I can prove that validation of eXist Xquery against the running database works, but auto-completion of function signatures does not, except the function signatures which are declared as part of XPath.
I assume this is a feature you haven't included yet, but it's a huge oversight for people wishing to really work with server-side XQuery building on eXist.
For illustration, if I take an example file from the eXist tutorial materials as shown below and validate it, I can prove it is valid. If I remove the 'request:get-parameter-names()' then it tells me the file is now invalid, but if I try to type request: and then force an autocompletion, I only see XPath functions, and request:get-parameter-names() does not appear.
I'm using eXist 1.2.4 - the latest stable version.
Example file >>>>>>>>>>>>
xquery version "1.0";
declare namespace request="http://exist-db.org/xquery/request";
for $name in request:get-parameter-names() return
Are you missing a feature? Request it's implementation here.