Change in `<Output>' element with if condition - xslt-2.0

Question

I have two input files like:
a.xml
<a>
<data>...</data>
</a>
b.xml
<b>
<data>...</data>
</b>
my xslt
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="2.0">
<xsl:output method="xml" encoding="UTF-8" indent="yes"/>
<xsl:template match="node()|#*">
<xsl:copy>
<xsl:apply-templates select="node()|#*"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
I want to check first root element, if it is <a> than <xsl:output> is
<xsl:output method="xml" encoding="UTF-8" indent="yes"/>
else
<xsl:output method="xml" encoding="us-ascii" indent="no"/>
Thanks in advance.

Answer 1

Well, XSLT is XML so you can of course use XSLT to create another XSLT with the desired output encoding and you can then run it in a separate step.
As an alternative you could check the root element not being an a element and then delegate outputting to xsl:result-document where you can change the encoding:
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
exclude-result-prefixes="xs"
version="2.0">
<xsl:template match="#* | node()">
<xsl:copy>
<xsl:apply-templates select="#* | node()"/>
</xsl:copy>
</xsl:template>
<xsl:template match="document-node()[*[not(self::a)]]">
<xsl:result-document encoding="US-ASCII">
<xsl:apply-templates/>
</xsl:result-document>
</xsl:template>
</xsl:stylesheet>
http://xsltfiddle.liberty-development.net/3Nqn5Y8