GHC.HsToCore.Monad

Documentation

type DsM = TcRnIf DsGblEnv DsLclEnv

Desugaring monad. See also TcM.

mapM :: (Traversable t, Monad m) => (a -> m b) -> t a -> m (t b)

Map each element of a structure to a monadic action, evaluate these actions from left to right, and collect the results. For a version that ignores the results see mapM_.

Examples

mapM is literally a traverse with a type signature restricted to Monad. Its implementation may be more efficient due to additional power of Monad.

mapAndUnzipM :: Applicative m => (a -> m (b, c)) -> [a] -> m ([b], [c])

The mapAndUnzipM function maps its first argument over a list, returning the result as a pair of lists. This function is mainly used with complicated data structures or a state monad.

initDs :: HscEnv -> TcGblEnv -> DsM a -> IO (Messages DsMessage, Maybe a)

Run a DsM action inside the IO monad.

initDsTc :: DsM a -> TcM (Messages DsMessage, Maybe a)

Run a DsM action inside the TcM monad.

initTcDsForSolver :: TcM a -> DsM a

initDsWithModGuts :: HscEnv -> ModGuts -> DsM a -> IO (Messages DsMessage, Maybe a)

Run a DsM action in the context of an existing ModGuts

fixDs :: (a -> DsM a) -> DsM a

foldlM :: (Foldable t, Monad m) => (b -> a -> m b) -> b -> t a -> m b

Left-to-right monadic fold over the elements of a structure.

Given a structure t with elements (a, b, ..., w, x, y), the result of a fold with an operator function f is equivalent to:

foldlM f z t = do
    aa <- f z a
    bb <- f aa b
    ...
    xx <- f ww x
    yy <- f xx y
    return yy -- Just @return z@ when the structure is empty

For a Monad m, given two functions f1 :: a -> m b and f2 :: b -> m c, their Kleisli composition (f1 >=> f2) :: a -> m c is defined by:

(f1 >=> f2) a = f1 a >>= f2

Another way of thinking about foldlM is that it amounts to an application to z of a Kleisli composition:

foldlM f z t =
    flip f a >=> flip f b >=> ... >=> flip f x >=> flip f y $ z

The monadic effects of foldlM are sequenced from left to right.

If at some step the bind operator (>>=) short-circuits (as with, e.g., mzero in a MonadPlus), the evaluated effects will be from an initial segment of the element sequence. If you want to evaluate the monadic effects in right-to-left order, or perhaps be able to short-circuit after processing a tail of the sequence of elements, you'll need to use foldrM instead.

If the monadic effects don't short-circuit, the outermost application of f is to the rightmost element y, so that, ignoring effects, the result looks like a left fold:

((((z `f` a) `f` b) ... `f` w) `f` x) `f` y

Examples

Basic usage:

>>> let f a e = do { print e ; return $ e : a }
>>> foldlM f [] [0..3]
0
1
2
3
[3,2,1,0]

foldrM :: (Foldable t, Monad m) => (a -> b -> m b) -> b -> t a -> m b

Right-to-left monadic fold over the elements of a structure.

Given a structure t with elements (a, b, c, ..., x, y), the result of a fold with an operator function f is equivalent to:

foldrM f z t = do
    yy <- f y z
    xx <- f x yy
    ...
    bb <- f b cc
    aa <- f a bb
    return aa -- Just @return z@ when the structure is empty

For a Monad m, given two functions f1 :: a -> m b and f2 :: b -> m c, their Kleisli composition (f1 >=> f2) :: a -> m c is defined by:

(f1 >=> f2) a = f1 a >>= f2

Another way of thinking about foldrM is that it amounts to an application to z of a Kleisli composition:

foldrM f z t = f y >=> f x >=> ... >=> f b >=> f a $ z

The monadic effects of foldrM are sequenced from right to left, and e.g. folds of infinite lists will diverge.

If at some step the bind operator (>>=) short-circuits (as with, e.g., mzero in a MonadPlus), the evaluated effects will be from a tail of the element sequence. If you want to evaluate the monadic effects in left-to-right order, or perhaps be able to short-circuit after an initial sequence of elements, you'll need to use foldlM instead.

If the monadic effects don't short-circuit, the outermost application of f is to the leftmost element a, so that, ignoring effects, the result looks like a right fold:

a `f` (b `f` (c `f` (... (x `f` (y `f` z))))).

Examples

Basic usage:

>>> let f i acc = do { print i ; return $ i : acc }
>>> foldrM f [] [0..3]
3
2
1
0
[0,1,2,3]

whenGOptM :: GeneralFlag -> TcRnIf gbl lcl () -> TcRnIf gbl lcl ()

unsetGOptM :: GeneralFlag -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a

unsetWOptM :: WarningFlag -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a

xoptM :: Extension -> TcRnIf gbl lcl Bool

class Functor f => Applicative (f :: Type -> Type) where

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

Lift a value.

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

Sequential application.

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

Example

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

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

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

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

Sequence actions, discarding the value of the first argument.

Examples

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

Sequence actions, discarding the value of the second argument.

Instances

Applicative ZipList

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

Defined in Control.Applicative

Methods

pure :: a -> ZipList a

(<*>) :: ZipList (a -> b) -> ZipList a -> ZipList b

liftA2 :: (a -> b -> c) -> ZipList a -> ZipList b -> ZipList c

(*>) :: ZipList a -> ZipList b -> ZipList b

(<*) :: ZipList a -> ZipList b -> ZipList a

Applicative Complex

Since: base-4.9.0.0

Defined in Data.Complex

Methods

pure :: a -> Complex a

(<*>) :: Complex (a -> b) -> Complex a -> Complex b

liftA2 :: (a -> b -> c) -> Complex a -> Complex b -> Complex c

(*>) :: Complex a -> Complex b -> Complex b

(<*) :: Complex a -> Complex b -> Complex a

Applicative Identity

Since: base-4.8.0.0

Defined in Data.Functor.Identity

Methods

pure :: a -> Identity a

(<*>) :: Identity (a -> b) -> Identity a -> Identity b

liftA2 :: (a -> b -> c) -> Identity a -> Identity b -> Identity c

(*>) :: Identity a -> Identity b -> Identity b

(<*) :: Identity a -> Identity b -> Identity a

Applicative First

Since: base-4.8.0.0

Defined in Data.Monoid

Methods

pure :: a -> First a

(<*>) :: First (a -> b) -> First a -> First b

liftA2 :: (a -> b -> c) -> First a -> First b -> First c

(*>) :: First a -> First b -> First b

(<*) :: First a -> First b -> First a

Applicative Last

Since: base-4.8.0.0

Defined in Data.Monoid

Methods

pure :: a -> Last a

(<*>) :: Last (a -> b) -> Last a -> Last b

liftA2 :: (a -> b -> c) -> Last a -> Last b -> Last c

(*>) :: Last a -> Last b -> Last b

(<*) :: Last a -> Last b -> Last a

Applicative Down

Since: base-4.11.0.0

Defined in Data.Ord

Methods

pure :: a -> Down a

(<*>) :: Down (a -> b) -> Down a -> Down b

liftA2 :: (a -> b -> c) -> Down a -> Down b -> Down c

(*>) :: Down a -> Down b -> Down b

(<*) :: Down a -> Down b -> Down a

Applicative First

Since: base-4.9.0.0

Defined in Data.Semigroup

Methods

pure :: a -> First a

(<*>) :: First (a -> b) -> First a -> First b

liftA2 :: (a -> b -> c) -> First a -> First b -> First c

(*>) :: First a -> First b -> First b

(<*) :: First a -> First b -> First a

Applicative Last

Since: base-4.9.0.0

Defined in Data.Semigroup

Methods

pure :: a -> Last a

(<*>) :: Last (a -> b) -> Last a -> Last b

liftA2 :: (a -> b -> c) -> Last a -> Last b -> Last c

(*>) :: Last a -> Last b -> Last b

(<*) :: Last a -> Last b -> Last a

Applicative Max

Since: base-4.9.0.0

Defined in Data.Semigroup

Methods

pure :: a -> Max a

(<*>) :: Max (a -> b) -> Max a -> Max b

liftA2 :: (a -> b -> c) -> Max a -> Max b -> Max c

(*>) :: Max a -> Max b -> Max b

(<*) :: Max a -> Max b -> Max a

Applicative Min

Since: base-4.9.0.0

Defined in Data.Semigroup

Methods

pure :: a -> Min a

(<*>) :: Min (a -> b) -> Min a -> Min b

liftA2 :: (a -> b -> c) -> Min a -> Min b -> Min c

(*>) :: Min a -> Min b -> Min b

(<*) :: Min a -> Min b -> Min a

Applicative Dual

Since: base-4.8.0.0

Defined in Data.Semigroup.Internal

Methods

pure :: a -> Dual a

(<*>) :: Dual (a -> b) -> Dual a -> Dual b

liftA2 :: (a -> b -> c) -> Dual a -> Dual b -> Dual c

(*>) :: Dual a -> Dual b -> Dual b

(<*) :: Dual a -> Dual b -> Dual a

Applicative Product

Since: base-4.8.0.0

Defined in Data.Semigroup.Internal

Methods

pure :: a -> Product a

(<*>) :: Product (a -> b) -> Product a -> Product b

liftA2 :: (a -> b -> c) -> Product a -> Product b -> Product c

(*>) :: Product a -> Product b -> Product b

(<*) :: Product a -> Product b -> Product a

Applicative Sum

Since: base-4.8.0.0

Defined in Data.Semigroup.Internal

Methods

pure :: a -> Sum a

(<*>) :: Sum (a -> b) -> Sum a -> Sum b

liftA2 :: (a -> b -> c) -> Sum a -> Sum b -> Sum c

(*>) :: Sum a -> Sum b -> Sum b

(<*) :: Sum a -> Sum b -> Sum a

Applicative STM

Since: base-4.8.0.0

Defined in GHC.Conc.Sync

Methods

pure :: a -> STM a

(<*>) :: STM (a -> b) -> STM a -> STM b

liftA2 :: (a -> b -> c) -> STM a -> STM b -> STM c

(*>) :: STM a -> STM b -> STM b

(<*) :: STM a -> STM b -> STM a

Applicative Par1

Since: base-4.9.0.0

Defined in GHC.Generics

Methods

pure :: a -> Par1 a

(<*>) :: Par1 (a -> b) -> Par1 a -> Par1 b

liftA2 :: (a -> b -> c) -> Par1 a -> Par1 b -> Par1 c

(*>) :: Par1 a -> Par1 b -> Par1 b

(<*) :: Par1 a -> Par1 b -> Par1 a

Applicative P

Since: base-4.5.0.0

Defined in Text.ParserCombinators.ReadP

Methods

pure :: a -> P a

(<*>) :: P (a -> b) -> P a -> P b

liftA2 :: (a -> b -> c) -> P a -> P b -> P c

(*>) :: P a -> P b -> P b

(<*) :: P a -> P b -> P a

Applicative ReadP

Since: base-4.6.0.0

Defined in Text.ParserCombinators.ReadP

Methods

pure :: a -> ReadP a

(<*>) :: ReadP (a -> b) -> ReadP a -> ReadP b

liftA2 :: (a -> b -> c) -> ReadP a -> ReadP b -> ReadP c

(*>) :: ReadP a -> ReadP b -> ReadP b

(<*) :: ReadP a -> ReadP b -> ReadP a

Applicative ReadPrec

Since: base-4.6.0.0

Defined in Text.ParserCombinators.ReadPrec

Methods

pure :: a -> ReadPrec a

(<*>) :: ReadPrec (a -> b) -> ReadPrec a -> ReadPrec b

liftA2 :: (a -> b -> c) -> ReadPrec a -> ReadPrec b -> ReadPrec c

(*>) :: ReadPrec a -> ReadPrec b -> ReadPrec b

(<*) :: ReadPrec a -> ReadPrec b -> ReadPrec a

Applicative Get

Defined in Data.Binary.Get.Internal

Methods

pure :: a -> Get a

(<*>) :: Get (a -> b) -> Get a -> Get b

liftA2 :: (a -> b -> c) -> Get a -> Get b -> Get c

(*>) :: Get a -> Get b -> Get b

(<*) :: Get a -> Get b -> Get a

Applicative PutM

Defined in Data.Binary.Put

Methods

pure :: a -> PutM a

(<*>) :: PutM (a -> b) -> PutM a -> PutM b

liftA2 :: (a -> b -> c) -> PutM a -> PutM b -> PutM c

(*>) :: PutM a -> PutM b -> PutM b

(<*) :: PutM a -> PutM b -> PutM a

Applicative Put

Defined in Data.ByteString.Builder.Internal

Methods

pure :: a -> Put a

(<*>) :: Put (a -> b) -> Put a -> Put b

liftA2 :: (a -> b -> c) -> Put a -> Put b -> Put c

(*>) :: Put a -> Put b -> Put b

(<*) :: Put a -> Put b -> Put a

Applicative Seq

Since: containers-0.5.4

Defined in Data.Sequence.Internal

Methods

pure :: a -> Seq a

(<*>) :: Seq (a -> b) -> Seq a -> Seq b

liftA2 :: (a -> b -> c) -> Seq a -> Seq b -> Seq c

(*>) :: Seq a -> Seq b -> Seq b

(<*) :: Seq a -> Seq b -> Seq a

Applicative Tree

Defined in Data.Tree

Methods

pure :: a -> Tree a

(<*>) :: Tree (a -> b) -> Tree a -> Tree b

liftA2 :: (a -> b -> c) -> Tree a -> Tree b -> Tree c

(*>) :: Tree a -> Tree b -> Tree b

(<*) :: Tree a -> Tree b -> Tree a

Applicative PD

Defined in GHC.Cmm.Parser.Monad

Methods

pure :: a -> PD a

(<*>) :: PD (a -> b) -> PD a -> PD b

liftA2 :: (a -> b -> c) -> PD a -> PD b -> PD c

(*>) :: PD a -> PD b -> PD b

(<*) :: PD a -> PD b -> PD a

Applicative NatM

Defined in GHC.CmmToAsm.Monad

Methods

pure :: a -> NatM a

(<*>) :: NatM (a -> b) -> NatM a -> NatM b

liftA2 :: (a -> b -> c) -> NatM a -> NatM b -> NatM c

(*>) :: NatM a -> NatM b -> NatM b

(<*) :: NatM a -> NatM b -> NatM a

Applicative LlvmM

Defined in GHC.CmmToLlvm.Base

Methods

pure :: a -> LlvmM a

(<*>) :: LlvmM (a -> b) -> LlvmM a -> LlvmM b

liftA2 :: (a -> b -> c) -> LlvmM a -> LlvmM b -> LlvmM c

(*>) :: LlvmM a -> LlvmM b -> LlvmM b

(<*) :: LlvmM a -> LlvmM b -> LlvmM a

Applicative SimplM

Defined in GHC.Core.Opt.Simplify.Monad

Methods

pure :: a -> SimplM a

(<*>) :: SimplM (a -> b) -> SimplM a -> SimplM b

liftA2 :: (a -> b -> c) -> SimplM a -> SimplM b -> SimplM c

(*>) :: SimplM a -> SimplM b -> SimplM b

(<*) :: SimplM a -> SimplM b -> SimplM a

Applicative HookedUse

Defined in GHC.Driver.Pipeline.Execute

Methods

pure :: a -> HookedUse a

(<*>) :: HookedUse (a -> b) -> HookedUse a -> HookedUse b

liftA2 :: (a -> b -> c) -> HookedUse a -> HookedUse b -> HookedUse c

(*>) :: HookedUse a -> HookedUse b -> HookedUse b

(<*) :: HookedUse a -> HookedUse b -> HookedUse a

Applicative MatchResult

Product is an "or" on falliblity---the combined match result is infallible only if the left and right argument match results both were.

This is useful for combining a bunch of alternatives together and then getting the overall falliblity of the entire group. See mkDataConCase for an example.

Defined in GHC.HsToCore.Monad

Methods

pure :: a -> MatchResult a

(<*>) :: MatchResult (a -> b) -> MatchResult a -> MatchResult b

liftA2 :: (a -> b -> c) -> MatchResult a -> MatchResult b -> MatchResult c

(*>) :: MatchResult a -> MatchResult b -> MatchResult b

(<*) :: MatchResult a -> MatchResult b -> MatchResult a

Applicative CpsRn

Defined in GHC.Rename.Pat

Methods

pure :: a -> CpsRn a

(<*>) :: CpsRn (a -> b) -> CpsRn a -> CpsRn b

liftA2 :: (a -> b -> c) -> CpsRn a -> CpsRn b -> CpsRn c

(*>) :: CpsRn a -> CpsRn b -> CpsRn b

(<*) :: CpsRn a -> CpsRn b -> CpsRn a

Applicative LiftM

Defined in GHC.Stg.Lift.Monad

Methods

pure :: a -> LiftM a

(<*>) :: LiftM (a -> b) -> LiftM a -> LiftM b

liftA2 :: (a -> b -> c) -> LiftM a -> LiftM b -> LiftM c

(*>) :: LiftM a -> LiftM b -> LiftM b

(<*) :: LiftM a -> LiftM b -> LiftM a

Applicative CmmParse

Defined in GHC.StgToCmm.ExtCode

Methods

pure :: a -> CmmParse a

(<*>) :: CmmParse (a -> b) -> CmmParse a -> CmmParse b

liftA2 :: (a -> b -> c) -> CmmParse a -> CmmParse b -> CmmParse c

(*>) :: CmmParse a -> CmmParse b -> CmmParse b

(<*) :: CmmParse a -> CmmParse b -> CmmParse a

Applicative FCode

Defined in GHC.StgToCmm.Monad

Methods

pure :: a -> FCode a

(<*>) :: FCode (a -> b) -> FCode a -> FCode b

liftA2 :: (a -> b -> c) -> FCode a -> FCode b -> FCode c

(*>) :: FCode a -> FCode b -> FCode b

(<*) :: FCode a -> FCode b -> FCode a

Applicative TcS

Defined in GHC.Tc.Solver.Monad

Methods

pure :: a -> TcS a

(<*>) :: TcS (a -> b) -> TcS a -> TcS b

liftA2 :: (a -> b -> c) -> TcS a -> TcS b -> TcS c

(*>) :: TcS a -> TcS b -> TcS b

(<*) :: TcS a -> TcS b -> TcS a

Applicative NormM

Defined in GHC.Core.FamInstEnv

Methods

pure :: a -> NormM a

(<*>) :: NormM (a -> b) -> NormM a -> NormM b

liftA2 :: (a -> b -> c) -> NormM a -> NormM b -> NormM c

(*>) :: NormM a -> NormM b -> NormM b

(<*) :: NormM a -> NormM b -> NormM a

Applicative LintM

Defined in GHC.Core.Lint

Methods

pure :: a -> LintM a

(<*>) :: LintM (a -> b) -> LintM a -> LintM b

liftA2 :: (a -> b -> c) -> LintM a -> LintM b -> LintM c

(*>) :: LintM a -> LintM b -> LintM b

(<*) :: LintM a -> LintM b -> LintM a

Applicative RuleM

Defined in GHC.Core.Opt.ConstantFold

Methods

pure :: a -> RuleM a

(<*>) :: RuleM (a -> b) -> RuleM a -> RuleM b

liftA2 :: (a -> b -> c) -> RuleM a -> RuleM b -> RuleM c

(*>) :: RuleM a -> RuleM b -> RuleM b

(<*) :: RuleM a -> RuleM b -> RuleM a

Applicative CoreM

Defined in GHC.Core.Opt.Monad

Methods

pure :: a -> CoreM a

(<*>) :: CoreM (a -> b) -> CoreM a -> CoreM b

liftA2 :: (a -> b -> c) -> CoreM a -> CoreM b -> CoreM c

(*>) :: CoreM a -> CoreM b -> CoreM b

(<*) :: CoreM a -> CoreM b -> CoreM a

Applicative UM

Defined in GHC.Core.Unify

Methods

pure :: a -> UM a

(<*>) :: UM (a -> b) -> UM a -> UM b

liftA2 :: (a -> b -> c) -> UM a -> UM b -> UM c

(*>) :: UM a -> UM b -> UM b

(<*) :: UM a -> UM b -> UM a

Applicative UnifyResultM

Defined in GHC.Core.Unify

Methods

pure :: a -> UnifyResultM a

(<*>) :: UnifyResultM (a -> b) -> UnifyResultM a -> UnifyResultM b

liftA2 :: (a -> b -> c) -> UnifyResultM a -> UnifyResultM b -> UnifyResultM c

(*>) :: UnifyResultM a -> UnifyResultM b -> UnifyResultM b

(<*) :: UnifyResultM a -> UnifyResultM b -> UnifyResultM a

Applicative Pair

Defined in GHC.Data.Pair

Methods

pure :: a -> Pair a

(<*>) :: Pair (a -> b) -> Pair a -> Pair b

liftA2 :: (a -> b -> c) -> Pair a -> Pair b -> Pair c

(*>) :: Pair a -> Pair b -> Pair b

(<*) :: Pair a -> Pair b -> Pair a

Applicative Maybe

Defined in GHC.Data.Strict

Methods

pure :: a -> Maybe a

(<*>) :: Maybe (a -> b) -> Maybe a -> Maybe b

liftA2 :: (a -> b -> c) -> Maybe a -> Maybe b -> Maybe c

(*>) :: Maybe a -> Maybe b -> Maybe b

(<*) :: Maybe a -> Maybe b -> Maybe a

Applicative Hsc

Defined in GHC.Driver.Env.Types

Methods

pure :: a -> Hsc a

(<*>) :: Hsc (a -> b) -> Hsc a -> Hsc b

liftA2 :: (a -> b -> c) -> Hsc a -> Hsc b -> Hsc c

(*>) :: Hsc a -> Hsc b -> Hsc b

(<*) :: Hsc a -> Hsc b -> Hsc a

Applicative Ghc

Defined in GHC.Driver.Monad

Methods

pure :: a -> Ghc a

(<*>) :: Ghc (a -> b) -> Ghc a -> Ghc b

liftA2 :: (a -> b -> c) -> Ghc a -> Ghc b -> Ghc c

(*>) :: Ghc a -> Ghc b -> Ghc b

(<*) :: Ghc a -> Ghc b -> Ghc a

Applicative P

Defined in GHC.Parser.Lexer

Methods

pure :: a -> P a

(<*>) :: P (a -> b) -> P a -> P b

liftA2 :: (a -> b -> c) -> P a -> P b -> P c

(*>) :: P a -> P b -> P b

(<*) :: P a -> P b -> P a

Applicative PV

Defined in GHC.Parser.PostProcess

Methods

pure :: a -> PV a

(<*>) :: PV (a -> b) -> PV a -> PV b

liftA2 :: (a -> b -> c) -> PV a -> PV b -> PV c

(*>) :: PV a -> PV b -> PV b

(<*) :: PV a -> PV b -> PV a

Applicative TcPluginM

Defined in GHC.Tc.Types

Methods

pure :: a -> TcPluginM a

(<*>) :: TcPluginM (a -> b) -> TcPluginM a -> TcPluginM b

liftA2 :: (a -> b -> c) -> TcPluginM a -> TcPluginM b -> TcPluginM c

(*>) :: TcPluginM a -> TcPluginM b -> TcPluginM b

(<*) :: TcPluginM a -> TcPluginM b -> TcPluginM a

Applicative UniqSM

Defined in GHC.Types.Unique.Supply

Methods

pure :: a -> UniqSM a

(<*>) :: UniqSM (a -> b) -> UniqSM a -> UniqSM b

liftA2 :: (a -> b -> c) -> UniqSM a -> UniqSM b -> UniqSM c

(*>) :: UniqSM a -> UniqSM b -> UniqSM b

(<*) :: UniqSM a -> UniqSM b -> UniqSM a

Applicative Q

Defined in Language.Haskell.TH.Syntax

Methods

pure :: a -> Q a

(<*>) :: Q (a -> b) -> Q a -> Q b

liftA2 :: (a -> b -> c) -> Q a -> Q b -> Q c

(*>) :: Q a -> Q b -> Q b

(<*) :: Q a -> Q b -> Q a

Applicative IO

Since: base-2.1

Defined in GHC.Base

Methods

pure :: a -> IO a

(<*>) :: IO (a -> b) -> IO a -> IO b

liftA2 :: (a -> b -> c) -> IO a -> IO b -> IO c

(*>) :: IO a -> IO b -> IO b

(<*) :: IO a -> IO b -> IO a

Applicative Q

Defined in Language.Haskell.TH.Syntax

Methods

pure :: a -> Q a

(<*>) :: Q (a -> b) -> Q a -> Q b

liftA2 :: (a -> b -> c) -> Q a -> Q b -> Q c

(*>) :: Q a -> Q b -> Q b

(<*) :: Q a -> Q b -> Q a

Applicative NonEmpty

Since: base-4.9.0.0

Defined in GHC.Base

Methods

pure :: a -> NonEmpty a

(<*>) :: NonEmpty (a -> b) -> NonEmpty a -> NonEmpty b

liftA2 :: (a -> b -> c) -> NonEmpty a -> NonEmpty b -> NonEmpty c

(*>) :: NonEmpty a -> NonEmpty b -> NonEmpty b

(<*) :: NonEmpty a -> NonEmpty b -> NonEmpty a

Applicative Maybe

Since: base-2.1

Defined in GHC.Base

Methods

pure :: a -> Maybe a

(<*>) :: Maybe (a -> b) -> Maybe a -> Maybe b

liftA2 :: (a -> b -> c) -> Maybe a -> Maybe b -> Maybe c

(*>) :: Maybe a -> Maybe b -> Maybe b

(<*) :: Maybe a -> Maybe b -> Maybe a

Applicative Solo

Since: base-4.15

Defined in GHC.Base

Methods

pure :: a -> Solo a

(<*>) :: Solo (a -> b) -> Solo a -> Solo b

liftA2 :: (a -> b -> c) -> Solo a -> Solo b -> Solo c

(*>) :: Solo a -> Solo b -> Solo b

(<*) :: Solo a -> Solo b -> Solo a

Applicative []

Since: base-2.1

Defined in GHC.Base

Methods

pure :: a -> [a]

(<*>) :: [a -> b] -> [a] -> [b]

liftA2 :: (a -> b -> c) -> [a] -> [b] -> [c]

(*>) :: [a] -> [b] -> [b]

(<*) :: [a] -> [b] -> [a]

Monad m => Applicative (WrappedMonad m)

Since: base-2.1

Defined in Control.Applicative

Methods

pure :: a -> WrappedMonad m a

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

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

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

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

Arrow a => Applicative (ArrowMonad a)

Since: base-4.6.0.0

Defined in Control.Arrow

Methods

pure :: a0 -> ArrowMonad a a0

(<*>) :: ArrowMonad a (a0 -> b) -> ArrowMonad a a0 -> ArrowMonad a b

liftA2 :: (a0 -> b -> c) -> ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a c

(*>) :: ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a b

(<*) :: ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a a0

Applicative (Either e)

Since: base-3.0

Defined in Data.Either

Methods

pure :: a -> Either e a

(<*>) :: Either e (a -> b) -> Either e a -> Either e b

liftA2 :: (a -> b -> c) -> Either e a -> Either e b -> Either e c

(*>) :: Either e a -> Either e b -> Either e b

(<*) :: Either e a -> Either e b -> Either e a

Applicative (StateL s)

Since: base-4.0

Defined in Data.Functor.Utils

Methods

pure :: a -> StateL s a

(<*>) :: StateL s (a -> b) -> StateL s a -> StateL s b

liftA2 :: (a -> b -> c) -> StateL s a -> StateL s b -> StateL s c

(*>) :: StateL s a -> StateL s b -> StateL s b

(<*) :: StateL s a -> StateL s b -> StateL s a

Applicative (StateR s)

Since: base-4.0

Defined in Data.Functor.Utils

Methods

pure :: a -> StateR s a

(<*>) :: StateR s (a -> b) -> StateR s a -> StateR s b

liftA2 :: (a -> b -> c) -> StateR s a -> StateR s b -> StateR s c

(*>) :: StateR s a -> StateR s b -> StateR s b

(<*) :: StateR s a -> StateR s b -> StateR s a

Applicative (Proxy :: Type -> Type)

Since: base-4.7.0.0

Defined in Data.Proxy

Methods

pure :: a -> Proxy a

(<*>) :: Proxy (a -> b) -> Proxy a -> Proxy b

liftA2 :: (a -> b -> c) -> Proxy a -> Proxy b -> Proxy c

(*>) :: Proxy a -> Proxy b -> Proxy b

(<*) :: Proxy a -> Proxy b -> Proxy a

Applicative (U1 :: Type -> Type)

Since: base-4.9.0.0

Defined in GHC.Generics

Methods

pure :: a -> U1 a

(<*>) :: U1 (a -> b) -> U1 a -> U1 b

liftA2 :: (a -> b -> c) -> U1 a -> U1 b -> U1 c

(*>) :: U1 a -> U1 b -> U1 b

(<*) :: U1 a -> U1 b -> U1 a

Applicative (ST s)

Since: base-4.4.0.0

Defined in GHC.ST

Methods

pure :: a -> ST s a

(<*>) :: ST s (a -> b) -> ST s a -> ST s b

liftA2 :: (a -> b -> c) -> ST s a -> ST s b -> ST s c

(*>) :: ST s a -> ST s b -> ST s b

(<*) :: ST s a -> ST s b -> ST s a

Applicative (SetM s)

Defined in Data.Graph

Methods

pure :: a -> SetM s a

(<*>) :: SetM s (a -> b) -> SetM s a -> SetM s b

liftA2 :: (a -> b -> c) -> SetM s a -> SetM s b -> SetM s c

(*>) :: SetM s a -> SetM s b -> SetM s b

(<*) :: SetM s a -> SetM s b -> SetM s a

Applicative (RegM freeRegs)

Defined in GHC.CmmToAsm.Reg.Linear.State

Methods

pure :: a -> RegM freeRegs a

(<*>) :: RegM freeRegs (a -> b) -> RegM freeRegs a -> RegM freeRegs b

liftA2 :: (a -> b -> c) -> RegM freeRegs a -> RegM freeRegs b -> RegM freeRegs c

(*>) :: RegM freeRegs a -> RegM freeRegs b -> RegM freeRegs b

(<*) :: RegM freeRegs a -> RegM freeRegs b -> RegM freeRegs a

Applicative (State s)

Defined in GHC.Utils.Monad.State.Lazy

Methods

pure :: a -> State s a

(<*>) :: State s (a -> b) -> State s a -> State s b

liftA2 :: (a -> b -> c) -> State s a -> State s b -> State s c

(*>) :: State s a -> State s b -> State s b

(<*) :: State s a -> State s b -> State s a

Applicative (IOEnv m)

Defined in GHC.Data.IOEnv

Methods

pure :: a -> IOEnv m a

(<*>) :: IOEnv m (a -> b) -> IOEnv m a -> IOEnv m b

liftA2 :: (a -> b -> c) -> IOEnv m a -> IOEnv m b -> IOEnv m c

(*>) :: IOEnv m a -> IOEnv m b -> IOEnv m b

(<*) :: IOEnv m a -> IOEnv m b -> IOEnv m a

Applicative (MaybeErr err)

Defined in GHC.Data.Maybe

Methods

pure :: a -> MaybeErr err a

(<*>) :: MaybeErr err (a -> b) -> MaybeErr err a -> MaybeErr err b

liftA2 :: (a -> b -> c) -> MaybeErr err a -> MaybeErr err b -> MaybeErr err c

(*>) :: MaybeErr err a -> MaybeErr err b -> MaybeErr err b

(<*) :: MaybeErr err a -> MaybeErr err b -> MaybeErr err a

Monad m => Applicative (EwM m)

Defined in GHC.Driver.CmdLine

Methods

pure :: a -> EwM m a

(<*>) :: EwM m (a -> b) -> EwM m a -> EwM m b

liftA2 :: (a -> b -> c) -> EwM m a -> EwM m b -> EwM m c

(*>) :: EwM m a -> EwM m b -> EwM m b

(<*) :: EwM m a -> EwM m b -> EwM m a

Applicative m => Applicative (GhcT m)

Defined in GHC.Driver.Monad

Methods

pure :: a -> GhcT m a

(<*>) :: GhcT m (a -> b) -> GhcT m a -> GhcT m b

liftA2 :: (a -> b -> c) -> GhcT m a -> GhcT m b -> GhcT m c

(*>) :: GhcT m a -> GhcT m b -> GhcT m b

(<*) :: GhcT m a -> GhcT m b -> GhcT m a

Applicative (CmdLineP s)

Defined in GHC.Driver.Session

Methods

pure :: a -> CmdLineP s a

(<*>) :: CmdLineP s (a -> b) -> CmdLineP s a -> CmdLineP s b

liftA2 :: (a -> b -> c) -> CmdLineP s a -> CmdLineP s b -> CmdLineP s c

(*>) :: CmdLineP s a -> CmdLineP s b -> CmdLineP s b

(<*) :: CmdLineP s a -> CmdLineP s b -> CmdLineP s a

Applicative (State s)

Defined in GHC.Utils.Monad.State.Strict

Methods

pure :: a -> State s a

(<*>) :: State s (a -> b) -> State s a -> State s b

liftA2 :: (a -> b -> c) -> State s a -> State s b -> State s c

(*>) :: State s a -> State s b -> State s b

(<*) :: State s a -> State s b -> State s a

Applicative m => Applicative (ListT m)

Defined in Control.Monad.Trans.List

Methods

pure :: a -> ListT m a

(<*>) :: ListT m (a -> b) -> ListT m a -> ListT m b

liftA2 :: (a -> b -> c) -> ListT m a -> ListT m b -> ListT m c

(*>) :: ListT m a -> ListT m b -> ListT m b

(<*) :: ListT m a -> ListT m b -> ListT m a

(Functor m, Monad m) => Applicative (MaybeT m)

Defined in Control.Monad.Trans.Maybe

Methods

pure :: a -> MaybeT m a

(<*>) :: MaybeT m (a -> b) -> MaybeT m a -> MaybeT m b

liftA2 :: (a -> b -> c) -> MaybeT m a -> MaybeT m b -> MaybeT m c

(*>) :: MaybeT m a -> MaybeT m b -> MaybeT m b

(<*) :: MaybeT m a -> MaybeT m b -> MaybeT m a

Monoid a => Applicative ((,) a)

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

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

Since: base-2.1

Defined in GHC.Base

Methods

pure :: a0 -> (a, a0)

(<*>) :: (a, a0 -> b) -> (a, a0) -> (a, b)

liftA2 :: (a0 -> b -> c) -> (a, a0) -> (a, b) -> (a, c)

(*>) :: (a, a0) -> (a, b) -> (a, b)

(<*) :: (a, a0) -> (a, b) -> (a, a0)

Arrow a => Applicative (WrappedArrow a b)

Since: base-2.1

Defined in Control.Applicative

Methods

pure :: a0 -> WrappedArrow a b a0

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

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

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

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

Applicative m => Applicative (Kleisli m a)

Since: base-4.14.0.0

Defined in Control.Arrow

Methods

pure :: a0 -> Kleisli m a a0

(<*>) :: Kleisli m a (a0 -> b) -> Kleisli m a a0 -> Kleisli m a b

liftA2 :: (a0 -> b -> c) -> Kleisli m a a0 -> Kleisli m a b -> Kleisli m a c

(*>) :: Kleisli m a a0 -> Kleisli m a b -> Kleisli m a b

(<*) :: Kleisli m a a0 -> Kleisli m a b -> Kleisli m a a0

Monoid m => Applicative (Const m :: Type -> Type)

Since: base-2.0.1

Defined in Data.Functor.Const

Methods

pure :: a -> Const m a

(<*>) :: Const m (a -> b) -> Const m a -> Const m b

liftA2 :: (a -> b -> c) -> Const m a -> Const m b -> Const m c

(*>) :: Const m a -> Const m b -> Const m b

(<*) :: Const m a -> Const m b -> Const m a

Applicative f => Applicative (Ap f)

Since: base-4.12.0.0

Defined in Data.Monoid

Methods

pure :: a -> Ap f a

(<*>) :: Ap f (a -> b) -> Ap f a -> Ap f b

liftA2 :: (a -> b -> c) -> Ap f a -> Ap f b -> Ap f c

(*>) :: Ap f a -> Ap f b -> Ap f b

(<*) :: Ap f a -> Ap f b -> Ap f a

Applicative f => Applicative (Alt f)

Since: base-4.8.0.0

Defined in Data.Semigroup.Internal

Methods

pure :: a -> Alt f a

(<*>) :: Alt f (a -> b) -> Alt f a -> Alt f b

liftA2 :: (a -> b -> c) -> Alt f a -> Alt f b -> Alt f c

(*>) :: Alt f a -> Alt f b -> Alt f b

(<*) :: Alt f a -> Alt f b -> Alt f a

Applicative f => Applicative (Rec1 f)

Since: base-4.9.0.0

Defined in GHC.Generics

Methods

pure :: a -> Rec1 f a

(<*>) :: Rec1 f (a -> b) -> Rec1 f a -> Rec1 f b

liftA2 :: (a -> b -> c) -> Rec1 f a -> Rec1 f b -> Rec1 f c

(*>) :: Rec1 f a -> Rec1 f b -> Rec1 f b

(<*) :: Rec1 f a -> Rec1 f b -> Rec1 f a

(Applicative f, Monad f) => Applicative (WhenMissing f x)

Equivalent to ReaderT k (ReaderT x (MaybeT f)).

Since: containers-0.5.9

Defined in Data.IntMap.Internal

Methods

pure :: a -> WhenMissing f x a

(<*>) :: WhenMissing f x (a -> b) -> WhenMissing f x a -> WhenMissing f x b

liftA2 :: (a -> b -> c) -> WhenMissing f x a -> WhenMissing f x b -> WhenMissing f x c

(*>) :: WhenMissing f x a -> WhenMissing f x b -> WhenMissing f x b

(<*) :: WhenMissing f x a -> WhenMissing f x b -> WhenMissing f x a

Applicative (Stream m a)

Defined in GHC.Data.Stream

Methods

pure :: a0 -> Stream m a a0

(<*>) :: Stream m a (a0 -> b) -> Stream m a a0 -> Stream m a b

liftA2 :: (a0 -> b -> c) -> Stream m a a0 -> Stream m a b -> Stream m a c

(*>) :: Stream m a a0 -> Stream m a b -> Stream m a b

(<*) :: Stream m a a0 -> Stream m a b -> Stream m a a0

Monad m => Applicative (StreamS m a)

Defined in GHC.Data.Stream

Methods

pure :: a0 -> StreamS m a a0

(<*>) :: StreamS m a (a0 -> b) -> StreamS m a a0 -> StreamS m a b

liftA2 :: (a0 -> b -> c) -> StreamS m a a0 -> StreamS m a b -> StreamS m a c

(*>) :: StreamS m a a0 -> StreamS m a b -> StreamS m a b

(<*) :: StreamS m a a0 -> StreamS m a b -> StreamS m a a0

(Functor m, Monad m) => Applicative (ErrorT e m)

Defined in Control.Monad.Trans.Error

Methods

pure :: a -> ErrorT e m a

(<*>) :: ErrorT e m (a -> b) -> ErrorT e m a -> ErrorT e m b

liftA2 :: (a -> b -> c) -> ErrorT e m a -> ErrorT e m b -> ErrorT e m c

(*>) :: ErrorT e m a -> ErrorT e m b -> ErrorT e m b

(<*) :: ErrorT e m a -> ErrorT e m b -> ErrorT e m a

(Functor m, Monad m) => Applicative (ExceptT e m)

Defined in Control.Monad.Trans.Except

Methods

pure :: a -> ExceptT e m a

(<*>) :: ExceptT e m (a -> b) -> ExceptT e m a -> ExceptT e m b

liftA2 :: (a -> b -> c) -> ExceptT e m a -> ExceptT e m b -> ExceptT e m c

(*>) :: ExceptT e m a -> ExceptT e m b -> ExceptT e m b

(<*) :: ExceptT e m a -> ExceptT e m b -> ExceptT e m a

Applicative m => Applicative (IdentityT m)

Defined in Control.Monad.Trans.Identity

Methods

pure :: a -> IdentityT m a

(<*>) :: IdentityT m (a -> b) -> IdentityT m a -> IdentityT m b

liftA2 :: (a -> b -> c) -> IdentityT m a -> IdentityT m b -> IdentityT m c

(*>) :: IdentityT m a -> IdentityT m b -> IdentityT m b

(<*) :: IdentityT m a -> IdentityT m b -> IdentityT m a

Applicative m => Applicative (ReaderT r m)

Defined in Control.Monad.Trans.Reader

Methods

pure :: a -> ReaderT r m a

(<*>) :: ReaderT r m (a -> b) -> ReaderT r m a -> ReaderT r m b

liftA2 :: (a -> b -> c) -> ReaderT r m a -> ReaderT r m b -> ReaderT r m c

(*>) :: ReaderT r m a -> ReaderT r m b -> ReaderT r m b

(<*) :: ReaderT r m a -> ReaderT r m b -> ReaderT r m a

(Functor m, Monad m) => Applicative (StateT s m)

Defined in Control.Monad.Trans.State.Lazy

Methods

pure :: a -> StateT s m a

(<*>) :: StateT s m (a -> b) -> StateT s m a -> StateT s m b

liftA2 :: (a -> b -> c) -> StateT s m a -> StateT s m b -> StateT s m c

(*>) :: StateT s m a -> StateT s m b -> StateT s m b

(<*) :: StateT s m a -> StateT s m b -> StateT s m a

(Functor m, Monad m) => Applicative (StateT s m)

Defined in Control.Monad.Trans.State.Strict

Methods

pure :: a -> StateT s m a

(<*>) :: StateT s m (a -> b) -> StateT s m a -> StateT s m b

liftA2 :: (a -> b -> c) -> StateT s m a -> StateT s m b -> StateT s m c

(*>) :: StateT s m a -> StateT s m b -> StateT s m b

(<*) :: StateT s m a -> StateT s m b -> StateT s m a

(Functor m, Monad m) => Applicative (WriterT w m)

Defined in Control.Monad.Trans.Writer.CPS

Methods

pure :: a -> WriterT w m a

(<*>) :: WriterT w m (a -> b) -> WriterT w m a -> WriterT w m b

liftA2 :: (a -> b -> c) -> WriterT w m a -> WriterT w m b -> WriterT w m c

(*>) :: WriterT w m a -> WriterT w m b -> WriterT w m b

(<*) :: WriterT w m a -> WriterT w m b -> WriterT w m a

(Monoid w, Applicative m) => Applicative (WriterT w m)

Defined in Control.Monad.Trans.Writer.Lazy

Methods

pure :: a -> WriterT w m a

(<*>) :: WriterT w m (a -> b) -> WriterT w m a -> WriterT w m b

liftA2 :: (a -> b -> c) -> WriterT w m a -> WriterT w m b -> WriterT w m c

(*>) :: WriterT w m a -> WriterT w m b -> WriterT w m b

(<*) :: WriterT w m a -> WriterT w m b -> WriterT w m a

(Monoid w, Applicative m) => Applicative (WriterT w m)

Defined in Control.Monad.Trans.Writer.Strict

Methods

pure :: a -> WriterT w m a

(<*>) :: WriterT w m (a -> b) -> WriterT w m a -> WriterT w m b

liftA2 :: (a -> b -> c) -> WriterT w m a -> WriterT w m b -> WriterT w m c

(*>) :: WriterT w m a -> WriterT w m b -> WriterT w m b

(<*) :: WriterT w m a -> WriterT w m b -> WriterT w m a

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

Since: base-4.14.0.0

Defined in GHC.Base

Methods

pure :: a0 -> (a, b, a0)

(<*>) :: (a, b, a0 -> b0) -> (a, b, a0) -> (a, b, b0)

liftA2 :: (a0 -> b0 -> c) -> (a, b, a0) -> (a, b, b0) -> (a, b, c)

(*>) :: (a, b, a0) -> (a, b, b0) -> (a, b, b0)

(<*) :: (a, b, a0) -> (a, b, b0) -> (a, b, a0)

(Applicative f, Applicative g) => Applicative (Product f g)

Since: base-4.9.0.0

Defined in Data.Functor.Product

Methods

pure :: a -> Product f g a

(<*>) :: Product f g (a -> b) -> Product f g a -> Product f g b

liftA2 :: (a -> b -> c) -> Product f g a -> Product f g b -> Product f g c

(*>) :: Product f g a -> Product f g b -> Product f g b

(<*) :: Product f g a -> Product f g b -> Product f g a

(Applicative f, Applicative g) => Applicative (f :*: g)

Since: base-4.9.0.0

Defined in GHC.Generics

Methods

pure :: a -> (f :*: g) a

(<*>) :: (f :*: g) (a -> b) -> (f :*: g) a -> (f :*: g) b

liftA2 :: (a -> b -> c) -> (f :*: g) a -> (f :*: g) b -> (f :*: g) c

(*>) :: (f :*: g) a -> (f :*: g) b -> (f :*: g) b

(<*) :: (f :*: g) a -> (f :*: g) b -> (f :*: g) a

Monoid c => Applicative (K1 i c :: Type -> Type)

Since: base-4.12.0.0

Defined in GHC.Generics

Methods

pure :: a -> K1 i c a

(<*>) :: K1 i c (a -> b) -> K1 i c a -> K1 i c b

liftA2 :: (a -> b -> c0) -> K1 i c a -> K1 i c b -> K1 i c c0

(*>) :: K1 i c a -> K1 i c b -> K1 i c b

(<*) :: K1 i c a -> K1 i c b -> K1 i c a

(Monad f, Applicative f) => Applicative (WhenMatched f x y)

Equivalent to ReaderT Key (ReaderT x (ReaderT y (MaybeT f)))

Since: containers-0.5.9

Defined in Data.IntMap.Internal

Methods

pure :: a -> WhenMatched f x y a

(<*>) :: WhenMatched f x y (a -> b) -> WhenMatched f x y a -> WhenMatched f x y b

liftA2 :: (a -> b -> c) -> WhenMatched f x y a -> WhenMatched f x y b -> WhenMatched f x y c

(*>) :: WhenMatched f x y a -> WhenMatched f x y b -> WhenMatched f x y b

(<*) :: WhenMatched f x y a -> WhenMatched f x y b -> WhenMatched f x y a

(Applicative f, Monad f) => Applicative (WhenMissing f k x)

Equivalent to ReaderT k (ReaderT x (MaybeT f)) .

Since: containers-0.5.9

Defined in Data.Map.Internal

Methods

pure :: a -> WhenMissing f k x a

(<*>) :: WhenMissing f k x (a -> b) -> WhenMissing f k x a -> WhenMissing f k x b

liftA2 :: (a -> b -> c) -> WhenMissing f k x a -> WhenMissing f k x b -> WhenMissing f k x c

(*>) :: WhenMissing f k x a -> WhenMissing f k x b -> WhenMissing f k x b

(<*) :: WhenMissing f k x a -> WhenMissing f k x b -> WhenMissing f k x a

Applicative (ContT r m)

Defined in Control.Monad.Trans.Cont

Methods

pure :: a -> ContT r m a

(<*>) :: ContT r m (a -> b) -> ContT r m a -> ContT r m b

liftA2 :: (a -> b -> c) -> ContT r m a -> ContT r m b -> ContT r m c

(*>) :: ContT r m a -> ContT r m b -> ContT r m b

(<*) :: ContT r m a -> ContT r m b -> ContT r m a

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

Since: base-4.14.0.0

Defined in GHC.Base

Methods

pure :: a0 -> (a, b, c, a0)

(<*>) :: (a, b, c, a0 -> b0) -> (a, b, c, a0) -> (a, b, c, b0)

liftA2 :: (a0 -> b0 -> c0) -> (a, b, c, a0) -> (a, b, c, b0) -> (a, b, c, c0)

(*>) :: (a, b, c, a0) -> (a, b, c, b0) -> (a, b, c, b0)

(<*) :: (a, b, c, a0) -> (a, b, c, b0) -> (a, b, c, a0)

Applicative ((->) r)

Since: base-2.1

Defined in GHC.Base

Methods

pure :: a -> r -> a

(<*>) :: (r -> (a -> b)) -> (r -> a) -> r -> b

liftA2 :: (a -> b -> c) -> (r -> a) -> (r -> b) -> r -> c

(*>) :: (r -> a) -> (r -> b) -> r -> b

(<*) :: (r -> a) -> (r -> b) -> r -> a

(Applicative f, Applicative g) => Applicative (Compose f g)

Since: base-4.9.0.0

Defined in Data.Functor.Compose

Methods

pure :: a -> Compose f g a

(<*>) :: Compose f g (a -> b) -> Compose f g a -> Compose f g b

liftA2 :: (a -> b -> c) -> Compose f g a -> Compose f g b -> Compose f g c

(*>) :: Compose f g a -> Compose f g b -> Compose f g b

(<*) :: Compose f g a -> Compose f g b -> Compose f g a

(Applicative f, Applicative g) => Applicative (f :.: g)

Since: base-4.9.0.0

Defined in GHC.Generics

Methods

pure :: a -> (f :.: g) a

(<*>) :: (f :.: g) (a -> b) -> (f :.: g) a -> (f :.: g) b

liftA2 :: (a -> b -> c) -> (f :.: g) a -> (f :.: g) b -> (f :.: g) c

(*>) :: (f :.: g) a -> (f :.: g) b -> (f :.: g) b

(<*) :: (f :.: g) a -> (f :.: g) b -> (f :.: g) a

Applicative f => Applicative (M1 i c f)

Since: base-4.9.0.0

Defined in GHC.Generics

Methods

pure :: a -> M1 i c f a

(<*>) :: M1 i c f (a -> b) -> M1 i c f a -> M1 i c f b

liftA2 :: (a -> b -> c0) -> M1 i c f a -> M1 i c f b -> M1 i c f c0

(*>) :: M1 i c f a -> M1 i c f b -> M1 i c f b

(<*) :: M1 i c f a -> M1 i c f b -> M1 i c f a

(Monad f, Applicative f) => Applicative (WhenMatched f k x y)

Equivalent to ReaderT k (ReaderT x (ReaderT y (MaybeT f)))

Since: containers-0.5.9

Defined in Data.Map.Internal

Methods

pure :: a -> WhenMatched f k x y a

(<*>) :: WhenMatched f k x y (a -> b) -> WhenMatched f k x y a -> WhenMatched f k x y b

liftA2 :: (a -> b -> c) -> WhenMatched f k x y a -> WhenMatched f k x y b -> WhenMatched f k x y c

(*>) :: WhenMatched f k x y a -> WhenMatched f k x y b -> WhenMatched f k x y b

(<*) :: WhenMatched f k x y a -> WhenMatched f k x y b -> WhenMatched f k x y a

(Monoid w, Functor m, Monad m) => Applicative (RWST r w s m)

Defined in Control.Monad.Trans.RWS.Lazy

Methods

pure :: a -> RWST r w s m a

(<*>) :: RWST r w s m (a -> b) -> RWST r w s m a -> RWST r w s m b

liftA2 :: (a -> b -> c) -> RWST r w s m a -> RWST r w s m b -> RWST r w s m c

(*>) :: RWST r w s m a -> RWST r w s m b -> RWST r w s m b

(<*) :: RWST r w s m a -> RWST r w s m b -> RWST r w s m a

(Monoid w, Functor m, Monad m) => Applicative (RWST r w s m)

Defined in Control.Monad.Trans.RWS.Strict

Methods

pure :: a -> RWST r w s m a

(<*>) :: RWST r w s m (a -> b) -> RWST r w s m a -> RWST r w s m b

liftA2 :: (a -> b -> c) -> RWST r w s m a -> RWST r w s m b -> RWST r w s m c

(*>) :: RWST r w s m a -> RWST r w s m b -> RWST r w s m b

(<*) :: RWST r w s m a -> RWST r w s m b -> RWST r w s m a

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

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

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)

duplicateLocalDs :: Id -> DsM Id

newSysLocalDs :: Mult -> Type -> DsM Id

newSysLocalsDs :: [Scaled Type] -> DsM [Id]

newUniqueId :: Id -> Mult -> Type -> DsM Id

newFailLocalDs :: Mult -> Type -> DsM Id

newPredVarDs :: PredType -> DsM Var

getSrcSpanDs :: DsM SrcSpan

putSrcSpanDs :: SrcSpan -> DsM a -> DsM a

putSrcSpanDsA :: SrcSpanAnn' ann -> DsM a -> DsM a

mkPrintUnqualifiedDs :: DsM PrintUnqualified

newUnique :: TcRnIf gbl lcl Unique

data UniqSupply

Unique Supply

A value of type UniqSupply is unique, and it can supply one distinct Unique. Also, from the supply, one can also manufacture an arbitrary number of further UniqueSupply values, which will be distinct from the first and from all others.

newUniqueSupply :: TcRnIf gbl lcl UniqSupply

getGhcModeDs :: DsM GhcMode

dsGetFamInstEnvs :: DsM FamInstEnvs

dsLookupGlobal :: Name -> DsM TyThing

dsLookupGlobalId :: Name -> DsM Id

dsLookupTyCon :: Name -> DsM TyCon

dsLookupDataCon :: Name -> DsM DataCon

dsLookupConLike :: Name -> DsM ConLike

getCCIndexDsM :: FastString -> DsM CostCentreIndex

See getCCIndexM.

type DsMetaEnv = NameEnv DsMetaVal

data DsMetaVal

Constructors

DsBound Id

DsSplice (HsExpr GhcTc)

dsGetMetaEnv :: DsM (NameEnv DsMetaVal)

dsLookupMetaEnv :: Name -> DsM (Maybe DsMetaVal)

dsExtendMetaEnv :: DsMetaEnv -> DsM a -> DsM a

getPmNablas :: DsM Nablas

Get the current pattern match oracle state. See dsl_nablas.

updPmNablas :: Nablas -> DsM a -> DsM a

Set the pattern match oracle state within the scope of the given action. See dsl_nablas.

dsGetCompleteMatches :: DsM CompleteMatches

The COMPLETE pragmas that are in scope.

type DsWarning = (SrcSpan, SDoc)

diagnosticDs :: DsMessage -> DsM ()

Emit a diagnostic for the current source location. In case the diagnostic is a warning, the latter will be ignored and discarded if the relevant WarningFlag is not set in the DynFlags. See Note [Discarding Messages] in Error.

errDsCoreExpr :: DsMessage -> DsM CoreExpr

Issue an error, but return the expression for (), so that we can continue reporting errors.

failWithDs :: DsMessage -> DsM a

failDs :: DsM a

discardWarningsDs :: DsM a -> DsM a

data DsMatchContext

Constructors

DsMatchContext (HsMatchContext GhcRn) SrcSpan

Instances

Outputable DsMatchContext

Defined in GHC.HsToCore.Monad

Methods

ppr :: DsMatchContext -> SDoc

data EquationInfo

Constructors

EqnInfo

Fields

• eqn_pats :: [Pat GhcTc]

  The patterns for an equation

  NB: We have already applied decideBangHood to these patterns. See Note [decideBangHood] in GHC.HsToCore.Utils

• eqn_orig :: Origin

  Was this equation present in the user source?

  This helps us avoid warnings on patterns that GHC elaborated.

  For instance, the pattern -1 :: Word gets desugared into W# -1## :: Word, but we shouldn't warn about an overflowed literal for both of these cases.

• eqn_rhs :: MatchResult CoreExpr

  What to do after match

Instances

Outputable EquationInfo

Defined in GHC.HsToCore.Monad

Methods

ppr :: EquationInfo -> SDoc

data MatchResult a

This is a value of type a with potentially a CoreExpr-shaped hole in it. This is used to deal with cases where we are potentially handling pattern match failure, and want to later specify how failure is handled.

Constructors

MR_Infallible (DsM a)

We represent the case where there is no hole without a function from CoreExpr, like this, because sometimes we have nothing to put in the hole and so want to be sure there is in fact no hole.

MR_Fallible (CoreExpr -> DsM a)

Instances

Applicative MatchResult

Product is an "or" on falliblity---the combined match result is infallible only if the left and right argument match results both were.

This is useful for combining a bunch of alternatives together and then getting the overall falliblity of the entire group. See mkDataConCase for an example.

Defined in GHC.HsToCore.Monad

Methods

pure :: a -> MatchResult a

(<*>) :: MatchResult (a -> b) -> MatchResult a -> MatchResult b

liftA2 :: (a -> b -> c) -> MatchResult a -> MatchResult b -> MatchResult c

(*>) :: MatchResult a -> MatchResult b -> MatchResult b

(<*) :: MatchResult a -> MatchResult b -> MatchResult a

Functor MatchResult

Defined in GHC.HsToCore.Monad

Methods

fmap :: (a -> b) -> MatchResult a -> MatchResult b

(<$) :: a -> MatchResult b -> MatchResult a

runMatchResult :: CoreExpr -> MatchResult a -> DsM a

type DsWrapper = CoreExpr -> CoreExpr

idDsWrapper :: DsWrapper

pprRuntimeTrace

Arguments

:: String

header

-> SDoc

information to output

-> CoreExpr

expression

-> DsM CoreExpr

Inject a trace message into the compiled program. Whereas pprTrace prints out information *while compiling*, pprRuntimeTrace captures that information and causes it to be printed *at runtime* using Debug.Trace.trace.

pprRuntimeTrace hdr doc expr

will produce an expression that looks like

trace (hdr + doc) expr

When using this to debug a module that Debug.Trace depends on, it is necessary to import {-# SOURCE #-} Debug.Trace () in that module. We could avoid this inconvenience by wiring in Debug.Trace.trace, but that doesn't seem worth the effort and maintenance cost.

Orphan instances

MonadThings (IOEnv (Env DsGblEnv DsLclEnv))

Methods

lookupThing :: Name -> IOEnv (Env DsGblEnv DsLclEnv) TyThing

lookupId :: Name -> IOEnv (Env DsGblEnv DsLclEnv) Id

lookupDataCon :: Name -> IOEnv (Env DsGblEnv DsLclEnv) DataCon

lookupTyCon :: Name -> IOEnv (Env DsGblEnv DsLclEnv) TyCon