W3cubDocs

/Haskell 9

Control.Monad.Instances

Copyright	(c) The University of Glasgow 2001
License	BSD-style (see the file libraries/base/LICENSE)
Maintainer	[email protected]
Stability	provisional
Portability	portable
Safe Haskell	Trustworthy
Language	Haskell2010

Description

Deprecated: This module now contains no instances and will be removed in the future

This module is DEPRECATED and will be removed in the future!

Functor and Monad instances for (->) r and Functor instances for (,) a and Either a.

class Functor (f :: Type -> Type) where Source

A type f is a Functor if it provides a function fmap which, given any types a and b lets you apply any function from (a -> b) to turn an f a into an f b, preserving the structure of f. Furthermore f needs to adhere to the following:

Identity: fmap id == id
Composition: fmap (f . g) == fmap f . fmap g

Note, that the second law follows from the free theorem of the type fmap and the first law, so you need only check that the former condition holds. See these articles by School of Haskell or David Luposchainsky for an explanation.

Minimal complete definition

fmap

Methods

fmap :: (a -> b) -> f a -> f b Source

fmap is used to apply a function of type (a -> b) to a value of type f a, where f is a functor, to produce a value of type f b. Note that for any type constructor with more than one parameter (e.g., Either), only the last type parameter can be modified with fmap (e.g., b in `Either a b`).

Some type constructors with two parameters or more have a Bifunctor instance that allows both the last and the penultimate parameters to be mapped over.

Examples

Expand

Convert from a Maybe Int to a Maybe String using show:

>>> fmap show Nothing
Nothing
>>> fmap show (Just 3)
Just "3"

Convert from an Either Int Int to an Either Int String using show:

>>> fmap show (Left 17)
Left 17
>>> fmap show (Right 17)
Right "17"

Double each element of a list:

>>> fmap (*2) [1,2,3]
[2,4,6]

Apply even to the second element of a pair:

>>> fmap even (2,2)
(2,True)

It may seem surprising that the function is only applied to the last element of the tuple compared to the list example above which applies it to every element in the list. To understand, remember that tuples are type constructors with multiple type parameters: a tuple of 3 elements (a,b,c) can also be written (,,) a b c and its Functor instance is defined for Functor ((,,) a b) (i.e., only the third parameter is free to be mapped over with fmap).

It explains why fmap can be used with tuples containing values of different types as in the following example:

>>> fmap even ("hello", 1.0, 4)
("hello",1.0,True)

(<$) :: a -> f b -> f a infixl 4 Source

Replace all locations in the input with the same value. The default definition is fmap . const, but this may be overridden with a more efficient version.

Examples

Expand

Perform a computation with Maybe and replace the result with a constant value if it is Just:

>>> 'a' <$ Just 2
Just 'a'
>>> 'a' <$ Nothing
Nothing

Instances

Instances details

Functor Complex Source	Since: base-4.9.0.0
Instance details Defined in Data.Complex Methods fmap :: (a -> b) -> Complex a -> Complex b Source (<$) :: a -> Complex b -> Complex a Source
Functor First Source	Since: base-4.9.0.0
Instance details Defined in Data.Semigroup Methods fmap :: (a -> b) -> First a -> First b Source (<$) :: a -> First b -> First a Source
Functor Last Source	Since: base-4.9.0.0
Instance details Defined in Data.Semigroup Methods fmap :: (a -> b) -> Last a -> Last b Source (<$) :: a -> Last b -> Last a Source
Functor Max Source	Since: base-4.9.0.0
Instance details Defined in Data.Semigroup Methods fmap :: (a -> b) -> Max a -> Max b Source (<$) :: a -> Max b -> Max a Source
Functor Min Source	Since: base-4.9.0.0
Instance details Defined in Data.Semigroup Methods fmap :: (a -> b) -> Min a -> Min b Source (<$) :: a -> Min b -> Min a Source
Functor ArgDescr Source	Since: base-4.7.0.0
Instance details Defined in System.Console.GetOpt Methods fmap :: (a -> b) -> ArgDescr a -> ArgDescr b Source (<$) :: a -> ArgDescr b -> ArgDescr a Source
Functor ArgOrder Source	Since: base-4.7.0.0
Instance details Defined in System.Console.GetOpt Methods fmap :: (a -> b) -> ArgOrder a -> ArgOrder b Source (<$) :: a -> ArgOrder b -> ArgOrder a Source
Functor OptDescr Source	Since: base-4.7.0.0
Instance details Defined in System.Console.GetOpt Methods fmap :: (a -> b) -> OptDescr a -> OptDescr b Source (<$) :: a -> OptDescr b -> OptDescr a Source
Functor NonEmpty Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Base Methods fmap :: (a -> b) -> NonEmpty a -> NonEmpty b Source (<$) :: a -> NonEmpty b -> NonEmpty a Source
Functor STM Source	Since: base-4.3.0.0
Instance details Defined in GHC.Internal.Conc.Sync Methods fmap :: (a -> b) -> STM a -> STM b Source (<$) :: a -> STM b -> STM a Source
Functor Handler Source	Since: base-4.6.0.0
Instance details Defined in GHC.Internal.Control.Exception Methods fmap :: (a -> b) -> Handler a -> Handler b Source (<$) :: a -> Handler b -> Handler a Source
Functor Identity Source	Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Data.Functor.Identity Methods fmap :: (a -> b) -> Identity a -> Identity b Source (<$) :: a -> Identity b -> Identity a Source
Functor First Source	Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Data.Monoid Methods fmap :: (a -> b) -> First a -> First b Source (<$) :: a -> First b -> First a Source
Functor Last Source	Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Data.Monoid Methods fmap :: (a -> b) -> Last a -> Last b Source (<$) :: a -> Last b -> Last a Source
Functor Down Source	Since: base-4.11.0.0
Instance details Defined in GHC.Internal.Data.Ord Methods fmap :: (a -> b) -> Down a -> Down b Source (<$) :: a -> Down b -> Down a Source
Functor Dual Source	Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Data.Semigroup.Internal Methods fmap :: (a -> b) -> Dual a -> Dual b Source (<$) :: a -> Dual b -> Dual a Source
Functor Product Source	Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Data.Semigroup.Internal Methods fmap :: (a -> b) -> Product a -> Product b Source (<$) :: a -> Product b -> Product a Source
Functor Sum Source	Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Data.Semigroup.Internal Methods fmap :: (a -> b) -> Sum a -> Sum b Source (<$) :: a -> Sum b -> Sum a Source
Functor ZipList Source	Since: base-2.1
Instance details Defined in GHC.Internal.Functor.ZipList Methods fmap :: (a -> b) -> ZipList a -> ZipList b Source (<$) :: a -> ZipList b -> ZipList a Source
Functor NoIO Source	Since: base-4.8.0.0
Instance details Defined in GHC.Internal.GHCi Methods fmap :: (a -> b) -> NoIO a -> NoIO b Source (<$) :: a -> NoIO b -> NoIO a Source
Functor Par1 Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods fmap :: (a -> b) -> Par1 a -> Par1 b Source (<$) :: a -> Par1 b -> Par1 a Source
Functor Q Source
Instance details Defined in GHC.Internal.TH.Syntax Methods fmap :: (a -> b) -> Q a -> Q b Source (<$) :: a -> Q b -> Q a Source
Functor TyVarBndr Source
Instance details Defined in GHC.Internal.TH.Syntax Methods fmap :: (a -> b) -> TyVarBndr a -> TyVarBndr b Source (<$) :: a -> TyVarBndr b -> TyVarBndr a Source
Functor P Source	Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Text.ParserCombinators.ReadP Methods fmap :: (a -> b) -> P a -> P b Source (<$) :: a -> P b -> P a Source
Functor ReadP Source	Since: base-2.1
Instance details Defined in GHC.Internal.Text.ParserCombinators.ReadP Methods fmap :: (a -> b) -> ReadP a -> ReadP b Source (<$) :: a -> ReadP b -> ReadP a Source
Functor ReadPrec Source	Since: base-2.1
Instance details Defined in GHC.Internal.Text.ParserCombinators.ReadPrec Methods fmap :: (a -> b) -> ReadPrec a -> ReadPrec b Source (<$) :: a -> ReadPrec b -> ReadPrec a Source
Functor IO Source	Since: base-2.1
Instance details Defined in GHC.Internal.Base Methods fmap :: (a -> b) -> IO a -> IO b Source (<$) :: a -> IO b -> IO a Source
Functor Maybe Source	Since: base-2.1
Instance details Defined in GHC.Internal.Base Methods fmap :: (a -> b) -> Maybe a -> Maybe b Source (<$) :: a -> Maybe b -> Maybe a Source
Functor Solo Source	Since: base-4.15
Instance details Defined in GHC.Internal.Base Methods fmap :: (a -> b) -> Solo a -> Solo b Source (<$) :: a -> Solo b -> Solo a Source
Functor [] Source	Since: base-2.1
Instance details Defined in GHC.Internal.Base Methods fmap :: (a -> b) -> [a] -> [b] Source (<$) :: a -> [b] -> [a] Source
Monad m => Functor (WrappedMonad m) Source	Since: base-2.1
Instance details Defined in Control.Applicative Methods fmap :: (a -> b) -> WrappedMonad m a -> WrappedMonad m b Source (<$) :: a -> WrappedMonad m b -> WrappedMonad m a Source
Functor (Arg a) Source	Since: base-4.9.0.0
Instance details Defined in Data.Semigroup Methods fmap :: (a0 -> b) -> Arg a a0 -> Arg a b Source (<$) :: a0 -> Arg a b -> Arg a a0 Source
Functor (Array i) Source	Since: base-2.1
Instance details Defined in GHC.Internal.Arr Methods fmap :: (a -> b) -> Array i a -> Array i b Source (<$) :: a -> Array i b -> Array i a Source
Arrow a => Functor (ArrowMonad a) Source	Since: base-4.6.0.0
Instance details Defined in GHC.Internal.Control.Arrow Methods fmap :: (a0 -> b) -> ArrowMonad a a0 -> ArrowMonad a b Source (<$) :: a0 -> ArrowMonad a b -> ArrowMonad a a0 Source
Functor (ST s) Source	Since: base-2.1
Instance details Defined in GHC.Internal.Control.Monad.ST.Lazy.Imp Methods fmap :: (a -> b) -> ST s a -> ST s b Source (<$) :: a -> ST s b -> ST s a Source
Functor (Either a) Source	Since: base-3.0
Instance details Defined in GHC.Internal.Data.Either Methods fmap :: (a0 -> b) -> Either a a0 -> Either a b Source (<$) :: a0 -> Either a b -> Either a a0 Source
Functor (StateL s) Source	Since: base-4.0
Instance details Defined in GHC.Internal.Data.Functor.Utils Methods fmap :: (a -> b) -> StateL s a -> StateL s b Source (<$) :: a -> StateL s b -> StateL s a Source
Functor (StateR s) Source	Since: base-4.0
Instance details Defined in GHC.Internal.Data.Functor.Utils Methods fmap :: (a -> b) -> StateR s a -> StateR s b Source (<$) :: a -> StateR s b -> StateR s a Source
Functor (Proxy :: Type -> Type) Source	Since: base-4.7.0.0
Instance details Defined in GHC.Internal.Data.Proxy Methods fmap :: (a -> b) -> Proxy a -> Proxy b Source (<$) :: a -> Proxy b -> Proxy a Source
Functor (U1 :: Type -> Type) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods fmap :: (a -> b) -> U1 a -> U1 b Source (<$) :: a -> U1 b -> U1 a Source
Functor (V1 :: Type -> Type) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods fmap :: (a -> b) -> V1 a -> V1 b Source (<$) :: a -> V1 b -> V1 a Source
Functor (ST s) Source	Since: base-2.1
Instance details Defined in GHC.Internal.ST Methods fmap :: (a -> b) -> ST s a -> ST s b Source (<$) :: a -> ST s b -> ST s a Source
Functor ((,) a) Source	Since: base-2.1
Instance details Defined in GHC.Internal.Base Methods fmap :: (a0 -> b) -> (a, a0) -> (a, b) Source (<$) :: a0 -> (a, b) -> (a, a0) Source
Arrow a => Functor (WrappedArrow a b) Source	Since: base-2.1
Instance details Defined in Control.Applicative Methods fmap :: (a0 -> b0) -> WrappedArrow a b a0 -> WrappedArrow a b b0 Source (<$) :: a0 -> WrappedArrow a b b0 -> WrappedArrow a b a0 Source
Functor m => Functor (Kleisli m a) Source	Since: base-4.14.0.0
Instance details Defined in GHC.Internal.Control.Arrow Methods fmap :: (a0 -> b) -> Kleisli m a a0 -> Kleisli m a b Source (<$) :: a0 -> Kleisli m a b -> Kleisli m a a0 Source
Functor (Const m :: Type -> Type) Source	Since: base-2.1
Instance details Defined in GHC.Internal.Data.Functor.Const Methods fmap :: (a -> b) -> Const m a -> Const m b Source (<$) :: a -> Const m b -> Const m a Source
Monad m => Functor (StateT s m) Source	Since: base-4.18.0.0
Instance details Defined in GHC.Internal.Data.Functor.Utils Methods fmap :: (a -> b) -> StateT s m a -> StateT s m b Source (<$) :: a -> StateT s m b -> StateT s m a Source
Functor f => Functor (Ap f) Source	Since: base-4.12.0.0
Instance details Defined in GHC.Internal.Data.Monoid Methods fmap :: (a -> b) -> Ap f a -> Ap f b Source (<$) :: a -> Ap f b -> Ap f a Source
Functor f => Functor (Alt f) Source	Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Data.Semigroup.Internal Methods fmap :: (a -> b) -> Alt f a -> Alt f b Source (<$) :: a -> Alt f b -> Alt f a Source
(Generic1 f, Functor (Rep1 f)) => Functor (Generically1 f) Source	Since: base-4.17.0.0
Instance details Defined in GHC.Internal.Generics Methods fmap :: (a -> b) -> Generically1 f a -> Generically1 f b Source (<$) :: a -> Generically1 f b -> Generically1 f a Source
Functor f => Functor (Rec1 f) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods fmap :: (a -> b) -> Rec1 f a -> Rec1 f b Source (<$) :: a -> Rec1 f b -> Rec1 f a Source
Functor (URec (Ptr ()) :: Type -> Type) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods fmap :: (a -> b) -> URec (Ptr ()) a -> URec (Ptr ()) b Source (<$) :: a -> URec (Ptr ()) b -> URec (Ptr ()) a Source
Functor (URec Char :: Type -> Type) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods fmap :: (a -> b) -> URec Char a -> URec Char b Source (<$) :: a -> URec Char b -> URec Char a Source
Functor (URec Double :: Type -> Type) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods fmap :: (a -> b) -> URec Double a -> URec Double b Source (<$) :: a -> URec Double b -> URec Double a Source
Functor (URec Float :: Type -> Type) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods fmap :: (a -> b) -> URec Float a -> URec Float b Source (<$) :: a -> URec Float b -> URec Float a Source
Functor (URec Int :: Type -> Type) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods fmap :: (a -> b) -> URec Int a -> URec Int b Source (<$) :: a -> URec Int b -> URec Int a Source
Functor (URec Word :: Type -> Type) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods fmap :: (a -> b) -> URec Word a -> URec Word b Source (<$) :: a -> URec Word b -> URec Word a Source
Functor ((,,) a b) Source	Since: base-4.14.0.0
Instance details Defined in GHC.Internal.Base Methods fmap :: (a0 -> b0) -> (a, b, a0) -> (a, b, b0) Source (<$) :: a0 -> (a, b, b0) -> (a, b, a0) Source
(Functor f, Functor g) => Functor (Product f g) Source	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Product Methods fmap :: (a -> b) -> Product f g a -> Product f g b Source (<$) :: a -> Product f g b -> Product f g a Source
(Functor f, Functor g) => Functor (Sum f g) Source	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Sum Methods fmap :: (a -> b) -> Sum f g a -> Sum f g b Source (<$) :: a -> Sum f g b -> Sum f g a Source
(Functor f, Functor g) => Functor (f :*: g) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods fmap :: (a -> b) -> (f :: g) a -> (f :: g) b Source (<$) :: a -> (f :: g) b -> (f :: g) a Source
(Functor f, Functor g) => Functor (f :+: g) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods fmap :: (a -> b) -> (f :+: g) a -> (f :+: g) b Source (<$) :: a -> (f :+: g) b -> (f :+: g) a Source
Functor (K1 i c :: Type -> Type) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods fmap :: (a -> b) -> K1 i c a -> K1 i c b Source (<$) :: a -> K1 i c b -> K1 i c a Source
Functor ((,,,) a b c) Source	Since: base-4.14.0.0
Instance details Defined in GHC.Internal.Base Methods fmap :: (a0 -> b0) -> (a, b, c, a0) -> (a, b, c, b0) Source (<$) :: a0 -> (a, b, c, b0) -> (a, b, c, a0) Source
Functor ((->) r) Source	Since: base-2.1
Instance details Defined in GHC.Internal.Base Methods fmap :: (a -> b) -> (r -> a) -> r -> b Source (<$) :: a -> (r -> b) -> r -> a Source
(Functor f, Functor g) => Functor (Compose f g) Source	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Compose Methods fmap :: (a -> b) -> Compose f g a -> Compose f g b Source (<$) :: a -> Compose f g b -> Compose f g a Source
(Functor f, Functor g) => Functor (f :.: g) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods fmap :: (a -> b) -> (f :.: g) a -> (f :.: g) b Source (<$) :: a -> (f :.: g) b -> (f :.: g) a Source
Functor f => Functor (M1 i c f) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods fmap :: (a -> b) -> M1 i c f a -> M1 i c f b Source (<$) :: a -> M1 i c f b -> M1 i c f a Source
Functor ((,,,,) a b c d) Source	Since: base-4.18.0.0
Instance details Defined in GHC.Internal.Base Methods fmap :: (a0 -> b0) -> (a, b, c, d, a0) -> (a, b, c, d, b0) Source (<$) :: a0 -> (a, b, c, d, b0) -> (a, b, c, d, a0) Source
Functor ((,,,,,) a b c d e) Source	Since: base-4.18.0.0
Instance details Defined in GHC.Internal.Base Methods fmap :: (a0 -> b0) -> (a, b, c, d, e, a0) -> (a, b, c, d, e, b0) Source (<$) :: a0 -> (a, b, c, d, e, b0) -> (a, b, c, d, e, a0) Source
Functor ((,,,,,,) a b c d e f) Source	Since: base-4.18.0.0
Instance details Defined in GHC.Internal.Base Methods fmap :: (a0 -> b0) -> (a, b, c, d, e, f, a0) -> (a, b, c, d, e, f, b0) Source (<$) :: a0 -> (a, b, c, d, e, f, b0) -> (a, b, c, d, e, f, a0) Source

class Applicative m => Monad (m :: Type -> Type) where Source

The Monad class defines the basic operations over a monad, a concept from a branch of mathematics known as category theory. From the perspective of a Haskell programmer, however, it is best to think of a monad as an abstract datatype of actions. Haskell's do expressions provide a convenient syntax for writing monadic expressions.

Instances of Monad should satisfy the following:

Left identity: return a >>= k = k a
Right identity: m >>= return = m
Associativity: m >>= (\x -> k x >>= h) = (m >>= k) >>= h

Furthermore, the Monad and Applicative operations should relate as follows:

```
pure = return
```

m1 <*> m2 = m1 >>= (\x1 -> m2 >>= (\x2 -> return (x1 x2)))

The above laws imply:

```
fmap f xs  =  xs >>= return . f
```
```
(>>) = (*>)
```

and that pure and (<*>) satisfy the applicative functor laws.

The instances of Monad for List, Maybe and IO defined in the Prelude satisfy these laws.

Minimal complete definition

(>>=)

Methods

(>>=) :: m a -> (a -> m b) -> m b infixl 1 Source

Sequentially compose two actions, passing any value produced by the first as an argument to the second.

'as >>= bs' can be understood as the do expression

do a <- as
   bs a

An alternative name for this function is 'bind', but some people may refer to it as 'flatMap', which results from it being equivalent to

\x f -> join (fmap f x) :: Monad m => m a -> (a -> m b) -> m b

which can be seen as mapping a value with Monad m => m a -> m (m b) and then 'flattening' m (m b) to m b using join.

(>>) :: m a -> m b -> m b infixl 1 Source

Sequentially compose two actions, discarding any value produced by the first, like sequencing operators (such as the semicolon) in imperative languages.

'as >> bs' can be understood as the do expression

do as
   bs

or in terms of (>>=) as

as >>= const bs

return :: a -> m a Source

Inject a value into the monadic type. This function should not be different from its default implementation as pure. The justification for the existence of this function is merely historic.

Instances

Instances details

Monad Complex Source	Since: base-4.9.0.0
Instance details Defined in Data.Complex Methods (>>=) :: Complex a -> (a -> Complex b) -> Complex b Source (>>) :: Complex a -> Complex b -> Complex b Source return :: a -> Complex a Source
Monad First Source	Since: base-4.9.0.0
Instance details Defined in Data.Semigroup Methods (>>=) :: First a -> (a -> First b) -> First b Source (>>) :: First a -> First b -> First b Source return :: a -> First a Source
Monad Last Source	Since: base-4.9.0.0
Instance details Defined in Data.Semigroup Methods (>>=) :: Last a -> (a -> Last b) -> Last b Source (>>) :: Last a -> Last b -> Last b Source return :: a -> Last a Source
Monad Max Source	Since: base-4.9.0.0
Instance details Defined in Data.Semigroup Methods (>>=) :: Max a -> (a -> Max b) -> Max b Source (>>) :: Max a -> Max b -> Max b Source return :: a -> Max a Source
Monad Min Source	Since: base-4.9.0.0
Instance details Defined in Data.Semigroup Methods (>>=) :: Min a -> (a -> Min b) -> Min b Source (>>) :: Min a -> Min b -> Min b Source return :: a -> Min a Source
Monad NonEmpty Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Base Methods (>>=) :: NonEmpty a -> (a -> NonEmpty b) -> NonEmpty b Source (>>) :: NonEmpty a -> NonEmpty b -> NonEmpty b Source return :: a -> NonEmpty a Source
Monad STM Source	Since: base-4.3.0.0
Instance details Defined in GHC.Internal.Conc.Sync Methods (>>=) :: STM a -> (a -> STM b) -> STM b Source (>>) :: STM a -> STM b -> STM b Source return :: a -> STM a Source
Monad Identity Source	Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Data.Functor.Identity Methods (>>=) :: Identity a -> (a -> Identity b) -> Identity b Source (>>) :: Identity a -> Identity b -> Identity b Source return :: a -> Identity a Source
Monad First Source	Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Data.Monoid Methods (>>=) :: First a -> (a -> First b) -> First b Source (>>) :: First a -> First b -> First b Source return :: a -> First a Source
Monad Last Source	Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Data.Monoid Methods (>>=) :: Last a -> (a -> Last b) -> Last b Source (>>) :: Last a -> Last b -> Last b Source return :: a -> Last a Source
Monad Down Source	Since: base-4.11.0.0
Instance details Defined in GHC.Internal.Data.Ord Methods (>>=) :: Down a -> (a -> Down b) -> Down b Source (>>) :: Down a -> Down b -> Down b Source return :: a -> Down a Source
Monad Dual Source	Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Data.Semigroup.Internal Methods (>>=) :: Dual a -> (a -> Dual b) -> Dual b Source (>>) :: Dual a -> Dual b -> Dual b Source return :: a -> Dual a Source
Monad Product Source	Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Data.Semigroup.Internal Methods (>>=) :: Product a -> (a -> Product b) -> Product b Source (>>) :: Product a -> Product b -> Product b Source return :: a -> Product a Source
Monad Sum Source	Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Data.Semigroup.Internal Methods (>>=) :: Sum a -> (a -> Sum b) -> Sum b Source (>>) :: Sum a -> Sum b -> Sum b Source return :: a -> Sum a Source
Monad NoIO Source	Since: base-4.4.0.0
Instance details Defined in GHC.Internal.GHCi Methods (>>=) :: NoIO a -> (a -> NoIO b) -> NoIO b Source (>>) :: NoIO a -> NoIO b -> NoIO b Source return :: a -> NoIO a Source
Monad Par1 Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods (>>=) :: Par1 a -> (a -> Par1 b) -> Par1 b Source (>>) :: Par1 a -> Par1 b -> Par1 b Source return :: a -> Par1 a Source
Monad Q Source
Instance details Defined in GHC.Internal.TH.Syntax Methods (>>=) :: Q a -> (a -> Q b) -> Q b Source (>>) :: Q a -> Q b -> Q b Source return :: a -> Q a Source
Monad P Source	Since: base-2.1
Instance details Defined in GHC.Internal.Text.ParserCombinators.ReadP Methods (>>=) :: P a -> (a -> P b) -> P b Source (>>) :: P a -> P b -> P b Source return :: a -> P a Source
Monad ReadP Source	Since: base-2.1
Instance details Defined in GHC.Internal.Text.ParserCombinators.ReadP Methods (>>=) :: ReadP a -> (a -> ReadP b) -> ReadP b Source (>>) :: ReadP a -> ReadP b -> ReadP b Source return :: a -> ReadP a Source
Monad ReadPrec Source	Since: base-2.1
Instance details Defined in GHC.Internal.Text.ParserCombinators.ReadPrec Methods (>>=) :: ReadPrec a -> (a -> ReadPrec b) -> ReadPrec b Source (>>) :: ReadPrec a -> ReadPrec b -> ReadPrec b Source return :: a -> ReadPrec a Source
Monad IO Source	Since: base-2.1
Instance details Defined in GHC.Internal.Base Methods (>>=) :: IO a -> (a -> IO b) -> IO b Source (>>) :: IO a -> IO b -> IO b Source return :: a -> IO a Source
Monad Maybe Source	Since: base-2.1
Instance details Defined in GHC.Internal.Base Methods (>>=) :: Maybe a -> (a -> Maybe b) -> Maybe b Source (>>) :: Maybe a -> Maybe b -> Maybe b Source return :: a -> Maybe a Source
Monad Solo Source	Since: base-4.15
Instance details Defined in GHC.Internal.Base Methods (>>=) :: Solo a -> (a -> Solo b) -> Solo b Source (>>) :: Solo a -> Solo b -> Solo b Source return :: a -> Solo a Source
Monad [] Source	Since: base-2.1
Instance details Defined in GHC.Internal.Base Methods (>>=) :: [a] -> (a -> [b]) -> [b] Source (>>) :: [a] -> [b] -> [b] Source return :: a -> [a] Source
Monad m => Monad (WrappedMonad m) Source	Since: base-4.7.0.0
Instance details Defined in Control.Applicative Methods (>>=) :: WrappedMonad m a -> (a -> WrappedMonad m b) -> WrappedMonad m b Source (>>) :: WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m b Source return :: a -> WrappedMonad m a Source
ArrowApply a => Monad (ArrowMonad a) Source	Since: base-2.1
Instance details Defined in GHC.Internal.Control.Arrow Methods (>>=) :: ArrowMonad a a0 -> (a0 -> ArrowMonad a b) -> ArrowMonad a b Source (>>) :: ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a b Source return :: a0 -> ArrowMonad a a0 Source
Monad (ST s) Source	Since: base-2.1
Instance details Defined in GHC.Internal.Control.Monad.ST.Lazy.Imp Methods (>>=) :: ST s a -> (a -> ST s b) -> ST s b Source (>>) :: ST s a -> ST s b -> ST s b Source return :: a -> ST s a Source
Monad (Either e) Source	Since: base-4.4.0.0
Instance details Defined in GHC.Internal.Data.Either Methods (>>=) :: Either e a -> (a -> Either e b) -> Either e b Source (>>) :: Either e a -> Either e b -> Either e b Source return :: a -> Either e a Source
Monad (Proxy :: Type -> Type) Source	Since: base-4.7.0.0
Instance details Defined in GHC.Internal.Data.Proxy Methods (>>=) :: Proxy a -> (a -> Proxy b) -> Proxy b Source (>>) :: Proxy a -> Proxy b -> Proxy b Source return :: a -> Proxy a Source
Monad (U1 :: Type -> Type) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods (>>=) :: U1 a -> (a -> U1 b) -> U1 b Source (>>) :: U1 a -> U1 b -> U1 b Source return :: a -> U1 a Source
Monad (ST s) Source	Since: base-2.1
Instance details Defined in GHC.Internal.ST Methods (>>=) :: ST s a -> (a -> ST s b) -> ST s b Source (>>) :: ST s a -> ST s b -> ST s b Source return :: a -> ST s a Source
Monoid a => Monad ((,) a) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Base Methods (>>=) :: (a, a0) -> (a0 -> (a, b)) -> (a, b) Source (>>) :: (a, a0) -> (a, b) -> (a, b) Source return :: a0 -> (a, a0) Source
Monad m => Monad (Kleisli m a) Source	Since: base-4.14.0.0
Instance details Defined in GHC.Internal.Control.Arrow Methods (>>=) :: Kleisli m a a0 -> (a0 -> Kleisli m a b) -> Kleisli m a b Source (>>) :: Kleisli m a a0 -> Kleisli m a b -> Kleisli m a b Source return :: a0 -> Kleisli m a a0 Source
Monad m => Monad (StateT s m) Source	Since: base-4.18.0.0
Instance details Defined in GHC.Internal.Data.Functor.Utils Methods (>>=) :: StateT s m a -> (a -> StateT s m b) -> StateT s m b Source (>>) :: StateT s m a -> StateT s m b -> StateT s m b Source return :: a -> StateT s m a Source
Monad f => Monad (Ap f) Source	Since: base-4.12.0.0
Instance details Defined in GHC.Internal.Data.Monoid Methods (>>=) :: Ap f a -> (a -> Ap f b) -> Ap f b Source (>>) :: Ap f a -> Ap f b -> Ap f b Source return :: a -> Ap f a Source
Monad f => Monad (Alt f) Source	Since: base-4.8.0.0
Instance details Defined in GHC.Internal.Data.Semigroup.Internal Methods (>>=) :: Alt f a -> (a -> Alt f b) -> Alt f b Source (>>) :: Alt f a -> Alt f b -> Alt f b Source return :: a -> Alt f a Source
Monad f => Monad (Rec1 f) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods (>>=) :: Rec1 f a -> (a -> Rec1 f b) -> Rec1 f b Source (>>) :: Rec1 f a -> Rec1 f b -> Rec1 f b Source return :: a -> Rec1 f a Source
(Monoid a, Monoid b) => Monad ((,,) a b) Source	Since: base-4.14.0.0
Instance details Defined in GHC.Internal.Base Methods (>>=) :: (a, b, a0) -> (a0 -> (a, b, b0)) -> (a, b, b0) Source (>>) :: (a, b, a0) -> (a, b, b0) -> (a, b, b0) Source return :: a0 -> (a, b, a0) Source
(Monad f, Monad g) => Monad (Product f g) Source	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Product Methods (>>=) :: Product f g a -> (a -> Product f g b) -> Product f g b Source (>>) :: Product f g a -> Product f g b -> Product f g b Source return :: a -> Product f g a Source
(Monad f, Monad g) => Monad (f :*: g) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods (>>=) :: (f :: g) a -> (a -> (f :: g) b) -> (f :: g) b Source (>>) :: (f :: g) a -> (f :: g) b -> (f :: g) b Source return :: a -> (f :*: g) a Source
(Monoid a, Monoid b, Monoid c) => Monad ((,,,) a b c) Source	Since: base-4.14.0.0
Instance details Defined in GHC.Internal.Base Methods (>>=) :: (a, b, c, a0) -> (a0 -> (a, b, c, b0)) -> (a, b, c, b0) Source (>>) :: (a, b, c, a0) -> (a, b, c, b0) -> (a, b, c, b0) Source return :: a0 -> (a, b, c, a0) Source
Monad ((->) r) Source	Since: base-2.1
Instance details Defined in GHC.Internal.Base Methods (>>=) :: (r -> a) -> (a -> r -> b) -> r -> b Source (>>) :: (r -> a) -> (r -> b) -> r -> b Source return :: a -> r -> a Source
Monad f => Monad (M1 i c f) Source	Since: base-4.9.0.0
Instance details Defined in GHC.Internal.Generics Methods (>>=) :: M1 i c f a -> (a -> M1 i c f b) -> M1 i c f b Source (>>) :: M1 i c f a -> M1 i c f b -> M1 i c f b Source return :: a -> M1 i c f a Source

© The University of Glasgow and others
Licensed under a BSD-style license (see top of the page).
https://downloads.haskell.org/~ghc/9.12.1/docs/libraries/base-4.21.0.0-8e62/Control-Monad-Instances.html