moving Traversable and Foldable to Prelude (Was: Control.Monad proposal: Add whenJust)

[Henning Thielemann]

On Mon, 20 May 2013, Andreas Abel wrote:

> Maybe instead of fiddling with the current Prelude (which might break 
> backwards compatibility), we should design a new prelude which is not 
> automatically loaded but contains roughly the current prelude (with the list 
> functions generalized to collections) plus the "modern" type class stack: 
> Functor, Applicative, Monad, Foldable, Traversable, Monoid etc.

I think the Hackage category Prelude gives a good overview over such 
projects:
    http://hackage.haskell.org/package/#cat:prelude