[Haskell-cafe] Non-exported type classes?
lennart at augustsson.net
Sat Mar 3 19:13:50 EST 2007
Yes, as far as I can tell, C would be limited to Z and S.
On Mar 4, 2007, at 00:03 , Roberto Zunino wrote:
> What is the effect of declaring a class in a module and not exporting
> it? Would that prevent to add more instances to that class other than
> those already defined in the module?
> More in detail, consider this module:
> module Peano (Z,S,C) where
> data Z
> data S a
> -- Not exported
> class Peano b where
> instance Peano Z where
> instance Peano a => Peano (S a) where
> -- Exported
> class Peano a => C a where
> Would that limit the instances of the class C to the Peano type
> Roberto Zunino.
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