[Haskell-cafe] Monad instance for Data.Set, again

[Henning Thielemann]

On Fri, 28 Mar 2008, Wolfgang Jeltsch wrote:

> But it is possible to give a construction of an Ord dictionary from an 
> AssociatedMonad dictionary.  See the attached code.  It works like a 
> charm. :-)

Yeah, type families! In which GHC release they will be included?

  Sometimes I wonder how many single type extensions we will see in future 
or whether there will be one mechanism which subsumes all existing ones in 
a simple manner. (Full logic programming on type level? Manual 
determination of the class dictionary to be used?)