XSLT: Using variables in a key function (cont.) - xslt

Question

I have a following XML file:
<titles>
<book title="XML Today" author="David Perry"/>
<book title="XML and Microsoft" author="David Perry"/>
<book title="XML Productivity" author="Jim Kim"/>
<book title="XSLT 1.0" author="Albert Jones"/>
<book title="XSLT 2.0" author="Albert Jones"/>
<book title="XSLT Manual" author="Jane Doe"/>
</titles>
and the transformation to eliminate the elements with #author starting with 'David' or 'Jane':
<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:msxsl="urn:schemas-microsoft-com:xslt" exclude-result-prefixes="msxsl">
<xsl:output method="xml" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:key name="author1-search" match="book[starts-with(#author, 'David')]" use="#title"/>
<xsl:template match="book [key('author1-search', #title)]" />
<xsl:key name="author2-search" match="book[starts-with(#author, 'Jane')]" use="#title"/>
<xsl:template match="book [key('author2-search', #title)]" />
<xsl:template match="#* | node()" name="identity">
<xsl:copy>
<xsl:apply-templates select="#* | node()"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
The expected result will be the following XML file:
<titles>
<book title="XML Productivity" author="Jim Kim"/>
<book title="XSLT 1.0" author="Albert Jones"/>
<book title="XSLT 2.0" author="Albert Jones"/>
</titles>
In his reply to the XSLT: Using variables in a key function question Dimitre Novatchev has shown the method to use iteration to display books written by the selected authors using keys and the Exslt function node-set() with the inline xsl parameter
<xsl:param name="pAuthors">
<x>David Perry</x>
<x>Jane Doe</x>
</xsl:param>
Is it possible to apply this method to rewrite the transformation above so that it would use the pAuthors parameter and contain just one generic search key (instead of author1-search, author2-search, and so on)? XSLT 2.0 and the document() function are not supported.
Thanks in advance, Leo

Answer 1

From guesses looking in the code, I believe, the OP is how to use XSLT keys in helping eliminate books written by any author from a given set of authors.
This transformation:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:ext="http://exslt.org/common">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:param name="pAuthors">
<x>David Perry</x>
<x>Jane Doe</x>
</xsl:param>
<xsl:variable name="vParams" select= "
ext:node-set($pAuthors)/*"/>
<xsl:key name="kBookByAuthor" match="book"
use="#author"/>
<xsl:variable name="vBooksToExclude" select=
"key('kBookByAuthor', $vParams)"/>
<xsl:template match="node()|#*" name="identity">
<xsl:copy>
<xsl:apply-templates select="node()|#*"/>
</xsl:copy>
</xsl:template>
<xsl:template match="book">
<xsl:if test="count(.|$vBooksToExclude) != count($vBooksToExclude)">
<xsl:call-template name="identity"/>
</xsl:if>
</xsl:template>
</xsl:stylesheet>
when applied on the provided XML document:
<titles>
<book title="XML Today" author="David Perry"/>
<book title="XML and Microsoft" author="David Perry"/>
<book title="XML Productivity" author="Jim Kim"/>
<book title="XSLT 1.0" author="Albert Jones"/>
<book title="XSLT 2.0" author="Albert Jones"/>
<book title="XSLT Manual" author="Jane Doe"/>
</titles>
produces the wanted, correct result, in which any book that has an author from the provided set of authors (David Perry and Jane Doe), is skipped:
<titles>
<book title="XML Productivity" author="Jim Kim"/>
<book title="XSLT 1.0" author="Albert Jones"/>
<book title="XSLT 2.0" author="Albert Jones"/>
</titles>
Explanation:
We use the following XPath expression to determine whether a node $n doesn't belong to a node-set $s:
count($n | $s) != count($s)
Final update:
As the OP wants, here we exclude from copying to the output all books, that have an author, whose first name is provided as one of many values in an external/global parameter. We still use a single key.
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:ext="http://exslt.org/common">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:param name="pAuthors">
<x>David</x>
<x>Jane</x>
</xsl:param>
<xsl:variable name="vParams" select= "
ext:node-set($pAuthors)/*"/>
<xsl:key name="kBookByAuthor" match="book"
use="substring-before(#author, ' ')"/>
<xsl:variable name="vBooksToExclude" select=
"key('kBookByAuthor', $vParams)"/>
<xsl:template match="node()|#*" name="identity">
<xsl:copy>
<xsl:apply-templates select="node()|#*"/>
</xsl:copy>
</xsl:template>
<xsl:template match="book">
<xsl:if test="count(.|$vBooksToExclude) != count($vBooksToExclude)">
<xsl:call-template name="identity"/>
</xsl:if>
</xsl:template>
</xsl:stylesheet>
when this transformation is applied on the following XML document (added another David author):
<titles>
<book title="XML Today" author="David Perry"/>
<book title="XML and Microsoft" author="David Perry"/>
<book title="Just example" author="David Masters"/>
<book title="XML Productivity" author="Jim Kim"/>
<book title="XSLT 1.0" author="Albert Jones"/>
<book title="XSLT 2.0" author="Albert Jones"/>
<book title="XSLT Manual" author="Jane Doe"/>
</titles>
produces the wanted, correct result:
<titles>
<book title="XML Productivity" author="Jim Kim" />
<book title="XSLT 1.0" author="Albert Jones" />
<book title="XSLT 2.0" author="Albert Jones" />
</titles>