[Bug 6777] In HTML documents, no-namespace expression must match http://www.w3.org/1999/xhtml nodes

http://www.w3.org/Bugs/Public/show_bug.cgi?id=6777





--- Comment #22 from David Carlisle <davidc@nag.co.uk>  2009-04-06 20:22:43 ---
This bug is clearly misclassified (against XPath2.x) when the issue appears to
be an Xpath 1.0 one. It would seem that the default element namespace in Xpath2
would meet the requirements.

So what is being requested is actually an XPath 1.2 specification which is
XPath 1.0 but with the addition of the default element namespace feature. I
can't see there being much enthusiasm for a new version of xpath 1 this long
after xpath 2 has been released.

One possible route forward would be for the HTML5 spec to do do what Henri
indicated is not feasible.

> Requiring the XPath 1.0 processor to be
> replaced with an XPath 2.0 processor entirely is not a feasible first step.


HTML5 could (like many specs before it) define a profile/subset of xpath2.

(In this case, basically default to BC mode, initialise the default element
namespace to xhtml, don't allow "for" or  "," operators and restrict the
function library to those functions that were in xpath 1). Any Xpath 1 engine
that could not make the small number of changes to support such a profile of
xpath 2 probably isn't going to change at all anyway so it doesn't matter what
spec you make for them.

Defining things in terms of a subset of XPath2 rather than an extension of
XPath 1 gives more or less equivalent functionality now, but with a much
clearer path forward to future versions using full XPath 2.x.

I find it ironic that a breaking change in xpath (which would confuse all
existing xpath users) is being proposed in the name of preserving existing
content when for example changes such as outlawing the use of

<?xml-stylesheet href="../style/foo.xsl"

in Firefox 3.x broke a large fraction of existing pages (when used from
the local filesystem). If it's thought acceptable to force people to rearrange
the directory structure of their site and all the links in all their pages, why
is it unacceptable to  admit that you have changed the namespace used in the
html to XDM mapping, and that people using xpath will need to update to the new
reality?

David
(interested observer, I'm not on any relevant WG)


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Received on Monday, 6 April 2009 20:22:53 UTC