On Tue, Mar 24, 2009 at 4:42 PM, Sittampalam, Ganesh
Sittampalam, Ganesh wrote:
I've tried this now. Various new failures, which I don't have time to investigate all of tonight, but the first one I looked at is in the 'cgi' package, and is because the Functor instances for ReaderT r m and WriterT w m now (correctly) depend on Functor m, whereas in mtl they depend on Monad m.
As long as we're on the topic of class constraints, is there any reason that the Monad instance for ContT m has a class constraint on the type of 'm'? I'm pretty sure we can lose it, as well as the similar class constraint on the instance of MonadCont. That's one of the most important things about the (ContT m) monad to me - it's a monad transformer that doesn't hit the class dictionary of what it's wrapping around. Antoine