On Sun, Nov 27, 2022 at 04:41:01PM +0100, Christian Grün scripsit:
Hi Graydon,
Hi Christian,
[customary patient careful explanation of side-effect free language design snipped]
I am sorry; I didn't even do a terrible job of explaining the use case, because that was what my head was stuck in. Mea culpa!
What I want is something similar to transform() but for a main query module, so I'm going to call it query(). I want this because I frequently find myself using XQuery to test XML content sets, and keeping the individual tests to an individual query module is much simpler than trying to stuff everything into an eventually enormous set of functions. But then they all have to be run individually and the specific results aggregated together somehow to get the overall result.
It's possible to do this with the scripting functionality but I find that gets hard to maintain and I'd really like an XQuery layer that allows using multiple modules in a single at-least-notional query.
(The quality improvement I've experienced in XSLT from using transform() and keeping every step of the transformation small and comprehensible has been large; such an improvement may not generalize well, but if it does, being able to treat a query module as a function seems highly worthwhile for implementing anything complex in XQuery.)
I am not sure if my hypothetical query() function would be equivalent to
fn:load-xquery-module($module-uri as xs:string, $options as map(*)) as map(*)
from the 4.0 version of the functions spec at https://www.saxonica.com/qt4specs/FO/Overview-diff.html#func-load-xquery-mod...
My idea would be
fn:query($module-uri as xs:string, $context as item()*, $options as map(*)) as map(*)
where a db is explicitly available as a value for $context. (I realize that document-node()* is not the type of a BaseX db, but given the optimizer will substitute db:get() for collection() I figure it's close...)
So it would be possible to do:
let $contentSet as xs:string := fn:query('load-set.xq', (), $options)?db-name
let $test1Result as map(*) := fn:query('test1.xq', $contentSet, $test-options)
let $test2Result as map(*) := fn:query('test2.xq', $contentSet, $test-options)
And so on.
I emphatically don't want to be able to update a DB and then query it further in a single query module; I am sharply aware I'm not smart enough not to mess that up!
Does that make any more sense?
Thanks!