What I have usually seen in that case is:
(xs:string(readingMaterial),xs:string(publication))[1]
which allows for prioritization in case there are actually both for some
unforeseen reason
On 01/27/2014 09:55 AM, Ihe Onwuka wrote:
I am using one transformation for two different data sources with two
different schemas.
One site may call a resoure readingMaterial another site may call the
same concept a publication, but they are otherwise similar and you may
want to treat them as such.
(xs:string(readingMaterial),xs:string(publication))[.]
when you know they are mutually exclusive in your document but you
want to process them in the same way.
On Mon, Jan 27, 2014 at 2:45 PM, Michael Kay <[email protected]> wrote:
On 27 Jan 2014, at 13:59, Ghislain Fourny <[email protected]> wrote:
Hi Ihe,
You are right that it is a filter expression.
However, I think [.] is not very common in "real world" code, except maybe for
very precise use cases (like filtering out empty strings, etc). Usually you would put
either a position or a boolean predicate inside a filter expression -- not just a context
item expression.
What [.] does, if I am not missing anything, is that it only keeps:
1. Numerics equal to their position in the left-hand-side sequence
and
2. Non-numerics that have an Effective Boolean Value of true, like non-empty
strings, nodes, the true boolean, etc.
I mention on p648 of my XSLT /XPath book that the expression
some $s in $S satisfies CONDITION
is equivalent to
exists(for $s in $S return boolean(CONDITION)[.])
though I don't suppose that really counts as a use case.
I think the only case I've used in anger is probably count(tokenize($x, '
')[.]) which eliminates the zero-length tokens that can arise at the start
and/or end of the sequence.
Michael Kay
Saxonica
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