Anyone? I can handle monads, but I have something (actually in F#) that feels like it should be something like a indexed writer monad (which F# probably wouldn't support). So I thought I'd do some research in Haskell. I know little or nothing about indexed monad (though I have built the indexed state monad in C#). So I would assume there would be an indexed monoid (that looks at bit like a tuple?)... e.g. (a,b) ++ (c,d) = (a,b,c,d) (a,b,c,d) ++ (e) = (a,b,c,d,e) ? There seems to be some stuff about "update monads", but it doesn't really look like a writer. I could do with playing around with an indexed writer, in order to get my head around what I'm doing....then try and capture what I'm doing...then try (and fail) to port it back. CONFIDENTIALITY NOTICE This e-mail (and any attached files) is confidential and protected by copyright (and other intellectual property rights). If you are not the intended recipient please e-mail the sender and then delete the email and any attached files immediately. Any further use or dissemination is prohibited. While MTV Networks Europe has taken steps to ensure that this email and any attachments are virus free, it is your responsibility to ensure that this message and any attachments are virus free and do not affect your systems / data. Communicating by email is not 100% secure and carries risks such as delay, data corruption, non-delivery, wrongful interception and unauthorised amendment. If you communicate with us by e-mail, you acknowledge and assume these risks, and you agree to take appropriate measures to minimise these risks when e-mailing us. MTV Networks International, MTV Networks UK & Ireland, Greenhouse, Nickelodeon Viacom Consumer Products, VBSi, Viacom Brand Solutions International, Be Viacom, Viacom International Media Networks and VIMN and Comedy Central are all trading names of MTV Networks Europe. MTV Networks Europe is a partnership between MTV Networks Europe Inc. and Viacom Networks Europe Inc. Address for service in Great Britain is 17-29 Hawley Crescent, London, NW1 8TT.