Multi-document xslt, value-of with addition misbehaving - xslt

Question

I am trying to write something for another individual and im stuck on the final part of the stylesheet.
We have two XML Documents:
TestXML.xml:
<rootNode>
<header>
<title agg="sum">1</title>
<records agg="sum">10</records>
<number agg="min">5</number>
</header>
</rootNode>
and TestXMLTwo.xml:
<rootNode>
<header>
<title agg="sum">2</title>
<records agg="sum">20</records>
<number agg="min">15</number>
</header>
</rootNode>
Where if the node has its agg attribute equal to 'sum' we combine the values of the two documents nodes. I am doing this using:
<xsl:param name="InputFileOne">[EditedOut]\TestXML.xml</xsl:param>
<xsl:param name="InputFileTwo">[EditedOut]\TestXMLTwo.xml</xsl:param>
<xsl:template match="node()|#*">
<xsl:call-template name="ConcatFiles"/>
</xsl:template>
<xsl:template name="ConcatFiles">
<xsl:variable name="tempStoreDocOne" select ="document($InputFileOne)/rootNode/header" />
<xsl:variable name="tempStoreDocTwo" select ="document($InputFileTwo)/rootNode/header" />
<xsl:element name="rootNode">
<xsl:element name="header">
<xsl:for-each select="$tempStoreDocOne/node()">
<xsl:choose>
<xsl:when test="./#agg = 'sum'">
<xsl:variable name="tempElementDocTwo" select ="$tempStoreDocTwo/."/>
<xsl:element name="{name(.)}">
<xsl:value-of select=". + $tempElementDocTwo"/>
</xsl:element>
</xsl:when>
<xsl:otherwise>
<xsl:element name="{name(.)}">
<xsl:value-of select="."/>
</xsl:element>
</xsl:otherwise>
</xsl:choose>
</xsl:for-each>
</xsl:element>
</xsl:element>
</xsl:template>
However on the line <xsl:value-of select=". + $tempElementDocTwo"/> I just get a value of '22016' for the <title> and 22025 for the <records>. Can someone enlighten me as to where I'm going wrong?

Answer 1

Change <xsl:for-each select="$tempStoreDocOne/node()"> to <xsl:for-each select="$tempStoreDocOne/*">, then add a variable storing the position i.e.
<xsl:variable name="pos" select="position()"/>
inside of the for-each, then change
<xsl:variable name="tempElementDocTwo" select ="$tempStoreDocTwo/."/>
to
<xsl:variable name="tempElementDocTwo" select ="$tempStoreDocTwo/*[$pos]"/>
Currently you are accessing the string value of the complete header element in the second document which is the concatenation of its descendant nodes while you want to access the child element with the same position as the one in the first document.

Answer 2

Here is a much simpler and shorter solution (no explicit conditionals):
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:param name="pDoc2">
<rootNode>
<header>
<title agg="sum">2</title>
<records agg="sum">20</records>
<number agg="min">15</number>
</header>
</rootNode>
</xsl:param>
<xsl:variable name="vDoc2" select="document('')/*/xsl:param"/>
<xsl:template match="node()|#*">
<xsl:copy>
<xsl:apply-templates select="node()|#*"/>
</xsl:copy>
</xsl:template>
<xsl:template match="header/*[#agg='sum']">
<title>
<xsl:value-of select=
". + $vDoc2/*/header/*[name()=name(current()) and #agg='sum']"/>
</title>
</xsl:template>
</xsl:stylesheet>
When this transformation is applied on the first XML document (the second is inlined in the transformation just for convenience):
<rootNode>
<header>
<title agg="sum">1</title>
<records agg="sum">10</records>
<number agg="min">5</number>
</header>
</rootNode>
the wanted, correct result is produced:
<rootNode>
<header>
<title>3</title>
<title>30</title>
<number agg="min">5</number>
</header>
</rootNode>