Safe Haskell | Safe |
---|---|
Language | Haskell2010 |
This module reexports functions to work with monoids plus adds extra useful functions.
Synopsis
- class Semigroup a => Monoid a where
- newtype First a = First {}
- newtype Last a = Last {}
- newtype Dual a = Dual {
- getDual :: a
- newtype Endo a = Endo {
- appEndo :: a -> a
- newtype All = All {}
- newtype Any = Any {}
- newtype Sum a = Sum {
- getSum :: a
- newtype Product a = Product {
- getProduct :: a
- newtype Alt (f :: k -> Type) (a :: k) :: forall k. (k -> Type) -> k -> Type = Alt {
- getAlt :: f a
- class Semigroup a where
- mtimesDefault :: (Integral b, Monoid a) => b -> a -> a
- cycle1 :: Semigroup m => m -> m
- data WrappedMonoid m
- newtype Option a = Option {}
- stimesMonoid :: (Integral b, Monoid a) => b -> a -> a
- stimesIdempotent :: Integral b => b -> a -> a
- stimesIdempotentMonoid :: (Integral b, Monoid a) => b -> a -> a
- maybeToMonoid :: Monoid m => Maybe m -> m
Documentation
class Semigroup a => Monoid a where #
The class of monoids (types with an associative binary operation that has an identity). Instances should satisfy the following laws:
x
<>
mempty
= xmempty
<>
x = xx
(<>
(y<>
z) = (x<>
y)<>
zSemigroup
law)mconcat
=foldr
'(<>)'mempty
The method names refer to the monoid of lists under concatenation, but there are many other instances.
Some types can be viewed as a monoid in more than one way,
e.g. both addition and multiplication on numbers.
In such cases we often define newtype
s and make those instances
of Monoid
, e.g. Sum
and Product
.
NOTE: Semigroup
is a superclass of Monoid
since base-4.11.0.0.
Identity of mappend
An associative operation
NOTE: This method is redundant and has the default
implementation
since base-4.11.0.0.mappend
= '(<>)'
Fold a list using the monoid.
For most types, the default definition for mconcat
will be
used, but the function is included in the class definition so
that an optimized version can be provided for specific types.
Instances
Monoid Ordering | Since: base-2.1 |
Monoid () | Since: base-2.1 |
Monoid All | Since: base-2.1 |
Monoid Any | Since: base-2.1 |
Monoid ShortByteString | |
Defined in Data.ByteString.Short.Internal mappend :: ShortByteString -> ShortByteString -> ShortByteString # mconcat :: [ShortByteString] -> ShortByteString # | |
Monoid ByteString | |
Defined in Data.ByteString.Lazy.Internal mempty :: ByteString # mappend :: ByteString -> ByteString -> ByteString # mconcat :: [ByteString] -> ByteString # | |
Monoid ByteString | |
Defined in Data.ByteString.Internal mempty :: ByteString # mappend :: ByteString -> ByteString -> ByteString # mconcat :: [ByteString] -> ByteString # | |
Monoid Builder | |
Monoid IntSet | |
Monoid ByteArray | |
Monoid [a] | Since: base-2.1 |
Semigroup a => Monoid (Maybe a) | Lift a semigroup into Since 4.11.0: constraint on inner Since: base-2.1 |
Monoid a => Monoid (IO a) | Since: base-4.9.0.0 |
Monoid p => Monoid (Par1 p) | Since: base-4.12.0.0 |
(Ord a, Bounded a) => Monoid (Min a) | Since: base-4.9.0.0 |
(Ord a, Bounded a) => Monoid (Max a) | Since: base-4.9.0.0 |
Monoid m => Monoid (WrappedMonoid m) | Since: base-4.9.0.0 |
Defined in Data.Semigroup mempty :: WrappedMonoid m # mappend :: WrappedMonoid m -> WrappedMonoid m -> WrappedMonoid m # mconcat :: [WrappedMonoid m] -> WrappedMonoid m # | |
Semigroup a => Monoid (Option a) | Since: base-4.9.0.0 |
Monoid a => Monoid (Identity a) | Since: base-4.9.0.0 |
Monoid (First a) | Since: base-2.1 |
Monoid (Last a) | Since: base-2.1 |
Monoid a => Monoid (Dual a) | Since: base-2.1 |
Monoid (Endo a) | Since: base-2.1 |
Num a => Monoid (Sum a) | Since: base-2.1 |
Num a => Monoid (Product a) | Since: base-2.1 |
Monoid a => Monoid (Down a) | Since: base-4.11.0.0 |
Monoid (IntMap a) | |
Monoid (Seq a) | |
Ord a => Monoid (Set a) | |
Monoid a => Monoid (May a) | |
Monoid (PrimArray a) | Since: primitive-0.6.4.0 |
Monoid (SmallArray a) | |
Defined in Data.Primitive.SmallArray mempty :: SmallArray a # mappend :: SmallArray a -> SmallArray a -> SmallArray a # mconcat :: [SmallArray a] -> SmallArray a # | |
Monoid (Array a) | |
(Hashable a, Eq a) => Monoid (HashSet a) | |
Storable a => Monoid (Vector a) | |
Prim a => Monoid (Vector a) | |
Monoid (Vector a) | |
Monoid (MergeSet a) | |
Monoid b => Monoid (a -> b) | Since: base-2.1 |
Monoid (U1 p) | Since: base-4.12.0.0 |
(Monoid a, Monoid b) => Monoid (a, b) | Since: base-2.1 |
Monoid (Proxy s) | Since: base-4.7.0.0 |
Ord k => Monoid (Map k v) | |
Monoid a => Monoid (Err e a) | |
(Eq k, Hashable k) => Monoid (HashMap k v) | |
Applicative f => Monoid (Traversed a f) | |
Monoid (f p) => Monoid (Rec1 f p) | Since: base-4.12.0.0 |
(Monoid a, Monoid b, Monoid c) => Monoid (a, b, c) | Since: base-2.1 |
Monoid a => Monoid (Const a b) | Since: base-4.9.0.0 |
(Applicative f, Monoid a) => Monoid (Ap f a) | Since: base-4.12.0.0 |
Alternative f => Monoid (Alt f a) | Since: base-4.8.0.0 |
(Monad m, Monoid r) => Monoid (Effect m r a) | |
Monoid c => Monoid (K1 i c p) | Since: base-4.12.0.0 |
(Monoid (f p), Monoid (g p)) => Monoid ((f :*: g) p) | Since: base-4.12.0.0 |
(Monoid a, Monoid b, Monoid c, Monoid d) => Monoid (a, b, c, d) | Since: base-2.1 |
Monoid (f p) => Monoid (M1 i c f p) | Since: base-4.12.0.0 |
Monoid (f (g p)) => Monoid ((f :.: g) p) | Since: base-4.12.0.0 |
(Monoid a, Monoid b, Monoid c, Monoid d, Monoid e) => Monoid (a, b, c, d, e) | Since: base-2.1 |
Maybe monoid returning the leftmost non-Nothing value.
is isomorphic to First
a
, but precedes it
historically.Alt
Maybe
a
>>>
getFirst (First (Just "hello") <> First Nothing <> First (Just "world"))
Just "hello"
Use of this type is discouraged. Note the following equivalence:
Data.Monoid.First x === Maybe (Data.Semigroup.First x)
In addition to being equivalent in the structural sense, the two
also have Monoid
instances that behave the same. This type will
be marked deprecated in GHC 8.8, and removed in GHC 8.10.
Users are advised to use the variant from Data.Semigroup and wrap
it in Maybe
.
Instances
Monad First | Since: base-4.8.0.0 |
Functor First | Since: base-4.8.0.0 |
Applicative First | Since: base-4.8.0.0 |
Foldable First | Since: base-4.8.0.0 |
Defined in Data.Foldable fold :: Monoid m => First m -> m # foldMap :: Monoid m => (a -> m) -> First a -> m # foldr :: (a -> b -> b) -> b -> First a -> b # foldr' :: (a -> b -> b) -> b -> First a -> b # foldl :: (b -> a -> b) -> b -> First a -> b # foldl' :: (b -> a -> b) -> b -> First a -> b # foldr1 :: (a -> a -> a) -> First a -> a # foldl1 :: (a -> a -> a) -> First a -> a # elem :: Eq a => a -> First a -> Bool # maximum :: Ord a => First a -> a # minimum :: Ord a => First a -> a # | |
Traversable First | Since: base-4.8.0.0 |
NFData1 First | Since: deepseq-1.4.3.0 |
Defined in Control.DeepSeq | |
Eq a => Eq (First a) | Since: base-2.1 |
Data a => Data (First a) | Since: base-4.8.0.0 |
Defined in Data.Data gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> First a -> c (First a) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (First a) # toConstr :: First a -> Constr # dataTypeOf :: First a -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (First a)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (First a)) # gmapT :: (forall b. Data b => b -> b) -> First a -> First a # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> First a -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> First a -> r # gmapQ :: (forall d. Data d => d -> u) -> First a -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> First a -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> First a -> m (First a) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> First a -> m (First a) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> First a -> m (First a) # | |
Ord a => Ord (First a) | Since: base-2.1 |
Read a => Read (First a) | Since: base-2.1 |
Show a => Show (First a) | Since: base-2.1 |
Generic (First a) | |
Semigroup (First a) | Since: base-4.9.0.0 |
Monoid (First a) | Since: base-2.1 |
NFData a => NFData (First a) | Since: deepseq-1.4.0.0 |
Defined in Control.DeepSeq | |
Container (First a) Source # | |
Defined in Universum.Container.Class toList :: First a -> [Element (First a)] Source # null :: First a -> Bool Source # foldr :: (Element (First a) -> b -> b) -> b -> First a -> b Source # foldl :: (b -> Element (First a) -> b) -> b -> First a -> b Source # foldl' :: (b -> Element (First a) -> b) -> b -> First a -> b Source # length :: First a -> Int Source # elem :: Element (First a) -> First a -> Bool Source # maximum :: First a -> Element (First a) Source # minimum :: First a -> Element (First a) Source # foldMap :: Monoid m => (Element (First a) -> m) -> First a -> m Source # fold :: First a -> Element (First a) Source # foldr' :: (Element (First a) -> b -> b) -> b -> First a -> b Source # foldr1 :: (Element (First a) -> Element (First a) -> Element (First a)) -> First a -> Element (First a) Source # foldl1 :: (Element (First a) -> Element (First a) -> Element (First a)) -> First a -> Element (First a) Source # notElem :: Element (First a) -> First a -> Bool Source # all :: (Element (First a) -> Bool) -> First a -> Bool Source # any :: (Element (First a) -> Bool) -> First a -> Bool Source # and :: First a -> Bool Source # or :: First a -> Bool Source # find :: (Element (First a) -> Bool) -> First a -> Maybe (Element (First a)) Source # | |
Generic1 First | |
type Rep (First a) | Since: base-4.7.0.0 |
Defined in Data.Monoid | |
type Element (First a) Source # | |
Defined in Universum.Container.Class | |
type Rep1 First | Since: base-4.7.0.0 |
Defined in Data.Monoid |
Maybe monoid returning the rightmost non-Nothing value.
is isomorphic to Last
a
, and thus to
Dual
(First
a)Dual
(Alt
Maybe
a)
>>>
getLast (Last (Just "hello") <> Last Nothing <> Last (Just "world"))
Just "world"
Use of this type is discouraged. Note the following equivalence:
Data.Monoid.Last x === Maybe (Data.Semigroup.Last x)
In addition to being equivalent in the structural sense, the two
also have Monoid
instances that behave the same. This type will
be marked deprecated in GHC 8.8, and removed in GHC 8.10.
Users are advised to use the variant from Data.Semigroup and wrap
it in Maybe
.
Instances
Monad Last | Since: base-4.8.0.0 |
Functor Last | Since: base-4.8.0.0 |
Applicative Last | Since: base-4.8.0.0 |
Foldable Last | Since: base-4.8.0.0 |
Defined in Data.Foldable fold :: Monoid m => Last m -> m # foldMap :: Monoid m => (a -> m) -> Last a -> m # foldr :: (a -> b -> b) -> b -> Last a -> b # foldr' :: (a -> b -> b) -> b -> Last a -> b # foldl :: (b -> a -> b) -> b -> Last a -> b # foldl' :: (b -> a -> b) -> b -> Last a -> b # foldr1 :: (a -> a -> a) -> Last a -> a # foldl1 :: (a -> a -> a) -> Last a -> a # elem :: Eq a => a -> Last a -> Bool # maximum :: Ord a => Last a -> a # | |
Traversable Last | Since: base-4.8.0.0 |
NFData1 Last | Since: deepseq-1.4.3.0 |
Defined in Control.DeepSeq | |
Eq a => Eq (Last a) | Since: base-2.1 |
Data a => Data (Last a) | Since: base-4.8.0.0 |
Defined in Data.Data gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Last a -> c (Last a) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Last a) # toConstr :: Last a -> Constr # dataTypeOf :: Last a -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Last a)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Last a)) # gmapT :: (forall b. Data b => b -> b) -> Last a -> Last a # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Last a -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Last a -> r # gmapQ :: (forall d. Data d => d -> u) -> Last a -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Last a -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Last a -> m (Last a) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Last a -> m (Last a) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Last a -> m (Last a) # | |
Ord a => Ord (Last a) | Since: base-2.1 |
Read a => Read (Last a) | Since: base-2.1 |
Show a => Show (Last a) | Since: base-2.1 |
Generic (Last a) | |
Semigroup (Last a) | Since: base-4.9.0.0 |
Monoid (Last a) | Since: base-2.1 |
NFData a => NFData (Last a) | Since: deepseq-1.4.0.0 |
Defined in Control.DeepSeq | |
Container (Last a) Source # | |
Defined in Universum.Container.Class toList :: Last a -> [Element (Last a)] Source # null :: Last a -> Bool Source # foldr :: (Element (Last a) -> b -> b) -> b -> Last a -> b Source # foldl :: (b -> Element (Last a) -> b) -> b -> Last a -> b Source # foldl' :: (b -> Element (Last a) -> b) -> b -> Last a -> b Source # length :: Last a -> Int Source # elem :: Element (Last a) -> Last a -> Bool Source # maximum :: Last a -> Element (Last a) Source # minimum :: Last a -> Element (Last a) Source # foldMap :: Monoid m => (Element (Last a) -> m) -> Last a -> m Source # fold :: Last a -> Element (Last a) Source # foldr' :: (Element (Last a) -> b -> b) -> b -> Last a -> b Source # foldr1 :: (Element (Last a) -> Element (Last a) -> Element (Last a)) -> Last a -> Element (Last a) Source # foldl1 :: (Element (Last a) -> Element (Last a) -> Element (Last a)) -> Last a -> Element (Last a) Source # notElem :: Element (Last a) -> Last a -> Bool Source # all :: (Element (Last a) -> Bool) -> Last a -> Bool Source # any :: (Element (Last a) -> Bool) -> Last a -> Bool Source # and :: Last a -> Bool Source # find :: (Element (Last a) -> Bool) -> Last a -> Maybe (Element (Last a)) Source # | |
Generic1 Last | |
type Rep (Last a) | Since: base-4.7.0.0 |
Defined in Data.Monoid | |
type Element (Last a) Source # | |
Defined in Universum.Container.Class | |
type Rep1 Last | Since: base-4.7.0.0 |
Defined in Data.Monoid |
The dual of a Monoid
, obtained by swapping the arguments of mappend
.
>>>
getDual (mappend (Dual "Hello") (Dual "World"))
"WorldHello"
Instances
Monad Dual | Since: base-4.8.0.0 |
Functor Dual | Since: base-4.8.0.0 |
Applicative Dual | Since: base-4.8.0.0 |
Foldable Dual | Since: base-4.8.0.0 |
Defined in Data.Foldable fold :: Monoid m => Dual m -> m # foldMap :: Monoid m => (a -> m) -> Dual a -> m # foldr :: (a -> b -> b) -> b -> Dual a -> b # foldr' :: (a -> b -> b) -> b -> Dual a -> b # foldl :: (b -> a -> b) -> b -> Dual a -> b # foldl' :: (b -> a -> b) -> b -> Dual a -> b # foldr1 :: (a -> a -> a) -> Dual a -> a # foldl1 :: (a -> a -> a) -> Dual a -> a # elem :: Eq a => a -> Dual a -> Bool # maximum :: Ord a => Dual a -> a # | |
Traversable Dual | Since: base-4.8.0.0 |
NFData1 Dual | Since: deepseq-1.4.3.0 |
Defined in Control.DeepSeq | |
Bounded a => Bounded (Dual a) | Since: base-2.1 |
Eq a => Eq (Dual a) | Since: base-2.1 |
Data a => Data (Dual a) | Since: base-4.8.0.0 |
Defined in Data.Data gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Dual a -> c (Dual a) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Dual a) # toConstr :: Dual a -> Constr # dataTypeOf :: Dual a -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Dual a)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Dual a)) # gmapT :: (forall b. Data b => b -> b) -> Dual a -> Dual a # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Dual a -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Dual a -> r # gmapQ :: (forall d. Data d => d -> u) -> Dual a -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Dual a -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Dual a -> m (Dual a) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Dual a -> m (Dual a) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Dual a -> m (Dual a) # | |
Ord a => Ord (Dual a) | Since: base-2.1 |
Read a => Read (Dual a) | Since: base-2.1 |
Show a => Show (Dual a) | Since: base-2.1 |
Generic (Dual a) | |
Semigroup a => Semigroup (Dual a) | Since: base-4.9.0.0 |
Monoid a => Monoid (Dual a) | Since: base-2.1 |
NFData a => NFData (Dual a) | Since: deepseq-1.4.0.0 |
Defined in Control.DeepSeq | |
Prim a => Prim (Dual a) | Since: primitive-0.6.5.0 |
Defined in Data.Primitive.Types alignment# :: Dual a -> Int# # indexByteArray# :: ByteArray# -> Int# -> Dual a # readByteArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Dual a#) # writeByteArray# :: MutableByteArray# s -> Int# -> Dual a -> State# s -> State# s # setByteArray# :: MutableByteArray# s -> Int# -> Int# -> Dual a -> State# s -> State# s # indexOffAddr# :: Addr# -> Int# -> Dual a # readOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Dual a#) # writeOffAddr# :: Addr# -> Int# -> Dual a -> State# s -> State# s # setOffAddr# :: Addr# -> Int# -> Int# -> Dual a -> State# s -> State# s # | |
Container (Dual a) Source # | |
Defined in Universum.Container.Class toList :: Dual a -> [Element (Dual a)] Source # null :: Dual a -> Bool Source # foldr :: (Element (Dual a) -> b -> b) -> b -> Dual a -> b Source # foldl :: (b -> Element (Dual a) -> b) -> b -> Dual a -> b Source # foldl' :: (b -> Element (Dual a) -> b) -> b -> Dual a -> b Source # length :: Dual a -> Int Source # elem :: Element (Dual a) -> Dual a -> Bool Source # maximum :: Dual a -> Element (Dual a) Source # minimum :: Dual a -> Element (Dual a) Source # foldMap :: Monoid m => (Element (Dual a) -> m) -> Dual a -> m Source # fold :: Dual a -> Element (Dual a) Source # foldr' :: (Element (Dual a) -> b -> b) -> b -> Dual a -> b Source # foldr1 :: (Element (Dual a) -> Element (Dual a) -> Element (Dual a)) -> Dual a -> Element (Dual a) Source # foldl1 :: (Element (Dual a) -> Element (Dual a) -> Element (Dual a)) -> Dual a -> Element (Dual a) Source # notElem :: Element (Dual a) -> Dual a -> Bool Source # all :: (Element (Dual a) -> Bool) -> Dual a -> Bool Source # any :: (Element (Dual a) -> Bool) -> Dual a -> Bool Source # and :: Dual a -> Bool Source # find :: (Element (Dual a) -> Bool) -> Dual a -> Maybe (Element (Dual a)) Source # | |
Generic1 Dual | |
type Rep (Dual a) | Since: base-4.7.0.0 |
Defined in Data.Semigroup.Internal | |
type Element (Dual a) Source # | |
Defined in Universum.Container.Class | |
type Rep1 Dual | Since: base-4.7.0.0 |
Defined in Data.Semigroup.Internal |
The monoid of endomorphisms under composition.
>>>
let computation = Endo ("Hello, " ++) <> Endo (++ "!")
>>>
appEndo computation "Haskell"
"Hello, Haskell!"
Boolean monoid under conjunction (&&
).
>>>
getAll (All True <> mempty <> All False)
False
>>>
getAll (mconcat (map (\x -> All (even x)) [2,4,6,7,8]))
False
Instances
Bounded All | Since: base-2.1 |
Eq All | Since: base-2.1 |
Data All | Since: base-4.8.0.0 |
Defined in Data.Data gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> All -> c All # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c All # dataTypeOf :: All -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c All) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c All) # gmapT :: (forall b. Data b => b -> b) -> All -> All # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> All -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> All -> r # gmapQ :: (forall d. Data d => d -> u) -> All -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> All -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> All -> m All # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> All -> m All # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> All -> m All # | |
Ord All | Since: base-2.1 |
Read All | Since: base-2.1 |
Show All | Since: base-2.1 |
Generic All | |
Semigroup All | Since: base-4.9.0.0 |
Monoid All | Since: base-2.1 |
NFData All | Since: deepseq-1.4.0.0 |
Defined in Control.DeepSeq | |
type Rep All | Since: base-4.7.0.0 |
Defined in Data.Semigroup.Internal |
Boolean monoid under disjunction (||
).
>>>
getAny (Any True <> mempty <> Any False)
True
>>>
getAny (mconcat (map (\x -> Any (even x)) [2,4,6,7,8]))
True
Instances
Bounded Any | Since: base-2.1 |
Eq Any | Since: base-2.1 |
Data Any | Since: base-4.8.0.0 |
Defined in Data.Data gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Any -> c Any # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Any # dataTypeOf :: Any -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Any) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Any) # gmapT :: (forall b. Data b => b -> b) -> Any -> Any # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Any -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Any -> r # gmapQ :: (forall d. Data d => d -> u) -> Any -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Any -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Any -> m Any # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Any -> m Any # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Any -> m Any # | |
Ord Any | Since: base-2.1 |
Read Any | Since: base-2.1 |
Show Any | Since: base-2.1 |
Generic Any | |
Semigroup Any | Since: base-4.9.0.0 |
Monoid Any | Since: base-2.1 |
NFData Any | Since: deepseq-1.4.0.0 |
Defined in Control.DeepSeq | |
type Rep Any | Since: base-4.7.0.0 |
Defined in Data.Semigroup.Internal |
Monoid under addition.
>>>
getSum (Sum 1 <> Sum 2 <> mempty)
3
Instances
Monad Sum | Since: base-4.8.0.0 |
Functor Sum | Since: base-4.8.0.0 |
Applicative Sum | Since: base-4.8.0.0 |
Foldable Sum | Since: base-4.8.0.0 |
Defined in Data.Foldable fold :: Monoid m => Sum m -> m # foldMap :: Monoid m => (a -> m) -> Sum a -> m # foldr :: (a -> b -> b) -> b -> Sum a -> b # foldr' :: (a -> b -> b) -> b -> Sum a -> b # foldl :: (b -> a -> b) -> b -> Sum a -> b # foldl' :: (b -> a -> b) -> b -> Sum a -> b # foldr1 :: (a -> a -> a) -> Sum a -> a # foldl1 :: (a -> a -> a) -> Sum a -> a # elem :: Eq a => a -> Sum a -> Bool # maximum :: Ord a => Sum a -> a # | |
Traversable Sum | Since: base-4.8.0.0 |
NFData1 Sum | Since: deepseq-1.4.3.0 |
Defined in Control.DeepSeq | |
Bounded a => Bounded (Sum a) | Since: base-2.1 |
Eq a => Eq (Sum a) | Since: base-2.1 |
Data a => Data (Sum a) | Since: base-4.8.0.0 |
Defined in Data.Data gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Sum a -> c (Sum a) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Sum a) # dataTypeOf :: Sum a -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Sum a)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Sum a)) # gmapT :: (forall b. Data b => b -> b) -> Sum a -> Sum a # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Sum a -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Sum a -> r # gmapQ :: (forall d. Data d => d -> u) -> Sum a -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Sum a -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Sum a -> m (Sum a) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Sum a -> m (Sum a) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Sum a -> m (Sum a) # | |
Num a => Num (Sum a) | Since: base-4.7.0.0 |
Ord a => Ord (Sum a) | Since: base-2.1 |
Read a => Read (Sum a) | Since: base-2.1 |
Show a => Show (Sum a) | Since: base-2.1 |
Generic (Sum a) | |
Num a => Semigroup (Sum a) | Since: base-4.9.0.0 |
Num a => Monoid (Sum a) | Since: base-2.1 |
NFData a => NFData (Sum a) | Since: deepseq-1.4.0.0 |
Defined in Control.DeepSeq | |
Prim a => Prim (Sum a) | Since: primitive-0.6.5.0 |
Defined in Data.Primitive.Types alignment# :: Sum a -> Int# # indexByteArray# :: ByteArray# -> Int# -> Sum a # readByteArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Sum a#) # writeByteArray# :: MutableByteArray# s -> Int# -> Sum a -> State# s -> State# s # setByteArray# :: MutableByteArray# s -> Int# -> Int# -> Sum a -> State# s -> State# s # indexOffAddr# :: Addr# -> Int# -> Sum a # readOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Sum a#) # writeOffAddr# :: Addr# -> Int# -> Sum a -> State# s -> State# s # setOffAddr# :: Addr# -> Int# -> Int# -> Sum a -> State# s -> State# s # | |
Container (Sum a) Source # | |
Defined in Universum.Container.Class toList :: Sum a -> [Element (Sum a)] Source # null :: Sum a -> Bool Source # foldr :: (Element (Sum a) -> b -> b) -> b -> Sum a -> b Source # foldl :: (b -> Element (Sum a) -> b) -> b -> Sum a -> b Source # foldl' :: (b -> Element (Sum a) -> b) -> b -> Sum a -> b Source # length :: Sum a -> Int Source # elem :: Element (Sum a) -> Sum a -> Bool Source # maximum :: Sum a -> Element (Sum a) Source # minimum :: Sum a -> Element (Sum a) Source # foldMap :: Monoid m => (Element (Sum a) -> m) -> Sum a -> m Source # fold :: Sum a -> Element (Sum a) Source # foldr' :: (Element (Sum a) -> b -> b) -> b -> Sum a -> b Source # foldr1 :: (Element (Sum a) -> Element (Sum a) -> Element (Sum a)) -> Sum a -> Element (Sum a) Source # foldl1 :: (Element (Sum a) -> Element (Sum a) -> Element (Sum a)) -> Sum a -> Element (Sum a) Source # notElem :: Element (Sum a) -> Sum a -> Bool Source # all :: (Element (Sum a) -> Bool) -> Sum a -> Bool Source # any :: (Element (Sum a) -> Bool) -> Sum a -> Bool Source # find :: (Element (Sum a) -> Bool) -> Sum a -> Maybe (Element (Sum a)) Source # | |
Generic1 Sum | |
type Rep (Sum a) | Since: base-4.7.0.0 |
Defined in Data.Semigroup.Internal | |
type Element (Sum a) Source # | |
Defined in Universum.Container.Class | |
type Rep1 Sum | Since: base-4.7.0.0 |
Defined in Data.Semigroup.Internal |
Monoid under multiplication.
>>>
getProduct (Product 3 <> Product 4 <> mempty)
12
Product | |
|
Instances
Monad Product | Since: base-4.8.0.0 |
Functor Product | Since: base-4.8.0.0 |
Applicative Product | Since: base-4.8.0.0 |
Foldable Product | Since: base-4.8.0.0 |
Defined in Data.Foldable fold :: Monoid m => Product m -> m # foldMap :: Monoid m => (a -> m) -> Product a -> m # foldr :: (a -> b -> b) -> b -> Product a -> b # foldr' :: (a -> b -> b) -> b -> Product a -> b # foldl :: (b -> a -> b) -> b -> Product a -> b # foldl' :: (b -> a -> b) -> b -> Product a -> b # foldr1 :: (a -> a -> a) -> Product a -> a # foldl1 :: (a -> a -> a) -> Product a -> a # elem :: Eq a => a -> Product a -> Bool # maximum :: Ord a => Product a -> a # minimum :: Ord a => Product a -> a # | |
Traversable Product | Since: base-4.8.0.0 |
NFData1 Product | Since: deepseq-1.4.3.0 |
Defined in Control.DeepSeq | |
Bounded a => Bounded (Product a) | Since: base-2.1 |
Eq a => Eq (Product a) | Since: base-2.1 |
Data a => Data (Product a) | Since: base-4.8.0.0 |
Defined in Data.Data gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Product a -> c (Product a) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Product a) # toConstr :: Product a -> Constr # dataTypeOf :: Product a -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Product a)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Product a)) # gmapT :: (forall b. Data b => b -> b) -> Product a -> Product a # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Product a -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Product a -> r # gmapQ :: (forall d. Data d => d -> u) -> Product a -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Product a -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Product a -> m (Product a) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Product a -> m (Product a) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Product a -> m (Product a) # | |
Num a => Num (Product a) | Since: base-4.7.0.0 |
Defined in Data.Semigroup.Internal | |
Ord a => Ord (Product a) | Since: base-2.1 |
Defined in Data.Semigroup.Internal | |
Read a => Read (Product a) | Since: base-2.1 |
Show a => Show (Product a) | Since: base-2.1 |
Generic (Product a) | |
Num a => Semigroup (Product a) | Since: base-4.9.0.0 |
Num a => Monoid (Product a) | Since: base-2.1 |
NFData a => NFData (Product a) | Since: deepseq-1.4.0.0 |
Defined in Control.DeepSeq | |
Prim a => Prim (Product a) | Since: primitive-0.6.5.0 |
Defined in Data.Primitive.Types sizeOf# :: Product a -> Int# # alignment# :: Product a -> Int# # indexByteArray# :: ByteArray# -> Int# -> Product a # readByteArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Product a#) # writeByteArray# :: MutableByteArray# s -> Int# -> Product a -> State# s -> State# s # setByteArray# :: MutableByteArray# s -> Int# -> Int# -> Product a -> State# s -> State# s # indexOffAddr# :: Addr# -> Int# -> Product a # readOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Product a#) # writeOffAddr# :: Addr# -> Int# -> Product a -> State# s -> State# s # setOffAddr# :: Addr# -> Int# -> Int# -> Product a -> State# s -> State# s # | |
Container (Product a) Source # | |
Defined in Universum.Container.Class toList :: Product a -> [Element (Product a)] Source # null :: Product a -> Bool Source # foldr :: (Element (Product a) -> b -> b) -> b -> Product a -> b Source # foldl :: (b -> Element (Product a) -> b) -> b -> Product a -> b Source # foldl' :: (b -> Element (Product a) -> b) -> b -> Product a -> b Source # length :: Product a -> Int Source # elem :: Element (Product a) -> Product a -> Bool Source # maximum :: Product a -> Element (Product a) Source # minimum :: Product a -> Element (Product a) Source # foldMap :: Monoid m => (Element (Product a) -> m) -> Product a -> m Source # fold :: Product a -> Element (Product a) Source # foldr' :: (Element (Product a) -> b -> b) -> b -> Product a -> b Source # foldr1 :: (Element (Product a) -> Element (Product a) -> Element (Product a)) -> Product a -> Element (Product a) Source # foldl1 :: (Element (Product a) -> Element (Product a) -> Element (Product a)) -> Product a -> Element (Product a) Source # notElem :: Element (Product a) -> Product a -> Bool Source # all :: (Element (Product a) -> Bool) -> Product a -> Bool Source # any :: (Element (Product a) -> Bool) -> Product a -> Bool Source # and :: Product a -> Bool Source # or :: Product a -> Bool Source # find :: (Element (Product a) -> Bool) -> Product a -> Maybe (Element (Product a)) Source # safeHead :: Product a -> Maybe (Element (Product a)) Source # | |
Generic1 Product | |
type Rep (Product a) | Since: base-4.7.0.0 |
Defined in Data.Semigroup.Internal | |
type Element (Product a) Source # | |
Defined in Universum.Container.Class | |
type Rep1 Product | Since: base-4.7.0.0 |
Defined in Data.Semigroup.Internal |
newtype Alt (f :: k -> Type) (a :: k) :: forall k. (k -> Type) -> k -> Type #
Monoid under <|>
.
Since: base-4.8.0.0
Instances
Generic1 (Alt f :: k -> Type) | |
Monad f => Monad (Alt f) | Since: base-4.8.0.0 |
Functor f => Functor (Alt f) | Since: base-4.8.0.0 |
Applicative f => Applicative (Alt f) | Since: base-4.8.0.0 |
Foldable f => Foldable (Alt f) | Since: base-4.12.0.0 |
Defined in Data.Foldable fold :: Monoid m => Alt f m -> m # foldMap :: Monoid m => (a -> m) -> Alt f a -> m # foldr :: (a -> b -> b) -> b -> Alt f a -> b # foldr' :: (a -> b -> b) -> b -> Alt f a -> b # foldl :: (b -> a -> b) -> b -> Alt f a -> b # foldl' :: (b -> a -> b) -> b -> Alt f a -> b # foldr1 :: (a -> a -> a) -> Alt f a -> a # foldl1 :: (a -> a -> a) -> Alt f a -> a # elem :: Eq a => a -> Alt f a -> Bool # maximum :: Ord a => Alt f a -> a # minimum :: Ord a => Alt f a -> a # | |
Traversable f => Traversable (Alt f) | Since: base-4.12.0.0 |
Alternative f => Alternative (Alt f) | Since: base-4.8.0.0 |
MonadPlus f => MonadPlus (Alt f) | Since: base-4.8.0.0 |
Enum (f a) => Enum (Alt f a) | Since: base-4.8.0.0 |
Eq (f a) => Eq (Alt f a) | Since: base-4.8.0.0 |
(Data (f a), Data a, Typeable f) => Data (Alt f a) | Since: base-4.8.0.0 |
Defined in Data.Data gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Alt f a -> c (Alt f a) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Alt f a) # toConstr :: Alt f a -> Constr # dataTypeOf :: Alt f a -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Alt f a)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Alt f a)) # gmapT :: (forall b. Data b => b -> b) -> Alt f a -> Alt f a # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Alt f a -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Alt f a -> r # gmapQ :: (forall d. Data d => d -> u) -> Alt f a -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Alt f a -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Alt f a -> m (Alt f a) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Alt f a -> m (Alt f a) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Alt f a -> m (Alt f a) # | |
Num (f a) => Num (Alt f a) | Since: base-4.8.0.0 |
Ord (f a) => Ord (Alt f a) | Since: base-4.8.0.0 |
Read (f a) => Read (Alt f a) | Since: base-4.8.0.0 |
Show (f a) => Show (Alt f a) | Since: base-4.8.0.0 |
Generic (Alt f a) | |
Alternative f => Semigroup (Alt f a) | Since: base-4.9.0.0 |
Alternative f => Monoid (Alt f a) | Since: base-4.8.0.0 |
type Rep1 (Alt f :: k -> Type) | Since: base-4.8.0.0 |
Defined in Data.Semigroup.Internal | |
type Rep (Alt f a) | Since: base-4.8.0.0 |
Defined in Data.Semigroup.Internal |
The class of semigroups (types with an associative binary operation).
Instances should satisfy the associativity law:
Since: base-4.9.0.0
(<>) :: a -> a -> a infixr 6 #
An associative operation.
Reduce a non-empty list with <>
The default definition should be sufficient, but this can be overridden for efficiency.
stimes :: Integral b => b -> a -> a #
Repeat a value n
times.
Given that this works on a Semigroup
it is allowed to fail if
you request 0 or fewer repetitions, and the default definition
will do so.
By making this a member of the class, idempotent semigroups
and monoids can upgrade this to execute in O(1) by
picking stimes =
or stimesIdempotent
stimes =
respectively.stimesIdempotentMonoid
Instances
Semigroup Ordering | Since: base-4.9.0.0 |
Semigroup () | Since: base-4.9.0.0 |
Semigroup Void | Since: base-4.9.0.0 |
Semigroup All | Since: base-4.9.0.0 |
Semigroup Any | Since: base-4.9.0.0 |
Semigroup ShortByteString | |
Defined in Data.ByteString.Short.Internal (<>) :: ShortByteString -> ShortByteString -> ShortByteString # sconcat :: NonEmpty ShortByteString -> ShortByteString # stimes :: Integral b => b -> ShortByteString -> ShortByteString # | |
Semigroup ByteString | |
Defined in Data.ByteString.Lazy.Internal (<>) :: ByteString -> ByteString -> ByteString # sconcat :: NonEmpty ByteString -> ByteString # stimes :: Integral b => b -> ByteString -> ByteString # | |
Semigroup ByteString | |
Defined in Data.ByteString.Internal (<>) :: ByteString -> ByteString -> ByteString # sconcat :: NonEmpty ByteString -> ByteString # stimes :: Integral b => b -> ByteString -> ByteString # | |
Semigroup Builder | |
Semigroup IntSet | Since: containers-0.5.7 |
Semigroup ByteArray | |
Semigroup [a] | Since: base-4.9.0.0 |
Semigroup a => Semigroup (Maybe a) | Since: base-4.9.0.0 |
Semigroup a => Semigroup (IO a) | Since: base-4.10.0.0 |
Semigroup p => Semigroup (Par1 p) | Since: base-4.12.0.0 |
Ord a => Semigroup (Min a) | Since: base-4.9.0.0 |
Ord a => Semigroup (Max a) | Since: base-4.9.0.0 |
Semigroup (First a) | Since: base-4.9.0.0 |
Semigroup (Last a) | Since: base-4.9.0.0 |
Monoid m => Semigroup (WrappedMonoid m) | Since: base-4.9.0.0 |
Defined in Data.Semigroup (<>) :: WrappedMonoid m -> WrappedMonoid m -> WrappedMonoid m # sconcat :: NonEmpty (WrappedMonoid m) -> WrappedMonoid m # stimes :: Integral b => b -> WrappedMonoid m -> WrappedMonoid m # | |
Semigroup a => Semigroup (Option a) | Since: base-4.9.0.0 |
Semigroup a => Semigroup (Identity a) | Since: base-4.9.0.0 |
Semigroup (First a) | Since: base-4.9.0.0 |
Semigroup (Last a) | Since: base-4.9.0.0 |
Semigroup a => Semigroup (Dual a) | Since: base-4.9.0.0 |
Semigroup (Endo a) | Since: base-4.9.0.0 |
Num a => Semigroup (Sum a) | Since: base-4.9.0.0 |
Num a => Semigroup (Product a) | Since: base-4.9.0.0 |
Semigroup a => Semigroup (Down a) | Since: base-4.11.0.0 |
Semigroup (NonEmpty a) | Since: base-4.9.0.0 |
Semigroup (IntMap a) | Since: containers-0.5.7 |
Semigroup (Seq a) | Since: containers-0.5.7 |
Ord a => Semigroup (Set a) | Since: containers-0.5.7 |
Semigroup a => Semigroup (May a) | |
Semigroup (PrimArray a) | Since: primitive-0.6.4.0 |
Semigroup (SmallArray a) | Since: primitive-0.6.3.0 |
Defined in Data.Primitive.SmallArray (<>) :: SmallArray a -> SmallArray a -> SmallArray a # sconcat :: NonEmpty (SmallArray a) -> SmallArray a # stimes :: Integral b => b -> SmallArray a -> SmallArray a # | |
Semigroup (Array a) | Since: primitive-0.6.3.0 |
(Hashable a, Eq a) => Semigroup (HashSet a) | |
Storable a => Semigroup (Vector a) | |
Prim a => Semigroup (Vector a) | |
Semigroup (Vector a) | |
Semigroup (MergeSet a) | |
Semigroup b => Semigroup (a -> b) | Since: base-4.9.0.0 |
Semigroup (Either a b) | Since: base-4.9.0.0 |
Semigroup (V1 p) | Since: base-4.12.0.0 |
Semigroup (U1 p) | Since: base-4.12.0.0 |
(Semigroup a, Semigroup b) => Semigroup (a, b) | Since: base-4.9.0.0 |
Semigroup (Proxy s) | Since: base-4.9.0.0 |
Ord k => Semigroup (Map k v) | |
Semigroup a => Semigroup (Err e a) | |
(Eq k, Hashable k) => Semigroup (HashMap k v) | |
Applicative f => Semigroup (Traversed a f) | |
Semigroup (f p) => Semigroup (Rec1 f p) | Since: base-4.12.0.0 |
(Semigroup a, Semigroup b, Semigroup c) => Semigroup (a, b, c) | Since: base-4.9.0.0 |
Semigroup a => Semigroup (Const a b) | Since: base-4.9.0.0 |
(Applicative f, Semigroup a) => Semigroup (Ap f a) | Since: base-4.12.0.0 |
Alternative f => Semigroup (Alt f a) | Since: base-4.9.0.0 |
(Monad m, Semigroup r) => Semigroup (Effect m r a) | |
Semigroup c => Semigroup (K1 i c p) | Since: base-4.12.0.0 |
(Semigroup (f p), Semigroup (g p)) => Semigroup ((f :*: g) p) | Since: base-4.12.0.0 |
(Semigroup a, Semigroup b, Semigroup c, Semigroup d) => Semigroup (a, b, c, d) | Since: base-4.9.0.0 |
Semigroup (f p) => Semigroup (M1 i c f p) | Since: base-4.12.0.0 |
Semigroup (f (g p)) => Semigroup ((f :.: g) p) | Since: base-4.12.0.0 |
(Semigroup a, Semigroup b, Semigroup c, Semigroup d, Semigroup e) => Semigroup (a, b, c, d, e) | Since: base-4.9.0.0 |
mtimesDefault :: (Integral b, Monoid a) => b -> a -> a #
data WrappedMonoid m #
Provide a Semigroup for an arbitrary Monoid.
NOTE: This is not needed anymore since Semigroup
became a superclass of
Monoid
in base-4.11 and this newtype be deprecated at some point in the future.
Instances
Option
is effectively Maybe
with a better instance of
Monoid
, built off of an underlying Semigroup
instead of an
underlying Monoid
.
Ideally, this type would not exist at all and we would just fix the
Monoid
instance of Maybe
.
In GHC 8.4 and higher, the Monoid
instance for Maybe
has been
corrected to lift a Semigroup
instance instead of a Monoid
instance. Consequently, this type is no longer useful. It will be
marked deprecated in GHC 8.8 and removed in GHC 8.10.
Instances
Monad Option | Since: base-4.9.0.0 |
Functor Option | Since: base-4.9.0.0 |
MonadFix Option | Since: base-4.9.0.0 |
Defined in Data.Semigroup | |
Applicative Option | Since: base-4.9.0.0 |
Foldable Option | Since: base-4.9.0.0 |
Defined in Data.Semigroup fold :: Monoid m => Option m -> m # foldMap :: Monoid m => (a -> m) -> Option a -> m # foldr :: (a -> b -> b) -> b -> Option a -> b # foldr' :: (a -> b -> b) -> b -> Option a -> b # foldl :: (b -> a -> b) -> b -> Option a -> b # foldl' :: (b -> a -> b) -> b -> Option a -> b # foldr1 :: (a -> a -> a) -> Option a -> a # foldl1 :: (a -> a -> a) -> Option a -> a # elem :: Eq a => a -> Option a -> Bool # maximum :: Ord a => Option a -> a # minimum :: Ord a => Option a -> a # | |
Traversable Option | Since: base-4.9.0.0 |
Alternative Option | Since: base-4.9.0.0 |
MonadPlus Option | Since: base-4.9.0.0 |
NFData1 Option | Since: deepseq-1.4.3.0 |
Defined in Control.DeepSeq | |
Eq a => Eq (Option a) | Since: base-4.9.0.0 |
Data a => Data (Option a) | Since: base-4.9.0.0 |
Defined in Data.Semigroup gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Option a -> c (Option a) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Option a) # toConstr :: Option a -> Constr # dataTypeOf :: Option a -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Option a)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Option a)) # gmapT :: (forall b. Data b => b -> b) -> Option a -> Option a # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Option a -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Option a -> r # gmapQ :: (forall d. Data d => d -> u) -> Option a -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Option a -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Option a -> m (Option a) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Option a -> m (Option a) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Option a -> m (Option a) # | |
Ord a => Ord (Option a) | Since: base-4.9.0.0 |
Defined in Data.Semigroup | |
Read a => Read (Option a) | Since: base-4.9.0.0 |
Show a => Show (Option a) | Since: base-4.9.0.0 |
Generic (Option a) | |
Semigroup a => Semigroup (Option a) | Since: base-4.9.0.0 |
Semigroup a => Monoid (Option a) | Since: base-4.9.0.0 |
NFData a => NFData (Option a) | Since: deepseq-1.4.2.0 |
Defined in Control.DeepSeq | |
Hashable a => Hashable (Option a) | |
Defined in Data.Hashable.Class | |
Generic1 Option | |
type Rep (Option a) | Since: base-4.9.0.0 |
Defined in Data.Semigroup | |
type Rep1 Option | Since: base-4.9.0.0 |
Defined in Data.Semigroup |
stimesMonoid :: (Integral b, Monoid a) => b -> a -> a #
stimesIdempotent :: Integral b => b -> a -> a #
stimesIdempotentMonoid :: (Integral b, Monoid a) => b -> a -> a #