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/Haskell 8

Control.Monad.Trans.Identity

Copyright (c) 2007 Magnus Therning
License BSD-style (see the file LICENSE)
Maintainer [email protected]
Stability experimental
Portability portable
Safe Haskell Safe
Language Haskell98

Description

The identity monad transformer.

This is useful for functions parameterized by a monad transformer.

The identity monad transformer

newtype IdentityT f a Source

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

Constructors

IdentityT

Fields

Instances

MonadTrans (IdentityT *)

Methods

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

Monad m => Monad (IdentityT * m)

Methods

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

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

return :: a -> IdentityT * m a Source

fail :: String -> IdentityT * m a Source

Functor m => Functor (IdentityT * m)

Methods

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

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

MonadFix m => MonadFix (IdentityT * m)

Methods

mfix :: (a -> IdentityT * m a) -> IdentityT * m a Source

MonadFail m => MonadFail (IdentityT * m)

Methods

fail :: String -> IdentityT * m a Source

Applicative m => Applicative (IdentityT * m)

Methods

pure :: a -> IdentityT * m a Source

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

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

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

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

Foldable f => Foldable (IdentityT * f)

Methods

fold :: Monoid m => IdentityT * f m -> m Source

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

foldr :: (a -> b -> b) -> b -> IdentityT * f a -> b Source

foldr' :: (a -> b -> b) -> b -> IdentityT * f a -> b Source

foldl :: (b -> a -> b) -> b -> IdentityT * f a -> b Source

foldl' :: (b -> a -> b) -> b -> IdentityT * f a -> b Source

foldr1 :: (a -> a -> a) -> IdentityT * f a -> a Source

foldl1 :: (a -> a -> a) -> IdentityT * f a -> a Source

toList :: IdentityT * f a -> [a] Source

null :: IdentityT * f a -> Bool Source

length :: IdentityT * f a -> Int Source

elem :: Eq a => a -> IdentityT * f a -> Bool Source

maximum :: Ord a => IdentityT * f a -> a Source

minimum :: Ord a => IdentityT * f a -> a Source

sum :: Num a => IdentityT * f a -> a Source

product :: Num a => IdentityT * f a -> a Source

Traversable f => Traversable (IdentityT * f)

Methods

traverse :: Applicative f => (a -> f b) -> IdentityT * f a -> f (IdentityT * f b) Source

sequenceA :: Applicative f => IdentityT * f (f a) -> f (IdentityT * f a) Source

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

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

Eq1 f => Eq1 (IdentityT * f)

Methods

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

Ord1 f => Ord1 (IdentityT * f)

Methods

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

Read1 f => Read1 (IdentityT * f)

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)

Methods

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

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

MonadZip m => MonadZip (IdentityT * m)

Methods

mzip :: IdentityT * m a -> IdentityT * m b -> IdentityT * m (a, b) Source

mzipWith :: (a -> b -> c) -> IdentityT * m a -> IdentityT * m b -> IdentityT * m c Source

munzip :: IdentityT * m (a, b) -> (IdentityT * m a, IdentityT * m b) Source

MonadIO m => MonadIO (IdentityT * m)

Methods

liftIO :: IO a -> IdentityT * m a Source

Alternative m => Alternative (IdentityT * m)

Methods

empty :: IdentityT * m a Source

(<|>) :: IdentityT * m a -> IdentityT * m a -> IdentityT * m a Source

some :: IdentityT * m a -> IdentityT * m [a] Source

many :: IdentityT * m a -> IdentityT * m [a] Source

MonadPlus m => MonadPlus (IdentityT * m)

Methods

mzero :: IdentityT * m a Source

mplus :: IdentityT * m a -> IdentityT * m a -> IdentityT * m a Source

(Eq1 f, Eq a) => Eq (IdentityT * f a)

Methods

(==) :: IdentityT * f a -> IdentityT * f a -> Bool

(/=) :: IdentityT * f a -> IdentityT * f a -> Bool

(Ord1 f, Ord a) => Ord (IdentityT * f a)

Methods

compare :: IdentityT * f a -> IdentityT * f a -> Ordering

(<) :: IdentityT * f a -> IdentityT * f a -> Bool

(<=) :: IdentityT * f a -> IdentityT * f a -> Bool

(>) :: IdentityT * f a -> IdentityT * f a -> Bool

(>=) :: IdentityT * f a -> IdentityT * f a -> Bool

max :: IdentityT * f a -> IdentityT * f a -> IdentityT * f a

min :: IdentityT * f a -> IdentityT * f a -> IdentityT * f a

(Read1 f, Read a) => Read (IdentityT * f a)
(Show1 f, Show a) => Show (IdentityT * f a)

Methods

showsPrec :: Int -> IdentityT * f a -> ShowS Source

show :: IdentityT * f a -> String Source

showList :: [IdentityT * f a] -> ShowS Source

mapIdentityT :: (m a -> n b) -> IdentityT m a -> IdentityT n b Source

Lift a unary operation to the new monad.

Lifting other operations

liftCatch :: Catch e m a -> Catch e (IdentityT m) a Source

Lift a catchE operation to the new monad.

liftCallCC :: CallCC m a b -> CallCC (IdentityT m) a b Source

Lift a callCC operation to the new monad.

© The University of Glasgow and others
Licensed under a BSD-style license (see top of the page).
https://downloads.haskell.org/~ghc/8.2.1/docs/html/libraries/transformers-0.5.2.0/Control-Monad-Trans-Identity.html