Safe Haskell	Unsafe
Language	Haskell2010

Control.Monad.STE.Internal

Synopsis

Documentation

newtype STE e s a Source

Constructors

STE (STERep s a)

Instances

Monad (STE e s) Source
Functor (STE e s) Source
MonadFix (STE e s) Source
Applicative (STE e s) Source
(~) * SomeException err => MonadThrow (STE err s) Source
PrimMonad (STE e s) Source
PrimBase (STE e s) Source
type PrimState (STE e s) = s Source

unSTE :: STE e s a -> STERep s a Source

type STERep s a = State# s -> (#State# s, a#) Source

data STEret s a Source

Constructors

STEret (State# s) a

runSTE :: (forall s. STE e s a) -> (Either e a -> b) -> b Source

runSTE is the workhorse of the STE monad. Runs an STE computation, and also does the toplevel handling of the abortive throwSTE operator. The naive way to handle errors is to simply write handleSTE id md. runSTE does not and cannot (by design) handle pure or async exceptions.

throwSTE :: forall e s a. e -> STE e s a Source

throwSTE is the STE sibling of throwIO, and its argument must match the e parameter in STE e s a. There is also no Exception e constraint. throwSTE should be thought of as an "abort" operation which is guaranteed to be caught/handled by runSTE.

handleSTE :: (Either e a -> b) -> (forall s. STE e s a) -> b Source

handleSTE is a flipped convenience function version of runSTE

unsafeInterleaveSTE :: STE e s a -> STE e s a Source

liftSTE :: STE e s a -> State# s -> STEret s a Source

fixSTE :: (a -> STE e s a) -> STE e s a Source

Allow the result of a state transformer computation to be used (lazily) inside the computation. Note that if f is strict, fixSTE f = _|_.

runBasicSTE :: (forall s. STE e s a) -> a Source

data RealWorld :: *

RealWorld is deeply magical. It is primitive, but it is not unlifted (hence ptrArg). We never manipulate values of type RealWorld; it's only used in the type system, to parameterise State#.

unsafeIOToSTE :: IO a -> STE e s a Source

unsafeSTEToIO :: STE e s a -> IO a Source