An advanced open source fulltext indexing package available from: http://www.xapian.org
It includes bindings for some scripting languages including a SWIG generated Tcl binding, properly packaged as a stubs enabled Tcl package since version 0.84.
schlenk This could be a base for a very nice search engine to be added to tclhttpd or rivet for example. Or maybe even as an additional search engine for the wiki?