Re: Non-monolithic version of 'sequence' for IO monad?

Is there any way, short of using unsafePerformIO, to implement a combinator f :: [IO a] -> IO [a] in a way that the the result is produced lazily?

The problem with sequence :: (Monad m) => [m a] -> m [a] sequence = foldr (liftM2 (:)) (return []) where liftM2 f a b = do { a' <- a; b' <- b; return (f a' b') } is that it consumes the entire input before producing a result.

Are you *really* sure that the latter consumes its entire input before producing any result? It looks pretty lazy to me, and I seem to be able to give it an infinite list of computations and yet start receiving results immediately.... Regards, Malcolm