Copyright | (c) Edward Kmett 2011 (c) Conal Elliott 2008 |
---|---|
License | BSD3 |
Maintainer | ekmett@gmail.com |
Stability | experimental |
Safe Haskell | Safe-Inferred |
Language | Haskell2010 |
Representable functors on Hask are all monads, because they are isomorphic to
a Reader
monad.
Synopsis
- type Reader f = ReaderT f Identity
- runReader :: Representable f => Reader f b -> Rep f -> b
- newtype ReaderT f m b = ReaderT {
- getReaderT :: f (m b)
- readerT :: Representable f => (Rep f -> m b) -> ReaderT f m b
- runReaderT :: Representable f => ReaderT f m b -> Rep f -> m b
- class Monad m => MonadReader r (m :: Type -> Type) | m -> r where
- module Data.Functor.Rep
Representable functor monad
Monad Transformer
newtype ReaderT f m b Source #
ReaderT | |
|
Instances
runReaderT :: Representable f => ReaderT f m b -> Rep f -> m b Source #
class Monad m => MonadReader r (m :: Type -> Type) | m -> r where #
See examples in Control.Monad.Reader.
Note, the partially applied function type (->) r
is a simple reader monad.
See the instance
declaration below.
Retrieves the monad environment.
:: (r -> r) | The function to modify the environment. |
-> m a |
|
-> m a |
Executes a computation in a modified environment.
:: (r -> a) | The selector function to apply to the environment. |
-> m a |
Retrieves a function of the current environment.
Instances
(Representable f, Rep f ~ a) => MonadReader a (Co f) Source # | |
(Functor m, MonadReader e m) => MonadReader e (Free m) | |
MonadReader r m => MonadReader r (MaybeT m) | |
MonadReader r m => MonadReader r (ListT m) | |
(Representable g, MonadReader e m) => MonadReader e (StateT g m) Source # | |
(Functor f, Functor m, MonadReader r m) => MonadReader r (FreeT f m) | |
(Monoid w, MonadReader r m) => MonadReader r (WriterT w m) | |
(Monoid w, MonadReader r m) => MonadReader r (WriterT w m) | |
MonadReader r m => MonadReader r (StateT s m) | |
MonadReader r m => MonadReader r (StateT s m) | |
Monad m => MonadReader r (ReaderT r m) | |
MonadReader r m => MonadReader r (IdentityT m) | |
MonadReader r m => MonadReader r (ExceptT e m) | Since: mtl-2.2 |
(Error e, MonadReader r m) => MonadReader r (ErrorT e m) | |
MonadReader r ((->) r :: Type -> Type) | |
MonadReader r' m => MonadReader r' (ContT r m) | |
(Monad m, Monoid w) => MonadReader r (RWST r w s m) | |
(Monad m, Monoid w) => MonadReader r (RWST r w s m) | |
module Data.Functor.Rep