This is the mail archive of the
xsl-list@mulberrytech.com
mailing list .
RE: attribute nodes
- To: xsl-list at lists dot mulberrytech dot com
- Subject: RE: [xsl] attribute nodes
- From: "Christopher R. Maden" <crism at maden dot org>
- Date: Sat, 05 May 2001 00:58:56 -0700
- References: <000601c0d3ab$552154d0$944a3c3e@PCUKMKA>
- Reply-To: xsl-list at lists dot mulberrytech dot com
At 22:29 4-05-2001, Michael Fitzgerald wrote:
>Thanks all for answers. In the traditional tree data model in CS, a good
>forty years old at least, "if p is the parent of node c, we also say that c
>is a child of p." [1] XSLT/XPath in a sense breaks this traditional
>relationship wrt attributes, perhaps only as a convenience for tree
>traversal. I don't know. I'm asking. -Mike
And Michael Kay answered, accurately, to my recollection. What additional
information are you seeking?
You'll note that the Aho & Ullman definition appears almost verbatim in the
XML 1.0 Recommendation. It applies only to elements - a child element has
a parent element, and a parent element may have child elements. XPath
adopted that model, and extended the terminology where it was logical: for
comments, processing instructions, and text nodes, which are ordered within
the three. Attributes are not children; I've never seen a discussion of
XML that describes them as such, and they don't fit with the observed user
expectations of children. They are illustrated as decorations on a tree or
tags on boxes, not as descendants or nested boxes.
But this presents a problem. We have the attribute axis for referencing
attribute nodes, distinct from the child axis. But an attribute has an
"owner" that it is interesting to discuss; what do we call it? There was
some considerable debate about breaking the symmetry of child and parent,
but for simplicity and least surprise (except among hard-core CS nerds),
the final decision seems to have worked well.
-Chris
--
Christopher R. Maden, XML Consultant
DTDs/schemas - conversion - ebooks - publishing - Web - B2B - training
<URL: http://crism.maden.org/consulting/ >
PGP Fingerprint: BBA6 4085 DED0 E176 D6D4 5DFC AC52 F825 AFEC 58DA
XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list