Safe Haskell | None |
---|---|
Language | Haskell2010 |
See Control.Monad.Reader.
- class Monad m => MonadReader tag r m | m tag -> r where
- asks :: MonadReader tag r m => proxy tag -> (r -> a) -> m a
- type Reader tag r = ReaderT tag r Identity
- runReader :: proxy tag -> Reader tag r a -> r -> a
- type ReaderT tag r = TaggedTrans tag (ReaderT r)
- readerT :: proxy tag -> (r -> m a) -> ReaderT tag r m a
- runReaderT :: proxy tag -> ReaderT tag r m a -> r -> m a
MonadReader class
class Monad m => MonadReader tag r m | m tag -> r where Source
See MonadReader
.
ask :: proxy tag -> m r Source
Retrieves the monad environment.
:: proxy tag | |
-> (r -> r) | The function to modify the environment. |
-> m a |
|
-> m a |
Executes a computation in a modified environment.
:: proxy tag | |
-> (r -> a) | The selector function to apply to the environment. |
-> m a |
Retrieves a function of the current environment.
(LiftLocal t, Monad (t m), MonadReader k tag r m) => MonadReader k tag r (t m) Source | |
(Monad m, (~) * r r') => MonadReader k tag r (ReaderT k tag r' m) Source |
:: MonadReader tag r m | |
=> proxy tag | |
-> (r -> a) | The selector function to apply to the environment. |
-> m a |
Retrieves a function of the current environment.
The Reader monad
runReader :: proxy tag -> Reader tag r a -> r -> a Source
Runs a ReaderT
with the given environment
and returns the final value.
The ReaderT monad transformer
type ReaderT tag r = TaggedTrans tag (ReaderT r) Source
readerT :: proxy tag -> (r -> m a) -> ReaderT tag r m a Source
Constructor for computations in the reader monad transformer.
runReaderT :: proxy tag -> ReaderT tag r m a -> r -> m a Source
Runs a ReaderT
with the given environment
and returns the final value.