Re: [xsl] Understanding axis

Subject: Re: [xsl] Understanding axis
From: Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>
Date: Tue, 29 Oct 2002 12:57:25 -0500
Hi Adam,

At 11:32 AM 10/29/2002, you wrote:
I've been learning the use of axis in transformations and I stumbled on
something that didn't seem to make sense...

local-name( */* )
local-name( */child::* )

return the same values.

Yes. XPath */* and */child::* are both short for XPath child::*/child::*

I would have thought...

local-name( */child::* )
local-name( */*/* )

would be the same (which they aren't).

Nope, they're not. Writing 'child::' does not add a step to the XPath; it merely makes explicit the child axis, which the processor assumes by default if no other axis is named.

Could somebody help me reason out why it is this way?

The XPath spec is clear on how all the abbreviations work, though they can be a bit tricky to learn since they don't all work the same way (some abbreviate an entire step, others only the axis specifier part of a step; or in the case of '//', more than a step is abbreviated).

 This seems to
complicate scenarios where I would only want certain nodes based upon their
children without changing context. For instance, something like:

<xsl:for-each select="*/child::*[local-name()=$v]">

read as I only want */* where they have a child named $v.

If you want grandchildren elements only that have a child named $v, that's


If you want child elements only that have a child named $v, that's


The latter can be expanded as child::*[child::*[local-name()=$v]]. I'll let you expand the first one.

I hope that helps,

====================================================================== Wendell Piez mailto:wapiez@xxxxxxxxxxxxxxxx Mulberry Technologies, Inc. 17 West Jefferson Street Direct Phone: 301/315-9635 Suite 207 Phone: 301/315-9631 Rockville, MD 20850 Fax: 301/315-8285 ---------------------------------------------------------------------- Mulberry Technologies: A Consultancy Specializing in SGML and XML ======================================================================

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