2010/10/27 Andy Stewart <lazycat.manatee at gmail.com>: > Serguey Zefirov <sergueyz at gmail.com> writes: >> I think that you should use TH properly, without compiler and logical errors. >> >> What actually do you want? > I'm build multi-processes communication program. You don't need TH here, I think. You can write a class Ask: class Ask a where ask :: YourMonad a and then instance it: instance Ask Int where ask = liftIO $ do { putStrLn "Enter integer:"; l <- getLine; return $ read l} instance Ask Char where ask = liftIO $ do { putStrLn "Enter char:"; l <- getLine; return $ head l} instance Ask String where ask = liftIO $ do { putStrLn "Enter string:"; l <- getLine; return l} instance (Ask a, Ask b, Ask c) => Ask (a,b,c) where ask = liftIO $ do { a <- ask; b <- ask; c <- ask; return (a,b,c)} You can pass ask values between processes, receiving results of asking. TH is great and good, but it is that only when you absolutely exhausted of usual Haskell options.