Re: suggestion: A common type class for mutable variables

9 Jun 2013


      Henning Thielemann wrote:
...
On Mon, 3 Jun 2013, Edward Kmett wrote:
...
The first option is
class Monad m => MonadRef r m | m -> r where
  newRef :: a -> m (r a)
  ...
I thought the functional dependency should be the other way round:
From the reference type to the monad where it lives in.
You can have it both ways.

class Monad m => RefM m r | m -> r, r -> m where
    -- | Create a new reference.
    newRef :: a -> m (r a)
    [...]

Cheers,

Bertram

Re: suggestion: A common type class for mutable variables

Bertram Felgenhauer