xslt variable strangness
<a><xsl:copy-of select="(@attrib|exsl:node-set(0))"/></a>
 <b><xsl:copy-of select="(@attrib|exsl:node-set(0))[position()=1]"/></b>

 <x><xsl:copy-of select="(@attrib|exsl:node-set(0))[1]"/></x>
 <xsl:variable name="value" select="@attrib"/>
 <y><xsl:copy-of select="($value|exsl:node-set(0))[1]"/></y>

<a attrib="1">0</a>
 <b attrib="1"/>

 <x>0</x>
 <y attrib="1"/>

concat(@attrib,
       substring(0, 2 -not(@attrib))
       )

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>

 <xsl:template match="x">
  <xsl:value-of select=
   "concat(@attrib,
           substring('0', 2 -not(@attrib))
           )"/>

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 </xsl:template>
</xsl:stylesheet>

<t>
 <x attrib="abc"/>
 <x/>
</t>

abc

==========

 0

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