base-4.10.1.0: Basic libraries

Copyright | (c) Andy Gill 2001 (c) Oregon Graduate Institute of Science and Technology 2001
License | BSD-style (see the file LICENSE)
Maintainer | ross@soi.city.ac.uk
Stability | experimental
Portability | portable
Safe Haskell | Trustworthy
Language | Haskell2010

Data.Functor.Identity

Description

The identity functor and monad.

This trivial type constructor serves two purposes:

- It can be used with functions parameterized by functor or monad classes.
- It can be used as a base monad to which a series of monad transformers may be applied to construct a composite monad. Most monad transformer modules include the special case of applying the transformer to `Identity`. For example, `State s` is an abbreviation for `StateT s `Identity``.

Since: 4.8.0.0

Synopsis

- newtype Identity a = Identity {
  - runIdentity :: a
  }

# Documentation

newtype Identity a #

Identity functor and monad. (a non-strict monad)

Since: 4.8.0.0

Constructors

Identity |

Fields

- runIdentity :: a

Instances

Monad Identity # | Since: 4.8.0.0
Methods (>>=) :: Identity a -> (a -> Identity b) -> Identity b # (>>) :: Identity a -> Identity b -> Identity b # return :: a -> Identity a # fail :: String -> Identity a #
Functor Identity # | Since: 4.8.0.0
Methods fmap :: (a -> b) -> Identity a -> Identity b # (<$) :: a -> Identity b -> Identity a #
MonadFix Identity # | Since: 4.8.0.0
Methods mfix :: (a -> Identity a) -> Identity a #
Applicative Identity # | Since: 4.8.0.0
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 #
Foldable Identity # | Since: 4.8.0.0

Methods

fold :: Monoid m => Identity m -> m #

foldMap :: Monoid m => (a -> m) -> Identity a -> m #

foldr :: (a -> b -> b) -> b -> Identity a -> b #

foldr' :: (a -> b -> b) -> b -> Identity a -> b #

foldl :: (b -> a -> b) -> b -> Identity a -> b #

foldl' :: (b -> a -> b) -> b -> Identity a -> b #

foldr1 :: (a -> a -> a) -> Identity a -> a #

foldl1 :: (a -> a -> a) -> Identity a -> a #

toList :: Identity a -> [a] #

null :: Identity a -> Bool #

length :: Identity a -> Int #

elem :: Eq a => a -> Identity a -> Bool #

maximum :: Ord a => Identity a -> a #

minimum :: Ord a => Identity a -> a #

sum :: Num a => Identity a -> a #

product :: Num a => Identity a -> a #

Traversable Identity # |
Methods traverse :: Applicative f => (a -> f b) -> Identity a -> f (Identity b) # sequenceA :: Applicative f => Identity (f a) -> f (Identity a) # mapM :: Monad m => (a -> m b) -> Identity a -> m (Identity b) # sequence :: Monad m => Identity (m a) -> m (Identity a) #
MonadZip Identity # | Since: 4.8.0.0
Methods mzip :: Identity a -> Identity b -> Identity (a, b) # mzipWith :: (a -> b -> c) -> Identity a -> Identity b -> Identity c # munzip :: Identity (a, b) -> (Identity a, Identity b) #
Show1 Identity # | Since: 4.9.0.0
Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Identity a -> ShowS # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Identity a] -> ShowS #
Read1 Identity # | Since: 4.9.0.0
Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Identity a) # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Identity a] # liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Identity a) # liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Identity a] #
Ord1 Identity # | Since: 4.9.0.0
Methods liftCompare :: (a -> b -> Ordering) -> Identity a -> Identity b -> Ordering #
Eq1 Identity # | Since: 4.9.0.0
Methods liftEq :: (a -> b -> Bool) -> Identity a -> Identity b -> Bool #
Bounded a => Bounded (Identity a) # |
Methods minBound :: Identity a # maxBound :: Identity a #
Enum a => Enum (Identity a) # |
Methods succ :: Identity a -> Identity a # pred :: Identity a -> Identity a # toEnum :: Int -> Identity a # fromEnum :: Identity a -> Int # enumFrom :: Identity a -> [Identity a] # enumFromThen :: Identity a -> Identity a -> [Identity a] # enumFromTo :: Identity a -> Identity a -> [Identity a] # enumFromThenTo :: Identity a -> Identity a -> Identity a -> [Identity a] #
Eq a => Eq (Identity a) # |
Methods (==) :: Identity a -> Identity a -> Bool Source # (/=) :: Identity a -> Identity a -> Bool Source #
Floating a => Floating (Identity a) # |

Methods

pi :: Identity a #

exp :: Identity a -> Identity a #

log :: Identity a -> Identity a #

sqrt :: Identity a -> Identity a #

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

logBase :: Identity a -> Identity a -> Identity a #

sin :: Identity a -> Identity a #

cos :: Identity a -> Identity a #

tan :: Identity a -> Identity a #

asin :: Identity a -> Identity a #

acos :: Identity a -> Identity a #

atan :: Identity a -> Identity a #

sinh :: Identity a -> Identity a #

cosh :: Identity a -> Identity a #

tanh :: Identity a -> Identity a #

asinh :: Identity a -> Identity a #

acosh :: Identity a -> Identity a #

atanh :: Identity a -> Identity a #

log1p :: Identity a -> Identity a #

expm1 :: Identity a -> Identity a #

log1pexp :: Identity a -> Identity a #

log1mexp :: Identity a -> Identity a #

Fractional a => Fractional (Identity a) # |
Methods (/) :: Identity a -> Identity a -> Identity a # recip :: Identity a -> Identity a # fromRational :: Rational -> Identity a #
Integral a => Integral (Identity a) # |
Methods quot :: Identity a -> Identity a -> Identity a # rem :: Identity a -> Identity a -> Identity a # div :: Identity a -> Identity a -> Identity a # mod :: Identity a -> Identity a -> Identity a # quotRem :: Identity a -> Identity a -> (Identity a, Identity a) # divMod :: Identity a -> Identity a -> (Identity a, Identity a) # toInteger :: Identity a -> Integer #
Data a => Data (Identity a) # | Since: 4.9.0.0

Methods

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

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

toConstr :: Identity a -> Constr #

dataTypeOf :: Identity a -> DataType #

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

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

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

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

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

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

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

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

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

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

Num a => Num (Identity a) # |
Methods (+) :: Identity a -> Identity a -> Identity a # (-) :: Identity a -> Identity a -> Identity a # (*) :: Identity a -> Identity a -> Identity a # negate :: Identity a -> Identity a # abs :: Identity a -> Identity a # signum :: Identity a -> Identity a # fromInteger :: Integer -> Identity a #
Ord a => Ord (Identity a) # |
Methods compare :: Identity a -> Identity a -> Ordering Source # (<) :: Identity a -> Identity a -> Bool Source # (<=) :: Identity a -> Identity a -> Bool Source # (>) :: Identity a -> Identity a -> Bool Source # (>=) :: Identity a -> Identity a -> Bool Source # max :: Identity a -> Identity a -> Identity a Source # min :: Identity a -> Identity a -> Identity a Source #
Read a => Read (Identity a) # | This instance would be equivalent to the derived instances of the `Identity` newtype if the `runIdentity` field were removed Since: 4.8.0.0
Methods readsPrec :: Int -> ReadS (Identity a) # readList :: ReadS [Identity a] # readPrec :: ReadPrec (Identity a) # readListPrec :: ReadPrec [Identity a] #
Real a => Real (Identity a) # |
Methods toRational :: Identity a -> Rational #
RealFloat a => RealFloat (Identity a) # |

Methods

floatRadix :: Identity a -> Integer #

floatDigits :: Identity a -> Int #

floatRange :: Identity a -> (Int, Int) #

decodeFloat :: Identity a -> (Integer, Int) #

encodeFloat :: Integer -> Int -> Identity a #

exponent :: Identity a -> Int #

significand :: Identity a -> Identity a #

scaleFloat :: Int -> Identity a -> Identity a #

isNaN :: Identity a -> Bool #

isInfinite :: Identity a -> Bool #

isDenormalized :: Identity a -> Bool #

isNegativeZero :: Identity a -> Bool #

isIEEE :: Identity a -> Bool #

atan2 :: Identity a -> Identity a -> Identity a #

RealFrac a => RealFrac (Identity a) # |
Methods properFraction :: Integral b => Identity a -> (b, Identity a) # truncate :: Integral b => Identity a -> b # round :: Integral b => Identity a -> b # ceiling :: Integral b => Identity a -> b # floor :: Integral b => Identity a -> b #
Show a => Show (Identity a) # | This instance would be equivalent to the derived instances of the `Identity` newtype if the `runIdentity` field were removed Since: 4.8.0.0
Methods showsPrec :: Int -> Identity a -> ShowS # show :: Identity a -> String # showList :: [Identity a] -> ShowS #
Ix a => Ix (Identity a) # |
Methods range :: (Identity a, Identity a) -> [Identity a] # index :: (Identity a, Identity a) -> Identity a -> Int # unsafeIndex :: (Identity a, Identity a) -> Identity a -> Int inRange :: (Identity a, Identity a) -> Identity a -> Bool # rangeSize :: (Identity a, Identity a) -> Int # unsafeRangeSize :: (Identity a, Identity a) -> Int
IsString a => IsString (Identity a) # |
Methods fromString :: String -> Identity a #
Generic (Identity a) # |
Associated Types type Rep (Identity a) :: * -> * # Methods from :: Identity a -> Rep (Identity a) x # to :: Rep (Identity a) x -> Identity a #
Semigroup a => Semigroup (Identity a) # | Since: 4.9.0.0
Methods (<>) :: Identity a -> Identity a -> Identity a # sconcat :: NonEmpty (Identity a) -> Identity a # stimes :: Integral b => b -> Identity a -> Identity a #
Monoid a => Monoid (Identity a) # |
Methods mempty :: Identity a # mappend :: Identity a -> Identity a -> Identity a # mconcat :: [Identity a] -> Identity a #
FiniteBits a => FiniteBits (Identity a) # |
Methods finiteBitSize :: Identity a -> Int # countLeadingZeros :: Identity a -> Int # countTrailingZeros :: Identity a -> Int #
Bits a => Bits (Identity a) # |

Methods

(.&.) :: Identity a -> Identity a -> Identity a #

(.|.) :: Identity a -> Identity a -> Identity a #

xor :: Identity a -> Identity a -> Identity a #

complement :: Identity a -> Identity a #

shift :: Identity a -> Int -> Identity a #

rotate :: Identity a -> Int -> Identity a #

zeroBits :: Identity a #

bit :: Int -> Identity a #

setBit :: Identity a -> Int -> Identity a #

clearBit :: Identity a -> Int -> Identity a #

complementBit :: Identity a -> Int -> Identity a #

testBit :: Identity a -> Int -> Bool #

bitSizeMaybe :: Identity a -> Maybe Int #

bitSize :: Identity a -> Int #

isSigned :: Identity a -> Bool #

shiftL :: Identity a -> Int -> Identity a #

unsafeShiftL :: Identity a -> Int -> Identity a #

shiftR :: Identity a -> Int -> Identity a #

unsafeShiftR :: Identity a -> Int -> Identity a #

rotateL :: Identity a -> Int -> Identity a #

rotateR :: Identity a -> Int -> Identity a #

popCount :: Identity a -> Int #

Storable a => Storable (Identity a) # |
Methods sizeOf :: Identity a -> Int # alignment :: Identity a -> Int # peekElemOff :: Ptr (Identity a) -> Int -> IO (Identity a) # pokeElemOff :: Ptr (Identity a) -> Int -> Identity a -> IO () # peekByteOff :: Ptr b -> Int -> IO (Identity a) # pokeByteOff :: Ptr b -> Int -> Identity a -> IO () # peek :: Ptr (Identity a) -> IO (Identity a) # poke :: Ptr (Identity a) -> Identity a -> IO () #
Generic1 * Identity # |
Associated Types type Rep1 Identity (f :: Identity -> *) :: k -> * # Methods from1 :: f a -> Rep1 Identity f a # to1 :: Rep1 Identity f a -> f a #
type Rep (Identity a) # |
type Rep (Identity a) = D1 * (MetaData "Identity" "Data.Functor.Identity" "base" True) (C1 * (MetaCons "Identity" PrefixI True) (S1 * (MetaSel (Just Symbol "runIdentity") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 * a)))
type Rep1 * Identity # |
type Rep1 * Identity = D1 * (MetaData "Identity" "Data.Functor.Identity" "base" True) (C1 * (MetaCons "Identity" PrefixI True) (S1 * (MetaSel (Just Symbol "runIdentity") NoSourceUnpackedness NoSourceStrictness DecidedLazy) Par1))