Querying rich text with Lux – XQuery for Lucene by Michael Sokolov.
Slide deck that highlights features of Lux, which is billed at its homepage as:
The XML Search Engine Lux is an open source XML search engine formed by fusing two excellent technologies: the Apache Lucene/Solr search index and the Saxon XQuery/XSLT processor.
Not surprisingly, I am in favor of using XML to provide context for data.
You can get a better feel for Lux by:
Reading Indexing Queries in Lux by Michael Sokolov (Balisage 2013)
Visiting the Lux homepage: http://luxdb.org
Downloading Lux Source: http://github.com/msokolov/lux
BTW, Michael does have experience with XML based content: safaribooksonline.com, oed.com, degruyter.com, oxfordreference.com and others.
PS: Remember any comments on XQuery 3.0 are due by November 19, 2013.