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RE: [xsl] attribute nodes

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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
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<URL: http://crism.maden.org/consulting/ >
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