Copyright	(c) Michael Szvetits 2020
License	BSD3 (see the file LICENSE)
Maintainer	typedbyte@qualified.name
Stability	stable
Portability	portable
Safe Haskell	None
Language	Haskell2010

Control.Effect.Machinery.Via

Description

This module defines the type Via which indicates that a specific effect is handled by a specific monad transformer (also known as effect handler or effect interpreter).

It also defines the G type, which is the global tag that is used for untagged effects.

Synopsis

newtype Via (eff :: Effect) (t :: Transformer) m a = Via {
- runVia :: t m a
}
data G

Documentation

newtype Via (eff :: Effect) (t :: Transformer) m a Source #

This type indicates that an effect (i.e., a type class) eff is handled by a specific monad transformer t. The type is a simple wrapper around the monad transformer itself. The whole purpose of this type is to guide the type system to pick the instance of type class eff given by the type t, and to delegate all other effects that are not eff to their handlers which are located somewhere further down the monad transformer stack.

Constructors

Via
Fields runVia :: t m a

Instances

Instances details

Control (RWS' tag r w s) t m => RWS' (tag :: k) r w s (Via eff t m) Source #
Instance details Defined in Control.Effect.RWS Methods ask' :: Via eff t m r Source # local' :: (r -> r) -> Via eff t m a -> Via eff t m a Source # tell' :: w -> Via eff t m () Source # listen' :: Via eff t m a -> Via eff t m (w, a) Source # censor' :: (w -> w) -> Via eff t m a -> Via eff t m a Source # get' :: Via eff t m s Source # put' :: s -> Via eff t m () Source #
Handle (RWS' tag r w s) t m => RWS' (tag :: k) r w s (Via (RWS' tag r w s) t m) Source #
Instance details Defined in Control.Effect.RWS Methods ask' :: Via (RWS' tag r w s) t m r Source # local' :: (r -> r) -> Via (RWS' tag r w s) t m a -> Via (RWS' tag r w s) t m a Source # tell' :: w -> Via (RWS' tag r w s) t m () Source # listen' :: Via (RWS' tag r w s) t m a -> Via (RWS' tag r w s) t m (w, a) Source # censor' :: (w -> w) -> Via (RWS' tag r w s) t m a -> Via (RWS' tag r w s) t m a Source # get' :: Via (RWS' tag r w s) t m s Source # put' :: s -> Via (RWS' tag r w s) t m () Source #
Lift (Map' tag k2 v) t m => Map' (tag :: k1) k2 v (Via eff t m) Source #
Instance details Defined in Control.Effect.Map Methods clear' :: Via eff t m () Source # lookup' :: k2 -> Via eff t m (Maybe v) Source # update' :: k2 -> Maybe v -> Via eff t m () Source #
Handle (Map' tag k2 v) t m => Map' (tag :: k1) k2 v (Via (Map' tag k2 v) t m) Source #
Instance details Defined in Control.Effect.Map Methods clear' :: Via (Map' tag k2 v) t m () Source # lookup' :: k2 -> Via (Map' tag k2 v) t m (Maybe v) Source # update' :: k2 -> Maybe v -> Via (Map' tag k2 v) t m () Source #
Control (Error' tag e) t m => Error' (tag :: k) e (Via eff t m) Source #
Instance details Defined in Control.Effect.Error Methods throwError' :: e -> Via eff t m a Source # catchError' :: Via eff t m a -> (e -> Via eff t m a) -> Via eff t m a Source #
Handle (Error' tag e) t m => Error' (tag :: k) e (Via (Error' tag e) t m) Source #
Instance details Defined in Control.Effect.Error Methods throwError' :: e -> Via (Error' tag e) t m a Source # catchError' :: Via (Error' tag e) t m a -> (e -> Via (Error' tag e) t m a) -> Via (Error' tag e) t m a Source #
Control (Reader' tag r) t m => Reader' (tag :: k) r (Via eff t m) Source #
Instance details Defined in Control.Effect.Reader Methods ask' :: Via eff t m r Source # local' :: (r -> r) -> Via eff t m a -> Via eff t m a Source # reader' :: (r -> a) -> Via eff t m a Source #
Handle (Reader' tag r) t m => Reader' (tag :: k) r (Via (Reader' tag r) t m) Source #
Instance details Defined in Control.Effect.Reader Methods ask' :: Via (Reader' tag r) t m r Source # local' :: (r -> r) -> Via (Reader' tag r) t m a -> Via (Reader' tag r) t m a Source # reader' :: (r -> a) -> Via (Reader' tag r) t m a Source #
Lift (State' tag s) t m => State' (tag :: k) s (Via eff t m) Source #
Instance details Defined in Control.Effect.State Methods get' :: Via eff t m s Source # put' :: s -> Via eff t m () Source # state' :: (s -> (s, a)) -> Via eff t m a Source #
Handle (State' tag s) t m => State' (tag :: k) s (Via (State' tag s) t m) Source #
Instance details Defined in Control.Effect.State Methods get' :: Via (State' tag s) t m s Source # put' :: s -> Via (State' tag s) t m () Source # state' :: (s -> (s, a)) -> Via (State' tag s) t m a Source #
Control (Writer' tag w) t m => Writer' (tag :: k) w (Via eff t m) Source #
Instance details Defined in Control.Effect.Writer Methods tell' :: w -> Via eff t m () Source # listen' :: Via eff t m a -> Via eff t m (w, a) Source # censor' :: (w -> w) -> Via eff t m a -> Via eff t m a Source #
Handle (Writer' tag w) t m => Writer' (tag :: k) w (Via (Writer' tag w) t m) Source #
Instance details Defined in Control.Effect.Writer Methods tell' :: w -> Via (Writer' tag w) t m () Source # listen' :: Via (Writer' tag w) t m a -> Via (Writer' tag w) t m (w, a) Source # censor' :: (w -> w) -> Via (Writer' tag w) t m a -> Via (Writer' tag w) t m a Source #
Handle (Cont' tag) t m => Cont' (tag :: k) (Via (Cont' tag) t m) Source #
Instance details Defined in Control.Effect.Cont Methods callCC' :: ((a -> Via (Cont' tag) t m b) -> Via (Cont' tag) t m a) -> Via (Cont' tag) t m a Source #
Control (Cont' tag) t m => Cont' (tag :: k) (Via eff t m) Source #
Instance details Defined in Control.Effect.Cont Methods callCC' :: ((a -> Via eff t m b) -> Via eff t m a) -> Via eff t m a Source #
Control (Resource' tag) t m => Resource' (tag :: k) (Via eff t m) Source #
Instance details Defined in Control.Effect.Resource Methods bracket' :: Via eff t m a -> (a -> Via eff t m c) -> (a -> Via eff t m b) -> Via eff t m b Source # bracketOnError' :: Via eff t m a -> (a -> Via eff t m c) -> (a -> Via eff t m b) -> Via eff t m b Source #
Handle (Resource' tag) t m => Resource' (tag :: k) (Via (Resource' tag) t m) Source #
Instance details Defined in Control.Effect.Resource Methods bracket' :: Via (Resource' tag) t m a -> (a -> Via (Resource' tag) t m c) -> (a -> Via (Resource' tag) t m b) -> Via (Resource' tag) t m b Source # bracketOnError' :: Via (Resource' tag) t m a -> (a -> Via (Resource' tag) t m c) -> (a -> Via (Resource' tag) t m b) -> Via (Resource' tag) t m b Source #
(Monad (t m), MonadBase b m, MonadTrans t) => MonadBase b (Via eff t m) Source #
Instance details Defined in Control.Effect.Machinery.Via Methods liftBase :: b α -> Via eff t m α #
(Monad (t m), MonadBaseControl b m, MonadTransControl t) => MonadBaseControl b (Via eff t m) Source #
Instance details Defined in Control.Effect.Machinery.Via Associated Types type StM (Via eff t m) a # Methods liftBaseWith :: (RunInBase (Via eff t m) b -> b a) -> Via eff t m a # restoreM :: StM (Via eff t m) a -> Via eff t m a #
Lift (Embed n) t m => Embed n (Via eff t m) Source #
Instance details Defined in Control.Effect.Embed Methods embed :: n a -> Via eff t m a Source #
Handle (Embed n) t m => Embed n (Via (Embed n) t m) Source #
Instance details Defined in Control.Effect.Embed Methods embed :: n a -> Via (Embed n) t m a Source #
MonadTrans t => MonadTrans (Via eff t) Source #
Instance details Defined in Control.Effect.Machinery.Via Methods lift :: Monad m => m a -> Via eff t m a #
MonadTransControl t => MonadTransControl (Via eff t) Source #
Instance details Defined in Control.Effect.Machinery.Via Associated Types type StT (Via eff t) a # Methods liftWith :: Monad m => (Run (Via eff t) -> m a) -> Via eff t m a # restoreT :: Monad m => m (StT (Via eff t) a) -> Via eff t m a #
Monad (t m) => Monad (Via eff t m) Source #
Instance details Defined in Control.Effect.Machinery.Via Methods (>>=) :: Via eff t m a -> (a -> Via eff t m b) -> Via eff t m b # (>>) :: Via eff t m a -> Via eff t m b -> Via eff t m b # return :: a -> Via eff t m a #
Functor (t m) => Functor (Via eff t m) Source #
Instance details Defined in Control.Effect.Machinery.Via Methods fmap :: (a -> b) -> Via eff t m a -> Via eff t m b # (<$) :: a -> Via eff t m b -> Via eff t m a #
Applicative (t m) => Applicative (Via eff t m) Source #
Instance details Defined in Control.Effect.Machinery.Via Methods pure :: a -> Via eff t m a # (<>) :: Via eff t m (a -> b) -> Via eff t m a -> Via eff t m b # liftA2 :: (a -> b -> c) -> Via eff t m a -> Via eff t m b -> Via eff t m c # (>) :: Via eff t m a -> Via eff t m b -> Via eff t m b # (<*) :: Via eff t m a -> Via eff t m b -> Via eff t m a #
MonadIO (t m) => MonadIO (Via eff t m) Source #
Instance details Defined in Control.Effect.Machinery.Via Methods liftIO :: IO a -> Via eff t m a #
type StT (Via eff t) a Source #
Instance details Defined in Control.Effect.Machinery.Via type StT (Via eff t) a = StT t a
type StM (Via eff t m) a Source #
Instance details Defined in Control.Effect.Machinery.Via type StM (Via eff t m) a = ComposeSt t m a

data G Source #

This type is used as tag for all untagged effects. In order words, every effect is tagged, even untagged ones, but all the untagged ones simply have the same tag G (short for "Global", because you can view tags as some kind of namespace mechanism, and all untagged effects live in the same global namespace).

If you don't want to use tagged effects (i.e., you write effect type classes without a tag type parameter), you can ignore this type completely.