Safe Haskell | Safe-Inferred |
---|---|
Language | Haskell2010 |
The multi-valued version of mtl's Reader / ReaderT
Synopsis
- newtype MultiReaderT x m a = MultiReaderT {
- runMultiReaderTRaw :: StateT (HList x) m a
- type MultiReaderTNull = MultiReaderT '[]
- type MultiReader x = MultiReaderT x Identity
- class Monad m => MonadMultiReader a m where
- mAsk :: m a
- class Monad m => MonadMultiGet a m where
- mGet :: m a
- runMultiReaderT :: Monad m => HList r -> MultiReaderT r m a -> m a
- runMultiReaderT_ :: Functor m => HList r -> MultiReaderT r m a -> m ()
- runMultiReaderTNil :: Monad m => MultiReaderT '[] m a -> m a
- runMultiReaderTNil_ :: Functor m => MultiReaderT '[] m a -> m ()
- withMultiReader :: Monad m => r -> MultiReaderT (r ': rs) m a -> MultiReaderT rs m a
- withMultiReader_ :: (Functor m, Monad m) => r -> MultiReaderT (r ': rs) m a -> MultiReaderT rs m ()
- withMultiReaders :: Monad m => HList r1 -> MultiReaderT (Append r1 r2) m a -> MultiReaderT r2 m a
- withMultiReaders_ :: (Functor m, Monad m) => HList r1 -> MultiReaderT (Append r1 r2) m a -> MultiReaderT r2 m ()
- withoutMultiReader :: Monad m => MultiReaderT rs m a -> MultiReaderT (r ': rs) m a
- inflateReader :: (Monad m, ContainsType r rs) => ReaderT r m a -> MultiReaderT rs m a
- mapMultiReaderT :: (m (a, HList w) -> m' (a', HList w)) -> MultiReaderT w m a -> MultiReaderT w m' a'
- mGetRaw :: Monad m => MultiReaderT a m (HList a)
- mPutRaw :: Monad m => HList s -> MultiReaderT s m ()
MultiReaderT
newtype MultiReaderT x m a Source #
A Reader transformer monad patameterized by:
- x - The list of types constituting the environment / input (to be read),
- m - The inner monad.
MultiReaderT
corresponds to mtl's ReaderT
, but can contain
a heterogenous list of types.
This heterogenous list is represented using Types.Data.List, i.e:
'[]
- The empty list,a ': b
- A list wherea
is an arbitrary type andb
is the rest list.
For example,
MultiReaderT '[Int, Bool] :: (* -> *) -> (* -> *)
is a Reader transformer containing the types [Int, Bool].
MultiReaderT | |
|
Instances
type MultiReaderTNull = MultiReaderT '[] Source #
A MultiReader transformer carrying an empty state.
type MultiReader x = MultiReaderT x Identity Source #
A reader monad parameterized by the list of types x of the environment / input to carry.
Similar to Reader r = ReaderT r Identity
MonadMultiReader class
class Monad m => MonadMultiReader a m where Source #
All methods must be defined.
The idea is: Any monad stack is instance of MonadMultiReader a
, iff
the stack contains a MultiReaderT x
with a element of x.
Instances
(MonadTrans t, Monad (t m), MonadMultiReader a m) => MonadMultiReader a (t m) Source # | |
Defined in Control.Monad.Trans.MultiReader.Class | |
(Monad m, ContainsType a c) => MonadMultiReader a (MultiReaderT c m) Source # | |
Defined in Control.Monad.Trans.MultiReader.Strict mAsk :: MultiReaderT c m a Source # | |
(Monad m, ContainsType a c) => MonadMultiReader a (MultiReaderT c m) Source # | |
Defined in Control.Monad.Trans.MultiReader.Lazy mAsk :: MultiReaderT c m a Source # | |
(Monad m, ContainsType a r) => MonadMultiReader a (MultiRWST r w s m) Source # | |
Defined in Control.Monad.Trans.MultiRWS.Strict | |
(Monad m, ContainsType a r) => MonadMultiReader a (MultiRWST r w s m) Source # | |
Defined in Control.Monad.Trans.MultiRWS.Lazy |
class Monad m => MonadMultiGet a m where Source #
In contrast to MonadMultiReader, MonadMultiGet is defined for State too, so it corresponds to read-access of any kind.
Note however that for MultiRWS, only the values from the state
part can
be accessed via MonadMultiGet
, due to limitations of the design of
MultiRWS
and of the type system. This is issue is resolved in the
MultiGST
type.
Instances
run-functions
runMultiReaderT :: Monad m => HList r -> MultiReaderT r m a -> m a Source #
runMultiReaderT_ :: Functor m => HList r -> MultiReaderT r m a -> m () Source #
runMultiReaderTNil :: Monad m => MultiReaderT '[] m a -> m a Source #
runMultiReaderTNil_ :: Functor m => MultiReaderT '[] m a -> m () Source #
with-functions (single reader)
withMultiReader :: Monad m => r -> MultiReaderT (r ': rs) m a -> MultiReaderT rs m a Source #
withMultiReader_ :: (Functor m, Monad m) => r -> MultiReaderT (r ': rs) m a -> MultiReaderT rs m () Source #
with-functions (multiple readers)
withMultiReaders :: Monad m => HList r1 -> MultiReaderT (Append r1 r2) m a -> MultiReaderT r2 m a Source #
withMultiReaders_ :: (Functor m, Monad m) => HList r1 -> MultiReaderT (Append r1 r2) m a -> MultiReaderT r2 m () Source #
without-function (single reader)
withoutMultiReader :: Monad m => MultiReaderT rs m a -> MultiReaderT (r ': rs) m a Source #
inflate-function (run ReaderT in MultiReaderT)
inflateReader :: (Monad m, ContainsType r rs) => ReaderT r m a -> MultiReaderT rs m a Source #
other functions
mapMultiReaderT :: (m (a, HList w) -> m' (a', HList w)) -> MultiReaderT w m a -> MultiReaderT w m' a' Source #
Map both the return value and the environment of a computation using the given function.
Note that there is a difference to mtl's ReaderT, where it is not possible to modify the environment.