Copyright	(c) 2007 Magnus Therning
License	BSD-style (see the file LICENSE)
Maintainer	R.Paterson@city.ac.uk
Stability	experimental
Portability	portable
Safe Haskell	Safe
Language	Haskell2010

Control.Monad.Trans.Identity

Contents

The identity monad transformer
Lifting other operations

Description

The identity monad transformer.

This is useful for functions parameterized by a monad transformer.

Synopsis

newtype IdentityT (f :: k -> Type) (a :: k) = IdentityT {
- runIdentityT :: f a
}
mapIdentityT :: forall {k1} {k2} m (a :: k1) n (b :: k2). (m a -> n b) -> IdentityT m a -> IdentityT n b
liftCatch :: forall {k} e m (a :: k). Catch e m a -> Catch e (IdentityT m) a
liftCallCC :: CallCC m a b -> CallCC (IdentityT m) a b

The identity monad transformer

newtype IdentityT (f :: k -> Type) (a :: k) Source #

The trivial monad transformer, which maps a monad to an equivalent monad.

Constructors

IdentityT
Fields runIdentityT :: f a

Instances

Instances details

Generic1 (IdentityT f :: k -> Type) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Associated Types

type Rep1 (IdentityT f :: k -> Type)
Instance details Defined in Control.Monad.Trans.Identity type Rep1 (IdentityT f :: k -> Type) = D1 ('MetaData "IdentityT" "Control.Monad.Trans.Identity" "transformers-0.6.1.2-72bd" 'True) (C1 ('MetaCons "IdentityT" 'PrefixI 'True) (S1 ('MetaSel ('Just "runIdentityT") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec1 f)))

Methods

from1 :: forall (a :: k). IdentityT f a -> Rep1 (IdentityT f) a #

to1 :: forall (a :: k). Rep1 (IdentityT f) a -> IdentityT f a #

MonadTrans (IdentityT :: (Type -> Type) -> Type -> Type) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Methods

lift :: Monad m => m a -> IdentityT m a Source #

Foldable1 m => Foldable1 (IdentityT m) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Methods

fold1 :: Semigroup m0 => IdentityT m m0 -> m0 Source #

foldMap1 :: Semigroup m0 => (a -> m0) -> IdentityT m a -> m0 Source #

foldMap1' :: Semigroup m0 => (a -> m0) -> IdentityT m a -> m0 Source #

toNonEmpty :: IdentityT m a -> NonEmpty a Source #

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

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

head :: IdentityT m a -> a Source #

last :: IdentityT m a -> a Source #

foldrMap1 :: (a -> b) -> (a -> b -> b) -> IdentityT m a -> b Source #

foldlMap1' :: (a -> b) -> (b -> a -> b) -> IdentityT m a -> b Source #

foldlMap1 :: (a -> b) -> (b -> a -> b) -> IdentityT m a -> b Source #

foldrMap1' :: (a -> b) -> (a -> b -> b) -> IdentityT m a -> b Source #

Eq1 f => Eq1 (IdentityT f) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Methods

liftEq :: (a -> b -> Bool) -> IdentityT f a -> IdentityT f b -> Bool Source #

Ord1 f => Ord1 (IdentityT f) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Methods

liftCompare :: (a -> b -> Ordering) -> IdentityT f a -> IdentityT f b -> Ordering Source #

Read1 f => Read1 (IdentityT f) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Methods

liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (IdentityT f a) Source #

liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [IdentityT f a] Source #

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (IdentityT f a) Source #

liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [IdentityT f a] Source #

Show1 f => Show1 (IdentityT f) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Methods

liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> IdentityT f a -> ShowS Source #

liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [IdentityT f a] -> ShowS Source #

Contravariant f => Contravariant (IdentityT f) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Methods

contramap :: (a' -> a) -> IdentityT f a -> IdentityT f a' Source #

(>$) :: b -> IdentityT f b -> IdentityT f a Source #

Alternative m => Alternative (IdentityT m) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Methods

empty :: IdentityT m a #

(<|>) :: IdentityT m a -> IdentityT m a -> IdentityT m a #

some :: IdentityT m a -> IdentityT m [a] #

many :: IdentityT m a -> IdentityT m [a] #

Applicative m => Applicative (IdentityT m) Source #

Instance details

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 #

Functor m => Functor (IdentityT m) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Methods

fmap :: (a -> b) -> IdentityT m a -> IdentityT m b #

(<$) :: a -> IdentityT m b -> IdentityT m a #

Monad m => Monad (IdentityT m) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Methods

(>>=) :: IdentityT m a -> (a -> IdentityT m b) -> IdentityT m b #

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

return :: a -> IdentityT m a #

MonadPlus m => MonadPlus (IdentityT m) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Methods

mzero :: IdentityT m a #

mplus :: IdentityT m a -> IdentityT m a -> IdentityT m a #

MonadFail m => MonadFail (IdentityT m) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Methods

fail :: String -> IdentityT m a #

MonadFix m => MonadFix (IdentityT m) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Methods

mfix :: (a -> IdentityT m a) -> IdentityT m a #

MonadIO m => MonadIO (IdentityT m) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Methods

liftIO :: IO a -> IdentityT m a #

MonadZip m => MonadZip (IdentityT m) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Methods

mzip :: IdentityT m a -> IdentityT m b -> IdentityT m (a, b) #

mzipWith :: (a -> b -> c) -> IdentityT m a -> IdentityT m b -> IdentityT m c #

munzip :: IdentityT m (a, b) -> (IdentityT m a, IdentityT m b) #

Foldable f => Foldable (IdentityT f) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Methods

fold :: Monoid m => IdentityT f m -> m #

foldMap :: Monoid m => (a -> m) -> IdentityT f a -> m #

foldMap' :: Monoid m => (a -> m) -> IdentityT f a -> m #

foldr :: (a -> b -> b) -> b -> IdentityT f a -> b #

foldr' :: (a -> b -> b) -> b -> IdentityT f a -> b #

foldl :: (b -> a -> b) -> b -> IdentityT f a -> b #

foldl' :: (b -> a -> b) -> b -> IdentityT f a -> b #

foldr1 :: (a -> a -> a) -> IdentityT f a -> a #

foldl1 :: (a -> a -> a) -> IdentityT f a -> a #

toList :: IdentityT f a -> [a] #

null :: IdentityT f a -> Bool #

length :: IdentityT f a -> Int #

elem :: Eq a => a -> IdentityT f a -> Bool #

maximum :: Ord a => IdentityT f a -> a #

minimum :: Ord a => IdentityT f a -> a #

sum :: Num a => IdentityT f a -> a #

product :: Num a => IdentityT f a -> a #

Traversable f => Traversable (IdentityT f) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Methods

traverse :: Applicative f0 => (a -> f0 b) -> IdentityT f a -> f0 (IdentityT f b) #

sequenceA :: Applicative f0 => IdentityT f (f0 a) -> f0 (IdentityT f a) #

mapM :: Monad m => (a -> m b) -> IdentityT f a -> m (IdentityT f b) #

sequence :: Monad m => IdentityT f (m a) -> m (IdentityT f a) #

Generic (IdentityT f a) Source #

Instance details

Defined in Control.Monad.Trans.Identity

Associated Types

type Rep (IdentityT f a)
Instance details Defined in Control.Monad.Trans.Identity type Rep (IdentityT f a) = D1 ('MetaData "IdentityT" "Control.Monad.Trans.Identity" "transformers-0.6.1.2-72bd" 'True) (C1 ('MetaCons "IdentityT" 'PrefixI 'True) (S1 ('MetaSel ('Just "runIdentityT") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (f a))))