Trouble selecting appropriate node-set depending on p

Hi All,

I'm new to the list and XSL.  So 1st of all, greetings to you all.  I'm
hoping someone here can point me in the right direction.

I'm writing a small xsl stylesheet to select a subset of nodes from an xml
document.  The important part looks like this...

<xsl:param name="PRODUCTGROUP" />
<xsl:param name="PLATFORM"  />
<xsl:param name="ITEM" />

<xsl:for-each select="/store/productGroup[@type =
$PRODUCTGROUP]/platform[@type=$PLATFORM]/item[@type=$ITEM]">

etc..


What happens is I pass in the values of productgroup, platform and item with
php.  I can then retrieve a list of all items the attributes of which match
the criteria.  This seems to work fine, the only trouble is, I'd like in
some cases to be able to choose all items, regardless of attributes, like
so...

<xsl:for-each select="/store/productGroup/platform/item">

or any combination, like so...

<xsl:for-each select="/store/productGroup/platform[@type=$PLATFORM]/item">

I guess I'm a bit unclear how to be able to choose between multiple
node-sets, depending on the whether or not one of the parameters is set.
I've been searching for info on this most of the afternoon, but can't seem
to find much.

If anyone has any suggestions, I'd be deeply appreciative.

Thanks!

-Travis








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