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RE: Non-existing node
- To: <xsl-list at lists dot mulberrytech dot com>
- Subject: RE: [xsl] Non-existing node
- From: "Michael Kay" <mhkay at iclway dot co dot uk>
- Date: Mon, 17 Sep 2001 14:09:40 +0100
- Reply-To: xsl-list at lists dot mulberrytech dot com
> In fact, comparing two empty node-sets to each other also gives false.
>
> Ok, but the parser has to compare against something, so my question is
> if there's any reserved word or something to refer to an
> empty-nodeset.
> Let's say the reserved word is "ENS" (Empty Node Set), that
> way you could
> write something like this:
>
> <xsl:if test="Parent/MyNode=ENS">...</xsl:if>
>
"=" doesn't compare the node-set with anything, it compares each node in the
node-set individually, and returns true if any of the comparisons is true.
To test whether a node-set Parent/MyNode is empty, just do
<xsl:if test="Parent/MyNode">: converting a node-set to a boolean returns
true if the node-set is non-empty.
There's no reserved word to refer to an empty node-set; if you need to write
an expression that represents an empty node-set, try:
<xsl:variable name="empty" select="/.."/>
Mike Kay
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