Safe Haskell	None
Language	Haskell2010

Foundation.Monad.Reader

Contents

MonadReader
ReaderT

Description

The Reader monad transformer.

This is useful to keep a non-modifiable value in a context

Synopsis

class Monad m => MonadReader m where
- type ReaderContext m
- ask :: m ( ReaderContext m)
data ReaderT r m a
runReaderT :: ReaderT r m a -> r -> m a

MonadReader

class Monad m => MonadReader m where Source #

Associated Types

type ReaderContext m Source #

Methods

ask :: m ( ReaderContext m) Source #

Instances

Instances details

Monad m => MonadReader ( ReaderT r m) Source #
Instance details Defined in Foundation.Monad.Reader Associated Types type ReaderContext ( ReaderT r m) Source # Methods ask :: ReaderT r m ( ReaderContext ( ReaderT r m)) Source #
MonadReader m => MonadReader ( ExceptT e m) Source #
Instance details Defined in Foundation.Monad.Except Associated Types type ReaderContext ( ExceptT e m) Source # Methods ask :: ExceptT e m ( ReaderContext ( ExceptT e m)) Source #

ReaderT

data ReaderT r m a Source #

Reader Transformer

Instances

Instances details

MonadTrans ( ReaderT r) Source #
Instance details Defined in Foundation.Monad.Reader Methods lift :: Monad m => m a -> ReaderT r m a Source #
Monad m => Monad ( ReaderT r m) Source #
Instance details Defined in Foundation.Monad.Reader Methods (>>=) :: ReaderT r m a -> (a -> ReaderT r m b) -> ReaderT r m b Source # (>>) :: ReaderT r m a -> ReaderT r m b -> ReaderT r m b Source # return :: a -> ReaderT r m a Source #
Functor m => Functor ( ReaderT r m) Source #
Instance details Defined in Foundation.Monad.Reader Methods fmap :: (a -> b) -> ReaderT r m a -> ReaderT r m b Source # (<$) :: a -> ReaderT r m b -> ReaderT r m a Source #
( Monad m, MonadFix m) => MonadFix ( ReaderT s m) Source #
Instance details Defined in Foundation.Monad.Reader Methods mfix :: (a -> ReaderT s m a) -> ReaderT s m a Source #
Applicative m => Applicative ( ReaderT r m) Source #
Instance details Defined in Foundation.Monad.Reader Methods pure :: a -> ReaderT r m a Source # (<>) :: ReaderT r m (a -> b) -> ReaderT r m a -> ReaderT r m b Source # liftA2 :: (a -> b -> c) -> ReaderT r m a -> ReaderT r m b -> ReaderT r m c Source # (>) :: ReaderT r m a -> ReaderT r m b -> ReaderT r m b Source # (<*) :: ReaderT r m a -> ReaderT r m b -> ReaderT r m a Source #
MonadIO m => MonadIO ( ReaderT r m) Source #
Instance details Defined in Foundation.Monad.Reader Methods liftIO :: IO a -> ReaderT r m a Source #
MonadFailure m => MonadFailure ( ReaderT r m) Source #
Instance details Defined in Foundation.Monad.Reader Associated Types type Failure ( ReaderT r m) Source # Methods mFail :: Failure ( ReaderT r m) -> ReaderT r m () Source #
MonadBracket m => MonadBracket ( ReaderT r m) Source #
Instance details Defined in Foundation.Monad.Reader Methods generalBracket :: ReaderT r m a -> (a -> b -> ReaderT r m ignored1) -> (a -> SomeException -> ReaderT r m ignored2) -> (a -> ReaderT r m b) -> ReaderT r m b Source #
MonadCatch m => MonadCatch ( ReaderT r m) Source #
Instance details Defined in Foundation.Monad.Reader Methods catch :: Exception e => ReaderT r m a -> (e -> ReaderT r m a) -> ReaderT r m a Source #
MonadThrow m => MonadThrow ( ReaderT r m) Source #
Instance details Defined in Foundation.Monad.Reader Methods throw :: Exception e => e -> ReaderT r m a Source #
Monad m => MonadReader ( ReaderT r m) Source #
Instance details Defined in Foundation.Monad.Reader Associated Types type ReaderContext ( ReaderT r m) Source # Methods ask :: ReaderT r m ( ReaderContext ( ReaderT r m)) Source #
type Failure ( ReaderT r m) Source #
Instance details Defined in Foundation.Monad.Reader type Failure ( ReaderT r m) = Failure m
type ReaderContext ( ReaderT r m) Source #
Instance details Defined in Foundation.Monad.Reader type ReaderContext ( ReaderT r m) = r

runReaderT :: ReaderT r m a -> r -> m a Source #