[Haskell-cafe] Non-exported type classes?
zunino at di.unipi.it
Sat Mar 3 19:03:45 EST 2007
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 S a
-- Not exported
class Peano b where
instance Peano Z where
instance Peano a => Peano (S a) where
class Peano a => C a where
Would that limit the instances of the class C to the Peano type naturals?
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