Hi, I wonder if the Xapian developers have any plan to support multiple independantly usable synonym expanders ? This could be useful for a number of usages which may need to be switched on/off independantly: - Expansion to similar meanings (current supposed usage) - Expansion to terms that have the same stem - Expansion to terms differing by character case only - Expansion to terms differing by diacritics only - Etc. Especially, switchable case-sensitivity is a recurrent user request. I was thinking of recycling the current mechanism I use for stem expansion (a key-value store based on a separate Xapian index), but a real solution integral to Xapian would be nicer. While experimenting I tried to modify the current mechanism with the following approaches, and compare the creation times and resulting size: - stem as unique term, expansions in document record (reference) - stem as unique term, expansions as additional terms. 50% bigger, slightly slower. - gdbm: stem as key, expansions as data: bigger, slower. - stem as term, expansions as synonyms: almost 3 times faster and 4 times smaller. Wow ! The performance and size of this index is not critical, but the synonyms approach is faster, easier to use and yields a smaller db. Hhmm... hard choice :) If I can only ever expect one synonym db, I guess I could also hack something based on prefixes inside the current synonyms mechanism ? Does this sound like a good approach ? Any idea that you can share on the subject would brighten my lantern and be appreciated... Cheers, J.F. Dockes