Cascading Attributes?

I have an XML element <text> with an optional attribute @class.  In the
template matching this element, I'd like to have a variable $class which
takes one of the following values, with lower number taking precedence:

1. a param called class passed to the template using <with-param>
2. optional attribute @class if it is defined
3. the string "none"

In other words, if my XSL is:

<xsl:apply-templates select="text"/>

I want $class to be text/@class if it is defined, otherwise "none".  But if
my XSL is:

<xsl:variable name="myvar">myclass</xsl:variable>
<xsl:apply-templates select="text">
	<xsl:with-param name="myvar"/>
</xsl:apply-templates>

I want $class to be "myclass", regardless of whether or not @class is
defined.  

I tried the following:

<xsl:template match="text">
	<xsl:param name="class">
		<xsl:choose>
			<xsl:when test="@class"><xsl:value-of
select="@class"/></xsl:when>
			<xsl:otherwise>none</xsl:otherwise>
		</xsl:choose>
	</xsl:param>
	<a href="{@href}" class="{$class}"><xsl:value-of select="."/></a>
</xsl:template>

But it doesn't work.  I'm sure I could probably figure it out, but I'm
looking for something elegant, or at least something easy to read.  Maybe
what I really want to know is why my XSL doesn't work, which is really
another way of asking, "How does <xsl:param> work?"


William Bagby.





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