[Bug 5198] .// in PathExpr[28] difficult for databinding products

http://www.w3.org/Bugs/Public/show_bug.cgi?id=5198





------- Comment #3 from noah_mendelsohn@us.ibm.com  2007-10-16 16:21 -------
Pete:  I've always been sympathetic to XSD being a language that supports
databinding well.  For example, I've argued for the very controversial UPA
feature in part on those grounds.

That said:  I'm not quite sure why the descendent axis causes trouble in
assertions.  Assertions cause extensional restriction in the language:  nothing
can be accepted by a type with an assertion that could not have been accepted
by a type without that assertion.  So, presuming that users continue to use
content models for the things that they do well (admittedly an assumption), I
think databinding tools could either:

* completely ignore assertions, and likely produce results no worse than would
have been obtained with schema 1.0

* take note of the many assertions that will likely be simple, such as @max >
@min, if those are useful.  (I would sooner thing these would be useful to a UI
framework than to a databinding tool, but either way they're pretty easy to
understand).

With or without descendent axes I think you can construct fairly complicated
XPaths that would be hard for a databinding tool to do much with;  it's not
clear to me that descendent makes things particularly worse, and it allows
checks of constructions that are very natural in XML.

Noah

Received on Tuesday, 16 October 2007 16:21:58 UTC