xslt merge sub nodes to one root node - xslt

Question

My input document consist of a root with several sub nodes.
...
<root>
<top>
<number>999</number>
<attr attr-name="Numbervalue">
<value>184</value>
</attr>
<attr attr-name="Initials">
<value>A.C.</value>
</attr>
<attr attr-name="Givenname">
<value>Anne</value>
</attr>
<attr attr-name="Surname">
<value>Bakker</value>
</attr>
<attr attr-name="Function">
<value>Developer</value>
</attr>
</top>
<top>
<number>999</number>
<attr attr-name="Numbervalue">
<value>1034</value>
</attr>
<attr attr-name="Initials">
<value>A.C.</value>
</attr>
<attr attr-name="Givenname">
<value>Anne</value>
</attr>
<attr attr-name="Surname">
<value>Bakker</value>
</attr>
<attr attr-name="Function">
<value>Consultant</value>
</attr>
</top>
</root>
...
I want to merge all subnodes from top into a merged top. Same attributes but different values should result in a multi-valued "value" node. Other nodes/fields (as "number") should be copied. Something like this:
...
<root>
<top>
<number>999</number>
<attr attr-name="Numbervalue">
<value>184</value>
<value>1034</value>
</attr>
<attr attr-name="Initials">
<value>A.C.</value>
</attr>
<attr attr-name="Givenname">
<value>Anne</value>
</attr>
<attr attr-name="Surname">
<value>Bakker</value>
</attr>
<attr attr-name="Function">
<value>Developer</value>
<value>Consultant</value>
</attr>
</top>
</root>
...
What i have tried:
...
<?xml version="1.0" encoding="UTF-8"?><xsl:stylesheet>
<xsl:template match="#* | node()">
<xsl:copy>
<xsl:apply-templates select="#* | node()"/>
</xsl:copy>
</xsl:template>
<xsl:template match="top">
<xsl:for-each select="./attr[#attr-name]">
<xsl:if test="string-length(.)"/>
<xsl:variable name="name" select="./#attr-name"/>
<xsl:variable name="value" select="normalize-space(./value)"/>
<attr>
<xsl:attribute name="attr-name">
<xsl:value-of select="$name"/>
</xsl:attribute>
<value>
<xsl:value-of select="$value"/>
</value>
</attr>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>
...
But this result in:
...
<root>
<attr attr-name="Numbervalue">
<value>184</value>
</attr>
<attr attr-name="Initials">
<value>A.C.</value>
</attr>
<attr attr-name="Givenname">
<value>Anne</value>
</attr>
<attr attr-name="Surname">
<value>Bakker</value>
</attr>
<attr attr-name="Function">
<value>Developer</value>
</attr>
<attr attr-name="Numbervalue">
<value>1034</value>
</attr>
<attr attr-name="Initials">
<value>A.C.</value>
</attr>
<attr attr-name="Givenname">
<value>Anne</value>
</attr>
<attr attr-name="Surname">
<value>Bakker</value>
</attr>
<attr attr-name="Function">
<value>Consultant</value>
</attr>
</root>
...
With this i am missing the top node and nodes like "number"
If the result looks like this (below) it is also acceptable:
...
<root>
<top>
<number>999</number>
<attr attr-name="Numbervalue">
<value>184</value>
<value>1034</value>
</attr>
<attr attr-name="Initials">
<value>A.C.</value>
<value>A.C.</value>
</attr>
<attr attr-name="Givenname">
<value>Anne</value>
<value>Anne</value>
</attr>
<attr attr-name="Surname">
<value>Bakker</value>
<value>Bakker</value>
</attr>
<attr attr-name="Function">
<value>Developer</value>
<value>Consultant</value>
</attr>
</top>
</root>
...
I am also experimenting with "Muenchian Grouping" but up till now this only results in errors.
A working solution should use only xslt 1.0.
Suggestion are very welcome!

Answer 1

If I am guessing correctly, you want to do:
XSLT 1.0
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:key name="k1" match="value" use="../#attr-name" />
<xsl:key name="k2" match="value" use="concat(., '|', ../#attr-name)" />
<xsl:template match="/root">
<root>
<top>
<xsl:copy-of select="top[1]/number"/>
<xsl:for-each select="top[1]/attr">
<attr attr-name="{#attr-name}">
<!-- get only distinct values of this attr -->
<xsl:copy-of select="key('k1', #attr-name)[count(. | key('k2', concat(., '|', ../#attr-name))[1]) = 1]"/>
</attr>
</xsl:for-each>
</top>
</root>
</xsl:template>
</xsl:stylesheet>
This takes the list of attr elements from the 1st top, gathers all the value elements that belong to the current attr (using the k1 key), and filters them using the Muenchian grouping expression (utilizing the k2 key) to output only the distinct values among them.