Safe Haskell | None |
---|---|
Language | Haskell2010 |
- type Reader tag r = ReaderT tag r Identity
- reader :: Monad m => proxy tag -> (r -> a) -> ReaderT tag r m a
- 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
- ask :: Monad m => proxy tag -> ReaderT tag r m r
- local :: proxy tag -> (r -> r) -> ReaderT tag r m a -> ReaderT tag r m a
The Reader monad
reader :: Monad m => proxy tag -> (r -> a) -> ReaderT tag r m a Source #
Constructor for computations in the reader monad
(the inverse of runReader
).
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.
Reader operations
:: proxy tag | |
-> (r -> r) | The function to modify the environment. |
-> ReaderT tag r m a | Computation to run in the modified environment. |
-> ReaderT tag r m a |
Execute a computation in a modified environment
(a specialization of withReaderT
).
runReaderT
tag (local
tag f m) =runReaderT
tag m . f