Choosing implementation depending on class instances using rewriting rules

[Niklas Broberg]

Hi Milan,

> Is there a way to write such a rewriting rule or there is no way of acquiring
> the Ord dictionary in rewrite rule? Or does anyone know any other way
> of implementing such a nub without explicitly listing all Ord instances?

Have a look at http://okmij.org/ftp/Haskell/types.html#class-based-dispatch

Cheers,

/Niklas