I advocated strongly freetext as a deliverable for the SPARQL WG, but there wasn't enough consensus to get it in. Also, my requirements were pretty simple, and did not require the full XPath/XQuery requirements that many others have. I summarised my requirements in the following advocacy message:
http://lists.w3.org/Archives/Public/public-rdf-dawg/2009AprJun/0174.html
The WG noted that these requirements could be met by transforming the search string to a regular expression in the application layer. Indeed it can. However, no engines are optimized for this and it can potential be much slower than the built-in free text index.
Virtuoso allready has such a system and we used intensively, but since this is not standardised, there is a query portability cost.
My feature request is thus that the engine optimizes for certain regular expressions so that they are as fast as using the bif:contains.
If the user search term is "dahut", then the regular expression boils down to
\bdahut\S*
I hope this is doable.
Ivan, please have a look and report back if this is feasible