Safe Haskell	None
Language	Haskell2010

Bluefin.Capability.Tell

Contents

Capability
Handlers
Effectful operations

Synopsis

data Tell w (e :: Effects)
runTell :: forall w (es :: Effects) r. Monoid w => (forall (e :: Effects). Tell w e -> Eff (e :& es) r) -> Eff es (r, w)
execTell :: forall w (es :: Effects) r. Monoid w => (forall (e :: Effects). Tell w e -> Eff (e :& es) r) -> Eff es w
tell :: forall (e :: Effects) (es :: Effects) w. e <: es => Tell w e -> w -> Eff es ()

Documentation

In most cases you'll probably prefer Yield to Tell, but Tell can still be useful in some cases, for example with Data.Monoid.Any to determine whether an event ever occurred.

Capability

data Tell w (e :: Effects) #

Instances

Instances details

e <: es => OneWayCoercible (Tell w e :: Type) (Tell w es :: Type)
Instance details Defined in Bluefin.Internal Methods oneWayCoercibleImpl :: OneWayCoercibleD (Tell w e) (Tell w es) #
Handle (Tell w)
Instance details Defined in Bluefin.Internal Methods handleImpl :: HandleD (Tell w) #
(TypeError ('Text "Tell cannot be cloned. Perhaps you want an STM channel?") :: Constraint) => CloneableHandle (Tell w)
Instance details Defined in Bluefin.Internal.CloneableHandle Methods cloneableHandleImpl :: CloneableHandleD (Tell w) #

Handlers

runTell #

Arguments

:: forall w (es :: Effects) r. Monoid w
=> (forall (e :: Effects). Tell w e -> Eff (e :& es) r)	͘
-> Eff es (r, w)

>>> getAny $ snd $ runPureEff $ runTell $ \w -> do
      -- Non-empty list (the tell event does happen)
      for_ [1 .. 10] $ \_ -> tell w (Any True)
True

execTell #

Arguments

:: forall w (es :: Effects) r. Monoid w
=> (forall (e :: Effects). Tell w e -> Eff (e :& es) r)	͘
-> Eff es w

>>> getAny $ runPureEff $ execTell $ \w -> do
      -- Non-empty list (the tell event does happen)
      for_ [1 .. 10] $ \_ -> tell w (Any True)
True

>>> getAny $ runPureEff $ execTell $ \w -> do
      -- Empty list (the tell event does not happen)
      for_ [] $ \_ -> tell w (Any True)
False

Effectful operations

tell #

Arguments

:: forall (e :: Effects) (es :: Effects) w. e <: es
=> Tell w e
-> w	͘
-> Eff es ()

>>> getAny $ runPureEff $ execWriter $ \w -> do
      -- Non-empty list (the tell event does happen)
      for_ [1 .. 10] $ \_ -> tell w (Any True)
True