Control.Monad.Primitive

primitive-0.6.2.0: Primitive memory-related operations

Copyright | (c) Roman Leshchinskiy 2009
License | BSD-style
Maintainer | Roman Leshchinskiy <rl@cse.unsw.edu.au>
Portability | non-portable
Safe Haskell | None
Language | Haskell2010

Control.Monad.Primitive

Description

Primitive state-transformer monads

Synopsis

- class Monad m => PrimMonad m where
  - type PrimState m
- data RealWorld :: *
- primitive_ :: PrimMonad m => (State# (PrimState m) -> State# (PrimState m)) -> m ()
- class PrimMonad m => PrimBase m where
- liftPrim :: (PrimBase m1, PrimMonad m2, PrimState m1 ~ PrimState m2) => m1 a -> m2 a
- primToPrim :: (PrimBase m1, PrimMonad m2, PrimState m1 ~ PrimState m2) => m1 a -> m2 a
- primToIO :: (PrimBase m, PrimState m ~ RealWorld) => m a -> IO a
- primToST :: PrimBase m => m a -> ST (PrimState m) a
- ioToPrim :: (PrimMonad m, PrimState m ~ RealWorld) => IO a -> m a
- stToPrim :: PrimMonad m => ST (PrimState m) a -> m a
- unsafePrimToPrim :: (PrimBase m1, PrimMonad m2) => m1 a -> m2 a
- unsafePrimToIO :: PrimBase m => m a -> IO a
- unsafePrimToST :: PrimBase m => m a -> ST s a
- unsafeIOToPrim :: PrimMonad m => IO a -> m a
- unsafeSTToPrim :: PrimMonad m => ST s a -> m a
- unsafeInlinePrim :: PrimBase m => m a -> a
- unsafeInlineIO :: IO a -> a
- unsafeInlineST :: ST s a -> a
- touch :: PrimMonad m => a -> m ()
- evalPrim :: forall a m. PrimMonad m => a -> m a

# Documentation

class Monad m => PrimMonad m where #

Class of monads which can perform primitive state-transformer actions

Minimal complete definition

primitive

Associated Types

type PrimState m #

State token type

Methods

primitive :: (State# (PrimState m) -> (#State# (PrimState m), a#)) -> m a #

Execute a primitive operation

Instances

PrimMonad IO # |
Associated Types type PrimState (IO :: * -> *) :: * # Methods primitive :: (State# (PrimState IO) -> (#VoidRep, PtrRepLifted, State# (PrimState IO), a#)) -> IO a #
PrimMonad (ST s) # |
Associated Types type PrimState (ST s :: * -> *) :: * # Methods primitive :: (State# (PrimState (ST s)) -> (#VoidRep, PtrRepLifted, State# (PrimState (ST s)), a#)) -> ST s a #
PrimMonad m => PrimMonad (MaybeT m) # |
Associated Types type PrimState (MaybeT m :: * -> *) :: * # Methods primitive :: (State# (PrimState (MaybeT m)) -> (#VoidRep, PtrRepLifted, State# (PrimState (MaybeT m)), a#)) -> MaybeT m a #
PrimMonad m => PrimMonad (ListT m) # |
Associated Types type PrimState (ListT m :: * -> *) :: * # Methods primitive :: (State# (PrimState (ListT m)) -> (#VoidRep, PtrRepLifted, State# (PrimState (ListT m)), a#)) -> ListT m a #
(Monoid w, PrimMonad m) => PrimMonad (WriterT w m) # |
Associated Types type PrimState (WriterT w m :: * -> *) :: * # Methods primitive :: (State# (PrimState (WriterT w m)) -> (#VoidRep, PtrRepLifted, State# (PrimState (WriterT w m)), a#)) -> WriterT w m a #
(Monoid w, PrimMonad m) => PrimMonad (WriterT w m) # |
Associated Types type PrimState (WriterT w m :: * -> *) :: * # Methods primitive :: (State# (PrimState (WriterT w m)) -> (#VoidRep, PtrRepLifted, State# (PrimState (WriterT w m)), a#)) -> WriterT w m a #
PrimMonad m => PrimMonad (StateT s m) # |
Associated Types type PrimState (StateT s m :: * -> *) :: * # Methods primitive :: (State# (PrimState (StateT s m)) -> (#VoidRep, PtrRepLifted, State# (PrimState (StateT s m)), a#)) -> StateT s m a #
PrimMonad m => PrimMonad (StateT s m) # |
Associated Types type PrimState (StateT s m :: * -> *) :: * # Methods primitive :: (State# (PrimState (StateT s m)) -> (#VoidRep, PtrRepLifted, State# (PrimState (StateT s m)), a#)) -> StateT s m a #
PrimMonad m => PrimMonad (IdentityT * m) # |
Associated Types type PrimState (IdentityT * m :: * -> *) :: * # Methods primitive :: (State# (PrimState (IdentityT * m)) -> (#VoidRep, PtrRepLifted, State# (PrimState (IdentityT * m)), a#)) -> IdentityT * m a #
(Error e, PrimMonad m) => PrimMonad (ErrorT e m) # |
Associated Types type PrimState (ErrorT e m :: * -> *) :: * # Methods primitive :: (State# (PrimState (ErrorT e m)) -> (#VoidRep, PtrRepLifted, State# (PrimState (ErrorT e m)), a#)) -> ErrorT e m a #
PrimMonad m => PrimMonad (ExceptT e m) # |
Associated Types type PrimState (ExceptT e m :: * -> *) :: * # Methods primitive :: (State# (PrimState (ExceptT e m)) -> (#VoidRep, PtrRepLifted, State# (PrimState (ExceptT e m)), a#)) -> ExceptT e m a #
PrimMonad m => PrimMonad (ReaderT * r m) # |
Associated Types type PrimState (ReaderT * r m :: * -> *) :: * # Methods primitive :: (State# (PrimState (ReaderT * r m)) -> (#VoidRep, PtrRepLifted, State# (PrimState (ReaderT * r m)), a#)) -> ReaderT * r m a #
(Monoid w, PrimMonad m) => PrimMonad (RWST r w s m) # |
Associated Types type PrimState (RWST r w s m :: * -> *) :: * # Methods primitive :: (State# (PrimState (RWST r w s m)) -> (#VoidRep, PtrRepLifted, State# (PrimState (RWST r w s m)), a#)) -> RWST r w s m a #
(Monoid w, PrimMonad m) => PrimMonad (RWST r w s m) # |
Associated Types type PrimState (RWST r w s m :: * -> *) :: * # Methods primitive :: (State# (PrimState (RWST r w s m)) -> (#VoidRep, PtrRepLifted, State# (PrimState (RWST r w s m)), a#)) -> RWST r w s m a #

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#`.

primitive_ :: PrimMonad m => (State# (PrimState m) -> State# (PrimState m)) -> m () #

Execute a primitive operation with no result

class PrimMonad m => PrimBase m where #

Class of primitive monads for state-transformer actions.

Unlike `PrimMonad`, this typeclass requires that the `Monad` be fully expressed as a state transformer, therefore disallowing other monad transformers on top of the base `IO` or `ST`.

Minimal complete definition

internal

Methods

internal :: m a -> State# (PrimState m) -> (#State# (PrimState m), a#) #

Expose the internal structure of the monad

Instances

PrimBase IO # |
Methods internal :: IO a -> State# (PrimState IO) -> (#VoidRep, PtrRepLifted, State# (PrimState IO), a#) #
PrimBase (ST s) # |
Methods internal :: ST s a -> State# (PrimState (ST s)) -> (#VoidRep, PtrRepLifted, State# (PrimState (ST s)), a#) #
PrimBase m => PrimBase (IdentityT * m) # |
Methods internal :: IdentityT * m a -> State# (PrimState (IdentityT * m)) -> (#VoidRep, PtrRepLifted, State# (PrimState (IdentityT * m)), a#) #

liftPrim :: (PrimBase m1, PrimMonad m2, PrimState m1 ~ PrimState m2) => m1 a -> m2 a #

Lifts a `PrimBase` into another `PrimMonad` with the same underlying state token type.

primToPrim :: (PrimBase m1, PrimMonad m2, PrimState m1 ~ PrimState m2) => m1 a -> m2 a #

Convert a `PrimBase` to another monad with the same state token.

primToIO :: (PrimBase m, PrimState m ~ RealWorld) => m a -> IO a #

Convert a `PrimBase` with a `RealWorld` state token to `IO`

primToST :: PrimBase m => m a -> ST (PrimState m) a #

Convert a `PrimBase` to `ST`

ioToPrim :: (PrimMonad m, PrimState m ~ RealWorld) => IO a -> m a #

Convert an `IO` action to a `PrimMonad`.

stToPrim :: PrimMonad m => ST (PrimState m) a -> m a #

Convert an `ST` action to a `PrimMonad`.

unsafePrimToPrim :: (PrimBase m1, PrimMonad m2) => m1 a -> m2 a #

Convert a `PrimBase` to another monad with a possibly different state token. This operation is highly unsafe!

unsafePrimToIO :: PrimBase m => m a -> IO a #

Convert any `PrimBase` to `IO`. This operation is highly unsafe!

unsafePrimToST :: PrimBase m => m a -> ST s a #

Convert any `PrimBase` to `ST` with an arbitrary state token. This operation is highly unsafe!

unsafeIOToPrim :: PrimMonad m => IO a -> m a #

Convert an `IO` action to any `PrimMonad`. This operation is highly unsafe!

unsafeSTToPrim :: PrimMonad m => ST s a -> m a #

Convert an `ST` action with an arbitraty state token to any `PrimMonad`. This operation is highly unsafe!

unsafeInlinePrim :: PrimBase m => m a -> a #

unsafeInlineIO :: IO a -> a #

unsafeInlineST :: ST s a -> a #

touch :: PrimMonad m => a -> m () #

evalPrim :: forall a m. PrimMonad m => a -> m a #

Create an action to force a value; generalizes `evaluate`