Re: [eXist-TEIXML] passing arguments to XQuery functions

[Joe W. <jo...@gm...>]

Hi Chris,

> Thanks again for your help on this, and to Joe for setting up this list for newbies like me.

I'm so happy to hear that you, together with Martin and Peter, have
found a solution!  Since I didn't participate in the discussion (work
busy-ness + a bad cold), let me offer some reflections:

First, Chris, you're graduating to a really exciting level of XQuery
development sophistication.  You're putting commonly used application
logic into functions and moving those functions into library modules.
This isolates the code, centralizes the functions, and makes the code
more portable, more reusable, and much easier to test.  Your function
takes an entire TEI document as an argument, and thus it can be used
on any TEI document in your database, now or as you add new documents.
 If your TEI document structure changes in the future, you only have
to modify this one function to ensure your application runs as before.

Second, namespaces were central to resolving the problem.  My rule is
that if I write a query and get nothing instead of the expected
result, namespace problems are the cause of the problem 90% of the
time.  If I check the XPath and the assumptions in the logic, and
everything still looks right, that 90% rises to 99%.  This isn't to
say that namespaces are evil; they're essential, but require
annoyingly absolute precision.

Third, default namespaces.  Declaring a default element namespace can
be very handy, particularly if all inputs and outputs are in the same
namespace and no elements are in the empty namespace.  But in my
experience, I often find myself removing such declarations.  Declaring
TEI or HTML as the default makes it difficult to address empty
namespaces ( *:foo is a kludge and not good for performance), and in
my applications I almost always mix TEI, HTML, and empty namespaced
nodes.  But absolutely, do try it out and keep this technique in your
arsenal, but I personally find it of use in marginal circumstances.

Finally, this list will have its first anniversary in a few months!
It'll be an opportunity for us to reflect on what we've learned this
year, and on what we can do looking ahead.

Thanks and best wishes to you all,
Joe