It is hard to tell from your code what you intend, but it works
however you want it to, so long as it type checks.
class Frame a where
type Whatever a
len :: Whatever a -> IO (Maybe Int)
row :: Whatever a -> MaybeT IO (DifTomoFrame a DIM1)
instance Frame DataFrameH5Path where
type Whatever DataFrameH5Path = DataFrameH5
len = undefined -- :: DataFrameH5 -> IO (Maybe Int)
row = undefined -- :: DataFrameH5 -> Int -> MaybeT (DifTomoFrame
DataFrameH5Path DIM1)
On Wed, Feb 22, 2017 at 11:19 AM, PICCA Frederic-Emmanuel
Hello thanks, I will investigate, but I like this solution. I can ad more type to a type family right ?
Is it possible with this type family to be able to link in the other way ?
a -> t
Cheers
Fred _______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners