| Safe Haskell | Safe-Inferred |
|---|---|
| Language | Haskell2010 |
Bluefin.HandleReader
Description
This is an old interface and will be deprecated in the future. You are encouraged to use Bluefin.Capability.AskCapability instead.
HandleReader is like Reader, generalized to
work for arbitrary Handles. localHandle
locally overrides the value of a capability in a well-scoped way. The
original capability will be restored when you exit the localHandle
block regardless of whether the exit was normal or via an
exception.
HandleReader supports functionality similiar to effectful's
interpose
and polysemy's
intercept,
that is, locally augmenting an effect with new behaviors. If you
want to do the same in Bluefin you may want to start with
Bluefin.GadtEffect..interpose
Synopsis
- data HandleReader (h :: Effects -> Type) (e :: Effects)
- runHandleReader :: forall (e1 :: Effects) (es :: Effects) h r. (e1 <: es, Handle h) => h e1 -> (forall (e :: Effects). HandleReader h e -> Eff (e :& es) r) -> Eff es r
- askHandle :: forall (e :: Effects) (es :: Effects) h. (e <: es, Handle h) => HandleReader h e -> Eff es (h es)
- asksHandle :: forall (e1 :: Effects) (es :: Effects) h r. (e1 <: es, Handle h) => HandleReader h e1 -> (forall (e :: Effects). h e -> Eff (e :& es) r) -> Eff es r
- localHandle :: forall (e :: Effects) (es :: Effects) h r. (e <: es, Handle h) => HandleReader h e -> (h es -> h es) -> Eff es r -> Eff es r
Handle
data HandleReader (h :: Effects -> Type) (e :: Effects) #
Instances
| e <: es => OneWayCoercible (HandleReader h e :: Type) (HandleReader h es :: Type) | |
Defined in Bluefin.Internal Methods oneWayCoercibleImpl :: OneWayCoercibleD (HandleReader h e) (HandleReader h es) # | |
| Handle (HandleReader h) | |
Defined in Bluefin.Internal Methods handleImpl :: HandleD (HandleReader h) # | |
| CloneableHandle h => CloneableHandle (HandleReader h) | |
Defined in Bluefin.Internal.CloneableHandle Methods cloneableHandleImpl :: CloneableHandleD (HandleReader h) | |
Handlers
runHandleReader :: forall (e1 :: Effects) (es :: Effects) h r. (e1 <: es, Handle h) => h e1 -> (forall (e :: Effects). HandleReader h e -> Eff (e :& es) r) -> Eff es r #
Effectful operations
askHandle :: forall (e :: Effects) (es :: Effects) h. (e <: es, Handle h) => HandleReader h e -> Eff es (h es) #
asksHandle :: forall (e1 :: Effects) (es :: Effects) h r. (e1 <: es, Handle h) => HandleReader h e1 -> (forall (e :: Effects). h e -> Eff (e :& es) r) -> Eff es r #
localHandle :: forall (e :: Effects) (es :: Effects) h r. (e <: es, Handle h) => HandleReader h e -> (h es -> h es) -> Eff es r -> Eff es r #