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Re: [xsl] Diagram of XPath axes

Subject: Re: [xsl] Diagram of XPath axes
From: Michael Kay <mike@xxxxxxxxxxxx>
Date: Fri, 25 May 2012 00:04:01 +0100

On 24/05/2012 18:02, Imsieke, Gerrit, le-tex wrote:
Just a side note: If you want to select the preceding elements *including the ancestors*, use the XPath 2 << operator [1], which selects the nodes that precede the current in document order [2].

In XSLT: select="*[. &lt;&lt; current()]"

It would be interesting to see a performance comparison of

//*[. << current()]


ancestor::* | preceding::*

Both are rather heavily exposed to testing the relative order of two nodes in document order, which in some tree implementations (e.g. DOM) can be very inefficient.

If you don't care about document order, however, (ancestor::*, preceding::*) should be fastest.

There's also (ancestor::*/(. | (preceding-sibling::*/descendant::*))) if anyone wants to try it out.

I do wish we had an "until" operator, so we could do //* until (. is current()). You can do that of course with a recursive function.

Michael Kay

Michael Kay

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