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module Func where
import Test.QuickCheck
-- class Functor f where
-- fmap :: (a -> b) -> f a -> f b
newtype Identity a = Identity a deriving (Eq, Show)
instance Functor Identity where
fmap f (Identity a) = Identity $ f a
instance Arbitrary a => Arbitrary (Identity a) where
arbitrary = fmap Identity arbitrary
data Pair a = Pair a a deriving (Eq, Show)
instance Functor Pair where
fmap f (Pair x y) = Pair (f x) (f y)
instance Arbitrary a => Arbitrary (Pair a) where
arbitrary = do
x <- arbitrary
y <- arbitrary
return $ Pair x y
data Two a b = Two a b deriving (Eq, Show)
instance Functor (Two a) where
fmap f (Two x y) = Two x (f y)
instance (Arbitrary a, Arbitrary b) => Arbitrary (Two a b) where
arbitrary = do
x <- arbitrary
y <- arbitrary
return $ Two x y
data Three a b c = Three a b c deriving (Eq, Show)
instance Functor (Three a b) where
fmap f (Three x y z) = Three x y (f z)
instance (Arbitrary a, Arbitrary b, Arbitrary c) => Arbitrary (Three a b c) where
arbitrary = do
x <- arbitrary
y <- arbitrary
z <- arbitrary
return $ Three x y z
data Three' a b = Three' a b b deriving (Eq, Show)
instance Functor (Three' a) where
fmap f (Three' x y z) = Three' x (f y) (f z)
instance (Arbitrary a, Arbitrary b) => Arbitrary (Three' a b) where
arbitrary = do
x <- arbitrary
y <- arbitrary
z <- arbitrary
return $ Three' x y z
data Four a b c d = Four a b c d deriving (Eq, Show)
instance Functor (Four a b c) where
fmap f (Four x y z t) = Four x y z (f t)
instance (Arbitrary a, Arbitrary b, Arbitrary c, Arbitrary d)
=> Arbitrary (Four a b c d) where
arbitrary = do
x <- arbitrary
y <- arbitrary
z <- arbitrary
t <- arbitrary
return $ Four x y z t
data Four' a b = Four' a a a b deriving (Eq, Show)
instance Functor (Four' a) where
fmap f (Four' x y z t) = Four' x y z (f t)
instance (Arbitrary a, Arbitrary b) => Arbitrary (Four' a b) where
arbitrary = do
x <- arbitrary
y <- arbitrary
z <- arbitrary
t <- arbitrary
return $ Four' x y z t
data Trivial = Trivial
|
