Cheers,
Abel

This conversation would be better conducted on the Saxon list...

You could pick up all constant expressions, of whatever type, using the test

if X instanceof Value
 return ((Value)X).getStringValue()

Note that if the expression is written as select="2+2", you will probably
get back the pre-evaluated result, "4".

You could pick up the special case of

<xsl:param>xyz</xsl:param>

using

if X instanceof TextFragmentValue
 return ((TextFragmentValue)X).getStringValue()

Michael Kay
http://www.saxonica.com/