base-4.18.1.0: Basic libraries

Copyright | Conor McBride and Ross Paterson 2005
License | BSD-style (see the LICENSE file in the distribution)
Maintainer | libraries@haskell.org
Stability | stable
Portability | portable
Safe Haskell | Trustworthy
Language | Haskell2010

Control.Applicative

Contents

- Applicative functors
- Alternatives
- Instances
- Utility functions

Description

This module describes a structure intermediate between a functor and a monad (technically, a strong lax monoidal functor). Compared with monads, this interface lacks the full power of the binding operation `>>=`, but

- it has more instances.
- it is sufficient for many uses, e.g. context-free parsing, or the `Traversable` class.
- instances can perform analysis of computations before they are executed, and thus produce shared optimizations.

This interface was introduced for parsers by Niklas Röjemo, because it admits more sharing than the monadic interface. The names here are mostly based on parsing work by Doaitse Swierstra.

For more details, see Applicative Programming with Effects, by Conor McBride and Ross Paterson.

Synopsis

- class Functor f => Applicative f where
  - pure :: a -> f a
  - (<*>) :: f (a -> b) -> f a -> f b
  - liftA2 :: (a -> b -> c) -> f a -> f b -> f c
  - (*>) :: f a -> f b -> f b
  - (<*) :: f a -> f b -> f a
- class Applicative f => Alternative f where
  - empty :: f a
  - (<|>) :: f a -> f a -> f a
  - some :: f a -> f [a]
  - many :: f a -> f [a]
- newtype Const a b = Const {
  - getConst :: a
  }
- newtype WrappedMonad m a = WrapMonad {
  - unwrapMonad :: m a
  }
- newtype WrappedArrow a b c = WrapArrow {
  - unwrapArrow :: a b c
  }
- newtype ZipList a = ZipList {
  - getZipList :: [a]
  }
- (<$>) :: Functor f => (a -> b) -> f a -> f b
- (<$) :: Functor f => a -> f b -> f a
- (<**>) :: Applicative f => f a -> f (a -> b) -> f b
- liftA :: Applicative f => (a -> b) -> f a -> f b
- liftA3 :: Applicative f => (a -> b -> c -> d) -> f a -> f b -> f c -> f d
- optional :: Alternative f => f a -> f (Maybe a)
- asum :: (Foldable t, Alternative f) => t (f a) -> f a

# Applicative functors

class Functor f => Applicative f where Source #

A functor with application, providing operations to

- embed pure expressions (`pure`), and
- sequence computations and combine their results (`<*>` and `liftA2`).

A minimal complete definition must include implementations of `pure` and of either `<*>` or `liftA2`. If it defines both, then they must behave the same as their default definitions:

    (<*>) = liftA2 id

    liftA2 f x y = f <$> x <*> y

Further, any definition must satisfy the following:

Identity

      pure id <*> v = v

Composition

      pure (.) <*> u <*> v <*> w = u <*> (v <*> w)

Homomorphism

      pure f <*> pure x = pure (f x)

Interchange

      u <*> pure y = pure ($ y) <*> u

The other methods have the following default definitions, which may be overridden with equivalent specialized implementations:

-     u *> v = (id <$ u) <*> v

-     u <* v = liftA2 const u v

As a consequence of these laws, the `Functor` instance for `f` will satisfy

-     fmap f x = pure f <*> x

It may be useful to note that supposing

    forall x y. p (q x y) = f x . g y

it follows from the above that

    liftA2 p (liftA2 q u v) = liftA2 f u . liftA2 g v

If `f` is also a `Monad`, it should satisfy

-     pure = return

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

-     (*>) = (>>)

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

Minimal complete definition

pure, ((<*>) | liftA2)

Methods

pure :: a -> f a Source #

Lift a value.

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

Sequential application.

A few functors support an implementation of `<*>` that is more efficient than the default one.

#### Example

Expand

Used in combination with `(`<$>`)`, `(`<*>`)` can be used to build a record.

    >>> data MyState = MyState {arg1 :: Foo, arg2 :: Bar, arg3 :: Baz}

    >>> produceFoo :: Applicative f => f Foo

    >>> produceBar :: Applicative f => f Bar
    >>> produceBaz :: Applicative f => f Baz

    >>> mkState :: Applicative f => f MyState
    >>> mkState = MyState <$> produceFoo <*> produceBar <*> produceBaz

liftA2 :: (a -> b -> c) -> f a -> f b -> f c Source #

Lift a binary function to actions.

Some functors support an implementation of `liftA2` that is more efficient than the default one. In particular, if `fmap` is an expensive operation, it is likely better to use `liftA2` than to `fmap` over the structure and then use `<*>`.

This became a typeclass method in 4.10.0.0. Prior to that, it was a function defined in terms of `<*>` and `fmap`.

#### Example

Expand

    >>> liftA2 (,) (Just 3) (Just 5)
    Just (3,5)

(*>) :: f a -> f b -> f b infixl 4 Source #

Sequence actions, discarding the value of the first argument.

#### Examples

Expand

If used in conjunction with the Applicative instance for `Maybe`, you can chain Maybe computations, with a possible "early return" in case of `Nothing`.

    >>> Just 2 *> Just 3
    Just 3

    >>> Nothing *> Just 3
    Nothing

Of course a more interesting use case would be to have effectful computations instead of just returning pure values.

    >>> import Data.Char
    >>> import Text.ParserCombinators.ReadP
    >>> let p = string "my name is " *> munch1 isAlpha <* eof
    >>> readP_to_S p "my name is Simon"
    [("Simon","")]

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

Sequence actions, discarding the value of the second argument.

#### Instances

Instances details

Applicative ZipList Source #

    f <$> ZipList xs1 <*> ... <*> ZipList xsN
        = ZipList (zipWithN f xs1 ... xsN)

where `zipWithN` refers to the `zipWith` function of the appropriate arity (`zipWith`, `zipWith3`, `zipWith4`, ...). For example:

    (\a b c -> stimes c [a, b]) <$> ZipList "abcd" <*> ZipList "567" <*> ZipList [1..]
        = ZipList (zipWith3 (\a b c -> stimes c [a, b]) "abcd" "567" [1..])
        = ZipList {getZipList = ["a5","b6b6","c7c7c7"]}

Since: base-2.1

Instance details Defined in Control.Applicative Methods pure :: a -> ZipList a Source # (<*>) :: ZipList (a -> b) -> ZipList a -> ZipList b Source # liftA2 :: (a -> b -> c) -> ZipList a -> ZipList b -> ZipList c Source # (*>) :: ZipList a -> ZipList b -> ZipList b Source # (<*) :: ZipList a -> ZipList b -> ZipList a Source #
Applicative Complex Source # | Since: base-4.9.0.0
Instance details Defined in Data.Complex Methods pure :: a -> Complex a Source # (<*>) :: Complex (a -> b) -> Complex a -> Complex b Source # liftA2 :: (a -> b -> c) -> Complex a -> Complex b -> Complex c Source # (*>) :: Complex a -> Complex b -> Complex b Source # (<*) :: Complex a -> Complex b -> Complex a Source #
Applicative Identity Source # | Since: base-4.8.0.0
Instance details Defined in Data.Functor.Identity Methods pure :: a -> Identity a Source # (<*>) :: Identity (a -> b) -> Identity a -> Identity b Source # liftA2 :: (a -> b -> c) -> Identity a -> Identity b -> Identity c Source # (*>) :: Identity a -> Identity b -> Identity b Source # (<*) :: Identity a -> Identity b -> Identity a Source #
Applicative First Source # | Since: base-4.8.0.0
Instance details Defined in Data.Monoid Methods pure :: a -> First a Source # (<*>) :: First (a -> b) -> First a -> First b Source # liftA2 :: (a -> b -> c) -> First a -> First b -> First c Source # (*>) :: First a -> First b -> First b Source # (<*) :: First a -> First b -> First a Source #
Applicative Last Source # | Since: base-4.8.0.0
Instance details Defined in Data.Monoid Methods pure :: a -> Last a Source # (<*>) :: Last (a -> b) -> Last a -> Last b Source # liftA2 :: (a -> b -> c) -> Last a -> Last b -> Last c Source # (*>) :: Last a -> Last b -> Last b Source # (<*) :: Last a -> Last b -> Last a Source #
Applicative Down Source # | Since: base-4.11.0.0
Instance details Defined in Data.Ord Methods pure :: a -> Down a Source # (<*>) :: Down (a -> b) -> Down a -> Down b Source # liftA2 :: (a -> b -> c) -> Down a -> Down b -> Down c Source # (*>) :: Down a -> Down b -> Down b Source # (<*) :: Down a -> Down b -> Down a Source #
Applicative First Source # | Since: base-4.9.0.0
Instance details Defined in Data.Semigroup Methods pure :: a -> First a Source # (<*>) :: First (a -> b) -> First a -> First b Source # liftA2 :: (a -> b -> c) -> First a -> First b -> First c Source # (*>) :: First a -> First b -> First b Source # (<*) :: First a -> First b -> First a Source #
Applicative Last Source # | Since: base-4.9.0.0
Instance details Defined in Data.Semigroup Methods pure :: a -> Last a Source # (<*>) :: Last (a -> b) -> Last a -> Last b Source # liftA2 :: (a -> b -> c) -> Last a -> Last b -> Last c Source # (*>) :: Last a -> Last b -> Last b Source # (<*) :: Last a -> Last b -> Last a Source #
Applicative Max Source # | Since: base-4.9.0.0
Instance details Defined in Data.Semigroup Methods pure :: a -> Max a Source # (<*>) :: Max (a -> b) -> Max a -> Max b Source # liftA2 :: (a -> b -> c) -> Max a -> Max b -> Max c Source # (*>) :: Max a -> Max b -> Max b Source # (<*) :: Max a -> Max b -> Max a Source #
Applicative Min Source # | Since: base-4.9.0.0
Instance details Defined in Data.Semigroup Methods pure :: a -> Min a Source # (<*>) :: Min (a -> b) -> Min a -> Min b Source # liftA2 :: (a -> b -> c) -> Min a -> Min b -> Min c Source # (*>) :: Min a -> Min b -> Min b Source # (<*) :: Min a -> Min b -> Min a Source #
Applicative Dual Source # | Since: base-4.8.0.0
Instance details Defined in Data.Semigroup.Internal Methods pure :: a -> Dual a Source # (<*>) :: Dual (a -> b) -> Dual a -> Dual b Source # liftA2 :: (a -> b -> c) -> Dual a -> Dual b -> Dual c Source # (*>) :: Dual a -> Dual b -> Dual b Source # (<*) :: Dual a -> Dual b -> Dual a Source #
Applicative Product Source # | Since: base-4.8.0.0
Instance details Defined in Data.Semigroup.Internal Methods pure :: a -> Product a Source # (<*>) :: Product (a -> b) -> Product a -> Product b Source # liftA2 :: (a -> b -> c) -> Product a -> Product b -> Product c Source # (*>) :: Product a -> Product b -> Product b Source # (<*) :: Product a -> Product b -> Product a Source #
Applicative Sum Source # | Since: base-4.8.0.0
Instance details Defined in Data.Semigroup.Internal Methods pure :: a -> Sum a Source # (<*>) :: Sum (a -> b) -> Sum a -> Sum b Source # liftA2 :: (a -> b -> c) -> Sum a -> Sum b -> Sum c Source # (*>) :: Sum a -> Sum b -> Sum b Source # (<*) :: Sum a -> Sum b -> Sum a Source #
Applicative NonEmpty Source # | Since: base-4.9.0.0
Instance details Defined in GHC.Base Methods pure :: a -> NonEmpty a Source # (<*>) :: NonEmpty (a -> b) -> NonEmpty a -> NonEmpty b Source # liftA2 :: (a -> b -> c) -> NonEmpty a -> NonEmpty b -> NonEmpty c Source # (*>) :: NonEmpty a -> NonEmpty b -> NonEmpty b Source # (<*) :: NonEmpty a -> NonEmpty b -> NonEmpty a Source #
Applicative STM Source # | Since: base-4.8.0.0
Instance details Defined in GHC.Conc.Sync Methods pure :: a -> STM a Source # (<*>) :: STM (a -> b) -> STM a -> STM b Source # liftA2 :: (a -> b -> c) -> STM a -> STM b -> STM c Source # (*>) :: STM a -> STM b -> STM b Source # (<*) :: STM a -> STM b -> STM a Source #
Applicative NoIO Source # | Since: base-4.8.0.0
Instance details Defined in GHC.GHCi Methods pure :: a -> NoIO a Source # (<*>) :: NoIO (a -> b) -> NoIO a -> NoIO b Source # liftA2 :: (a -> b -> c) -> NoIO a -> NoIO b -> NoIO c Source # (*>) :: NoIO a -> NoIO b -> NoIO b Source # (<*) :: NoIO a -> NoIO b -> NoIO a Source #
Applicative Par1 Source # | Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods pure :: a -> Par1 a Source # (<*>) :: Par1 (a -> b) -> Par1 a -> Par1 b Source # liftA2 :: (a -> b -> c) -> Par1 a -> Par1 b -> Par1 c Source # (*>) :: Par1 a -> Par1 b -> Par1 b Source # (<*) :: Par1 a -> Par1 b -> Par1 a Source #
Applicative ReadP Source # | Since: base-4.6.0.0
Instance details Defined in Text.ParserCombinators.ReadP Methods pure :: a -> ReadP a Source # (<*>) :: ReadP (a -> b) -> ReadP a -> ReadP b Source # liftA2 :: (a -> b -> c) -> ReadP a -> ReadP b -> ReadP c Source # (*>) :: ReadP a -> ReadP b -> ReadP b Source # (<*) :: ReadP a -> ReadP b -> ReadP a Source #
Applicative ReadPrec Source # | Since: base-4.6.0.0
Instance details Defined in Text.ParserCombinators.ReadPrec Methods pure :: a -> ReadPrec a Source # (<*>) :: ReadPrec (a -> b) -> ReadPrec a -> ReadPrec b Source # liftA2 :: (a -> b -> c) -> ReadPrec a -> ReadPrec b -> ReadPrec c Source # (*>) :: ReadPrec a -> ReadPrec b -> ReadPrec b Source # (<*) :: ReadPrec a -> ReadPrec b -> ReadPrec a Source #
Applicative IO Source # | Since: base-2.1
Instance details Defined in GHC.Base Methods pure :: a -> IO a Source # (<*>) :: IO (a -> b) -> IO a -> IO b Source # liftA2 :: (a -> b -> c) -> IO a -> IO b -> IO c Source # (*>) :: IO a -> IO b -> IO b Source # (<*) :: IO a -> IO b -> IO a Source #
Applicative Maybe Source # | Since: base-2.1
Instance details Defined in GHC.Base Methods pure :: a -> Maybe a Source # (<*>) :: Maybe (a -> b) -> Maybe a -> Maybe b Source # liftA2 :: (a -> b -> c) -> Maybe a -> Maybe b -> Maybe c Source # (*>) :: Maybe a -> Maybe b -> Maybe b Source # (<*) :: Maybe a -> Maybe b -> Maybe a Source #
Applicative Solo Source # | Since: base-4.15
Instance details Defined in GHC.Base Methods pure :: a -> Solo a Source # (<*>) :: Solo (a -> b) -> Solo a -> Solo b Source # liftA2 :: (a -> b -> c) -> Solo a -> Solo b -> Solo c Source # (*>) :: Solo a -> Solo b -> Solo b Source # (<*) :: Solo a -> Solo b -> Solo a Source #
Applicative List Source # | Since: base-2.1
Instance details Defined in GHC.Base Methods pure :: a -> [a] Source # (<*>) :: [a -> b] -> [a] -> [b] Source # liftA2 :: (a -> b -> c) -> [a] -> [b] -> [c] Source # (*>) :: [a] -> [b] -> [b] Source # (<*) :: [a] -> [b] -> [a] Source #
Monad m => Applicative (WrappedMonad m) Source # | Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

pure :: a -> WrappedMonad m a Source #

(<*>) :: WrappedMonad m (a -> b) -> WrappedMonad m a -> WrappedMonad m b Source #

liftA2 :: (a -> b -> c) -> WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m c Source #

(*>) :: WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m b Source #

(<*) :: WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m a Source #

Arrow a => Applicative (ArrowMonad a) Source # | Since: base-4.6.0.0
Instance details Defined in Control.Arrow Methods pure :: a0 -> ArrowMonad a a0 Source # (<*>) :: ArrowMonad a (a0 -> b) -> ArrowMonad a a0 -> ArrowMonad a b Source # liftA2 :: (a0 -> b -> c) -> ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a c Source # (*>) :: ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a b Source # (<*) :: ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a a0 Source #
Applicative (ST s) Source # | Since: base-2.1
Instance details Defined in Control.Monad.ST.Lazy.Imp Methods pure :: a -> ST s a Source # (<*>) :: ST s (a -> b) -> ST s a -> ST s b Source # liftA2 :: (a -> b -> c) -> ST s a -> ST s b -> ST s c Source # (*>) :: ST s a -> ST s b -> ST s b Source # (<*) :: ST s a -> ST s b -> ST s a Source #
Applicative (Either e) Source # | Since: base-3.0
Instance details Defined in Data.Either Methods pure :: a -> Either e a Source # (<*>) :: Either e (a -> b) -> Either e a -> Either e b Source # liftA2 :: (a -> b -> c) -> Either e a -> Either e b -> Either e c Source # (*>) :: Either e a -> Either e b -> Either e b Source # (<*) :: Either e a -> Either e b -> Either e a Source #
Applicative (Proxy :: Type -> Type) Source # | Since: base-4.7.0.0
Instance details Defined in Data.Proxy Methods pure :: a -> Proxy a Source # (<*>) :: Proxy (a -> b) -> Proxy a -> Proxy b Source # liftA2 :: (a -> b -> c) -> Proxy a -> Proxy b -> Proxy c Source # (*>) :: Proxy a -> Proxy b -> Proxy b Source # (<*) :: Proxy a -> Proxy b -> Proxy a Source #
Applicative (U1 :: Type -> Type) Source # | Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods pure :: a -> U1 a Source # (<*>) :: U1 (a -> b) -> U1 a -> U1 b Source # liftA2 :: (a -> b -> c) -> U1 a -> U1 b -> U1 c Source # (*>) :: U1 a -> U1 b -> U1 b Source # (<*) :: U1 a -> U1 b -> U1 a Source #
Applicative (ST s) Source # | Since: base-4.4.0.0
Instance details Defined in GHC.ST Methods pure :: a -> ST s a Source # (<*>) :: ST s (a -> b) -> ST s a -> ST s b Source # liftA2 :: (a -> b -> c) -> ST s a -> ST s b -> ST s c Source # (*>) :: ST s a -> ST s b -> ST s b Source # (<*) :: ST s a -> ST s b -> ST s a Source #

Monoid a => Applicative ((,) a) Source #

For tuples, the `Monoid` constraint on `a` determines how the first values merge. For example, `String`s concatenate:

    ("hello ", (+15)) <*> ("world!", 2002)
    ("hello world!",2017)

Since: base-2.1

Instance details Defined in GHC.Base Methods pure :: a0 -> (a, a0) Source # (<*>) :: (a, a0 -> b) -> (a, a0) -> (a, b) Source # liftA2 :: (a0 -> b -> c) -> (a, a0) -> (a, b) -> (a, c) Source # (*>) :: (a, a0) -> (a, b) -> (a, b) Source # (<*) :: (a, a0) -> (a, b) -> (a, a0) Source #
Arrow a => Applicative (WrappedArrow a b) Source # | Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

pure :: a0 -> WrappedArrow a b a0 Source #

(<*>) :: WrappedArrow a b (a0 -> b0) -> WrappedArrow a b a0 -> WrappedArrow a b b0 Source #

liftA2 :: (a0 -> b0 -> c) -> WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b c Source #

(*>) :: WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b b0 Source #

(<*) :: WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b a0 Source #

Applicative m => Applicative (Kleisli m a) Source # | Since: base-4.14.0.0
Instance details Defined in Control.Arrow Methods pure :: a0 -> Kleisli m a a0 Source # (<*>) :: Kleisli m a (a0 -> b) -> Kleisli m a a0 -> Kleisli m a b Source # liftA2 :: (a0 -> b -> c) -> Kleisli m a a0 -> Kleisli m a b -> Kleisli m a c Source # (*>) :: Kleisli m a a0 -> Kleisli m a b -> Kleisli m a b Source # (<*) :: Kleisli m a a0 -> Kleisli m a b -> Kleisli m a a0 Source #
Monoid m => Applicative (Const m :: Type -> Type) Source # | Since: base-2.0.1
Instance details Defined in Data.Functor.Const Methods pure :: a -> Const m a Source # (<*>) :: Const m (a -> b) -> Const m a -> Const m b Source # liftA2 :: (a -> b -> c) -> Const m a -> Const m b -> Const m c Source # (*>) :: Const m a -> Const m b -> Const m b Source # (<*) :: Const m a -> Const m b -> Const m a Source #
Applicative f => Applicative (Ap f) Source # | Since: base-4.12.0.0
Instance details Defined in Data.Monoid Methods pure :: a -> Ap f a Source # (<*>) :: Ap f (a -> b) -> Ap f a -> Ap f b Source # liftA2 :: (a -> b -> c) -> Ap f a -> Ap f b -> Ap f c Source # (*>) :: Ap f a -> Ap f b -> Ap f b Source # (<*) :: Ap f a -> Ap f b -> Ap f a Source #
Applicative f => Applicative (Alt f) Source # | Since: base-4.8.0.0
Instance details Defined in Data.Semigroup.Internal Methods pure :: a -> Alt f a Source # (<*>) :: Alt f (a -> b) -> Alt f a -> Alt f b Source # liftA2 :: (a -> b -> c) -> Alt f a -> Alt f b -> Alt f c Source # (*>) :: Alt f a -> Alt f b -> Alt f b Source # (<*) :: Alt f a -> Alt f b -> Alt f a Source #
(Generic1 f, Applicative (Rep1 f)) => Applicative (Generically1 f) Source # | Since: base-4.17.0.0

Instance details

Defined in GHC.Generics

Methods

pure :: a -> Generically1 f a Source #

(<*>) :: Generically1 f (a -> b) -> Generically1 f a -> Generically1 f b Source #

liftA2 :: (a -> b -> c) -> Generically1 f a -> Generically1 f b -> Generically1 f c Source #

(*>) :: Generically1 f a -> Generically1 f b -> Generically1 f b Source #

(<*) :: Generically1 f a -> Generically1 f b -> Generically1 f a Source #

Applicative f => Applicative (Rec1 f) Source # | Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods pure :: a -> Rec1 f a Source # (<*>) :: Rec1 f (a -> b) -> Rec1 f a -> Rec1 f b Source # liftA2 :: (a -> b -> c) -> Rec1 f a -> Rec1 f b -> Rec1 f c Source # (*>) :: Rec1 f a -> Rec1 f b -> Rec1 f b Source # (<*) :: Rec1 f a -> Rec1 f b -> Rec1 f a Source #
(Monoid a, Monoid b) => Applicative ((,,) a b) Source # | Since: base-4.14.0.0
Instance details Defined in GHC.Base Methods pure :: a0 -> (a, b, a0) Source # (<*>) :: (a, b, a0 -> b0) -> (a, b, a0) -> (a, b, b0) Source # liftA2 :: (a0 -> b0 -> c) -> (a, b, a0) -> (a, b, b0) -> (a, b, c) Source # (*>) :: (a, b, a0) -> (a, b, b0) -> (a, b, b0) Source # (<*) :: (a, b, a0) -> (a, b, b0) -> (a, b, a0) Source #
(Applicative f, Applicative g) => Applicative (Product f g) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Product Methods pure :: a -> Product f g a Source # (<*>) :: Product f g (a -> b) -> Product f g a -> Product f g b Source # liftA2 :: (a -> b -> c) -> Product f g a -> Product f g b -> Product f g c Source # (*>) :: Product f g a -> Product f g b -> Product f g b Source # (<*) :: Product f g a -> Product f g b -> Product f g a Source #
(Applicative f, Applicative g) => Applicative (f :*: g) Source # | Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods pure :: a -> (f :*: g) a Source # (<*>) :: (f :*: g) (a -> b) -> (f :*: g) a -> (f :*: g) b Source # liftA2 :: (a -> b -> c) -> (f :*: g) a -> (f :*: g) b -> (f :*: g) c Source # (*>) :: (f :*: g) a -> (f :*: g) b -> (f :*: g) b Source # (<*) :: (f :*: g) a -> (f :*: g) b -> (f :*: g) a Source #
Monoid c => Applicative (K1 i c :: Type -> Type) Source # | Since: base-4.12.0.0
Instance details Defined in GHC.Generics Methods pure :: a -> K1 i c a Source # (<*>) :: K1 i c (a -> b) -> K1 i c a -> K1 i c b Source # liftA2 :: (a -> b -> c0) -> K1 i c a -> K1 i c b -> K1 i c c0 Source # (*>) :: K1 i c a -> K1 i c b -> K1 i c b Source # (<*) :: K1 i c a -> K1 i c b -> K1 i c a Source #
(Monoid a, Monoid b, Monoid c) => Applicative ((,,,) a b c) Source # | Since: base-4.14.0.0
Instance details Defined in GHC.Base Methods pure :: a0 -> (a, b, c, a0) Source # (<*>) :: (a, b, c, a0 -> b0) -> (a, b, c, a0) -> (a, b, c, b0) Source # liftA2 :: (a0 -> b0 -> c0) -> (a, b, c, a0) -> (a, b, c, b0) -> (a, b, c, c0) Source # (*>) :: (a, b, c, a0) -> (a, b, c, b0) -> (a, b, c, b0) Source # (<*) :: (a, b, c, a0) -> (a, b, c, b0) -> (a, b, c, a0) Source #
Applicative ((->) r) Source # | Since: base-2.1
Instance details Defined in GHC.Base Methods pure :: a -> r -> a Source # (<*>) :: (r -> (a -> b)) -> (r -> a) -> r -> b Source # liftA2 :: (a -> b -> c) -> (r -> a) -> (r -> b) -> r -> c Source # (*>) :: (r -> a) -> (r -> b) -> r -> b Source # (<*) :: (r -> a) -> (r -> b) -> r -> a Source #
(Applicative f, Applicative g) => Applicative (Compose f g) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Compose Methods pure :: a -> Compose f g a Source # (<*>) :: Compose f g (a -> b) -> Compose f g a -> Compose f g b Source # liftA2 :: (a -> b -> c) -> Compose f g a -> Compose f g b -> Compose f g c Source # (*>) :: Compose f g a -> Compose f g b -> Compose f g b Source # (<*) :: Compose f g a -> Compose f g b -> Compose f g a Source #
(Applicative f, Applicative g) => Applicative (f :.: g) Source # | Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods pure :: a -> (f :.: g) a Source # (<*>) :: (f :.: g) (a -> b) -> (f :.: g) a -> (f :.: g) b Source # liftA2 :: (a -> b -> c) -> (f :.: g) a -> (f :.: g) b -> (f :.: g) c Source # (*>) :: (f :.: g) a -> (f :.: g) b -> (f :.: g) b Source # (<*) :: (f :.: g) a -> (f :.: g) b -> (f :.: g) a Source #
Applicative f => Applicative (M1 i c f) Source # | Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods pure :: a -> M1 i c f a Source # (<*>) :: M1 i c f (a -> b) -> M1 i c f a -> M1 i c f b Source # liftA2 :: (a -> b -> c0) -> M1 i c f a -> M1 i c f b -> M1 i c f c0 Source # (*>) :: M1 i c f 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 a Source #

# Alternatives

class Applicative f => Alternative f where Source #

A monoid on applicative functors.

If defined, `some` and `many` should be the least solutions of the equations:

-     some v = (:) <$> v <*> many v

-     many v = some v <|> pure []

Minimal complete definition

empty, (<|>)

Methods

empty :: f a Source #

The identity of `<|>`

(<|>) :: f a -> f a -> f a infixl 3 Source #

An associative binary operation

some :: f a -> f [a] Source #

One or more.

many :: f a -> f [a] Source #

Zero or more.

#### Instances

Instances details

Alternative ZipList Source # | Since: base-4.11.0.0
Instance details Defined in Control.Applicative Methods empty :: ZipList a Source # (<|>) :: ZipList a -> ZipList a -> ZipList a Source # some :: ZipList a -> ZipList [a] Source # many :: ZipList a -> ZipList [a] Source #
Alternative STM Source # | Takes the first non-`retry`ing `STM` action. Since: base-4.8.0.0
Instance details Defined in GHC.Conc.Sync Methods empty :: STM a Source # (<|>) :: STM a -> STM a -> STM a Source # some :: STM a -> STM [a] Source # many :: STM a -> STM [a] Source #
Alternative ReadP Source # | Since: base-4.6.0.0
Instance details Defined in Text.ParserCombinators.ReadP Methods empty :: ReadP a Source # (<|>) :: ReadP a -> ReadP a -> ReadP a Source # some :: ReadP a -> ReadP [a] Source # many :: ReadP a -> ReadP [a] Source #
Alternative ReadPrec Source # | Since: base-4.6.0.0
Instance details Defined in Text.ParserCombinators.ReadPrec Methods empty :: ReadPrec a Source # (<|>) :: ReadPrec a -> ReadPrec a -> ReadPrec a Source # some :: ReadPrec a -> ReadPrec [a] Source # many :: ReadPrec a -> ReadPrec [a] Source #
Alternative IO Source # | Takes the first non-throwing `IO` action's result. `empty` throws an exception. Since: base-4.9.0.0
Instance details Defined in GHC.Base Methods empty :: IO a Source # (<|>) :: IO a -> IO a -> IO a Source # some :: IO a -> IO [a] Source # many :: IO a -> IO [a] Source #
Alternative Maybe Source # | Picks the leftmost `Just` value, or, alternatively, `Nothing`. Since: base-2.1
Instance details Defined in GHC.Base Methods empty :: Maybe a Source # (<|>) :: Maybe a -> Maybe a -> Maybe a Source # some :: Maybe a -> Maybe [a] Source # many :: Maybe a -> Maybe [a] Source #
Alternative List Source # | Combines lists by concatenation, starting from the empty list. Since: base-2.1
Instance details Defined in GHC.Base Methods empty :: [a] Source # (<|>) :: [a] -> [a] -> [a] Source # some :: [a] -> [[a]] Source # many :: [a] -> [[a]] Source #
MonadPlus m => Alternative (WrappedMonad m) Source # | Since: base-2.1
Instance details Defined in Control.Applicative Methods empty :: WrappedMonad m a Source # (<|>) :: WrappedMonad m a -> WrappedMonad m a -> WrappedMonad m a Source # some :: WrappedMonad m a -> WrappedMonad m [a] Source # many :: WrappedMonad m a -> WrappedMonad m [a] Source #
ArrowPlus a => Alternative (ArrowMonad a) Source # | Since: base-4.6.0.0
Instance details Defined in Control.Arrow Methods empty :: ArrowMonad a a0 Source # (<|>) :: ArrowMonad a a0 -> ArrowMonad a a0 -> ArrowMonad a a0 Source # some :: ArrowMonad a a0 -> ArrowMonad a [a0] Source # many :: ArrowMonad a a0 -> ArrowMonad a [a0] Source #
Alternative (Proxy :: Type -> Type) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Proxy Methods empty :: Proxy a Source # (<|>) :: Proxy a -> Proxy a -> Proxy a Source # some :: Proxy a -> Proxy [a] Source # many :: Proxy a -> Proxy [a] Source #
Alternative (U1 :: Type -> Type) Source # | Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods empty :: U1 a Source # (<|>) :: U1 a -> U1 a -> U1 a Source # some :: U1 a -> U1 [a] Source # many :: U1 a -> U1 [a] Source #
(ArrowZero a, ArrowPlus a) => Alternative (WrappedArrow a b) Source # | Since: base-2.1
Instance details Defined in Control.Applicative Methods empty :: WrappedArrow a b a0 Source # (<|>) :: WrappedArrow a b a0 -> WrappedArrow a b a0 -> WrappedArrow a b a0 Source # some :: WrappedArrow a b a0 -> WrappedArrow a b [a0] Source # many :: WrappedArrow a b a0 -> WrappedArrow a b [a0] Source #
Alternative m => Alternative (Kleisli m a) Source # | Since: base-4.14.0.0
Instance details Defined in Control.Arrow Methods empty :: Kleisli m a a0 Source # (<|>) :: Kleisli m a a0 -> Kleisli m a a0 -> Kleisli m a a0 Source # some :: Kleisli m a a0 -> Kleisli m a [a0] Source # many :: Kleisli m a a0 -> Kleisli m a [a0] Source #
Alternative f => Alternative (Ap f) Source # | Since: base-4.12.0.0
Instance details Defined in Data.Monoid Methods empty :: Ap f a Source # (<|>) :: Ap f a -> Ap f a -> Ap f a Source # some :: Ap f a -> Ap f [a] Source # many :: Ap f a -> Ap f [a] Source #
Alternative f => Alternative (Alt f) Source # | Since: base-4.8.0.0
Instance details Defined in Data.Semigroup.Internal Methods empty :: Alt f a Source # (<|>) :: Alt f a -> Alt f a -> Alt f a Source # some :: Alt f a -> Alt f [a] Source # many :: Alt f a -> Alt f [a] Source #
(Generic1 f, Alternative (Rep1 f)) => Alternative (Generically1 f) Source # | Since: base-4.17.0.0
Instance details Defined in GHC.Generics Methods empty :: Generically1 f a Source # (<|>) :: Generically1 f a -> Generically1 f a -> Generically1 f a Source # some :: Generically1 f a -> Generically1 f [a] Source # many :: Generically1 f a -> Generically1 f [a] Source #
Alternative f => Alternative (Rec1 f) Source # | Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods empty :: Rec1 f a Source # (<|>) :: Rec1 f a -> Rec1 f a -> Rec1 f a Source # some :: Rec1 f a -> Rec1 f [a] Source # many :: Rec1 f a -> Rec1 f [a] Source #
(Alternative f, Alternative g) => Alternative (Product f g) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Product Methods empty :: Product f g a Source # (<|>) :: Product f g a -> Product f g a -> Product f g a Source # some :: Product f g a -> Product f g [a] Source # many :: Product f g a -> Product f g [a] Source #
(Alternative f, Alternative g) => Alternative (f :*: g) Source # | Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods empty :: (f :*: g) a Source # (<|>) :: (f :*: g) a -> (f :*: g) a -> (f :*: g) a Source # some :: (f :*: g) a -> (f :*: g) [a] Source # many :: (f :*: g) a -> (f :*: g) [a] Source #
(Alternative f, Applicative g) => Alternative (Compose f g) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Compose Methods empty :: Compose f g a Source # (<|>) :: Compose f g a -> Compose f g a -> Compose f g a Source # some :: Compose f g a -> Compose f g [a] Source # many :: Compose f g a -> Compose f g [a] Source #
(Alternative f, Applicative g) => Alternative (f :.: g) Source # | Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods empty :: (f :.: g) a Source # (<|>) :: (f :.: g) a -> (f :.: g) a -> (f :.: g) a Source # some :: (f :.: g) a -> (f :.: g) [a] Source # many :: (f :.: g) a -> (f :.: g) [a] Source #
Alternative f => Alternative (M1 i c f) Source # | Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods empty :: M1 i c f a Source # (<|>) :: M1 i c f a -> M1 i c f a -> M1 i c f a Source # some :: M1 i c f a -> M1 i c f [a] Source # many :: M1 i c f a -> M1 i c f [a] Source #

# Instances

newtype Const a b Source #

The `Const` functor.

Constructors

Const |

Fields

- getConst :: a

#### Instances

Instances details

Generic1 (Const a :: k -> Type) Source # |
Instance details Defined in Data.Functor.Const Associated Types type Rep1 (Const a) :: k -> Type Source # Methods from1 :: forall (a0 :: k0). Const a a0 -> Rep1 (Const a) a0 Source # to1 :: forall (a0 :: k0). Rep1 (Const a) a0 -> Const a a0 Source #
Bifoldable (Const :: Type -> Type -> Type) Source # | Since: base-4.10.0.0
Instance details Defined in Data.Bifoldable Methods bifold :: Monoid m => Const m m -> m Source # bifoldMap :: Monoid m => (a -> m) -> (b -> m) -> Const a b -> m Source # bifoldr :: (a -> c -> c) -> (b -> c -> c) -> c -> Const a b -> c Source # bifoldl :: (c -> a -> c) -> (c -> b -> c) -> c -> Const a b -> c Source #
Bifoldable1 (Const :: Type -> Type -> Type) Source # |
Instance details Defined in Data.Bifoldable1 Methods bifold1 :: Semigroup m => Const m m -> m Source # bifoldMap1 :: Semigroup m => (a -> m) -> (b -> m) -> Const a b -> m Source #
Bifunctor (Const :: Type -> Type -> Type) Source # | Since: base-4.8.0.0
Instance details Defined in Data.Bifunctor Methods bimap :: (a -> b) -> (c -> d) -> Const a c -> Const b d Source # first :: (a -> b) -> Const a c -> Const b c Source # second :: (b -> c) -> Const a b -> Const a c Source #
Bitraversable (Const :: Type -> Type -> Type) Source # | Since: base-4.10.0.0
Instance details Defined in Data.Bitraversable Methods bitraverse :: Applicative f => (a -> f c) -> (b -> f d) -> Const a b -> f (Const c d) Source #
Eq2 (Const :: Type -> Type -> Type) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq2 :: (a -> b -> Bool) -> (c -> d -> Bool) -> Const a c -> Const b d -> Bool Source #
Ord2 (Const :: Type -> Type -> Type) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare2 :: (a -> b -> Ordering) -> (c -> d -> Ordering) -> Const a c -> Const b d -> Ordering Source #
Read2 (Const :: Type -> Type -> Type) Source # | Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftReadsPrec2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> Int -> ReadS (Const a b) Source #

liftReadList2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> ReadS [Const a b] Source #

liftReadPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec (Const a b) Source #

liftReadListPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec [Const a b] Source #

Show2 (Const :: Type -> Type -> Type) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> Int -> Const a b -> ShowS Source # liftShowList2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> [Const a b] -> ShowS Source #
Foldable (Const m :: Type -> Type) Source # | Since: base-4.7.0.0

Instance details

Defined in Data.Functor.Const

Methods

fold :: Monoid m0 => Const m m0 -> m0 Source #

foldMap :: Monoid m0 => (a -> m0) -> Const m a -> m0 Source #

foldMap' :: Monoid m0 => (a -> m0) -> Const m a -> m0 Source #

foldr :: (a -> b -> b) -> b -> Const m a -> b Source #

foldr' :: (a -> b -> b) -> b -> Const m a -> b Source #

foldl :: (b -> a -> b) -> b -> Const m a -> b Source #

foldl' :: (b -> a -> b) -> b -> Const m a -> b Source #

foldr1 :: (a -> a -> a) -> Const m a -> a Source #

foldl1 :: (a -> a -> a) -> Const m a -> a Source #

toList :: Const m a -> [a] Source #

null :: Const m a -> Bool Source #

length :: Const m a -> Int Source #

elem :: Eq a => a -> Const m a -> Bool Source #

maximum :: Ord a => Const m a -> a Source #

minimum :: Ord a => Const m a -> a Source #

sum :: Num a => Const m a -> a Source #

product :: Num a => Const m a -> a Source #

Eq a => Eq1 (Const a :: Type -> Type) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftEq :: (a0 -> b -> Bool) -> Const a a0 -> Const a b -> Bool Source #
Ord a => Ord1 (Const a :: Type -> Type) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftCompare :: (a0 -> b -> Ordering) -> Const a a0 -> Const a b -> Ordering Source #
Read a => Read1 (Const a :: Type -> Type) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftReadsPrec :: (Int -> ReadS a0) -> ReadS [a0] -> Int -> ReadS (Const a a0) Source # liftReadList :: (Int -> ReadS a0) -> ReadS [a0] -> ReadS [Const a a0] Source # liftReadPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec (Const a a0) Source # liftReadListPrec :: ReadPrec a0 -> ReadPrec [a0] -> ReadPrec [Const a a0] Source #
Show a => Show1 (Const a :: Type -> Type) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Classes Methods liftShowsPrec :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> Int -> Const a a0 -> ShowS Source # liftShowList :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> [Const a a0] -> ShowS Source #
Contravariant (Const a :: Type -> Type) Source # |
Instance details Defined in Data.Functor.Contravariant Methods contramap :: (a' -> a0) -> Const a a0 -> Const a a' Source # (>$) :: b -> Const a b -> Const a a0 Source #
Traversable (Const m :: Type -> Type) Source # | Since: base-4.7.0.0
Instance details Defined in Data.Traversable Methods traverse :: Applicative f => (a -> f b) -> Const m a -> f (Const m b) Source # sequenceA :: Applicative f => Const m (f a) -> f (Const m a) Source # mapM :: Monad m0 => (a -> m0 b) -> Const m a -> m0 (Const m b) Source # sequence :: Monad m0 => Const m (m0 a) -> m0 (Const m a) Source #
Monoid m => Applicative (Const m :: Type -> Type) Source # | Since: base-2.0.1
Instance details Defined in Data.Functor.Const Methods pure :: a -> Const m a Source # (<*>) :: Const m (a -> b) -> Const m a -> Const m b Source # liftA2 :: (a -> b -> c) -> Const m a -> Const m b -> Const m c Source # (*>) :: Const m a -> Const m b -> Const m b Source # (<*) :: Const m a -> Const m b -> Const m a Source #
Functor (Const m :: Type -> Type) Source # | Since: base-2.1
Instance details Defined in Data.Functor.Const Methods fmap :: (a -> b) -> Const m a -> Const m b Source # (<$) :: a -> Const m b -> Const m a Source #
(Typeable k, Data a, Typeable b) => Data (Const a b) Source # | Since: base-4.10.0.0

Instance details

Defined in Data.Data

Methods

gfoldl :: (forall d b0. Data d => c (d -> b0) -> d -> c b0) -> (forall g. g -> c g) -> Const a b -> c (Const a b) Source #

gunfold :: (forall b0 r. Data b0 => c (b0 -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Const a b) Source #

toConstr :: Const a b -> Constr Source #

dataTypeOf :: Const a b -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Const a b)) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Const a b)) Source #

gmapT :: (forall b0. Data b0 => b0 -> b0) -> Const a b -> Const a b Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Const a b -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Const a b -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Const a b -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Const a b -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Const a b -> m (Const a b) Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Const a b -> m (Const a b) Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Const a b -> m (Const a b) Source #

IsString a => IsString (Const a b) Source # | Since: base-4.9.0.0
Instance details Defined in Data.String Methods fromString :: String -> Const a b Source #
Storable a => Storable (Const a b) Source # | Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

sizeOf :: Const a b -> Int Source #

alignment :: Const a b -> Int Source #

peekElemOff :: Ptr (Const a b) -> Int -> IO (Const a b) Source #

pokeElemOff :: Ptr (Const a b) -> Int -> Const a b -> IO () Source #

peekByteOff :: Ptr b0 -> Int -> IO (Const a b) Source #

pokeByteOff :: Ptr b0 -> Int -> Const a b -> IO () Source #

peek :: Ptr (Const a b) -> IO (Const a b) Source #

poke :: Ptr (Const a b) -> Const a b -> IO () Source #

Monoid a => Monoid (Const a b) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Const Methods mempty :: Const a b Source # mappend :: Const a b -> Const a b -> Const a b Source # mconcat :: [Const a b] -> Const a b Source #
Semigroup a => Semigroup (Const a b) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Const Methods (<>) :: Const a b -> Const a b -> Const a b Source # sconcat :: NonEmpty (Const a b) -> Const a b Source # stimes :: Integral b0 => b0 -> Const a b -> Const a b Source #
Bits a => Bits (Const a b) Source # | Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

(.&.) :: Const a b -> Const a b -> Const a b Source #

(.|.) :: Const a b -> Const a b -> Const a b Source #

xor :: Const a b -> Const a b -> Const a b Source #

complement :: Const a b -> Const a b Source #

shift :: Const a b -> Int -> Const a b Source #

rotate :: Const a b -> Int -> Const a b Source #

zeroBits :: Const a b Source #

bit :: Int -> Const a b Source #

setBit :: Const a b -> Int -> Const a b Source #

clearBit :: Const a b -> Int -> Const a b Source #

complementBit :: Const a b -> Int -> Const a b Source #

testBit :: Const a b -> Int -> Bool Source #

bitSizeMaybe :: Const a b -> Maybe Int Source #

bitSize :: Const a b -> Int Source #

isSigned :: Const a b -> Bool Source #

shiftL :: Const a b -> Int -> Const a b Source #

unsafeShiftL :: Const a b -> Int -> Const a b Source #

shiftR :: Const a b -> Int -> Const a b Source #

unsafeShiftR :: Const a b -> Int -> Const a b Source #

rotateL :: Const a b -> Int -> Const a b Source #

rotateR :: Const a b -> Int -> Const a b Source #

popCount :: Const a b -> Int Source #

FiniteBits a => FiniteBits (Const a b) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Const Methods finiteBitSize :: Const a b -> Int Source # countLeadingZeros :: Const a b -> Int Source # countTrailingZeros :: Const a b -> Int Source #
Bounded a => Bounded (Const a b) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Const Methods minBound :: Const a b Source # maxBound :: Const a b Source #
Enum a => Enum (Const a b) Source # | Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

succ :: Const a b -> Const a b Source #

pred :: Const a b -> Const a b Source #

toEnum :: Int -> Const a b Source #

fromEnum :: Const a b -> Int Source #

enumFrom :: Const a b -> [Const a b] Source #

enumFromThen :: Const a b -> Const a b -> [Const a b] Source #

enumFromTo :: Const a b -> Const a b -> [Const a b] Source #

enumFromThenTo :: Const a b -> Const a b -> Const a b -> [Const a b] Source #

Floating a => Floating (Const a b) Source # | Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

pi :: Const a b Source #

exp :: Const a b -> Const a b Source #

log :: Const a b -> Const a b Source #

sqrt :: Const a b -> Const a b Source #

(**) :: Const a b -> Const a b -> Const a b Source #

logBase :: Const a b -> Const a b -> Const a b Source #

sin :: Const a b -> Const a b Source #

cos :: Const a b -> Const a b Source #

tan :: Const a b -> Const a b Source #

asin :: Const a b -> Const a b Source #

acos :: Const a b -> Const a b Source #

atan :: Const a b -> Const a b Source #

sinh :: Const a b -> Const a b Source #

cosh :: Const a b -> Const a b Source #

tanh :: Const a b -> Const a b Source #

asinh :: Const a b -> Const a b Source #

acosh :: Const a b -> Const a b Source #

atanh :: Const a b -> Const a b Source #

log1p :: Const a b -> Const a b Source #

expm1 :: Const a b -> Const a b Source #

log1pexp :: Const a b -> Const a b Source #

log1mexp :: Const a b -> Const a b Source #

RealFloat a => RealFloat (Const a b) Source # | Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

floatRadix :: Const a b -> Integer Source #

floatDigits :: Const a b -> Int Source #

floatRange :: Const a b -> (Int, Int) Source #

decodeFloat :: Const a b -> (Integer, Int) Source #

encodeFloat :: Integer -> Int -> Const a b Source #

exponent :: Const a b -> Int Source #

significand :: Const a b -> Const a b Source #

scaleFloat :: Int -> Const a b -> Const a b Source #

isNaN :: Const a b -> Bool Source #

isInfinite :: Const a b -> Bool Source #

isDenormalized :: Const a b -> Bool Source #

isNegativeZero :: Const a b -> Bool Source #

isIEEE :: Const a b -> Bool Source #

atan2 :: Const a b -> Const a b -> Const a b Source #

Generic (Const a b) Source # |
Instance details Defined in Data.Functor.Const Associated Types type Rep (Const a b) :: Type -> Type Source # Methods from :: Const a b -> Rep (Const a b) x Source # to :: Rep (Const a b) x -> Const a b Source #
Ix a => Ix (Const a b) Source # | Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

range :: (Const a b, Const a b) -> [Const a b] Source #

index :: (Const a b, Const a b) -> Const a b -> Int Source #

unsafeIndex :: (Const a b, Const a b) -> Const a b -> Int Source #

inRange :: (Const a b, Const a b) -> Const a b -> Bool Source #

rangeSize :: (Const a b, Const a b) -> Int Source #

unsafeRangeSize :: (Const a b, Const a b) -> Int Source #

Num a => Num (Const a b) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Const Methods (+) :: Const a b -> Const a b -> Const a b Source # (-) :: Const a b -> Const a b -> Const a b Source # (*) :: Const a b -> Const a b -> Const a b Source # negate :: Const a b -> Const a b Source # abs :: Const a b -> Const a b Source # signum :: Const a b -> Const a b Source # fromInteger :: Integer -> Const a b Source #
Read a => Read (Const a b) Source # | This instance would be equivalent to the derived instances of the `Const` newtype if the `getConst` field were removed Since: base-4.8.0.0
Instance details Defined in Data.Functor.Const Methods readsPrec :: Int -> ReadS (Const a b) Source # readList :: ReadS [Const a b] Source # readPrec :: ReadPrec (Const a b) Source # readListPrec :: ReadPrec [Const a b] Source #
Fractional a => Fractional (Const a b) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Const Methods (/) :: Const a b -> Const a b -> Const a b Source # recip :: Const a b -> Const a b Source # fromRational :: Rational -> Const a b Source #
Integral a => Integral (Const a b) Source # | Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

quot :: Const a b -> Const a b -> Const a b Source #

rem :: Const a b -> Const a b -> Const a b Source #

div :: Const a b -> Const a b -> Const a b Source #

mod :: Const a b -> Const a b -> Const a b Source #

quotRem :: Const a b -> Const a b -> (Const a b, Const a b) Source #

divMod :: Const a b -> Const a b -> (Const a b, Const a b) Source #

toInteger :: Const a b -> Integer Source #

Real a => Real (Const a b) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Const Methods toRational :: Const a b -> Rational Source #
RealFrac a => RealFrac (Const a b) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Const Methods properFraction :: Integral b0 => Const a b -> (b0, Const a b) Source # truncate :: Integral b0 => Const a b -> b0 Source # round :: Integral b0 => Const a b -> b0 Source # ceiling :: Integral b0 => Const a b -> b0 Source # floor :: Integral b0 => Const a b -> b0 Source #
Show a => Show (Const a b) Source # | This instance would be equivalent to the derived instances of the `Const` newtype if the `getConst` field were removed Since: base-4.8.0.0
Instance details Defined in Data.Functor.Const Methods showsPrec :: Int -> Const a b -> ShowS Source # show :: Const a b -> String Source # showList :: [Const a b] -> ShowS Source #
Eq a => Eq (Const a b) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Const Methods (==) :: Const a b -> Const a b -> Bool Source # (/=) :: Const a b -> Const a b -> Bool Source #
Ord a => Ord (Const a b) Source # | Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Const

Methods

compare :: Const a b -> Const a b -> Ordering Source #

(<) :: Const a b -> Const a b -> Bool Source #

(<=) :: Const a b -> Const a b -> Bool Source #

(>) :: Const a b -> Const a b -> Bool Source #

(>=) :: Const a b -> Const a b -> Bool Source #

max :: Const a b -> Const a b -> Const a b Source #

min :: Const a b -> Const a b -> Const a b Source #

type Rep1 (Const a :: k -> Type) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Const type Rep1 (Const a :: k -> Type) = D1 ('MetaData "Const" "Data.Functor.Const" "base" 'True) (C1 ('MetaCons "Const" 'PrefixI 'True) (S1 ('MetaSel ('Just "getConst") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a)))
type Rep (Const a b) Source # | Since: base-4.9.0.0
Instance details Defined in Data.Functor.Const type Rep (Const a b) = D1 ('MetaData "Const" "Data.Functor.Const" "base" 'True) (C1 ('MetaCons "Const" 'PrefixI 'True) (S1 ('MetaSel ('Just "getConst") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a)))

newtype WrappedMonad m a Source #

Constructors

WrapMonad |

Fields

- unwrapMonad :: m a

#### Instances

Instances details

Generic1 (WrappedMonad m :: Type -> Type) Source # |
Instance details Defined in Control.Applicative Associated Types type Rep1 (WrappedMonad m) :: k -> Type Source # Methods from1 :: forall (a :: k). WrappedMonad m a -> Rep1 (WrappedMonad m) a Source # to1 :: forall (a :: k). Rep1 (WrappedMonad m) a -> WrappedMonad m a Source #
MonadPlus m => Alternative (WrappedMonad m) Source # | Since: base-2.1
Instance details Defined in Control.Applicative Methods empty :: WrappedMonad m a Source # (<|>) :: WrappedMonad m a -> WrappedMonad m a -> WrappedMonad m a Source # some :: WrappedMonad m a -> WrappedMonad m [a] Source # many :: WrappedMonad m a -> WrappedMonad m [a] Source #
Monad m => Applicative (WrappedMonad m) Source # | Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

pure :: a -> WrappedMonad m a Source #

(<*>) :: WrappedMonad m (a -> b) -> WrappedMonad m a -> WrappedMonad m b Source #

liftA2 :: (a -> b -> c) -> WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m c Source #

(*>) :: WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m b Source #

(<*) :: WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m 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 #
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 #
(Typeable m, Typeable a, Data (m a)) => Data (WrappedMonad m a) Source # | Since: base-4.14.0.0

Instance details

Defined in Data.Data

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> WrappedMonad m a -> c (WrappedMonad m a) Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (WrappedMonad m a) Source #

toConstr :: WrappedMonad m a -> Constr Source #

dataTypeOf :: WrappedMonad m a -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (WrappedMonad m a)) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (WrappedMonad m a)) Source #

gmapT :: (forall b. Data b => b -> b) -> WrappedMonad m a -> WrappedMonad m a Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> WrappedMonad m a -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> WrappedMonad m a -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> WrappedMonad m a -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> WrappedMonad m a -> u Source #

gmapM :: Monad m0 => (forall d. Data d => d -> m0 d) -> WrappedMonad m a -> m0 (WrappedMonad m a) Source #

gmapMp :: MonadPlus m0 => (forall d. Data d => d -> m0 d) -> WrappedMonad m a -> m0 (WrappedMonad m a) Source #

gmapMo :: MonadPlus m0 => (forall d. Data d => d -> m0 d) -> WrappedMonad m a -> m0 (WrappedMonad m a) Source #

Generic (WrappedMonad m a) Source # |
Instance details Defined in Control.Applicative Associated Types type Rep (WrappedMonad m a) :: Type -> Type Source # Methods from :: WrappedMonad m a -> Rep (WrappedMonad m a) x Source # to :: Rep (WrappedMonad m a) x -> WrappedMonad m a Source #
type Rep1 (WrappedMonad m :: Type -> Type) Source # | Since: base-4.7.0.0
Instance details Defined in Control.Applicative type Rep1 (WrappedMonad m :: Type -> Type) = D1 ('MetaData "WrappedMonad" "Control.Applicative" "base" 'True) (C1 ('MetaCons "WrapMonad" 'PrefixI 'True) (S1 ('MetaSel ('Just "unwrapMonad") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec1 m)))
type Rep (WrappedMonad m a) Source # | Since: base-4.7.0.0
Instance details Defined in Control.Applicative type Rep (WrappedMonad m a) = D1 ('MetaData "WrappedMonad" "Control.Applicative" "base" 'True) (C1 ('MetaCons "WrapMonad" 'PrefixI 'True) (S1 ('MetaSel ('Just "unwrapMonad") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (m a))))

newtype WrappedArrow a b c Source #

Constructors

WrapArrow |

Fields

- unwrapArrow :: a b c

#### Instances

Instances details

Generic1 (WrappedArrow a b :: Type -> Type) Source # |
Instance details Defined in Control.Applicative Associated Types type Rep1 (WrappedArrow a b) :: k -> Type Source # Methods from1 :: forall (a0 :: k). WrappedArrow a b a0 -> Rep1 (WrappedArrow a b) a0 Source # to1 :: forall (a0 :: k). Rep1 (WrappedArrow a b) a0 -> WrappedArrow a b a0 Source #
(ArrowZero a, ArrowPlus a) => Alternative (WrappedArrow a b) Source # | Since: base-2.1
Instance details Defined in Control.Applicative Methods empty :: WrappedArrow a b a0 Source # (<|>) :: WrappedArrow a b a0 -> WrappedArrow a b a0 -> WrappedArrow a b a0 Source # some :: WrappedArrow a b a0 -> WrappedArrow a b [a0] Source # many :: WrappedArrow a b a0 -> WrappedArrow a b [a0] Source #
Arrow a => Applicative (WrappedArrow a b) Source # | Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

pure :: a0 -> WrappedArrow a b a0 Source #

(<*>) :: WrappedArrow a b (a0 -> b0) -> WrappedArrow a b a0 -> WrappedArrow a b b0 Source #

liftA2 :: (a0 -> b0 -> c) -> WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b c Source #

(*>) :: WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b b0 Source #

(<*) :: WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b 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 #
(Typeable a, Typeable b, Typeable c, Data (a b c)) => Data (WrappedArrow a b c) Source # | Since: base-4.14.0.0

Instance details

Defined in Data.Data

Methods

gfoldl :: (forall d b0. Data d => c0 (d -> b0) -> d -> c0 b0) -> (forall g. g -> c0 g) -> WrappedArrow a b c -> c0 (WrappedArrow a b c) Source #

gunfold :: (forall b0 r. Data b0 => c0 (b0 -> r) -> c0 r) -> (forall r. r -> c0 r) -> Constr -> c0 (WrappedArrow a b c) Source #

toConstr :: WrappedArrow a b c -> Constr Source #

dataTypeOf :: WrappedArrow a b c -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c0 (t d)) -> Maybe (c0 (WrappedArrow a b c)) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c0 (t d e)) -> Maybe (c0 (WrappedArrow a b c)) Source #

gmapT :: (forall b0. Data b0 => b0 -> b0) -> WrappedArrow a b c -> WrappedArrow a b c Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> WrappedArrow a b c -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> WrappedArrow a b c -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> WrappedArrow a b c -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> WrappedArrow a b c -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> WrappedArrow a b c -> m (WrappedArrow a b c) Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> WrappedArrow a b c -> m (WrappedArrow a b c) Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> WrappedArrow a b c -> m (WrappedArrow a b c) Source #

Generic (WrappedArrow a b c) Source # |
Instance details Defined in Control.Applicative Associated Types type Rep (WrappedArrow a b c) :: Type -> Type Source # Methods from :: WrappedArrow a b c -> Rep (WrappedArrow a b c) x Source # to :: Rep (WrappedArrow a b c) x -> WrappedArrow a b c Source #
type Rep1 (WrappedArrow a b :: Type -> Type) Source # | Since: base-4.7.0.0
Instance details Defined in Control.Applicative type Rep1 (WrappedArrow a b :: Type -> Type) = D1 ('MetaData "WrappedArrow" "Control.Applicative" "base" 'True) (C1 ('MetaCons "WrapArrow" 'PrefixI 'True) (S1 ('MetaSel ('Just "unwrapArrow") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec1 (a b))))
type Rep (WrappedArrow a b c) Source # | Since: base-4.7.0.0
Instance details Defined in Control.Applicative type Rep (WrappedArrow a b c) = D1 ('MetaData "WrappedArrow" "Control.Applicative" "base" 'True) (C1 ('MetaCons "WrapArrow" 'PrefixI 'True) (S1 ('MetaSel ('Just "unwrapArrow") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (a b c))))

newtype ZipList a Source #

Lists, but with an `Applicative` functor based on zipping.

Constructors

ZipList |

Fields

- getZipList :: [a]

#### Instances

Instances details

Foldable ZipList Source # | Since: base-4.9.0.0

Instance details

Defined in Control.Applicative

Methods

fold :: Monoid m => ZipList m -> m Source #

foldMap :: Monoid m => (a -> m) -> ZipList a -> m Source #

foldMap' :: Monoid m => (a -> m) -> ZipList a -> m Source #

foldr :: (a -> b -> b) -> b -> ZipList a -> b Source #

foldr' :: (a -> b -> b) -> b -> ZipList a -> b Source #

foldl :: (b -> a -> b) -> b -> ZipList a -> b Source #

foldl' :: (b -> a -> b) -> b -> ZipList a -> b Source #

foldr1 :: (a -> a -> a) -> ZipList a -> a Source #

foldl1 :: (a -> a -> a) -> ZipList a -> a Source #

toList :: ZipList a -> [a] Source #

null :: ZipList a -> Bool Source #

length :: ZipList a -> Int Source #

elem :: Eq a => a -> ZipList a -> Bool Source #

maximum :: Ord a => ZipList a -> a Source #

minimum :: Ord a => ZipList a -> a Source #

sum :: Num a => ZipList a -> a Source #

product :: Num a => ZipList a -> a Source #

Traversable ZipList Source # | Since: base-4.9.0.0
Instance details Defined in Data.Traversable Methods traverse :: Applicative f => (a -> f b) -> ZipList a -> f (ZipList b) Source # sequenceA :: Applicative f => ZipList (f a) -> f (ZipList a) Source # mapM :: Monad m => (a -> m b) -> ZipList a -> m (ZipList b) Source # sequence :: Monad m => ZipList (m a) -> m (ZipList a) Source #
Alternative ZipList Source # | Since: base-4.11.0.0
Instance details Defined in Control.Applicative Methods empty :: ZipList a Source # (<|>) :: ZipList a -> ZipList a -> ZipList a Source # some :: ZipList a -> ZipList [a] Source # many :: ZipList a -> ZipList [a] Source #

Applicative ZipList Source #

    f <$> ZipList xs1 <*> ... <*> ZipList xsN
        = ZipList (zipWithN f xs1 ... xsN)

where `zipWithN` refers to the `zipWith` function of the appropriate arity (`zipWith`, `zipWith3`, `zipWith4`, ...). For example:

    (\a b c -> stimes c [a, b]) <$> ZipList "abcd" <*> ZipList "567" <*> ZipList [1..]
        = ZipList (zipWith3 (\a b c -> stimes c [a, b]) "abcd" "567" [1..])
        = ZipList {getZipList = ["a5","b6b6","c7c7c7"]}

Since: base-2.1

Instance details Defined in Control.Applicative Methods pure :: a -> ZipList a Source # (<*>) :: ZipList (a -> b) -> ZipList a -> ZipList b Source # liftA2 :: (a -> b -> c) -> ZipList a -> ZipList b -> ZipList c Source # (*>) :: ZipList a -> ZipList b -> ZipList b Source # (<*) :: ZipList a -> ZipList b -> ZipList a Source #
Functor ZipList Source # | Since: base-2.1
Instance details Defined in Control.Applicative Methods fmap :: (a -> b) -> ZipList a -> ZipList b Source # (<$) :: a -> ZipList b -> ZipList a Source #
Generic1 ZipList Source # |
Instance details Defined in Control.Applicative Associated Types type Rep1 ZipList :: k -> Type Source # Methods from1 :: forall (a :: k). ZipList a -> Rep1 ZipList a Source # to1 :: forall (a :: k). Rep1 ZipList a -> ZipList a Source #
Data a => Data (ZipList a) Source # | Since: base-4.14.0.0

Instance details

Defined in Data.Data

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> ZipList a -> c (ZipList a) Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (ZipList a) Source #

toConstr :: ZipList a -> Constr Source #

dataTypeOf :: ZipList a -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (ZipList a)) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (ZipList a)) Source #

gmapT :: (forall b. Data b => b -> b) -> ZipList a -> ZipList a Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> ZipList a -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> ZipList a -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> ZipList a -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> ZipList a -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> ZipList a -> m (ZipList a) Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> ZipList a -> m (ZipList a) Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> ZipList a -> m (ZipList a) Source #

Generic (ZipList a) Source # |
Instance details Defined in Control.Applicative Associated Types type Rep (ZipList a) :: Type -> Type Source # Methods from :: ZipList a -> Rep (ZipList a) x Source # to :: Rep (ZipList a) x -> ZipList a Source #
IsList (ZipList a) Source # | Since: base-4.15.0.0
Instance details Defined in GHC.IsList Associated Types type Item (ZipList a) Source # Methods fromList :: [Item (ZipList a)] -> ZipList a Source # fromListN :: Int -> [Item (ZipList a)] -> ZipList a Source # toList :: ZipList a -> [Item (ZipList a)] Source #
Read a => Read (ZipList a) Source # | Since: base-4.7.0.0
Instance details Defined in Control.Applicative Methods readsPrec :: Int -> ReadS (ZipList a) Source # readList :: ReadS [ZipList a] Source # readPrec :: ReadPrec (ZipList a) Source # readListPrec :: ReadPrec [ZipList a] Source #
Show a => Show (ZipList a) Source # | Since: base-4.7.0.0
Instance details Defined in Control.Applicative Methods showsPrec :: Int -> ZipList a -> ShowS Source # show :: ZipList a -> String Source # showList :: [ZipList a] -> ShowS Source #
Eq a => Eq (ZipList a) Source # | Since: base-4.7.0.0
Instance details Defined in Control.Applicative Methods (==) :: ZipList a -> ZipList a -> Bool Source # (/=) :: ZipList a -> ZipList a -> Bool Source #
Ord a => Ord (ZipList a) Source # | Since: base-4.7.0.0

Instance details

Defined in Control.Applicative

Methods

compare :: ZipList a -> ZipList a -> Ordering Source #

(<) :: ZipList a -> ZipList a -> Bool Source #

(<=) :: ZipList a -> ZipList a -> Bool Source #

(>) :: ZipList a -> ZipList a -> Bool Source #

(>=) :: ZipList a -> ZipList a -> Bool Source #

max :: ZipList a -> ZipList a -> ZipList a Source #

min :: ZipList a -> ZipList a -> ZipList a Source #

type Rep1 ZipList Source # | Since: base-4.7.0.0
Instance details Defined in Control.Applicative type Rep1 ZipList = D1 ('MetaData "ZipList" "Control.Applicative" "base" 'True) (C1 ('MetaCons "ZipList" 'PrefixI 'True) (S1 ('MetaSel ('Just "getZipList") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec1 List)))
type Rep (ZipList a) Source # | Since: base-4.7.0.0
Instance details Defined in Control.Applicative type Rep (ZipList a) = D1 ('MetaData "ZipList" "Control.Applicative" "base" 'True) (C1 ('MetaCons "ZipList" 'PrefixI 'True) (S1 ('MetaSel ('Just "getZipList") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 [a])))
type Item (ZipList a) Source # |
Instance details Defined in GHC.IsList type Item (ZipList a) = a

# Utility functions

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

An infix synonym for `fmap`.

The name of this operator is an allusion to `$`. Note the similarities between their types:

     ($)  ::              (a -> b) ->   a ->   b
    (<$>) :: Functor f => (a -> b) -> f a -> f b

Whereas `$` is function application, `<$>` is function application lifted over a `Functor`.

#### Examples

Expand

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

    >>> show <$> Nothing
    Nothing
    >>> show <$> Just 3
    Just "3"

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

    >>> show <$> Left 17
    Left 17
    >>> show <$> Right 17
    Right "17"

Double each element of a list:

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

Apply `even` to the second element of a pair:

    >>> even <$> (2,2)
    (2,True)

(<$) :: Functor f => 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

(<**>) :: Applicative f => f a -> f (a -> b) -> f b infixl 4 Source #

A variant of `<*>` with the arguments reversed.

liftA :: Applicative f => (a -> b) -> f a -> f b Source #

Lift a function to actions. Equivalent to Functor's `fmap` but implemented using only `Applicative`'s methods: ``liftA` f a = `pure` f `<*>` a`

As such this function may be used to implement a `Functor` instance from an `Applicative` one.

#### Examples

Expand

Using the Applicative instance for Lists:

    >>> liftA (+1) [1, 2]
    [2,3]

Or the Applicative instance for `Maybe`

    >>> liftA (+1) (Just 3)
    Just 4

liftA3 :: Applicative f => (a -> b -> c -> d) -> f a -> f b -> f c -> f d Source #

Lift a ternary function to actions.

optional :: Alternative f => f a -> f (Maybe a) Source #

One or none.

It is useful for modelling any computation that is allowed to fail.

#### Examples

Expand

Using the `Alternative` instance of Control.Monad.Except, the following functions:

    >>> import Control.Monad.Except

    >>> canFail = throwError "it failed" :: Except String Int
    >>> final = return 42                :: Except String Int

Can be combined by allowing the first function to fail:

    >>> runExcept $ canFail *> final
    Left "it failed"
    >>> runExcept $ optional canFail *> final
    Right 42

asum :: (Foldable t, Alternative f) => t (f a) -> f a Source #

The sum of a collection of actions using `(<|>)`, generalizing `concat`.

`asum` is just like `msum`, but generalised to `Alternative`.

#### Examples

Expand

Basic usage:

    >>> asum [Just "Hello", Nothing, Just "World"]
    Just "Hello"