Hi,

I want to create a list of IDs while transforming one part of the XML document, as the transformation of the second part is based on the IDs chosen before.

The input XML document looks like this:

<MainElement id="0" val="10"/>
<MainElement id="1" val="20"/>
<MainElement id="2" val="30"/>
<ExtElement mid="0" ... />
<ExtElement mid="0" ... />
<ExtElement mid="1" ... />
<ExtElement mid="2" ... />

The style sheet has a parameter, which allows to specify the desired maximum value. If the input parameter is a value of 20, the output should look like this:

<MainElement id="0" val="10"/>
<MainElement id="1" val="20"/>
<ExtElement mid="0" ... />
<ExtElement mid="0" ... />
<ExtElement mid="1" ... />

My question is now, how can I store the IDs of the MainElements while processing them in order to have the IDs available when processing the ExtElements (using XSLT 1.0).

Use the identity transform with a no-op template for each of
conditions where you don't want to copy the input to the result.  The
tricky part of looking up the <MainElement> from the <ExtElement> can
be done using a key:

<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

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

<MainElement id="0" val="10"/>
<MainElement id="1" val="20"/>

<ExtElement mid="0"/>
<ExtElement mid="0"/>
<ExtElement mid="1"/>

cheers
andrew
--
http://andrewjwelch.com