Copyright	© 2017 All rights reserved.
License	GPL-3
Maintainer	Evan Cofsky <evan@theunixman.com>
Stability	experimental
Portability	POSIX
Safe Haskell	None
Language	Haskell2010

IO.Base

Description

Synopsis

Documentation

module Control.Monad.Base

module Control.Monad.Trans.Control

data IO a :: * -> * #

A value of type IO a is a computation which, when performed, does some I/O before returning a value of type a.

There is really only one way to "perform" an I/O action: bind it to Main.main in your program. When your program is run, the I/O will be performed. It isn't possible to perform I/O from an arbitrary function, unless that function is itself in the IO monad and called at some point, directly or indirectly, from Main.main.

IO is a monad, so IO actions can be combined using either the do-notation or the >> and >>= operations from the Monad class.

Instances

Monad IO	Since: 2.1
Methods (>>=) :: IO a -> (a -> IO b) -> IO b # (>>) :: IO a -> IO b -> IO b # return :: a -> IO a # fail :: String -> IO a #
Functor IO	Since: 2.1
Methods fmap :: (a -> b) -> IO a -> IO b # (<$) :: a -> IO b -> IO a #
MonadFix IO	Since: 2.1
Methods mfix :: (a -> IO a) -> IO a #
MonadFail IO	Since: 4.9.0.0
Methods fail :: String -> IO a #
Applicative IO	Since: 2.1
Methods pure :: a -> IO a # (<>) :: IO (a -> b) -> IO a -> IO b # liftA2 :: (a -> b -> c) -> IO a -> IO b -> IO c # (>) :: IO a -> IO b -> IO b # (<*) :: IO a -> IO b -> IO a #
Alternative IO	Since: 4.9.0.0
Methods empty :: IO a # (<\|>) :: IO a -> IO a -> IO a # some :: IO a -> IO [a] # many :: IO a -> IO [a] #
MonadPlus IO	Since: 4.9.0.0
Methods mzero :: IO a # mplus :: IO a -> IO a -> IO a #
MonadIO IO	Since: 4.9.0.0
Methods liftIO :: IO a -> IO a #
MonadThrow IO
Methods throwM :: Exception e => e -> IO a #
MonadCatch IO
Methods catch :: Exception e => IO a -> (e -> IO a) -> IO a #
MonadMask IO
Methods mask :: ((forall a. IO a -> IO a) -> IO b) -> IO b # uninterruptibleMask :: ((forall a. IO a -> IO a) -> IO b) -> IO b #
PrimMonad IO
Associated Types type PrimState (IO :: * -> ) :: # Methods primitive :: (State# (PrimState IO) -> (#TupleRep [RuntimeRep], LiftedRep, State# (PrimState IO), a#)) -> IO a #
PrimBase IO
Methods internal :: IO a -> State# (PrimState IO) -> (#TupleRep [RuntimeRep], LiftedRep, State# (PrimState IO), a#) #
Quasi IO
Methods qNewName :: String -> IO Name # qReport :: Bool -> String -> IO () # qRecover :: IO a -> IO a -> IO a # qLookupName :: Bool -> String -> IO (Maybe Name) # qReify :: Name -> IO Info # qReifyFixity :: Name -> IO (Maybe Fixity) # qReifyInstances :: Name -> [Type] -> IO [Dec] # qReifyRoles :: Name -> IO [Role] # qReifyAnnotations :: Data a => AnnLookup -> IO [a] # qReifyModule :: Module -> IO ModuleInfo # qReifyConStrictness :: Name -> IO [DecidedStrictness] # qLocation :: IO Loc # qRunIO :: IO a -> IO a # qAddDependentFile :: FilePath -> IO () # qAddTopDecls :: [Dec] -> IO () # qAddForeignFile :: ForeignSrcLang -> String -> IO () # qAddModFinalizer :: Q () -> IO () # qGetQ :: Typeable * a => IO (Maybe a) # qPutQ :: Typeable * a => a -> IO () # qIsExtEnabled :: Extension -> IO Bool # qExtsEnabled :: IO [Extension] #
MonadBaseControl IO IO
Associated Types type StM (IO :: * -> ) a :: # Methods liftBaseWith :: (RunInBase IO IO -> IO a) -> IO a # restoreM :: StM IO a -> IO a #
MonadBase IO IO
Methods liftBase :: IO α -> IO α #
Semigroup a => Semigroup (IO a)	Since: 4.10.0.0
Methods (<>) :: IO a -> IO a -> IO a # sconcat :: NonEmpty (IO a) -> IO a # stimes :: Integral b => b -> IO a -> IO a #
Monoid a => Monoid (IO a)	Since: 4.9.0.0
Methods mempty :: IO a # mappend :: IO a -> IO a -> IO a # mconcat :: [IO a] -> IO a #
type PrimState IO
type PrimState IO = RealWorld
type StM IO a
type StM IO a = a