XQuery Extension Modules - eXist: A NoSQL Database and Application Development Platform - page 493

APPENDIX A
XQuery Extension Modules
This appendix provides an overview of the available XQuery extension modules in
eXist.
You might have noticed that in other chapters we've often mentioned and described
extension modules. For instance, “Controlling the Database from Code” on page 107
explains in part how to manipulate the database using the xmldb extension module.
This is because we think it is better to describe an extension module within its con‐
text as much as possible. However, there are a lot of extension modules we haven't
covered elsewhere, so we provide an overview here to assist you.
We won't handle all the extension modules that come with eXist. As is often the case
with open source products, experiments creep in and are not removed. Some of the
modules seem to hold interesting functionality, but documentation is missing. And
some are very specialized and of interest only to a very small group of users. We
therefore took the liberty to describe only those modules that we thought would be of
general interest and for which at least some kind of documentation was available
(often just the information in eXist's function documentation browser). Apologies to
all module creators whose modules we left out. If you think something we left out
deserves a place in this appendix, please drop us a line and we'll try to rectify this in a
future edition of the topic.
What we also won't do here is describe all functions in detail. eXist provides an
online function documentation browser, and we saw no reason to duplicate this
information; it would have made the topic too heavy and the information would
probably soon be out of date. What we will do is provide you with a list of modules
available in the version of eXist (2.1) that this topic was written for, tell you a little bit
about them, and provide examples when we think it is appropriate.