streamly-0.7.2: Beautiful Streaming, Concurrent and Reactive Composition

Copyright(c) 2019 Composewell Technologies
LicenseBSD3
Maintainerstreamly@composewell.com
Stabilityexperimental
PortabilityGHC
Safe HaskellNone
LanguageHaskell2010

Streamly.Internal.Mutable.Prim.Var

Contents

Description

A mutable variable in a mutation capable monad (IO/ST) holding a Prim value. This allows fast modification because of unboxed storage.

Multithread Consistency Notes

In general, any value that straddles a machine word cannot be guaranteed to be consistently read from another thread without a lock. GHC heap objects are always machine word aligned, therefore, a Var is also word aligned. On a 64-bit platform, writing a 64-bit aligned type from one thread and reading it from another thread should give consistent old or new value. The same holds true for 32-bit values on a 32-bit platform.

Synopsis

Documentation

data Var m a Source #

A Var holds a single Prim value.

type MonadMut = PrimMonad Source #

A monad that allows mutable operations using a state token.

class Prim a #

Class of types supporting primitive array operations. This includes interfacing with GC-managed memory (functions suffixed with ByteArray#) and interfacing with unmanaged memory (functions suffixed with Addr#). Endianness is platform-dependent.

Instances
Prim Char 
Instance details

Defined in Data.Primitive.Types

Prim Double 
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Defined in Data.Primitive.Types

Prim Float 
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Defined in Data.Primitive.Types

Prim Int 
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Prim Int8 
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Prim Int16 
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Prim Int32 
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Prim Int64 
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Prim Word 
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Prim Word8 
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Prim Word16 
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Prim Word32 
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Prim Word64 
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Defined in Data.Primitive.Types

Prim CDev 
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Defined in Data.Primitive.Types

Prim CIno 
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Defined in Data.Primitive.Types

Prim CMode 
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Defined in Data.Primitive.Types

Prim COff 
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Defined in Data.Primitive.Types

Prim CPid 
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Prim CSsize 
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Prim CGid 
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Prim CNlink 
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Prim CUid 
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Defined in Data.Primitive.Types

Prim CCc 
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Defined in Data.Primitive.Types

Prim CSpeed 
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Defined in Data.Primitive.Types

Prim CTcflag 
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Defined in Data.Primitive.Types

Prim CRLim 
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Prim CBlkSize 
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Defined in Data.Primitive.Types

Prim CBlkCnt 
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Prim CClockId 
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Prim CFsBlkCnt 
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Prim CFsFilCnt 
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Prim CId 
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Defined in Data.Primitive.Types

Prim CKey 
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Prim CTimer 
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Prim Fd 
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Prim CChar 
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Prim CSChar 
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Prim CUChar 
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Prim CShort 
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Prim CUShort 
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Prim CInt 
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Prim CUInt 
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Prim CLong 
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Prim CULong 
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Defined in Data.Primitive.Types

Prim CLLong 
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Prim CULLong 
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Defined in Data.Primitive.Types

Prim CBool 
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Prim CFloat 
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Prim CDouble 
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Prim CPtrdiff 
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Prim CSize 
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Prim CWchar 
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Prim CSigAtomic 
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Prim CClock 
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Defined in Data.Primitive.Types

Prim CTime 
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Prim CUSeconds 
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Prim CSUSeconds 
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Prim CIntPtr 
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Defined in Data.Primitive.Types

Prim CUIntPtr 
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Prim CIntMax 
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Prim CUIntMax 
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Prim (StablePtr a) 
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Prim (Ptr a) 
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Prim (FunPtr a) 
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Prim a => Prim (Min a)

Since: primitive-0.6.5.0

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Prim a => Prim (Max a)

Since: primitive-0.6.5.0

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Defined in Data.Primitive.Types

Prim a => Prim (First a)

Since: primitive-0.6.5.0

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Defined in Data.Primitive.Types

Prim a => Prim (Last a)

Since: primitive-0.6.5.0

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Prim a => Prim (Identity a)

Since: primitive-0.6.5.0

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Prim a => Prim (Dual a)

Since: primitive-0.6.5.0

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Prim a => Prim (Sum a)

Since: primitive-0.6.5.0

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Prim a => Prim (Product a)

Since: primitive-0.6.5.0

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Prim a => Prim (Down a)

Since: primitive-0.6.5.0

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Prim a => Prim (Const a b)

Since: primitive-0.6.5.0

Instance details

Defined in Data.Primitive.Types

Methods

sizeOf# :: Const a b -> Int# #

alignment# :: Const a b -> Int# #

indexByteArray# :: ByteArray# -> Int# -> Const a b #

readByteArray# :: MutableByteArray# s -> Int# -> State# s -> (#State# s, Const a b#) #

writeByteArray# :: MutableByteArray# s -> Int# -> Const a b -> State# s -> State# s #

setByteArray# :: MutableByteArray# s -> Int# -> Int# -> Const a b -> State# s -> State# s #

indexOffAddr# :: Addr# -> Int# -> Const a b #

readOffAddr# :: Addr# -> Int# -> State# s -> (#State# s, Const a b#) #

writeOffAddr# :: Addr# -> Int# -> Const a b -> State# s -> State# s #

setOffAddr# :: Addr# -> Int# -> Int# -> Const a b -> State# s -> State# s #

Construction

newVar :: forall m a. (MonadMut m, Prim a) => a -> m (Var m a) Source #

Create a new mutable variable.

Write

writeVar :: (MonadMut m, Prim a) => Var m a -> a -> m () Source #

Write a value to a mutable variable.

modifyVar' :: (MonadMut m, Prim a) => Var m a -> (a -> a) -> m () Source #

Modify the value of a mutable variable using a function with strict application.

Read

readVar :: (MonadMut m, Prim a) => Var m a -> m a Source #

Read a value from a variable.