Hello,
Is it unsafe to add the following catch-all MonadIO instance to
transformers' Control.Monad.IO.Class module?
{-# LANGUAGE FlexibleInstances, FlexibleContexts, UndecidableInstances #-}
instance (MonadTrans t, Monad (t m), MonadIO m) = MonadIO (t m) where
liftIO = lift . liftIO
It
On Fri, Oct 28, 2011 at 9:11 AM, Bas van Dijk v.dijk@gmail.com wrote:
Hello,
Is it unsafe to add the following catch-all MonadIO instance to
transformers' Control.Monad.IO.Class module?
{-# LANGUAGE FlexibleInstances, FlexibleContexts, UndecidableInstances #-}
instance (MonadTrans t,
Bas van Dijk writes:
Is it unsafe to add the following catch-all MonadIO instance to
transformers' Control.Monad.IO.Class module?
{-# LANGUAGE FlexibleInstances, FlexibleContexts, UndecidableInstances #-}
instance (MonadTrans t, Monad (t m), MonadIO m) = MonadIO (t m) where
liftIO =
On 28 October 2011 16:23, Antoine Latter aslat...@gmail.com wrote:
I would then need OverlappingInstances to declare a MonadIO instance
for any similar looking instance head (that is `t m`) where 't' was
not a proper MonadTrans instance, which sounds like a common enough
things to do.
I
Bas van Dijk v.dijk@gmail.com wrote:
I understand, portability is important for transformers. For
monad-control it's less of an issue because I already use other
language extensions (incl. RankNTypes).
So I think I go ahead and add a catch-all instance for MonadControlIO
to
On 28 October 2011 16:59, Ertugrul Soeylemez e...@ertes.de wrote:
I'm not sure whether this will work well. You will get overlapping
instances, and I don't see a way to hide instances when importing.
Perhaps the OverlappingInstances extension could help here.
You're right.
I didn't get an
