Safe Haskell	Safe-Inferred
Language	Haskell2010

Bluefin.Eff

Contents

Eff monad
Run an Eff
Resource management
Type classes
Effect tracking

Synopsis

data Eff (es :: Effects) a
runPureEff :: (forall (es :: Effects). Eff es a) -> a
runEff :: (forall (e :: Effects) (es :: Effects). IOE e -> Eff (e :& es) a) -> IO a
bracket :: forall (es :: Effects) a b. Eff es a -> (a -> Eff es ()) -> (a -> Eff es b) -> Eff es b
withMonadIO :: forall (e :: Effects) (es :: Effects) r. e :> es => IOE e -> (forall (m :: Type -> Type). MonadIO m => m r) -> Eff es r
withMonadFail :: forall (e :: Effects) (es :: Effects) r. e :> es => Exception String e -> (forall (m :: Type -> Type). MonadFail m => m r) -> Eff es r
data Effects
class (es1 :: Effects) :> (es2 :: Effects)
type (:&) = 'Union

`Eff` monad

data Eff (es :: Effects) a #

Instances

Instances details

Applicative (Eff es)
Instance details Defined in Bluefin.Internal Methods pure :: a -> Eff es a # (<>) :: Eff es (a -> b) -> Eff es a -> Eff es b # liftA2 :: (a -> b -> c) -> Eff es a -> Eff es b -> Eff es c # (>) :: Eff es a -> Eff es b -> Eff es b # (<*) :: Eff es a -> Eff es b -> Eff es a #
Functor (Eff es)
Instance details Defined in Bluefin.Internal Methods fmap :: (a -> b) -> Eff es a -> Eff es b # (<$) :: a -> Eff es b -> Eff es a #
Monad (Eff es)
Instance details Defined in Bluefin.Internal Methods (>>=) :: Eff es a -> (a -> Eff es b) -> Eff es b # (>>) :: Eff es a -> Eff es b -> Eff es b # return :: a -> Eff es a #

Run an `Eff`

runPureEff :: (forall (es :: Effects). Eff es a) -> a #

Run an Eff that doesn't contain any unhandled effects.

runEff #

Arguments

:: (forall (e :: Effects) (es :: Effects). IOE e -> Eff (e :& es) a)
-> IO a	͘

Run an Eff whose only unhandled effect is IO.

>>> runEff $ \io -> do
      effIO io (putStrLn "Hello world!")
Hello, world!

Resource management

bracket :: forall (es :: Effects) a b. Eff es a -> (a -> Eff es ()) -> (a -> Eff es b) -> Eff es b #

bracket acquire release body: acquire a resource, perform the body with it, and release the resource even if body threw an exception. This is essentially the same as Control.Exception.bracket, whose documentation you can inspect for further details.

Type classes

See Bluefin.Eff.IO for the most direct way of doing I/O in Bluefin. If you really want to use MonadIO you can use withMonadIO.

withMonadIO #

Arguments

:: forall (e :: Effects) (es :: Effects) r. e :> es
=> IOE e
-> (forall (m :: Type -> Type). MonadIO m => m r)	`MonadIO` operation
-> Eff es r	`MonadIO` operation run in `Eff`

Run MonadIO operations in Eff.

>>> runEff $ \io -> withMonadIO io $ liftIO $ do
      putStrLn "Hello world!"
Hello, world!

withMonadFail #

Arguments

:: forall (e :: Effects) (es :: Effects) r. e :> es
=> Exception String e	`Exception` to `throw` on `fail`
-> (forall (m :: Type -> Type). MonadFail m => m r)	`MonadFail` operation
-> Eff es r	`MonadFail` operation run in `Eff`

Run MonadFail operations in Eff.

>>> runPureEff $ try $ \e ->
      when (2 > 1) $
        withMonadFail e (fail "2 was bigger than 1")
Left "2 was bigger than 1"

Effect tracking

data Effects #

class (es1 :: Effects) :> (es2 :: Effects) #

Effect subset constraint

Instances

Instances details

e :> e	A set of effects `e` is a subset of itself
Instance details Defined in Bluefin.Internal
e :> (e :& es)	`e` is a subset of a larger set `e :& es`
Instance details Defined in Bluefin.Internal
e :> es => e :> (x :& es)	If `e` is subset of `es` then `e` is a subset of a larger set, `x :& es`
Instance details Defined in Bluefin.Internal

type (:&) = 'Union infixr 9 #

type (:&) :: Effects -> Effects -> Effects

Union of effects

Eff monad

Instances

Run an Eff

Resource management

Type classes

Effect tracking

Instances

`Eff` monad

Run an `Eff`