Safe Haskell	None
Language	Haskell98

Control.Monad.Finish

Description

Short-circuiting monad transformer and the corresponding generalizing monad type class.

Synopsis

Documentation

class Monad μ => MonadFinish f μ | μ -> f where Source #

Class of monads that support short-circuiting.

Minimal complete definition

finish

Methods

finish :: f -> μ α Source #

Short-circuit the computation with the provided value.

    finish f >>= rest = finish f

Instances

MonadFinish f μ => MonadFinish f (ListT μ) Source #
Methods finish :: f -> ListT μ α Source #
MonadFinish f μ => MonadFinish f (MaybeT μ) Source #
Methods finish :: f -> MaybeT μ α Source #
(MonadFinish f μ, Monoid w) => MonadFinish f (WriterT w μ) Source #
Methods finish :: f -> WriterT w μ α Source #
(MonadFinish f μ, Monoid w) => MonadFinish f (WriterT w μ) Source #
Methods finish :: f -> WriterT w μ α Source #
MonadFinish f μ => MonadFinish f (StateT s μ) Source #
Methods finish :: f -> StateT s μ α Source #
MonadFinish f μ => MonadFinish f (StateT s μ) Source #
Methods finish :: f -> StateT s μ α Source #
MonadFinish f μ => MonadFinish f (AbortT e μ) Source #
Methods finish :: f -> AbortT e μ α Source #
MonadFinish f μ => MonadFinish f (ExceptT e μ) Source #
Methods finish :: f -> ExceptT e μ α Source #
(MonadFinish f μ, Error e) => MonadFinish f (ErrorT e μ) Source #
Methods finish :: f -> ErrorT e μ α Source #
MonadFinish f μ => MonadFinish f (IdentityT * μ) Source #
Methods finish :: f -> IdentityT * μ α Source #
Monad μ => MonadFinish f (FinishT f μ) Source #
Methods finish :: f -> FinishT f μ α Source #
MonadFinish f μ => MonadFinish f (ReaderT * r μ) Source #
Methods finish :: f -> ReaderT * r μ α Source #
MonadFinish f μ => MonadFinish f (ContT * r μ) Source #
Methods finish :: f -> ContT * r μ α Source #
(MonadFinish f μ, Monoid w) => MonadFinish f (RWST r w s μ) Source #
Methods finish :: f -> RWST r w s μ α Source #
(MonadFinish f μ, Monoid w) => MonadFinish f (RWST r w s μ) Source #
Methods finish :: f -> RWST r w s μ α Source #

type Finish f α = FinishT f Identity α #

An alias for FinishT over Identity.

runFinish :: Finish f α -> Either f α #

runFinishT specialized for Finish.

runFinish' :: Finish α α -> α #

runFinishT' specialized to Finish.

newtype FinishT f μ α :: * -> (* -> *) -> * -> * #

A monad transformer that extends monad μ with the ability to short-circuit computations with a value of type f.

  runFinishT $ do someStuff
                  when condition $ finish reason
                  otherwiseContinue

Constructors

FinishT
Fields runFinishT :: μ (Either f α)

Instances

MonadBase η μ => MonadBase η (FinishT f μ)
Methods liftBase :: η α -> FinishT f μ α #
MonadBaseControl η μ => MonadBaseControl η (FinishT e μ)
Associated Types type StM (FinishT e μ :: * -> ) a :: # Methods liftBaseWith :: (RunInBase (FinishT e μ) η -> η a) -> FinishT e μ a # restoreM :: StM (FinishT e μ) a -> FinishT e μ a #
Monad μ => MonadFinish f (FinishT f μ) Source #
Methods finish :: f -> FinishT f μ α Source #
MonadTrans (FinishT f)
Methods lift :: Monad m => m a -> FinishT f m a #
MonadTransControl (FinishT f)
Associated Types type StT (FinishT f :: (* -> ) -> -> ) a :: # Methods liftWith :: Monad m => (Run (FinishT f) -> m a) -> FinishT f m a # restoreT :: Monad m => m (StT (FinishT f) a) -> FinishT f m a #
BindTrans (FinishT f)
Methods liftB :: Bind b => b a -> FinishT f b a #
Monad μ => Monad (FinishT f μ)
Methods (>>=) :: FinishT f μ a -> (a -> FinishT f μ b) -> FinishT f μ b # (>>) :: FinishT f μ a -> FinishT f μ b -> FinishT f μ b # return :: a -> FinishT f μ a # fail :: String -> FinishT f μ a #
Functor μ => Functor (FinishT f μ)
Methods fmap :: (a -> b) -> FinishT f μ a -> FinishT f μ b # (<$) :: a -> FinishT f μ b -> FinishT f μ a #
MonadFix μ => MonadFix (FinishT f μ)
Methods mfix :: (a -> FinishT f μ a) -> FinishT f μ a #
MonadFail μ => MonadFail (FinishT f μ)
Methods fail :: String -> FinishT f μ a #
(Functor μ, Monad μ) => Applicative (FinishT f μ)
Methods pure :: a -> FinishT f μ a # (<>) :: FinishT f μ (a -> b) -> FinishT f μ a -> FinishT f μ b # (>) :: FinishT f μ a -> FinishT f μ b -> FinishT f μ b # (<*) :: FinishT f μ a -> FinishT f μ b -> FinishT f μ a #
(Eq f, Eq1 μ) => Eq1 (FinishT f μ)
Methods liftEq :: (a -> b -> Bool) -> FinishT f μ a -> FinishT f μ b -> Bool #
(Ord f, Ord1 μ) => Ord1 (FinishT f μ)
Methods liftCompare :: (a -> b -> Ordering) -> FinishT f μ a -> FinishT f μ b -> Ordering #
(Read f, Read1 μ) => Read1 (FinishT f μ)
Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (FinishT f μ a) # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [FinishT f μ a] #
(Show f, Show1 μ) => Show1 (FinishT f μ)
Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> FinishT f μ a -> ShowS # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [FinishT f μ a] -> ShowS #
MonadZip μ => MonadZip (FinishT f μ)
Methods mzip :: FinishT f μ a -> FinishT f μ b -> FinishT f μ (a, b) # mzipWith :: (a -> b -> c) -> FinishT f μ a -> FinishT f μ b -> FinishT f μ c # munzip :: FinishT f μ (a, b) -> (FinishT f μ a, FinishT f μ b) #
MonadIO μ => MonadIO (FinishT f μ)
Methods liftIO :: IO a -> FinishT f μ a #
Pointed μ => Pointed (FinishT f μ)
Methods point :: a -> FinishT f μ a #
(Functor μ, Monad μ) => Apply (FinishT f μ)
Methods (<.>) :: FinishT f μ (a -> b) -> FinishT f μ a -> FinishT f μ b # (.>) :: FinishT f μ a -> FinishT f μ b -> FinishT f μ b # (<.) :: FinishT f μ a -> FinishT f μ b -> FinishT f μ a #
(Functor μ, Monad μ) => Bind (FinishT f μ)
Methods (>>-) :: FinishT f μ a -> (a -> FinishT f μ b) -> FinishT f μ b # join :: FinishT f μ (FinishT f μ a) -> FinishT f μ a #
(Eq f, Eq1 μ, Eq α) => Eq (FinishT f μ α)
Methods (==) :: FinishT f μ α -> FinishT f μ α -> Bool # (/=) :: FinishT f μ α -> FinishT f μ α -> Bool #
(Ord f, Ord1 μ, Ord α) => Ord (FinishT f μ α)
Methods compare :: FinishT f μ α -> FinishT f μ α -> Ordering # (<) :: FinishT f μ α -> FinishT f μ α -> Bool # (<=) :: FinishT f μ α -> FinishT f μ α -> Bool # (>) :: FinishT f μ α -> FinishT f μ α -> Bool # (>=) :: FinishT f μ α -> FinishT f μ α -> Bool # max :: FinishT f μ α -> FinishT f μ α -> FinishT f μ α # min :: FinishT f μ α -> FinishT f μ α -> FinishT f μ α #
(Read f, Read1 μ, Read α) => Read (FinishT f μ α)
Methods readsPrec :: Int -> ReadS (FinishT f μ α) # readList :: ReadS [FinishT f μ α] # readPrec :: ReadPrec (FinishT f μ α) # readListPrec :: ReadPrec [FinishT f μ α] #
(Show f, Show1 μ, Show α) => Show (FinishT f μ α)
Methods showsPrec :: Int -> FinishT f μ α -> ShowS # show :: FinishT f μ α -> String # showList :: [FinishT f μ α] -> ShowS #
type StT (FinishT f) α
type StT (FinishT f) α = Either f α
type StM (FinishT e μ) α
type StM (FinishT e μ) α = ComposeSt (FinishT e) μ α

runFinishT' :: Monad μ => FinishT α μ α -> μ α #

A version of runFinishT for the cases where you don't need to distinguish between short-circuits and regular computation results.

module Control.Monad

module Control.Monad.Fix

module Control.Monad.Trans