Re: [Haskell-cafe] Declaring variance of class parameters?

On Tue, Feb 27, 2007 at 02:00:29PM -0500, Jacques Carette wrote:

If I have a class, say class Symantics repr where int:: Int -> repr Int

and so on, I would like to *require* that 'repr' be covariant. Is there any way to do that?

class Functor repr => Symantics repr would be pretty close, and has the virtue of saying what you mean.