[Haskell-cafe] difference between class context and deriving

[Henning Thielemann]

On Tue, 2 Aug 2011, Patrick Browne wrote:

> What is the difference between using a class context and deriving in
> data type declaration?
> Are there certain situations in which one or the other is preferred?
>
> data Eq a => Set1 a = NilSet1 | ConsSet1 a (Set1 a)

Note that these contexts might get removed from the language:
    http://hackage.haskell.org/trac/haskell-prime/wiki/NoDatatypeContexts