Re: [xsl] Fetch a sequence of nodes from input file

[Michael Ludwig <mlu@xxxxxxxxxxxxx>]

David Carlisle schrieb:
> > http://www.w3.org/TR/xpath20/#id-node-comparisons
>
> > The spec does not seem to be talking about nodes from different
> > documents. Is this a deliberate omission?
>
> the definition does include nodes from different documents. If you
> follow the link to "document-order" from there you will see that it is
> defined (in an implementation defined way) for nodes in different
> documents.

Thanks, David. I evaluated the spec lazily.

> a system can't define << in a way that intermingles two trees.

Even if it could, that would be confusing.

> http://www.w3.org/TR/xpath20/#dt-document-order
>
> The relative order of nodes in distinct trees is stable but
> implementation-dependent, subject to the following constraint: If any
> node in a given tree T1 is before any node in a different tree T2,
> then all nodes in tree T1 are before all nodes in tree T2.

I had always thought of "document order" as the order of nodes in a
document (in a tree, so *tree order*), but in addition it can be read
as the order of documents in a collection (collection order, or *forest
order*).

> no having a defined order is more useful than NUL or an error, it
> allows you to process each node in some set exactly once. It's just
> that you don't get to chose which order separate documents are
> processed. This is what defines the behaviour of
> <xsl:for-each select="$t1/*|$t2/*">

Good example to illustrate the usefulness of the general rule. I can see
there is wisdom in it. Thanks!

--
Michael Ludwig