Safe Haskell	Safe-Inferred
Language	Haskell2010

Control.Monad.Trans.Has.Reader

Synopsis

ask :: HasReader r m => m r
type HasReader r (m :: Type -> Type) = Has (ReaderT r) m
newtype ReaderT r (m :: Type -> Type) a = ReaderT {
- runReaderT :: r -> m a
}

Documentation

ask :: HasReader r m => m r Source #

type HasReader r (m :: Type -> Type) = Has (ReaderT r) m Source #

newtype ReaderT r (m :: Type -> Type) a #

The reader monad transformer, which adds a read-only environment to the given monad.

The return function ignores the environment, while >>= passes the inherited environment to both subcomputations.

Constructors

ReaderT
Fields runReaderT :: r -> m a

Instances

Instances details

Generic1 (ReaderT r m :: Type -> Type)

Instance details

Defined in Control.Monad.Trans.Reader

Associated Types

type Rep1 (ReaderT r m :: Type -> Type)
Instance details Defined in Control.Monad.Trans.Reader type Rep1 (ReaderT r m :: Type -> Type) = D1 ('MetaData "ReaderT" "Control.Monad.Trans.Reader" "transformers-0.6.1.0-2e3a" 'True) (C1 ('MetaCons "ReaderT" 'PrefixI 'True) (S1 ('MetaSel ('Just "runReaderT") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) ((FUN 'Many r :: Type -> Type) :.: Rec1 m)))

Methods

from1 :: ReaderT r m a -> Rep1 (ReaderT r m) a #

to1 :: Rep1 (ReaderT r m) a -> ReaderT r m a #

MonadTrans (ReaderT r)

Instance details

Defined in Control.Monad.Trans.Reader

Methods

lift :: Monad m => m a -> ReaderT r m a #

MonadFail m => MonadFail (ReaderT r m)

Instance details

Defined in Control.Monad.Trans.Reader

Methods

fail :: String -> ReaderT r m a #

MonadFix m => MonadFix (ReaderT r m)

Instance details

Defined in Control.Monad.Trans.Reader

Methods

mfix :: (a -> ReaderT r m a) -> ReaderT r m a #

MonadIO m => MonadIO (ReaderT r m)

Instance details

Defined in Control.Monad.Trans.Reader

Methods

liftIO :: IO a -> ReaderT r m a #

MonadZip m => MonadZip (ReaderT r m)

Instance details

Defined in Control.Monad.Trans.Reader

Methods

mzip :: ReaderT r m a -> ReaderT r m b -> ReaderT r m (a, b) #

mzipWith :: (a -> b -> c) -> ReaderT r m a -> ReaderT r m b -> ReaderT r m c #

munzip :: ReaderT r m (a, b) -> (ReaderT r m a, ReaderT r m b) #

Contravariant m => Contravariant (ReaderT r m)

Instance details

Defined in Control.Monad.Trans.Reader

Methods

contramap :: (a' -> a) -> ReaderT r m a -> ReaderT r m a' #

(>$) :: b -> ReaderT r m b -> ReaderT r m a #

Alternative m => Alternative (ReaderT r m)

Instance details

Defined in Control.Monad.Trans.Reader

Methods

empty :: ReaderT r m a #

(<|>) :: ReaderT r m a -> ReaderT r m a -> ReaderT r m a #

some :: ReaderT r m a -> ReaderT r m [a] #

many :: ReaderT r m a -> ReaderT r m [a] #

Applicative m => Applicative (ReaderT r m)

Instance details

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 => Functor (ReaderT r m)

Instance details

Defined in Control.Monad.Trans.Reader

Methods

fmap :: (a -> b) -> ReaderT r m a -> ReaderT r m b #

(<$) :: a -> ReaderT r m b -> ReaderT r m a #

Monad m => Monad (ReaderT r m)

Instance details

Defined in Control.Monad.Trans.Reader

Methods

(>>=) :: ReaderT r m a -> (a -> ReaderT r m b) -> ReaderT r m b #

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

return :: a -> ReaderT r m a #

MonadPlus m => MonadPlus (ReaderT r m)

Instance details

Defined in Control.Monad.Trans.Reader

Methods

mzero :: ReaderT r m a #

mplus :: ReaderT r m a -> ReaderT r m a -> ReaderT r m a #

Generic (ReaderT r m a)

Instance details

Defined in Control.Monad.Trans.Reader

Associated Types

type Rep (ReaderT r m a)
Instance details Defined in Control.Monad.Trans.Reader type Rep (ReaderT r m a) = D1 ('MetaData "ReaderT" "Control.Monad.Trans.Reader" "transformers-0.6.1.0-2e3a" 'True) (C1 ('MetaCons "ReaderT" 'PrefixI 'True) (S1 ('MetaSel ('Just "runReaderT") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (r -> m a))))

Methods

from :: ReaderT r m a -> Rep (ReaderT r m a) x #

to :: Rep (ReaderT r m a) x -> ReaderT r m a #

type Rep1 (ReaderT r m :: Type -> Type)

Instance details

Defined in Control.Monad.Trans.Reader

type Rep1 (ReaderT r m :: Type -> Type) = D1 ('MetaData "ReaderT" "Control.Monad.Trans.Reader" "transformers-0.6.1.0-2e3a" 'True) (C1 ('MetaCons "ReaderT" 'PrefixI 'True) (S1 ('MetaSel ('Just "runReaderT") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) ((FUN 'Many r :: Type -> Type) :.: Rec1 m)))

type Rep (ReaderT r m a)

Instance details

Defined in Control.Monad.Trans.Reader

type Rep (ReaderT r m a) = D1 ('MetaData "ReaderT" "Control.Monad.Trans.Reader" "transformers-0.6.1.0-2e3a" 'True) (C1 ('MetaCons "ReaderT" 'PrefixI 'True) (S1 ('MetaSel ('Just "runReaderT") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (r -> m a))))