Andrew Dunstan wrote:
Hannu Krosing wrote:
Is it just that in you _can't_ use Xpath on fragments, and you _need_ to
pass full documents to Xpath ?
At least this is my reading of Xpath standard.
I think that's possibly overstating it., unless I have missed
something (W3 standards are sometimes not much more clear than the SQL
standards ;-( )
For instance, there's this, that implies at least that the tree might
not be a document:
A "/" at the beginning of a path expression is an abbreviation for
the initial step fn:root(self::node()) treat as document-node()/
(however, if the "/" is the entire path expression, the trailing "/"
is omitted from the expansion.) The effect of this initial step is
to begin the path at the root node of the tree that contains the
context node. If the context item is not a node, a type error is
raised [err:XPTY0020]. At evaluation time, if the root node above
the context node is not a document node, a dynamic error is raised
[err:XPDY0050].
The problem is that we certainly do have to provide a context node
(the standard is clear about that), and unless we want to convert a
non-document to a node-set as James suggested and then apply the xpath
expression to each node in the node-set, we have no way of sanely
specifying the context node.
No-one has come up with an answer to this, so I propose to remove the
hackery. That leaves the question of what to do when the xml is not a
well formed document ... raise an error?
cheers
andrew
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