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Re: Viewport and nested selected nodes

From: Richard Tobin <richard@inf.ed.ac.uk>
Date: Wed, 25 Oct 2006 00:41:20 +0100 (BST)
To: Alex Milowski <alex@milowski.org>, public-xml-processing-model-wg@w3.org
Message-Id: <20061024234120.4054511FD2B@macpro.inf.ed.ac.uk>

> So, in XSLT, a select attribute with a value of "//h:div" would return
> all the "h:div" elements in the document.  In our case, we're going
> to return only the outermost elements.  As such, it isn't the same thing
> as a select pattern in XSLT.  Given that, it seems like we're going
> to confuse users who come from XSLT-land.

That is a very good point.

The main disadvantage of match patterns is that some things aren't
readily expressible with them.  For example, "the first foo element
in the document".  As a select expression, that's

   (//foo)[1]

As a match pattern, the obvious equivalent is

   foo[not(preceding::foo)]

which is likely to be very expensive.

-- Richard
Received on Tuesday, 24 October 2006 23:41:27 GMT

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