Re: set:difference() using two different node sets

[email protected] wrote:
> We're trying to use set:difference() to compare two separate node-sets that
> we create in variables.  
> 
> Most of the examples I see for this use partial node-sets from the same
> parent node and compare those to get the difference (See the example found
> at: http://www.exslt.org/set/functions/difference/index.html).  My question
> is do the two node sets need to have the same parent, or can they be from
> two separate sources?

It's not about parent, but about node identity. set:difference() 
function filters nodes basing on their identity. At least that's my 
understanding of the definition below and that's how EXSLT.NET 
implements it:
"The set:difference function returns the difference between two node 
sets - those nodes that are in the node set passed as the first argument 
that are not in the node set passed as the second argument."

> In effect we are doing something like:
> 
> <xsl:variable name="v1">
> 	<xsl:for-each select="document('set1.xml')/*">
> 		<node id="@someId"/>
> 	</xsl:for-each>
> </xsl:variable>
> <xsl:variable name="v2">
> 	<xsl:for-each select="document('set2.xml')/*">
> 		<node id="@id"/>
> 	</xsl:for-each>
> </xsl:variable>
> 
> <xsl:copy-of select="set:difference(
> 				msxsl:node-set($v1), msxsl:node-set($v2))"/>
> 
> We are always getting the complete list found in $v1.  We're not sure if it
> is by design or a problem with the implementation of set:difference.

msxsl:node-set($v1) and msxsl:node-set($v2)contain separate sets of 
nodes, so set:difference() is useless here.
You seems to be looking for difference based on node equality. You can 
achieve it using something like
<xsl:variable name="_v1" select="msxsl:node-set($v1)/*"/>
<xsl:variable name="_v2" select="msxsl:node-set($v2)/*"/>
<xsl:copy-of select="$_v1[not(. = $_v2)]"/>

-- 
Oleg Tkachenko
http://blog.tkachenko.com