[Haskell-cafe] Generalized null / zero

[Mario Blažević]

On 01/28/14 21:25, Alvaro J. Genial wrote:
> 1. Is there a more general version of `null`? (e.g. for a Monad, 
> Functor, Applicative, Traversable or the like.)

There is the MonoidNull class from my monoid-subclasses library. It 
comes with plenty of standard instances.

http://hackage.haskell.org/package/monoid-subclasses-0.3.5/docs/Data-Monoid-Null.html