Re: Updating/understanding code from implicit configurations paper

19 Jan 2013


      Whoops. I forgot you need the explicit `forall` with scoped type variables. I thought there was something much more involved going on here. Thanks, Shachaf.

Eric

On Jan 18, 2013, at 17:54 , Shachaf Ben-Kiki  wrote:
...
On Fri, Jan 18, 2013 at 3:32 PM, Eric M. Pashman  wrote:
...
normalize :: (Modular s a, Integral a) => a -> M s a
   normalize x = (M (mod x (modulus (undefined :: s)))) :: M s a
If you want your type variables to be scoped, you have to annotate
them explicitly:
normalize :: forall s a. (Modular s a, Integral a) => a -> M s a
 normalize x = M (mod x (modulus (undefined :: s)))
See http://www.haskell.org/ghc/docs/7.4.2/html/users_guide/other-type-extensions....
Shachaf