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module Lib where
import Data.Monoid
import Data.Traversable
import Test.QuickCheck
import Test.QuickCheck.Checkers
--
-- Identity
--
newtype Identity a = Identity a
deriving (Eq, Ord, Show)
instance Functor Identity where
fmap f (Identity x) = Identity $ f x
instance Applicative Identity where
pure = Identity
(Identity f) <*> x = fmap f x
instance Foldable Identity where
foldr f acc (Identity x) = f x acc
instance Arbitrary a => Arbitrary (Identity a) where
arbitrary = fmap Identity $ arbitrary
instance Eq a => EqProp (Identity a) where
(=-=) = eq
instance Traversable Identity where
traverse f (Identity x) = Identity <$> f x
--
-- Constant
--
newtype Constant a b = Constant { getConstant :: a }
deriving (Eq, Ord, Show)
instance Functor (Constant a) where
fmap _ (Constant x) = Constant x
instance Monoid a => Applicative (Constant a) where
pure _ = Constant mempty
(Constant x) <*> (Constant y) = Constant $ mappend x y
instance (Arbitrary a, Arbitrary b) => Arbitrary (Constant a b) where
arbitrary = do
x <- arbitrary
return $ Constant x
instance (Eq a, Eq b) => EqProp (Constant a b) where
(=-=) = eq
instance Foldable (Constant a) where
foldMap _ (Constant _) = mempty
instance Traversable (Constant a) where
traverse f (Constant x) = pure $ Constant x
--
-- Maybe
--
data Optional a = Nada | Yep a deriving (Show, Eq, Ord)
instance Monoid a => Monoid (Optional a) where
mempty = Nada
mappend Nada _ = Nada
mappend _ Nada = Nada
mappend (Yep x) (Yep y) = Yep $ mappend x y
instance Applicative Optional where
pure = Yep
(Yep f) <*> (Yep x) = Yep $ f x
Nada <*> (Yep x) = Nada
_ <*> Nada = Nada
instance Functor Optional where
fmap _ Nada = Nada
fmap f (Yep x) = Yep $ f x
instance Foldable Optional where
foldr f acc Nada = acc
foldr f acc (Yep x) = f x acc
instance Traversable Optional where
traverse f Nada = pure Nada
traverse f (Yep x) = Yep <$> f x
instance (CoArbitrary a, Arbitrary a) => Arbitrary (Optional a) where
arbitrary = do
x <- arbitrary
frequency [ (1, return Nada)
, (2, return $ Yep x)
]
instance (Eq a) => EqProp (Optional a) where
(=-=) = eq
--
-- List
--
data List a = Nil | Cons a (List a) deriving (Eq, Show)
instance Functor List where
fmap _ Nil = Nil
fmap f (Cons x xs) = Cons (f x) (fmap f xs)
instance Foldable List where
foldr _ acc Nil = acc
foldr f acc (Cons x xs) = f x (foldr f acc xs)
instance Traversable List where
sequenceA Nil = pure Nil
sequenceA (Cons x xs) = Cons <$> x <*> (sequenceA xs)
instance Arbitrary a => Arbitrary (List a) where
arbitrary = sized go
where go 0 = pure Nil
go n = do
xs <- go (n - 1)
x <- arbitrary
return $ Cons x xs
instance (Eq a) => EqProp (List a) where
(=-=) = eq
--
-- Three
--
data Three a b c = Three a b c deriving (Show, Eq)
instance Functor (Three a b) where
fmap f (Three x y z) = Three x y (f z)
instance Foldable (Three a b) where
foldr f acc (Three x y z) = (f z acc)
instance Traversable (Three a b) where
traverse f (Three x y z) = fmap (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
instance (Eq a, Eq b, Eq c) => EqProp (Three a b c) where
(=-=) = eq
--
-- Pair
--
data Pair a b = Pair a b deriving (Eq, Show)
instance Functor (Pair a) where
fmap f (Pair x y) = Pair x (f y)
instance Foldable (Pair a) where
foldr f acc (Pair x y) = (f y acc)
instance Traversable (Pair a) where
traverse f (Pair x y) = fmap (Pair x) (f y)
instance (Arbitrary a, Arbitrary b) => Arbitrary (Pair a b) where
arbitrary = do
x <- arbitrary
y <- arbitrary
return $ Pair x y
instance (Eq a, Eq b) => EqProp (Pair a b) where
(=-=) = eq
--
-- Big
--
data Big a b = Big a b b deriving (Eq, Show)
instance Functor (Big a) where
fmap f (Big x y z) = Big x (f y) (f z)
instance Foldable (Big a) where
foldr f acc (Big _ y z) = (f y (f z acc))
instance Traversable (Big a) where
traverse f (Big x y z) = (Big x) <$> (f y) <*> (f z)
instance (Arbitrary a, Arbitrary b) => Arbitrary (Big a b) where
arbitrary = do
x <- arbitrary
y <- arbitrary
z <- arbitrary
return $ Big x y z
instance (Eq a, Eq b) => EqProp (Big a b) where
(=-=) = eq
--
-- Bigger
--
data Bigger a b = Bigger a b b b deriving (Eq, Show)
instance Functor (Bigger a) where
fmap f (Bigger x y z t) = Bigger x (f y) (f z) (f t)
instance Foldable (Bigger a) where
foldr f acc (Bigger _ y z t) = f y $ f z $ f t acc
instance Traversable (Bigger a) where
traverse f (Bigger x y z t) = (Bigger x) <$> (f y) <*> (f z) <*> (f t)
instance (Arbitrary a, Arbitrary b) => Arbitrary (Bigger a b) where
arbitrary = do
x <- arbitrary
y <- arbitrary
z <- arbitrary
t <- arbitrary
return $ Bigger x y z t
instance (Eq a, Eq b) => EqProp (Bigger a b) where
(=-=) = eq
|
