James Pye wrote:
On Feb 26, 2009, at 5:41 PM, Andrew Dunstan wrote:
http://www.exslt.org/exsl/functions/node-set/index.html
A node-set isn't a document.
yes.. :)
I guess what I'm saying is that if:
tinman=# SELECT XML'<foo/><bar/>';
xml
--------------
<foo/><bar/>
(1 row)
is considered to be valid per *SQL-XML*, then it should probably be
treated as a node-set in the context of xpath, not mangled with
<x>...</x>..
Certainly, I would expect an implicit "node-set() call" long before
wrapping the fragment in <x>...</x> and prefixing my xpath query.
However, I find the validity of the above, XML'<foo/><bar/>', a bit
disturbing to begin with. :P
In any case, this functionality doesn't appear to be in libxml2,
it's in libxslt according to the reference you provided.
I think that's *just* referencing the list of xslt implementations
that the extension function is known to be available in.. I doubt that
means to imply that the function or equivalent functionality is not
available in libxml2 itself. I'd wager that equivalent functionality
could be implemented if it weren't directly/already available.. =)
James,
can you point me at any call in libxml2 which will evaluate an xpath
expression in the context of a nodeset instead of a document? Quite
apart from anything else, xpath requires there to be a (single) context
node (see http://www.w3.org/TR/xpath20/#context ). For a doc, we set
that node to the document node, but what would it be for a node-set or a
fragment? If we can't get over that hurdle we're screwed in pursuing
your line of thought.
cheers
andrew
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