getting namespace uri by giving prefix in xslt - xslt-1.0

Question

I am using xsl 1.0. I need to get the namespace uri from prefix.
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:a1="http://example.com/arthemetic/integers/a1">
<soapenv:Header>
</soapenv:Header>
<soapenv:Body>
<a1:add>
</a1:add>
</soapenv:Body>
</soapenv:Envelope>
I want to get the namespace uri for prefix a1 is http://example.com/arthemetic/integers/v1
Here is the code that i am trying out,
<xsl:template match="/">
<xsl:variable name="operationName">
<xsl:value-of
select="name(/*[local-name()='Envelope']/*[local-name()='Body']/*[1])"></xsl:value-of>
</xsl:variable>
<xsl:variable name="prefix">
<xsl:value-of select="substring-before($operationName, ':')"></xsl:value-of>
</xsl:variable>
<xsl:variable name="ns-node"
select="namespace::node()[.= $prefix]" />
dfadsfdfadsf
<xsl:value-of select="$ns-node" />
</xsl:template>
</xsl:stylesheet>
But I am not receiving the namespace.

Answer 1

Use:
<xsl:value-of select="/*/namespace::a1"/>
Here is a complete transformation:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="text"/>
<xsl:template match="/">
<xsl:value-of select="/*/namespace::a1"/>
</xsl:template>
</xsl:stylesheet>
When this transformation is applied on the provided XML document:
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:a1="http://abc.com/arthemetic/integers/a1">
<soapenv:Header></soapenv:Header>
<soapenv:Body>
<a1:add></a1:add>
</soapenv:Body>
</soapenv:Envelope>
the wanted, correct result is produced:
http://abc.com/arthemetic/integers/a1