[Haskell-cafe] Declaring variance of class parameters?
ross at soi.city.ac.uk
Tue Feb 27 14:03:42 EST 2007
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.
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