[xquery-talk] Collections - family relationships

Adam Retter adam.retter at googlemail.com
Sat Jan 18 05:57:55 PST 2014

>> You know full well that the design isn't going to be improved in a subsequent release unless there's an issue that's a real  stopper, because people expect backwards compatibility.
> http://exist.2174344.n4.nabble.com/Signature-of-fn-filter-doesn-t-look-like-it-conforms-to-the-spec-td4662991.html

I am not sure that this is making the point you think it is! We
(eXist) chose to implement a *draft* standard in it's very early days
and make that available to our users. We previously made the same
decision with a draft version of XQuery Update. That is always a risky
decision as the draft may well change, in fact we almost certainly
expect it to. The Working Group are not expected to maintain backwards
compatibility through drafts, otherwise nothing would ever be

eXist was an early implementer of the draft standard and it allowed us
to provide feedback to the Working Group about any issues with
implementation, and/or suggestions based on real-world use of where it
may be improved. We requested that the function signatures were
changed, based on our experience. As it was a draft standard that was
acceptable to do. However, when the standard hits "Recommendation"
status, it is final, and it is at this point that backward
compatibility must be preserved as it is expected by XQuery
developers; hence being unable to change the functionality of doc.

Anyway, I am sure you realise that you could write your own function
in XSLT, let's call it 'doc-or-empty' and use it in place of doc to
achieve exactly what you want.

Adam Retter

skype: adam.retter
tweet: adamretter

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