Monoid

Monoid

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 = x

• mempty <> x = x

• x <> (y <> z) = (x <> y) <> z (Semigroup 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 newtypes and make those instances of Monoid, e.g. Sum and Product.

NOTE: Semigroup is a superclass of Monoid since base-4.11.0.0.

Minimal complete definition

mempty

Methods

mempty :: a

Identity of mappend

mconcat :: [a] -> a

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

Defined in GHC.Base

Methods

mempty :: Ordering

mappend :: Ordering -> Ordering -> Ordering

mconcat :: [Ordering] -> Ordering

Monoid ()

Since: base-2.1

Defined in GHC.Base

Methods

mempty :: ()

mappend :: () -> () -> ()

mconcat :: [()] -> ()

Monoid ByteString

Defined in Data.ByteString.Internal

Methods

mempty :: ByteString

mappend :: ByteString -> ByteString -> ByteString

mconcat :: [ByteString] -> ByteString

Monoid ByteString

Defined in Data.ByteString.Lazy.Internal

Methods

mempty :: ByteString

mappend :: ByteString -> ByteString -> ByteString

mconcat :: [ByteString] -> ByteString

Monoid Builder

Defined in Data.Text.Internal.Builder

Methods

mempty :: Builder

mappend :: Builder -> Builder -> Builder

mconcat :: [Builder] -> Builder

Monoid Builder

Defined in Data.ByteString.Builder.Internal

Methods

mempty :: Builder

mappend :: Builder -> Builder -> Builder

mconcat :: [Builder] -> Builder

Monoid Series

Defined in Data.Aeson.Encoding.Internal

Methods

mempty :: Series

mappend :: Series -> Series -> Series

mconcat :: [Series] -> Series

Monoid EventLifetime

Since: base-4.8.0.0

Defined in GHC.Event.Internal

Methods

mempty :: EventLifetime

mappend :: EventLifetime -> EventLifetime -> EventLifetime

mconcat :: [EventLifetime] -> EventLifetime

Monoid Event

Since: base-4.3.1.0

Defined in GHC.Event.Internal

Methods

mempty :: Event

mappend :: Event -> Event -> Event

mconcat :: [Event] -> Event

Monoid Lifetime

mappend takes the longer of two lifetimes.

Since: base-4.8.0.0

Defined in GHC.Event.Internal

Methods

mempty :: Lifetime

mappend :: Lifetime -> Lifetime -> Lifetime

mconcat :: [Lifetime] -> Lifetime

Monoid All

Since: base-2.1

Defined in Data.Semigroup.Internal

Methods

mempty :: All

mappend :: All -> All -> All

mconcat :: [All] -> All

Monoid Any

Since: base-2.1

Defined in Data.Semigroup.Internal

Methods

mempty :: Any

mappend :: Any -> Any -> Any

mconcat :: [Any] -> Any

Monoid ShortByteString

Defined in Data.ByteString.Short.Internal

Methods

mempty :: ShortByteString

mappend :: ShortByteString -> ShortByteString -> ShortByteString

mconcat :: [ShortByteString] -> ShortByteString

Monoid ByteArray

Defined in Data.Primitive.ByteArray

Methods

mempty :: ByteArray

mappend :: ByteArray -> ByteArray -> ByteArray

mconcat :: [ByteArray] -> ByteArray

Monoid IntSet

Defined in Data.IntSet.Internal

Methods

mempty :: IntSet

mappend :: IntSet -> IntSet -> IntSet

mconcat :: [IntSet] -> IntSet

Monoid IntMultiSet

Defined in Data.IntMultiSet

Methods

mempty :: IntMultiSet

mappend :: IntMultiSet -> IntMultiSet -> IntMultiSet

mconcat :: [IntMultiSet] -> IntMultiSet

Monoid PrefsMod

Defined in Options.Applicative.Builder

Methods

mempty :: PrefsMod

mappend :: PrefsMod -> PrefsMod -> PrefsMod

mconcat :: [PrefsMod] -> PrefsMod

Monoid ParseError

Defined in Options.Applicative.Types

Methods

mempty :: ParseError

mappend :: ParseError -> ParseError -> ParseError

mconcat :: [ParseError] -> ParseError

Monoid Completer

Defined in Options.Applicative.Types

Methods

mempty :: Completer

mappend :: Completer -> Completer -> Completer

mconcat :: [Completer] -> Completer

Monoid ParserHelp

Defined in Options.Applicative.Help.Types

Methods

mempty :: ParserHelp

mappend :: ParserHelp -> ParserHelp -> ParserHelp

mconcat :: [ParserHelp] -> ParserHelp

Monoid Doc

Defined in Text.PrettyPrint.HughesPJ

Methods

mempty :: Doc

mappend :: Doc -> Doc -> Doc

mconcat :: [Doc] -> Doc

Monoid AnsiStyle

mempty does nothing, which is equivalent to inheriting the style of the surrounding doc, or the terminal’s default if no style has been set yet.

Defined in Data.Text.Prettyprint.Doc.Render.Terminal.Internal

Methods

mempty :: AnsiStyle

mappend :: AnsiStyle -> AnsiStyle -> AnsiStyle

mconcat :: [AnsiStyle] -> AnsiStyle

Monoid ShortText

Defined in Data.Text.Short.Internal

Methods

mempty :: ShortText

mappend :: ShortText -> ShortText -> ShortText

mconcat :: [ShortText] -> ShortText

a :=> (Monoid (Dict a))

Defined in Data.Constraint

Methods

ins :: a :- Monoid (Dict a)

() :=> (Monoid [a])

Defined in Data.Constraint

Methods

ins :: () :- Monoid [a]

() :=> (Monoid Ordering)

Defined in Data.Constraint

Methods

ins :: () :- Monoid Ordering

() :=> (Monoid ())

Defined in Data.Constraint

Methods

ins :: () :- Monoid ()

Monoid [a]

Since: base-2.1

Defined in GHC.Base

Methods

mempty :: [a]

mappend :: [a] -> [a] -> [a]

mconcat :: [[a]] -> [a]

Semigroup a => Monoid (Maybe a)

Lift a semigroup into Maybe forming a Monoid according to http://en.wikipedia.org/wiki/Monoid: "Any semigroup S may be turned into a monoid simply by adjoining an element e not in S and defining e*e = e and e*s = s = s*e for all s ∈ S."

Since 4.11.0: constraint on inner a value generalised from Monoid to Semigroup.

Since: base-2.1

Defined in GHC.Base

Methods

mempty :: Maybe a

mappend :: Maybe a -> Maybe a -> Maybe a

mconcat :: [Maybe a] -> Maybe a

Monoid a => Monoid (IO a)

Since: base-4.9.0.0

Defined in GHC.Base

Methods

mempty :: IO a

mappend :: IO a -> IO a -> IO a

mconcat :: [IO a] -> IO a

Monoid (IResult a)

Defined in Data.Aeson.Types.Internal

Methods

mempty :: IResult a

mappend :: IResult a -> IResult a -> IResult a

mconcat :: [IResult a] -> IResult a

Monoid (Result a)

Defined in Data.Aeson.Types.Internal

Methods

mempty :: Result a

mappend :: Result a -> Result a -> Result a

mconcat :: [Result a] -> Result a

Monoid (Parser a)

Defined in Data.Aeson.Types.Internal

Methods

mempty :: Parser a

mappend :: Parser a -> Parser a -> Parser a

mconcat :: [Parser a] -> Parser a

(Semigroup a, Monoid a) => Monoid (Concurrently a)

Since: async-2.1.0

Defined in Control.Concurrent.Async

Methods

mempty :: Concurrently a

mappend :: Concurrently a -> Concurrently a -> Concurrently a

mconcat :: [Concurrently a] -> Concurrently a

(Ord a, Bounded a) => Monoid (Min a)

Since: base-4.9.0.0

Defined in Data.Semigroup

Methods

mempty :: Min a

mappend :: Min a -> Min a -> Min a

mconcat :: [Min a] -> Min a

(Ord a, Bounded a) => Monoid (Max a)

Since: base-4.9.0.0

Defined in Data.Semigroup

Methods

mempty :: Max a

mappend :: Max a -> Max a -> Max a

mconcat :: [Max a] -> Max a

Monoid m => Monoid (WrappedMonoid m)

Since: base-4.9.0.0

Defined in Data.Semigroup

Methods

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

Defined in Data.Semigroup

Methods

mempty :: Option a

mappend :: Option a -> Option a -> Option a

mconcat :: [Option a] -> Option a

Monoid a => Monoid (Identity a)

Defined in Data.Functor.Identity

Methods

mempty :: Identity a

mappend :: Identity a -> Identity a -> Identity a

mconcat :: [Identity a] -> Identity a

Monoid (First a)

Since: base-2.1

Defined in Data.Monoid

Methods

mempty :: First a

mappend :: First a -> First a -> First a

mconcat :: [First a] -> First a

Monoid (Last a)

Since: base-2.1

Defined in Data.Monoid

Methods

mempty :: Last a

mappend :: Last a -> Last a -> Last a

mconcat :: [Last a] -> Last a

Monoid a => Monoid (Dual a)

Since: base-2.1

Defined in Data.Semigroup.Internal

Methods

mempty :: Dual a

mappend :: Dual a -> Dual a -> Dual a

mconcat :: [Dual a] -> Dual a

Monoid (Endo a)

Since: base-2.1

Defined in Data.Semigroup.Internal

Methods

mempty :: Endo a

mappend :: Endo a -> Endo a -> Endo a

mconcat :: [Endo a] -> Endo a

Num a => Monoid (Sum a)

Since: base-2.1

Defined in Data.Semigroup.Internal

Methods

mempty :: Sum a

mappend :: Sum a -> Sum a -> Sum a

mconcat :: [Sum a] -> Sum a

Num a => Monoid (Product a)

Since: base-2.1

Defined in Data.Semigroup.Internal

Methods

mempty :: Product a

mappend :: Product a -> Product a -> Product a

mconcat :: [Product a] -> Product a

Monoid a => Monoid (Down a)

Since: base-4.11.0.0

Defined in Data.Ord

Methods

mempty :: Down a

mappend :: Down a -> Down a -> Down a

mconcat :: [Down a] -> Down a

PrimType ty => Monoid (UArray ty)

Defined in Basement.UArray.Base

Methods

mempty :: UArray ty

mappend :: UArray ty -> UArray ty -> UArray ty

mconcat :: [UArray ty] -> UArray ty

Monoid s => Monoid (CI s)

Defined in Data.CaseInsensitive.Internal

Methods

mempty :: CI s

mappend :: CI s -> CI s -> CI s

mconcat :: [CI s] -> CI s

a => Monoid (Dict a)

Defined in Data.Constraint

Methods

mempty :: Dict a

mappend :: Dict a -> Dict a -> Dict a

mconcat :: [Dict a] -> Dict a

Monoid (IntMap a)

Defined in Data.IntMap.Internal

Methods

mempty :: IntMap a

mappend :: IntMap a -> IntMap a -> IntMap a

mconcat :: [IntMap a] -> IntMap a

Monoid (Seq a)

Defined in Data.Sequence.Internal

Methods

mempty :: Seq a

mappend :: Seq a -> Seq a -> Seq a

mconcat :: [Seq a] -> Seq a

Ord a => Monoid (Set a)

Defined in Data.Set.Internal

Methods

mempty :: Set a

mappend :: Set a -> Set a -> Set a

mconcat :: [Set a] -> Set a

Monoid (Predicate a)

Defined in Data.Functor.Contravariant

Methods

mempty :: Predicate a

mappend :: Predicate a -> Predicate a -> Predicate a

mconcat :: [Predicate a] -> Predicate a

Monoid (Comparison a)

Defined in Data.Functor.Contravariant

Methods

mempty :: Comparison a

mappend :: Comparison a -> Comparison a -> Comparison a

mconcat :: [Comparison a] -> Comparison a

Monoid (Equivalence a)

Defined in Data.Functor.Contravariant

Methods

mempty :: Equivalence a

mappend :: Equivalence a -> Equivalence a -> Equivalence a

mconcat :: [Equivalence a] -> Equivalence a

Divisible divisible => Monoid (Supplied divisible)

Defined in Contravariant.Extras

Methods

mempty :: Supplied divisible

mappend :: Supplied divisible -> Supplied divisible -> Supplied divisible

mconcat :: [Supplied divisible] -> Supplied divisible

Monoid (DList a)

Defined in Data.DList

Methods

mempty :: DList a

mappend :: DList a -> DList a -> DList a

mconcat :: [DList a] -> DList a

Monoid (Heap a)

Defined in Data.Heap

Methods

mempty :: Heap a

mappend :: Heap a -> Heap a -> Heap a

mconcat :: [Heap a] -> Heap a

Prim a => Monoid (Vector a)

Defined in Data.Vector.Primitive

Methods

mempty :: Vector a

mappend :: Vector a -> Vector a -> Vector a

mconcat :: [Vector a] -> Vector a

Storable a => Monoid (Vector a)

Defined in Data.Vector.Storable

Methods

mempty :: Vector a

mappend :: Vector a -> Vector a -> Vector a

mconcat :: [Vector a] -> Vector a

(Hashable a, Eq a) => Monoid (HashSet a)

Defined in Data.HashSet

Methods

mempty :: HashSet a

mappend :: HashSet a -> HashSet a -> HashSet a

mconcat :: [HashSet a] -> HashSet a

Monoid (Vector a)

Defined in Data.Vector

Methods

mempty :: Vector a

mappend :: Vector a -> Vector a -> Vector a

mconcat :: [Vector a] -> Vector a

Ord a => Monoid (Min a)

Defined in Control.Lens.Internal.Fold

Methods

mempty :: Min a

mappend :: Min a -> Min a -> Min a

mconcat :: [Min a] -> Min a

Ord a => Monoid (Max a)

Defined in Control.Lens.Internal.Fold

Methods

mempty :: Max a

mappend :: Max a -> Max a -> Max a

mconcat :: [Max a] -> Max a

Monoid (Leftmost a)

Defined in Control.Lens.Internal.Fold

Methods

mempty :: Leftmost a

mappend :: Leftmost a -> Leftmost a -> Leftmost a

mconcat :: [Leftmost a] -> Leftmost a

Monoid (Rightmost a)

Defined in Control.Lens.Internal.Fold

Methods

mempty :: Rightmost a

mappend :: Rightmost a -> Rightmost a -> Rightmost a

mconcat :: [Rightmost a] -> Rightmost a

(Precise a, RealFloat a) => Monoid (Log a)

Defined in Numeric.Log

Methods

mempty :: Log a

mappend :: Log a -> Log a -> Log a

mconcat :: [Log a] -> Log a

Monoid a => Monoid (Managed a)

Defined in Control.Monad.Managed

Methods

mempty :: Managed a

mappend :: Managed a -> Managed a -> Managed a

mconcat :: [Managed a] -> Managed a

Monoid (Hints t)

Defined in Text.Megaparsec.Internal

Methods

mempty :: Hints t

mappend :: Hints t -> Hints t -> Hints t

mconcat :: [Hints t] -> Hints t

Ord a => Monoid (MultiSet a)

Defined in Data.MultiSet

Methods

mempty :: MultiSet a

mappend :: MultiSet a -> MultiSet a -> MultiSet a

mconcat :: [MultiSet a] -> MultiSet a

Monoid (InfoMod a)

Defined in Options.Applicative.Builder

Methods

mempty :: InfoMod a

mappend :: InfoMod a -> InfoMod a -> InfoMod a

mconcat :: [InfoMod a] -> InfoMod a

Monoid (DefaultProp a)

Defined in Options.Applicative.Builder.Internal

Methods

mempty :: DefaultProp a

mappend :: DefaultProp a -> DefaultProp a -> DefaultProp a

mconcat :: [DefaultProp a] -> DefaultProp a

Monoid (Doc a)

Defined in Text.PrettyPrint.Annotated.HughesPJ

Methods

mempty :: Doc a

mappend :: Doc a -> Doc a -> Doc a

mconcat :: [Doc a] -> Doc a

Monoid (Doc ann)

mempty = emptyDoc
mconcat = hcat

>>> mappend "hello" "world" :: Doc ann
helloworld

Defined in Data.Text.Prettyprint.Doc.Internal

Methods

mempty :: Doc ann

mappend :: Doc ann -> Doc ann -> Doc ann

mconcat :: [Doc ann] -> Doc ann

PrimUnlifted a => Monoid (UnliftedArray a)

Since: primitive-0.6.4.0

Defined in Data.Primitive.UnliftedArray

Methods

mempty :: UnliftedArray a

mappend :: UnliftedArray a -> UnliftedArray a -> UnliftedArray a

mconcat :: [UnliftedArray a] -> UnliftedArray a

Monoid (SmallArray a)

Defined in Data.Primitive.SmallArray

Methods

mempty :: SmallArray a

mappend :: SmallArray a -> SmallArray a -> SmallArray a

mconcat :: [SmallArray a] -> SmallArray a

Monoid (Array a)

Defined in Data.Primitive.Array

Methods

mempty :: Array a

mappend :: Array a -> Array a -> Array a

mconcat :: [Array a] -> Array a

Semigroup a => Monoid (Event a)

The combinator mempty represents an event that never occurs. It is a synonym,

mempty :: Event a
mempty = never

Defined in Reactive.Banana.Types

Methods

mempty :: Event a

mappend :: Event a -> Event a -> Event a

mconcat :: [Event a] -> Event a

(Upper a, Meet a) => Monoid (Meeting a)

Meeting mempty is the left- and right-identity.

let (l, r) = (mappend mempty (Meeting x), mappend (Meeting x) mempty) in l == Meeting x && r == Meeting (x :: Bool)

Defined in Data.Semilattice.Meet

Methods

mempty :: Meeting a

mappend :: Meeting a -> Meeting a -> Meeting a

mconcat :: [Meeting a] -> Meeting a

(Lower a, Join a) => Monoid (Joining a)

Joining mempty is the left- and right-identity.

\ x -> let (l, r) = (mappend mempty (Joining x), mappend (Joining x) mempty) in l == Joining x && r == Joining (x :: IntSet)

Defined in Data.Semilattice.Join

Methods

mempty :: Joining a

mappend :: Joining a -> Joining a -> Joining a

mconcat :: [Joining a] -> Joining a

Monoid (Builder element)

Provides support for O(1) concatenation.

Defined in VectorBuilder.Core.Builder

Methods

mempty :: Builder element

mappend :: Builder element -> Builder element -> Builder element

mconcat :: [Builder element] -> Builder element

Monoid (MergeSet a)

Defined in Data.Set.Internal

Methods

mempty :: MergeSet a

mappend :: MergeSet a -> MergeSet a -> MergeSet a

mconcat :: [MergeSet a] -> MergeSet a

Class (Semigroup a) (Monoid a)

Defined in Data.Constraint

Methods

cls :: Monoid a :- Semigroup a

(Monoid a) :=> (Monoid (Maybe a))

Defined in Data.Constraint

Methods

ins :: Monoid a :- Monoid (Maybe a)

(Monoid a) :=> (Monoid (Const a b))

Defined in Data.Constraint

Methods

ins :: Monoid a :- Monoid (Const a b)

(Monoid a) :=> (Monoid (Identity a))

Defined in Data.Constraint

Methods

ins :: Monoid a :- Monoid (Identity a)

(Monoid a) :=> (Monoid (IO a))

Defined in Data.Constraint

Methods

ins :: Monoid a :- Monoid (IO a)

(Monoid a) :=> (Applicative ((,) a))

Defined in Data.Constraint

Methods

ins :: Monoid a :- Applicative ((,) a)

(Monoid a) :=> (Applicative (Const a :: * -> *))

Defined in Data.Constraint

Methods

ins :: Monoid a :- Applicative (Const a)

Monoid b => Monoid (a -> b)

Since: base-2.1

Defined in GHC.Base

Methods

mempty :: a -> b

mappend :: (a -> b) -> (a -> b) -> a -> b

mconcat :: [a -> b] -> a -> b

(Monoid a, Monoid b) => Monoid (a, b)

Since: base-2.1

Defined in GHC.Base

Methods

mempty :: (a, b)

mappend :: (a, b) -> (a, b) -> (a, b)

mconcat :: [(a, b)] -> (a, b)

Monoid a => Monoid (ST s a)

Since: base-4.11.0.0

Defined in GHC.ST

Methods

mempty :: ST s a

mappend :: ST s a -> ST s a -> ST s a

mconcat :: [ST s a] -> ST s a

Monoid (Results s a)

Defined in Text.Earley.Parser.Internal

Methods

mempty :: Results s a

mappend :: Results s a -> Results s a -> Results s a

mconcat :: [Results s a] -> Results s a

Monoid a => Monoid (Op a b)

Defined in Data.Functor.Contravariant

Methods

mempty :: Op a b

mappend :: Op a b -> Op a b -> Op a b

mconcat :: [Op a b] -> Op a b

(Eq k, Hashable k) => Monoid (HashMap k v)

Defined in Data.HashMap.Base

Methods

mempty :: HashMap k v

mappend :: HashMap k v -> HashMap k v -> HashMap k v

mconcat :: [HashMap k v] -> HashMap k v

Ord k => Monoid (Map k v)

Defined in Data.Map.Internal

Methods

mempty :: Map k v

mappend :: Map k v -> Map k v -> Map k v

mconcat :: [Map k v] -> Map k v

Monoid (Proxy s)

Since: base-4.7.0.0

Defined in Data.Proxy

Methods

mempty :: Proxy s

mappend :: Proxy s -> Proxy s -> Proxy s

mconcat :: [Proxy s] -> Proxy s

Monoid (Mod t a)

Defined in Env.Internal.Parser

Methods

mempty :: Mod t a

mappend :: Mod t a -> Mod t a -> Mod t a

mconcat :: [Mod t a] -> Mod t a

Monoid b => Monoid (Fold a b)

Defined in Control.Foldl

Methods

mempty :: Fold a b

mappend :: Fold a b -> Fold a b -> Fold a b

mconcat :: [Fold a b] -> Fold a b

Monad m => Monoid (EndoM m a)

Defined in Control.Foldl

Methods

mempty :: EndoM m a

mappend :: EndoM m a -> EndoM m a -> EndoM m a

mconcat :: [EndoM m a] -> EndoM m a

(Monad m, Monoid a) => Monoid (GenT m a)

Defined in Hedgehog.Internal.Gen

Methods

mempty :: GenT m a

mappend :: GenT m a -> GenT m a -> GenT m a

mconcat :: [GenT m a] -> GenT m a

Monoid (ReifiedFold s a)

Defined in Control.Lens.Reified

Methods

mempty :: ReifiedFold s a

mappend :: ReifiedFold s a -> ReifiedFold s a -> ReifiedFold s a

mconcat :: [ReifiedFold s a] -> ReifiedFold s a

Monoid (f a) => Monoid (Indexing f a)

>>> "cat" ^@.. (folded <> folded)
[(0,'c'),(1,'a'),(2,'t'),(0,'c'),(1,'a'),(2,'t')]

>>> "cat" ^@.. indexing (folded <> folded)
[(0,'c'),(1,'a'),(2,'t'),(3,'c'),(4,'a'),(5,'t')]

Defined in Control.Lens.Internal.Indexed

Methods

mempty :: Indexing f a

mappend :: Indexing f a -> Indexing f a -> Indexing f a

mconcat :: [Indexing f a] -> Indexing f a

(Contravariant f, Applicative f) => Monoid (Folding f a)

Defined in Control.Lens.Internal.Fold

Methods

mempty :: Folding f a

mappend :: Folding f a -> Folding f a -> Folding f a

mconcat :: [Folding f a] -> Folding f a

Applicative f => Monoid (Traversed a f)

Defined in Control.Lens.Internal.Fold

Methods

mempty :: Traversed a f

mappend :: Traversed a f -> Traversed a f -> Traversed a f

mconcat :: [Traversed a f] -> Traversed a f

(Apply f, Applicative f) => Monoid (TraversedF a f)

Defined in Control.Lens.Internal.Fold

Methods

mempty :: TraversedF a f

mappend :: TraversedF a f -> TraversedF a f -> TraversedF a f

mconcat :: [TraversedF a f] -> TraversedF a f

Monad m => Monoid (Sequenced a m)

Defined in Control.Lens.Internal.Fold

Methods

mempty :: Sequenced a m

mappend :: Sequenced a m -> Sequenced a m -> Sequenced a m

mconcat :: [Sequenced a m] -> Sequenced a m

(Monad m, Semigroup a, Monoid a) => Monoid (ListT m a)

Defined in List.Transformer

Methods

mempty :: ListT m a

mappend :: ListT m a -> ListT m a -> ListT m a

mconcat :: [ListT m a] -> ListT m a

(Ord t, Ord e) => Monoid (ParseError t e)

Defined in Text.Megaparsec.Error

Methods

mempty :: ParseError t e

mappend :: ParseError t e -> ParseError t e -> ParseError t e

mconcat :: [ParseError t e] -> ParseError t e

Monoid (Mod f a)

Defined in Options.Applicative.Builder.Internal

Methods

mempty :: Mod f a

mappend :: Mod f a -> Mod f a -> Mod f a

mconcat :: [Mod f a] -> Mod f a

(Semigroup a, Monoid a, MonadUnliftIO m) => Monoid (Concurrently m a)

Since: unliftio-0.1.0.0

Defined in UnliftIO.Async

Methods

mempty :: Concurrently m a

mappend :: Concurrently m a -> Concurrently m a -> Concurrently m a

mconcat :: [Concurrently m a] -> Concurrently m a

(Monoid a, Monoid b) :=> (Monoid (a, b))

Defined in Data.Constraint

Methods

ins :: (Monoid a, Monoid b) :- Monoid (a, b)

(Monoid a, Monoid b, Monoid c) => Monoid (a, b, c)

Since: base-2.1

Defined in GHC.Base

Methods

mempty :: (a, b, c)

mappend :: (a, b, c) -> (a, b, c) -> (a, b, c)

mconcat :: [(a, b, c)] -> (a, b, c)

Monoid (Results s t a)

Defined in Text.Earley.Generator.Internal

Methods

mempty :: Results s t a

mappend :: Results s t a -> Results s t a -> Results s t a

mconcat :: [Results s t a] -> Results s t a

Monoid a => Monoid (Const a b)

Defined in Data.Functor.Const

Methods

mempty :: Const a b

mappend :: Const a b -> Const a b -> Const a b

mconcat :: [Const a b] -> Const a b

Alternative f => Monoid (Alt f a)

Since: base-4.8.0.0

Defined in Data.Semigroup.Internal

Methods

mempty :: Alt f a

mappend :: Alt f a -> Alt f a -> Alt f a

mconcat :: [Alt f a] -> Alt f a

(Monoid b, Monad m) => Monoid (FoldM m a b)

Defined in Control.Foldl

Methods

mempty :: FoldM m a b

mappend :: FoldM m a b -> FoldM m a b -> FoldM m a b

mconcat :: [FoldM m a b] -> FoldM m a b

Monoid (ReifiedIndexedFold i s a)

Defined in Control.Lens.Reified

Methods

mempty :: ReifiedIndexedFold i s a

mappend :: ReifiedIndexedFold i s a -> ReifiedIndexedFold i s a -> ReifiedIndexedFold i s a

mconcat :: [ReifiedIndexedFold i s a] -> ReifiedIndexedFold i s a

(Profunctor p, Arrow p, Semigroup b, Monoid b) => Monoid (Closure p a b)

Defined in Data.Profunctor.Closed

Methods

mempty :: Closure p a b

mappend :: Closure p a b -> Closure p a b -> Closure p a b

mconcat :: [Closure p a b] -> Closure p a b

ArrowPlus p => Monoid (Tambara p a b)

Defined in Data.Profunctor.Strong

Methods

mempty :: Tambara p a b

mappend :: Tambara p a b -> Tambara p a b -> Tambara p a b

mconcat :: [Tambara p a b] -> Tambara p a b

Reifies s (ReifiedMonoid a) => Monoid (ReflectedMonoid a s)

Defined in Data.Reflection

Methods

mempty :: ReflectedMonoid a s

mappend :: ReflectedMonoid a s -> ReflectedMonoid a s -> ReflectedMonoid a s

mconcat :: [ReflectedMonoid a s] -> ReflectedMonoid a s

(Semigroup a, Monoid a) => Monoid (Tagged s a)

Defined in Data.Tagged

Methods

mempty :: Tagged s a

mappend :: Tagged s a -> Tagged s a -> Tagged s a

mconcat :: [Tagged s a] -> Tagged s a

(Monoid a, Monoid b, Monoid c, Monoid d) => Monoid (a, b, c, d)

Since: base-2.1

Defined in GHC.Base

Methods

mempty :: (a, b, c, d)

mappend :: (a, b, c, d) -> (a, b, c, d) -> (a, b, c, d)

mconcat :: [(a, b, c, d)] -> (a, b, c, d)

Monoid (Prod r e t a)

Defined in Text.Earley.Grammar

Methods

mempty :: Prod r e t a

mappend :: Prod r e t a -> Prod r e t a -> Prod r e t a

mconcat :: [Prod r e t a] -> Prod r e t a

(Stream s, Monoid a) => Monoid (ParsecT e s m a)

Since: megaparsec-5.3.0

Defined in Text.Megaparsec.Internal

Methods

mempty :: ParsecT e s m a

mappend :: ParsecT e s m a -> ParsecT e s m a -> ParsecT e s m a

mconcat :: [ParsecT e s m a] -> ParsecT e s m a

(Monoid a, Monoid b, Monoid c, Monoid d, Monoid e) => Monoid (a, b, c, d, e)

Since: base-2.1

Defined in GHC.Base

Methods

mempty :: (a, b, c, d, e)

mappend :: (a, b, c, d, e) -> (a, b, c, d, e) -> (a, b, c, d, e)

mconcat :: [(a, b, c, d, e)] -> (a, b, c, d, e)

Contravariant g => Monoid (BazaarT p g a b t)

Defined in Control.Lens.Internal.Bazaar

Methods

mempty :: BazaarT p g a b t

mappend :: BazaarT p g a b t -> BazaarT p g a b t -> BazaarT p g a b t

mconcat :: [BazaarT p g a b t] -> BazaarT p g a b t

gmempty :: (Generic a, GMonoid (Rep a)) => a

Generically generate a Monoid mempty for any product-like type implementing Generic.

It is only defined for product types.

gmappend gmempty a = a = gmappend a gmempty