[Haskell] Re: Crazy class stuff
taralx at gmail.com
Tue Mar 13 03:55:54 EDT 2007
On 3/13/07, Taral <taralx at gmail.com> wrote:
> This is closer, but still doesn't work:
And this works, and I don't know why:
class MonadTrans' i o where
lift' :: (Monad i, Monad o) => i a -> o a
instance Monad m => MonadTrans' m m where
lift' = id
instance (MonadTrans t, Monad b, MonadTrans' a b) => MonadTrans' a (t b) where
lift' = lift . lift'
Taral <taralx at gmail.com>
"You can't prove anything."
-- Gödel's Incompetence Theorem
More information about the Haskell