RE: [xsl] generalized unique element

Subject: RE: [xsl] generalized unique element
From: "Michael Kay" <michael.h.kay@xxxxxxxxxxxx>
Date: Wed, 11 Sep 2002 15:47:13 +0100
> if i have to put a condition that name of the current 
> element(any element) 
> is not the same of any of the preceding elements ..how do i proceed 
> further..
> i cant get my heads on this..
> 
> tried doing something like..
> <xsl:if test="not(name(.) = preceding::node()/name())">
> 
> I am sure the above line is a mistake.

It is indeed a mistake. When the operands to "=" are node-sets, the
operator means "if any node on the left has the same string-value as a
node on the right". But XPath 1.0 doesn't allow sets of strings, and
preceding-node()/name() is therefore meaningless (and wrong).

There isn't an existential test of the kind you are looking for in XPath
1.0. This is why Muenchian grouping was invented, it achieves the
required effect using keys.

It all gets easier in XPath 2.0, where you can write

<xsl:if test="every $x in preceding-sibling::*
              satisfies name($x) != name(.)">

Michael Kay
Software AG
home: Michael.H.Kay@xxxxxxxxxxxx
work: Michael.Kay@xxxxxxxxxxxxxx 


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