Re: How can you tell if a variable exists?

["Scott Sanders" <scott@xxxxxxxxxxxx>]

> > How can you tell if a variable exists (or rather does not
> > exist), without erroring out of the stylesheet.
> >
> Referring to $v when there is no <xsl:param name="v"> or <xsl:variable
> name="v"> in scope is an error, and you can't trap this. But referring to
$v
> when there is a declaration of <xsl:param name="v"> should not give an
> exception, whether or not the parameter has been given a value.
>
> From the description of your problem, I would declare a global parameter
>
> <xsl:param name="v"/>
>
> and then in your code you can do
>
> <xsl:choose>
> <xsl:when test="not($v)"> <!-- parameter has not been supplied -->
> </xsl:when>
> <xsl:otherwise> <!--parameter has been supplied --> </xsl:otherwise>
> </xsl:choose>
>
> The reason this works is that when no actual parameter v is supplied, it
> takes its default value, which in this case is an empty string (because
the
> xsl:param has no select expression or content), and the test not($v)
returns
> true if $v is an empty string.

That works SWEET.  Thanks a lot.

Scott


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