GitLab

Parser change. Allow currying the context of a typeclass or instance. In keeping with Haskell's pervasive currying.

class (Functor t, Foldable t) => Traversable t where
  ..

instance (cls ~=> Typeable, cls ~=> Eq) => Eq (Dyn cls) where
 ..

instance ( FunctorOf src tgt1 f1
         , FunctorOf src tgt2 f2
         )
        => FunctorOf src (tgt1 × tgt2) (f1 &&& f2) where
  ..

class    (cls a, cls1 a) => (cls & cls1) a
instance (cls a, cls1 a) => (cls & cls1) a

=

class Functor t => Foldable t => Traversable t where
  ..

instance cls ~=> Typeable
      => cls ~=> Eq
      => Eq (Dyn cls)
  where
  ..

instance FunctorOf src tgt1 f1
      => FunctorOf src tgt2 f2
      => FunctorOf src (tgt1 × tgt2) (f1 &&& f2)
  where
  ..

class    cls a => cls1 a => (cls & cls1) a
instance cls a => cls1 a => (cls & cls1) a

Following normal constraints where this is equivalent,

f :: (Eq a, Ord a) => ..
f :: Eq a => Ord a => ..