Newbie question - grouping and subtotaling

Hi gurus,

I am just getting my feet wet with XML and XSLT. I have a problem that
requires transformation of some data that has rows (transformed into XML)
returned from a database into another XML that has the same rows, but has
additional rows that have subtotals.

The idea here is to be able to do the subtotals so that a VB program would
then simply read the XML document and display the report.

I have tried to plough through the MSXML 4.0 documentation and have tried
various things and have hit upong quite a few limitations of the XSLT
process.

e.g., if one tries to introduce an xml:key element, one cannot use
variables - isn't this a pain? I mean - if I wanted to write a generic XSLT
that could take any XML file with the appropriate data structure, shouldn't
I be able to apply a generic transform to convert it to another look? Isn't
that the function of XSLT?

Bear with me - I will explain my gripes.

The sample XML that I have is:

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="lib_cat2.xsl"?>
<catalog>
 <group_params>
  <outer_category>book</outer_category>
  <subtotal>price</subtotal>
  <category_level1>genre</category_level1>
  <category_level2>author</category_level2>
 </group_params>
 <book id="bk101">
  <author>Gambardella, Matthew</author>
  <title>XML Developer's Guide</title>
  <genre>Computer</genre>
  <price>44.95</price>
  <publish_date>2000-10-01</publish_date>
  <description>An in-depth look at creating applications
      with XML.</description>
 </book>


I want to be able to process ANY XML with this generic format - i.e, with
the <group_params> tag followed by various groupings, followed by the actual
data.

I tried to extend the lib_cat2.xsl example that comes with the MSXML 4.0
developer's kit - and hit upon the variables limitation. The next idea was
to use parameters - but that means the XSLT has already been 'contiminated'
with data.

I guess my developer roots are starting to show through. :-)

Could anyone help me?

Note: There is no HTML whatsoever involved in all of this.


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