as a 
string), and then process the node set you get back as input to your second 
pass. Putting two transforms together like this into a single stylesheet, 
it's probably wise to use modes to disciminate the passes and keep yourself 
from going nuts.



I hope that helps,
Wendell


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Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
Mulberry Technologies, Inc.                http://www.mulberrytech.com
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Suite 207                                          Phone: 301/315-9631
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