{- OPTIONS -ddump-splices #-} {-# LANGUAGE NoMonomorphismRestriction , KindSignatures , GADTs , TemplateHaskell , TypeOperators , RankNTypes , FlexibleContexts #-} module Main where import Control.Arrow import Control.Applicative import Control.Category import Prelude hiding ((.), id) import Test.HUnit import Data.Label import Data.Label.Derive (defaultNaming, mkLabelsWith) import Data.Label.Mono ((:~>)) import Data.Label.Failing (Failing) import Data.Tuple (swap) import Control.Monad.Reader (runReader) import Control.Monad.State (evalState, execState, runState) import qualified Data.Label.Base as L import qualified Data.Label.Failing as Failing import qualified Data.Label.Mono as Mono import qualified Data.Label.Partial as Partial import qualified Data.Label.Poly as Poly import qualified Data.Label.Total as Total import qualified Data.Label.Monadic as Monadic ------------------------------------------------------------------------------- data NoRecord = NoRecord Integer Bool deriving (Eq, Ord, Show) mkLabel ''NoRecord fclabels [d| newtype Newtype a = Newtype { unNewtype :: [a] } deriving (Eq, Ord, Show) |] newtypeL :: ArrowApply cat => Poly.Lens cat (Newtype a -> Newtype b) ([a] -> [b]) newtypeL = unNewtype data Record = Record { _fA :: Integer , _fB :: Maybe (Newtype Bool) , _fC :: Newtype Bool , _fD :: Either Integer Bool } deriving (Eq, Ord, Show) mkLabelsWith defaultNaming False False False False ''Record fD :: ArrowApply cat => Mono.Lens cat (Record) (Either Integer Bool) fC :: ArrowApply cat => Mono.Lens cat (Record) (Newtype Bool) fB :: ArrowApply cat => Mono.Lens cat (Record) (Maybe (Newtype Bool)) fA :: ArrowApply cat => Mono.Lens cat (Record) (Integer) data Multi = First { _mA :: Record , _mB :: Double , _mC :: Either String Float } | Second { _mB :: Double } deriving (Eq, Ord, Show) mkLabels [''Multi] data View = View { _vA :: Maybe (Newtype Bool) , _vB :: Either Integer Bool , _vC :: Newtype Bool } deriving (Eq, Ord, Show) mkLabelsWith defaultNaming True True False False ''View data Direction i a b c d = North { _dir :: i, _north :: a } | East { _dir :: i, _east :: b } | South { _dir :: i, _south :: c } | West { _dir :: i, _west :: d } | All { _dir :: i, _allDirs :: (a, b, c, d) } deriving (Eq, Ord, Show) mkLabelsWith defaultNaming True False True True ''Direction -- Higher kinded type variable, requires KindSignatures. data Fa f a = Fa { fa :: f a } mkLabel ''Fa ------------------------------------------------------------------------------- data Gadt a where C1 :: { ga :: Integer, gb :: Bool } -> Gadt (Int, Bool) C2 :: { gc :: Integer, gd :: Maybe Bool } -> Gadt Bool C3 :: { ge :: a, gf :: b } -> Gadt (a, b) C4 :: { gg :: a } -> Gadt [a] C5 :: { gd :: Maybe Bool } -> Gadt Bool C6 :: { gh :: [a] } -> Gadt (a, a, a) mkLabel ''Gadt _Ga :: (ArrowApply cat, ArrowChoice cat, ArrowZero cat) => Mono.Lens cat (Gadt (Int, Bool)) Integer _Gb :: (ArrowApply cat, ArrowChoice cat, ArrowZero cat) => Mono.Lens cat (Gadt (Int, Bool)) Bool _Gc :: (ArrowApply cat, ArrowChoice cat, ArrowZero cat) => Mono.Lens cat (Gadt Bool) Integer _Gd :: (ArrowApply cat ) => Mono.Lens cat (Gadt Bool) (Maybe Bool) _Ge :: (ArrowApply cat, ArrowChoice cat, ArrowZero cat) => Poly.Lens cat (Gadt (a, b) -> Gadt (c, b)) (a -> c) _Gf :: (ArrowApply cat, ArrowChoice cat, ArrowZero cat) => Poly.Lens cat (Gadt (a, b) -> Gadt (a, c)) (b -> c) _Gg :: (ArrowApply cat ) => Poly.Lens cat (Gadt [a] -> Gadt [b]) (a -> b) _Gh :: (ArrowApply cat ) => Poly.Lens cat (Gadt (a, a, a) -> Gadt (b, b, b)) ([a] -> [b]) _Ga = lGa; _Gb = lGb; _Gc = lGc; _Gd = lGd; _Ge = lGe; _Gf = lGf; _Gg = lGg; _Gh = lGh; ------------------------------------------------------------------------------- embed_fB :: Record :~> Newtype Bool embed_fB = Partial.embed fB manual_fA :: Record :-> Integer manual_fA = Total.lens _fA (\m f -> f { _fA = m (_fA f) }) manual_fA_m :: Mono.Lens (->) Record Integer manual_fA_m = lens _fA (\m f -> f { _fA = m (_fA f) }) manual_mA :: Multi :~> Record manual_mA = Partial.lens (\p -> case p of First {} -> Just (_mA p); _ -> Nothing) (\m p -> case p of First {} -> (\v -> p { _mA = v }) `fmap` m (_mA p); _ -> Nothing) mA_f :: Failing.Lens String (Multi -> Multi) (Record -> Record) mA_f = mA manual_mA_f :: Failing.Lens String (Multi -> Multi) (Record -> Record) manual_mA_f = Failing.lens (\p -> case p of First {} -> Right (_mA p); _ -> Left "mA") (\m p -> case p of First {} -> (\v -> p { _mA = v }) `fmap` m (_mA p); _ -> Left "mA") embed_fD :: Failing.Lens Integer (Record -> Record) (Bool -> Bool) embed_fD = Failing.embed fD manual_dir :: Poly.Lens (->) (Direction i a b c d -> Direction e a b c d) (i -> e) manual_dir = Poly.lens _dir (\(m, f) -> f {_dir = m (_dir f) }) north_f :: Poly.Lens (Failing String) (Direction i a b c d -> Direction i e b c d) (a -> e) north_f = north fAmA :: Multi :~> Integer fAmA = fA . mA recordView :: Record :-> View recordView = Poly.point $ View <$> vA >- fB <*> vB >- fD <*> vC >- fC newtypeId :: Newtype Bool :-> Newtype Bool newtypeId = Poly.point (id <$> id >- id) ------------------------------------------------------------------------------- fclabels [d| data View2 a = Con1 { field1 :: Bool , field2 :: (a, a) } | Con2 { field1 :: Bool , field3 :: [a] } deriving (Eq, Show) |] view :: View2 a :~> Either (Bool, (a, a)) (Bool, [a]) view = point $ Left <$> L.left >- con1 <|> Right <$> L.right >- con2 where con1 = point $ (,) <$> L.fst >- field1 <*> L.snd >- field2 con2 = point $ (,) <$> L.fst >- field1 <*> L.snd >- field3 ------------------------------------------------------------------------------- -- Test data type with large number (> 26) of fields. fclabels [d| data C = C { c_a :: (), c_b :: (), c_c :: (), c_d :: (), c_e :: (), c_f :: () , c_g :: (), c_h :: (), c_i :: (), c_j :: (), c_k :: (), c_l :: () , c_m :: (), c_n :: (), c_o :: (), c_p :: (), c_q :: (), c_r :: () , c_s :: (), c_t :: (), c_u :: (), c_v :: (), c_w :: (), c_x :: () , c_y :: (), c_z :: (), c_a0 :: (), c_b0 :: (), c_c0 :: (), c_d0 :: () } |] ------------------------------------------------------------------------------- newtype0, newtype1, newtype2 :: Newtype Bool newtype0 = Newtype [] newtype1 = Newtype [True] newtype2 = Newtype [False] record0, record1, record2, record3, record4, record5, record10, record11 :: Record record0 = Record 0 Nothing newtype0 (Left 1) record1 = Record 1 Nothing newtype0 (Left 1) record2 = Record 0 (Just newtype1) newtype0 (Left 1) record3 = Record 0 (Just newtype0) newtype0 (Left 1) record4 = Record 0 Nothing newtype0 (Right True) record5 = Record 0 Nothing newtype0 (Right False) record10 = Record 10 Nothing newtype0 (Left 1) record11 = Record 11 Nothing newtype0 (Left 1) first0, first1, first2 :: Multi first0 = First record0 0.0 (Right 1.0) first1 = First record0 1.0 (Right 1.0) first2 = First record1 0.0 (Right 1.0) second0, second1 :: Multi second0 = Second 0.0 second1 = Second 1.0 north0 :: Direction Integer () () () () north0 = North 0 () north1 :: Direction Bool () () () () north1 = North False () north2 :: Direction Integer Bool () () () north2 = North 0 False west0 :: Direction Integer () () () () west0 = West 0 () mulDiv :: Iso (->) Integer Double mulDiv = Iso (\i -> fromInteger i / 10) (\i -> round (i * 10)) addSub :: Iso (->) Double Integer addSub = Iso (\i -> round (i + 10)) (\i -> fromInteger i - 10) ------------------------------------------------------------------------------- main :: IO () main = do _ <- runTestTT allTests return () allTests :: Test allTests = TestList [ mono , totalMono , partialMono , failingMono , totalPoly , partialPoly , failingPoly , composition , applicativeTotal , applicativePartial , bijections , monadic , base ] mono :: Test mono = TestList [ eq "get manual_fA_m" (get manual_fA_m record0) 0 , eq "set manual_fA_m" (set manual_fA_m 1 record0) record1 , eq "mod manual_fA_m" (modify manual_fA_m (+ 1) record0) record1 ] where eq :: (Eq a, Show a) => String -> a -> a -> Test eq x = equality ("total mono " ++ x) totalMono :: Test totalMono = TestList [ eq "get fA" (Total.get fA record0) 0 , eq "set fA" (Total.set fA 1 record0) record1 , eq "mod fA" (Total.modify fA (+ 1) record0) record1 , eq "get manual_fA" (Total.get manual_fA record0) 0 , eq "set manual_fA" (Total.set manual_fA 1 record0) record1 , eq "mod manual_fA" (Total.modify manual_fA (+ 1) record0) record1 , eq "get mB" (Total.get mB first0) 0 , eq "set mB" (Total.set mB 1 first0) first1 , eq "mod mB" (Total.modify mB (+ 1) first0) first1 ] where eq :: (Eq a, Show a) => String -> a -> a -> Test eq x = equality ("total mono " ++ x) partialMono :: Test partialMono = TestList [ eq0 "get mA" (Partial.get mA first0) (Just record0) , eq0 "set mA" (Partial.set mA record1 first0) (Just first2) , eq0 "mod mA" (Partial.modify mA (Total.modify fA (+ 1)) first0) (Just first2) , eq0 "get manual_mA" (Partial.get manual_mA first0) (Just record0) , eq0 "set manual_mA" (Partial.set manual_mA record1 first0) (Just first2) , eq0 "mod manual_mA" (Partial.modify manual_mA (Total.modify fA (+ 1)) first0) (Just first2) , eq1 "get mA" (Partial.get mA second0) Nothing , eq1 "set mA" (Partial.set mA record1 second0) Nothing , eq1 "mod mA" (Partial.modify mA (Total.modify fA (+ 1)) second0) Nothing , eq1 "get manual_mA" (Partial.get manual_mA second0) Nothing , eq1 "set manual_mA" (Partial.set manual_mA record1 second0) Nothing , eq1 "mod manual_mA" (Partial.modify manual_mA (Total.modify fA (+ 1)) second0) Nothing , eq2 "set mA" (Partial.set' mA record1 first0) first2 , eq2 "mod mA" (Partial.modify' mA (Total.modify fA (+ 1)) first0) first2 , eq2 "set manual_mA" (Partial.set' manual_mA record1 first0) first2 , eq2 "mod manual_mA" (Partial.modify' manual_mA (Total.modify fA (+ 1)) first0) first2 , eq2 "set mA" (Partial.set' mA record1 second0) second0 , eq2 "mod mA" (Partial.modify' mA (Total.modify fA (+ 1)) second0) second0 , eq2 "set manual_mA" (Partial.set' manual_mA record1 second0) second0 , eq2 "mod manual_mA" (Partial.modify' manual_mA (Total.modify fA (+ 1)) second0) second0 , eq3 "get embed_fB" (Partial.get embed_fB record2) (Just newtype1) , eq3 "set embed_fB" (Partial.set embed_fB newtype0 record2) (Just record3) , eq3 "mod embed_fB" (Partial.modify embed_fB (const newtype0) record2) (Just record3) , eq4 "get embed_fB" (Partial.get embed_fB record0) Nothing , eq4 "set embed_fB" (Partial.set embed_fB newtype0 record0) Nothing , eq4 "mod embed_fB" (Partial.modify embed_fB (const newtype0) record0) Nothing ] where eq0, eq1, eq2, eq3, eq4 :: (Eq a, Show a) => String -> a -> a -> Test eq0 x = equality ("partial mono " ++ x) eq1 x = equality ("partial mono fail " ++ x) eq2 x = equality ("partial mono prime " ++ x) eq3 x = equality ("partial mono embed " ++ x) eq4 x = equality ("partial mono embed fail" ++ x) failingMono :: Test failingMono = TestList [ eq0 "get mA_f" (Failing.get mA_f first0) (Right record0) , eq0 "set mA_f" (Failing.set mA_f record1 first0) (Right first2) , eq0 "mod mA_f" (Failing.modify mA_f (Total.modify fA (+ 1)) first0) (Right first2) , eq0 "get manual_mA_f" (Failing.get manual_mA_f first0) (Right record0) , eq0 "set manual_mA_f" (Failing.set manual_mA_f record1 first0) (Right first2) , eq0 "mod manual_mA_f" (Failing.modify manual_mA_f (Total.modify fA (+ 1)) first0) (Right first2) , eq1 "get mA_f fail" (Failing.get mA_f second0) (Left "") , eq1 "set mA_f fail" (Failing.set mA_f record1 second0) (Left "") , eq1 "mod mA_f fail" (Failing.modify mA_f (Total.modify fA (+ 1)) second0) (Left "") , eq1 "get manual_mA_f" (Failing.get manual_mA_f second0) (Left "mA") , eq1 "set manual_mA_f" (Failing.set manual_mA_f record1 second0) (Left "mA") , eq1 "mod manual_mA_f" (Failing.modify manual_mA_f (Total.modify fA (+ 1)) second0) (Left "mA") , eq2 "set mA_f" (Failing.set' mA_f record1 first0) first2 , eq2 "mod mA_f" (Failing.modify' mA_f (Total.modify fA (+ 1)) first0) first2 , eq2 "set manual_mA_f" (Failing.set' manual_mA_f record1 first0) first2 , eq2 "mod manual_mA_f" (Failing.modify' manual_mA_f (Total.modify fA (+ 1)) first0) first2 , eq2 "set mA_f" (Failing.set' mA_f record1 second0) second0 , eq2 "mod mA_f" (Failing.modify' mA_f (Total.modify fA (+ 1)) second0) second0 , eq2 "set manual_mA_f" (Failing.set' manual_mA_f record1 second0) second0 , eq2 "mod manual_mA_f" (Failing.modify' manual_mA_f (Total.modify fA (+ 1)) second0) second0 , eq3 "get embed_fD" (Failing.get embed_fD record4) (Right True) , eq3 "set embed_fD" (Failing.set embed_fD False record4) (Right record5) , eq3 "mod embed_fD" (Failing.modify embed_fD not record4) (Right record5) , eq4 "get embed_fD" (Failing.get embed_fD record0) (Left 1) , eq4 "set embed_fD" (Failing.set embed_fD False record0) (Left 1) , eq4 "mod embed_fD" (Failing.modify embed_fD not record0) (Left 1) ] where eq0, eq1, eq2, eq3, eq4 :: (Eq a, Show a) => String -> a -> a -> Test eq0 x = equality ("failing mono " ++ x) eq1 x = equality ("failing mono fail " ++ x) eq2 x = equality ("failing mono prime " ++ x) eq3 x = equality ("failing mono embed " ++ x) eq4 x = equality ("failing mono embed fail " ++ x) totalPoly :: Test totalPoly = TestList [ eq "get dir" (Total.get dir north0) (0 :: Integer) , eq "set dir" (Total.set dir False north0) north1 , eq "mod dir" (Total.modify dir (> 1) north0) north1 , eq "get manual_dir" (Total.get manual_dir north0) 0 , eq "set manual_dir" (Total.set manual_dir False north0) north1 , eq "mod manual_dir" (Total.modify manual_dir (> 1) north0) north1 ] where eq :: (Eq a, Show a) => String -> a -> a -> Test eq x = equality ("total mono " ++ x) partialPoly :: Test partialPoly = TestList [ eq0 "get north" (Partial.get north north0) (Just ()) , eq0 "set north" (Partial.set north False north0) (Just north2) , eq0 "mod north" (Partial.modify north (> ()) north0) (Just north2) , eq1 "get north" (Partial.get north west0) Nothing , eq1 "set north" (Partial.set north False west0) Nothing , eq1 "mod north" (Partial.modify north (> ()) west0) Nothing ] where eq0, eq1 :: (Eq a, Show a) => String -> a -> a -> Test eq0 x = equality ("partial poly " ++ x) eq1 x = equality ("partial poly fail " ++ x) failingPoly :: Test failingPoly = TestList [ eq0 "get north" (Failing.get north_f north0) (Right ()) , eq0 "set north" (Failing.set north_f False north0) (Right north2) , eq0 "mod north" (Failing.modify north_f (> ()) north0) (Right north2) , eq1 "get north" (Failing.get north_f west0) (Left "north") , eq1 "set north" (Failing.set north_f False west0) (Left "north") , eq1 "mod north" (Failing.modify north_f (> ()) west0) (Left "north") ] where eq0, eq1 :: (Eq a, Show a) => String -> a -> a -> Test eq0 x = equality ("failing poly " ++ x) eq1 x = equality ("failing poly fail " ++ x) composition :: Test composition = TestList [ eq0 "get id" (Partial.get id first0) (Just first0) , eq0 "set id" (Partial.set id first2 first0) (Just first2) , eq0 "mod id" (Partial.modify id (const first2) first0) (Just first2) , eq0 "get fAmA" (Partial.get fAmA first0) (Just 0) , eq0 "set fAmA" (Partial.set fAmA 1 first0) (Just first2) , eq0 "mod fAmA" (Partial.modify fAmA (+ 1) first0) (Just first2) , eq0 "get id fAmA" (Partial.get (id . fAmA) first0) (Just 0) , eq0 "set id fAmA" (Partial.set (id . fAmA) 1 first0) (Just first2) , eq0 "mod id fAmA" (Partial.modify (id . fAmA) (+ 1) first0) (Just first2) , eq0 "get fAmA id" (Partial.get (fAmA . id) first0) (Just 0) , eq0 "set fAmA id" (Partial.set (fAmA . id) 1 first0) (Just first2) , eq0 "mod fAmA id" (Partial.modify (fAmA . id) (+ 1) first0) (Just first2) ] where eq0 :: (Eq a, Show a) => String -> a -> a -> Test eq0 x = equality ("composition partial mono" ++ x) applicativeTotal :: Test applicativeTotal = TestList [ eq "get vA" (Total.get (vA . recordView) record0) Nothing , eq "get vB" (Total.get (vB . recordView) record0) (Left 1) , eq "get vC" (Total.get (vC . recordView) record0) newtype0 , eq "set vA" (Total.set (vA . recordView) (Just newtype0) record2) record3 , eq "modify vA" (Total.modify (vA . recordView) (fmap (const newtype0)) record2) record3 , eq "get newtypeId" (Total.get newtypeId newtype0) newtype0 , eq "set newtypeId" (Total.set newtypeId newtype1 newtype0) newtype1 , eq "mod newtypeId" (Total.modify newtypeId (const newtype2) newtype0) newtype2 ] where eq :: (Eq a, Show a) => String -> a -> a -> Test eq x = equality ("applicative total mono" ++ x) myCon1 :: View2 Char myCon1 = Con1 False ('a', 'z') myCon2 :: View2 Char myCon2 = Con2 True "abc" applicativePartial :: Test applicativePartial = TestList [ eq "get" (Partial.get (L.snd . L.left . view) myCon1) (Just ('a', 'z')) , eq "get" (Partial.get (L.snd . L.left . view) myCon2) Nothing , eq "get" (Partial.get (L.snd . L.right . view) myCon1) Nothing , eq "get" (Partial.get (L.snd . L.right . view) myCon2) (Just "abc") , eq "mod" (Partial.modify (L.fst . L.left . view) not myCon1) (Just (Con1 True ('a', 'z'))) , eq "mod" (Partial.modify (L.fst . L.left . view) not myCon2) Nothing , eq "mod" (Partial.modify (L.fst . L.right . view) not myCon1) Nothing , eq "mod" (Partial.modify (L.fst . L.right . view) not myCon2) (Just (Con2 False "abc")) , eq "mod" (Partial.modify (L.snd . L.left . view) swap myCon1) (Just (Con1 False ('z', 'a'))) , eq "mod" (Partial.modify (L.snd . L.left . view) swap myCon2) Nothing , eq "mod" (Partial.modify (L.snd . L.right . view) reverse myCon1) Nothing , eq "mod" (Partial.modify (L.snd . L.right . view) reverse myCon2) (Just (Con2 True "cba")) ] where eq :: (Eq a, Show a) => String -> a -> a -> Test eq x = equality ("applicative partial mono" ++ x) bijections :: Test bijections = TestList [ eq "get mulDiv" (get (iso mulDiv . fA) record0) 0 , eq "set mulDiv" (set (iso mulDiv . fA) 1 record0) record10 , eq "mod mulDiv" (modify (iso mulDiv . fA) (+ 1) record0) record10 , eq "get addSub" (get (iso (inv addSub) . fA) record0) (-10) , eq "set addSub" (set (iso (inv addSub) . fA) 1 record0) record11 , eq "mod addSub" (modify (iso (inv addSub) . fA) (+ 1) record0) record1 , eq "get id mulDiv" (get (iso (id . mulDiv) . fA) record0) 0 , eq "set id mulDiv" (set (iso (id . mulDiv) . fA) 1 record0) record10 , eq "mod id mulDiv" (modify (iso (id . mulDiv) . fA) (+ 1) record0) record10 , eq "get id mulDiv" (get (iso (mulDiv . id) . fA) record0) 0 , eq "set id mulDiv" (set (iso (mulDiv . id) . fA) 1 record0) record10 , eq "mod id mulDiv" (modify (iso (mulDiv . id) . fA) (+ 1) record0) record10 ] where eq :: (Eq a, Show a) => String -> a -> a -> Test eq x = equality ("isomorphisms mono " ++ x) monadic :: Test monadic = TestList [ eq "asks id total" (runReader (Monadic.asks id) record0) record0 , eq "asks fC total" (runReader (Monadic.asks fC) record0) newtype0 , eq "gets id total" (evalState (Monadic.gets id) record0) record0 , eq "gets fC total" (evalState (Monadic.gets fC) record0) newtype0 , eq "put fA total" (execState (fA Monadic.=: 1) record0) record1 , eq "modify fA total" (execState (fA Monadic.=. (+ 1)) record0) record1 , eq "local fA total" (runReader (Monadic.local fA (+1) $ Monadic.asks id) record0) record1 , eq "modifyAndGet fA total" (runState (Monadic.modifyAndGet fA (\a -> (a+10, a+1))) record0) (10, record1) ] where eq :: (Eq a, Show a) => String -> a -> a -> Test eq x = equality ("total monadic " ++ x) base :: Test base = TestList [ eq "get head" (Partial.get L.head [1, 2, 3]) (Just (1::Int)) , eq "get head" (Partial.get L.head ([] :: [Int])) Nothing , eq "get tail" (Partial.get L.tail [1, 2, 3]) (Just [2, 3 ::Int]) , eq "get tail" (Partial.get L.tail ([] :: [Int])) Nothing , eq "get left" (Partial.get L.left (Left 'a')) (Just 'a') , eq "get left" (Partial.get L.left (Right 'a' :: Either () Char)) Nothing , eq "get right" (Partial.get L.right (Right 'a')) (Just 'a') , eq "get right" (Partial.get L.right (Left 'a' :: Either Char ())) Nothing , eq "get just" (Partial.get L.just (Just 'a')) (Just 'a') , eq "get just" (Partial.get L.just (Nothing :: Maybe Char)) Nothing , eq "get fst" (Total.get (L.fst . L.swap) ('a', ())) () , eq "get snd" (Total.get (L.snd . L.swap) ((), 'b')) () , eq "get fst3" (Total.get L.fst3 ('a', (), ())) 'a' , eq "get snd3" (Total.get L.snd3 ((), 'b', ())) 'b' , eq "get trd3" (Total.get L.trd3 ((), (), 'c')) 'c' , eq "mod head" (Partial.modify L.head (*2) [1, 2, 3]) (Just [2, 2, 3::Int]) , eq "mod head" (Partial.modify L.head (*2) ([]::[Int])) Nothing , eq "mod tail" (Partial.modify L.tail reverse [1, 2, 3]) (Just [1, 3, 2::Int]) , eq "mod tail" (Partial.modify L.tail reverse ([]::[Int])) Nothing , eq "mod left" (Partial.modify L.left (=='a') (Left 'a')) (Just (Left True :: Either Bool ())) , eq "mod left" (Partial.modify L.left (=='a') (Right ())) (Nothing :: Maybe (Either Bool ())) , eq "mod right" (Partial.modify L.right (=='c') (Right 'b')) (Just (Right False :: Either () Bool)) , eq "mod right" (Partial.modify L.right (=='c') (Left ())) (Nothing :: Maybe (Either () Bool)) , eq "mod just" (Partial.modify L.just (=='a') (Just 'a')) (Just (Just True)) , eq "mod just" (Partial.modify L.just (=='a') Nothing) Nothing , eq "mod fst" (Total.modify (L.fst . L.swap) (== 'a') ((), 'a')) ((), True) , eq "mod snd" (Total.modify (L.snd . L.swap) (== 'a') ('a', ())) (True, ()) , eq "mod fst3" (Total.modify L.fst3 (== 'a') ('a', (), ())) (True, (), ()) , eq "mod snd3" (Total.modify L.snd3 (== 'a') ((), 'b', ())) ((), False, ()) , eq "mod trd3" (Total.modify L.trd3 (== 'a') ((), (), 'c')) ((), (), False) ] where eq :: (Eq a, Show a) => String -> a -> a -> Test eq x = equality ("base" ++ x) equality :: (Eq a, Show a) => String -> a -> a -> Test equality d a b = TestCase (assertEqual d b a)