[Haskell-cafe] Quickcheck examples and Data.Word32
Joel Reymont
joelr1 at gmail.com
Thu Oct 27 19:13:07 EDT 2005
Just one more question...
data Prop = forall a b. (Eq a, Eq b, Show a, Packet b, Convertible a b)
=> Attr a b := a
deriving (Typeable)
data Attr a b = Attr String
(a -> Dynamic, Dynamic -> Maybe a)
(a -> b, b -> a)
makeAttr :: (Typeable a, Convertible a b) => String -> Attr a b
makeAttr name = Attr name
(toDyn, fromDynamic)
(convert_AB, convert_BA)
I can do this for Attr
instance (Typeable a, Arbitrary a, Typeable b, Arbitrary b,
Convertible a b) => Arbitrary (Attr a b) where
arbitrary = makeAttr `fmap` arbitrary
coarbitrary a = error "Not implemented"
How do I define an arbitrary prop, though? Following does not work:
arbitraryProp :: forall a b.(Arbitrary a, Arbitrary b) => Attr a b ->
Gen Prop
arbitraryProp = arbitrary := arbitrary
Thanks, Joel
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