Top level variables and parameters

I have the following stylesheet, where myvar is assigned to myparam (doesn't
matter what the xml source is)

<?xml version='1.0'?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="1.0">
  <xsl:param name="myparam"/>
  <xsl:variable name="myvar" select="$myparam"/>

  <xsl:template match="/">
    <xsl:apply-templates/>
  </xsl:template>
</xsl:stylesheet>

In xt, this works fine. In Xalan 1.0.1, this works fine. However, in Xalan
1.2, this gives an error:
"VariableReference given for variable out of context or without definition!
Name = myparam, source tree node: #document"

Does anybody know which behaviour is "correct"? ie is it valid to assign top
level variables using top level parameters? This is useful sometimes, say
when I pass in a nodeset as a parameter, and want to pick out a subset of
elements and assign them to a variable. Of course, I'm sure there are
alternative ways of doing what I want; the point is that I don't want to
rewrite some existing stylesheets in order to upgrade to Xalan 1.2 and then
find that this is non-standard behaviour.

Thanks
Phil Capon



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