Re: [Haskell-cafe] is closing a class this easy?

On Fri, Jul 17, 2009 at 4:38 PM, Conor McBride wrote:

class Private x where

public :: (forall x. Public x => x -> y) -> y public f = f Pike

data Pike = Pike instance Private Pike instance Public Pike

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But if I don't tell 'em Pike, I've ensured that blah can only be used in the argument to public.

Well I appreciated this bit even if no-one else did! :-) Also, that's a nifty trick if it works! D