Data.Primitive.SmallArray

Small arrays are boxed (im)mutable arrays.

The underlying structure of the Array type contains a card table, allowing segments of the array to be marked as having been mutated. This allows the garbage collector to only re-traverse segments of the array that have been marked during certain phases, rather than having to traverse the entire array.

SmallArray lacks this table. This means that it takes up less memory and has slightly faster writes. It is also more efficient during garbage collection so long as the card table would have a single entry covering the entire array. These advantages make them suitable for use as arrays that are known to be small.

The card size is 128, so for uses much larger than that, Array would likely be superior.

The underlying type, SmallArray#, was introduced in GHC 7.10, so prior to that version, this module simply implements small arrays as Array.

Documentation

data SmallArray a

Constructors

SmallArray (SmallArray# a)

Instances

Monad SmallArray

Defined in Data.Primitive.SmallArray

Methods

(>>=) :: SmallArray a -> (a -> SmallArray b) -> SmallArray b

(>>) :: SmallArray a -> SmallArray b -> SmallArray b

return :: a -> SmallArray a

fail :: String -> SmallArray a

Functor SmallArray

Defined in Data.Primitive.SmallArray

Methods

fmap :: (a -> b) -> SmallArray a -> SmallArray b

(<$) :: a -> SmallArray b -> SmallArray a

MonadFix SmallArray

Defined in Data.Primitive.SmallArray

Methods

mfix :: (a -> SmallArray a) -> SmallArray a

Applicative SmallArray

Defined in Data.Primitive.SmallArray

Methods

pure :: a -> SmallArray a

(<*>) :: SmallArray (a -> b) -> SmallArray a -> SmallArray b

liftA2 :: (a -> b -> c) -> SmallArray a -> SmallArray b -> SmallArray c

(*>) :: SmallArray a -> SmallArray b -> SmallArray b

(<*) :: SmallArray a -> SmallArray b -> SmallArray a

Foldable SmallArray

Defined in Data.Primitive.SmallArray

Methods

fold :: Monoid m => SmallArray m -> m

foldMap :: Monoid m => (a -> m) -> SmallArray a -> m

foldr :: (a -> b -> b) -> b -> SmallArray a -> b

foldr' :: (a -> b -> b) -> b -> SmallArray a -> b

foldl :: (b -> a -> b) -> b -> SmallArray a -> b

foldl' :: (b -> a -> b) -> b -> SmallArray a -> b

foldr1 :: (a -> a -> a) -> SmallArray a -> a

foldl1 :: (a -> a -> a) -> SmallArray a -> a

toList :: SmallArray a -> [a]

null :: SmallArray a -> Bool

length :: SmallArray a -> Int

elem :: Eq a => a -> SmallArray a -> Bool

maximum :: Ord a => SmallArray a -> a

minimum :: Ord a => SmallArray a -> a

sum :: Num a => SmallArray a -> a

product :: Num a => SmallArray a -> a

Traversable SmallArray

Defined in Data.Primitive.SmallArray

Methods

traverse :: Applicative f => (a -> f b) -> SmallArray a -> f (SmallArray b)

sequenceA :: Applicative f => SmallArray (f a) -> f (SmallArray a)

mapM :: Monad m => (a -> m b) -> SmallArray a -> m (SmallArray b)

sequence :: Monad m => SmallArray (m a) -> m (SmallArray a)

Eq1 SmallArray

Since: 0.6.4.0

Defined in Data.Primitive.SmallArray

Methods

liftEq :: (a -> b -> Bool) -> SmallArray a -> SmallArray b -> Bool

Ord1 SmallArray

Since: 0.6.4.0

Defined in Data.Primitive.SmallArray

Methods

liftCompare :: (a -> b -> Ordering) -> SmallArray a -> SmallArray b -> Ordering

Read1 SmallArray

Since: 0.6.4.0

Defined in Data.Primitive.SmallArray

Methods

liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (SmallArray a)

liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [SmallArray a]

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (SmallArray a)

liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [SmallArray a]

Show1 SmallArray

Since: 0.6.4.0

Defined in Data.Primitive.SmallArray

Methods

liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> SmallArray a -> ShowS

liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [SmallArray a] -> ShowS

MonadZip SmallArray

Defined in Data.Primitive.SmallArray

Methods

mzip :: SmallArray a -> SmallArray b -> SmallArray (a, b)

mzipWith :: (a -> b -> c) -> SmallArray a -> SmallArray b -> SmallArray c

munzip :: SmallArray (a, b) -> (SmallArray a, SmallArray b)

Alternative SmallArray

Defined in Data.Primitive.SmallArray

Methods

empty :: SmallArray a

(<|>) :: SmallArray a -> SmallArray a -> SmallArray a

some :: SmallArray a -> SmallArray [a]

many :: SmallArray a -> SmallArray [a]

MonadPlus SmallArray

Defined in Data.Primitive.SmallArray

Methods

mzero :: SmallArray a

mplus :: SmallArray a -> SmallArray a -> SmallArray a

IsList (SmallArray a)

Defined in Data.Primitive.SmallArray

Associated Types

type Item (SmallArray a) :: *

Methods

fromList :: [Item (SmallArray a)] -> SmallArray a

fromListN :: Int -> [Item (SmallArray a)] -> SmallArray a

toList :: SmallArray a -> [Item (SmallArray a)]

Eq a => Eq (SmallArray a)

Defined in Data.Primitive.SmallArray

Methods

(==) :: SmallArray a -> SmallArray a -> Bool

(/=) :: SmallArray a -> SmallArray a -> Bool

Data a => Data (SmallArray a)

Defined in Data.Primitive.SmallArray

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> SmallArray a -> c (SmallArray a)

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (SmallArray a)

toConstr :: SmallArray a -> Constr

dataTypeOf :: SmallArray a -> DataType

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (SmallArray a))

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (SmallArray a))

gmapT :: (forall b. Data b => b -> b) -> SmallArray a -> SmallArray a

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> SmallArray a -> r

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> SmallArray a -> r

gmapQ :: (forall d. Data d => d -> u) -> SmallArray a -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> SmallArray a -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> SmallArray a -> m (SmallArray a)

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> SmallArray a -> m (SmallArray a)

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> SmallArray a -> m (SmallArray a)

Ord a => Ord (SmallArray a)

Lexicographic ordering. Subject to change between major versions.

Defined in Data.Primitive.SmallArray

Methods

compare :: SmallArray a -> SmallArray a -> Ordering

(<) :: SmallArray a -> SmallArray a -> Bool

(<=) :: SmallArray a -> SmallArray a -> Bool

(>) :: SmallArray a -> SmallArray a -> Bool

(>=) :: SmallArray a -> SmallArray a -> Bool

max :: SmallArray a -> SmallArray a -> SmallArray a

min :: SmallArray a -> SmallArray a -> SmallArray a

Read a => Read (SmallArray a)

Defined in Data.Primitive.SmallArray

Methods

readsPrec :: Int -> ReadS (SmallArray a)

readList :: ReadS [SmallArray a]

readPrec :: ReadPrec (SmallArray a)

readListPrec :: ReadPrec [SmallArray a]

Show a => Show (SmallArray a)

Defined in Data.Primitive.SmallArray

Methods

showsPrec :: Int -> SmallArray a -> ShowS

show :: SmallArray a -> String

showList :: [SmallArray a] -> ShowS

Semigroup (SmallArray a)

Since: 0.6.3.0

Defined in Data.Primitive.SmallArray

Methods

(<>) :: SmallArray a -> SmallArray a -> SmallArray a

sconcat :: NonEmpty (SmallArray a) -> SmallArray a

stimes :: Integral b => b -> SmallArray a -> SmallArray a

Monoid (SmallArray a)

Defined in Data.Primitive.SmallArray

Methods

mempty :: SmallArray a

mappend :: SmallArray a -> SmallArray a -> SmallArray a

mconcat :: [SmallArray a] -> SmallArray a

PrimUnlifted (SmallArray a)

Defined in Data.Primitive.UnliftedArray

Methods

toArrayArray# :: SmallArray a -> ArrayArray#

fromArrayArray# :: ArrayArray# -> SmallArray a

type Item (SmallArray a)

Defined in Data.Primitive.SmallArray

type Item (SmallArray a) = a

data SmallMutableArray s a

Constructors

SmallMutableArray (SmallMutableArray# s a)

Instances

Eq (SmallMutableArray s a)

Defined in Data.Primitive.SmallArray

Methods

(==) :: SmallMutableArray s a -> SmallMutableArray s a -> Bool

(/=) :: SmallMutableArray s a -> SmallMutableArray s a -> Bool

(Typeable s, Typeable a) => Data (SmallMutableArray s a)

Defined in Data.Primitive.SmallArray

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> SmallMutableArray s a -> c (SmallMutableArray s a)

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (SmallMutableArray s a)

toConstr :: SmallMutableArray s a -> Constr

dataTypeOf :: SmallMutableArray s a -> DataType

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (SmallMutableArray s a))

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (SmallMutableArray s a))

gmapT :: (forall b. Data b => b -> b) -> SmallMutableArray s a -> SmallMutableArray s a

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> SmallMutableArray s a -> r

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> SmallMutableArray s a -> r

gmapQ :: (forall d. Data d => d -> u) -> SmallMutableArray s a -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> SmallMutableArray s a -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> SmallMutableArray s a -> m (SmallMutableArray s a)

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> SmallMutableArray s a -> m (SmallMutableArray s a)

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> SmallMutableArray s a -> m (SmallMutableArray s a)

PrimUnlifted (SmallMutableArray s a)

Defined in Data.Primitive.UnliftedArray

Methods

toArrayArray# :: SmallMutableArray s a -> ArrayArray#

fromArrayArray# :: ArrayArray# -> SmallMutableArray s a

newSmallArray

Arguments

:: PrimMonad m

=> Int

size

-> a

initial contents

-> m (SmallMutableArray (PrimState m) a)

Create a new small mutable array.

readSmallArray

Arguments

:: PrimMonad m

=> SmallMutableArray (PrimState m) a

array

-> Int

index

-> m a

Read the element at a given index in a mutable array.

writeSmallArray

Arguments

:: PrimMonad m

=> SmallMutableArray (PrimState m) a

array

-> Int

index

-> a

new element

-> m ()

Write an element at the given idex in a mutable array.

copySmallArray

Arguments

:: PrimMonad m

=> SmallMutableArray (PrimState m) a

destination

-> Int

destination offset

-> SmallArray a

source

-> Int

source offset

-> Int

length

-> m ()

Copy a slice of an immutable array into a mutable array.

copySmallMutableArray

Arguments

:: PrimMonad m

=> SmallMutableArray (PrimState m) a

destination

-> Int

destination offset

-> SmallMutableArray (PrimState m) a

source

-> Int

source offset

-> Int

length

-> m ()

Copy a slice of one mutable array into another.

indexSmallArray

Arguments

:: SmallArray a

array

-> Int

index

-> a

Look up an element in an immutable array.

indexSmallArrayM

Arguments

:: Monad m

=> SmallArray a

array

-> Int

index

-> m a

Look up an element in an immutable array.

The purpose of returning a result using a monad is to allow the caller to avoid retaining references to the array. Evaluating the return value will cause the array lookup to be performed, even though it may not require the element of the array to be evaluated (which could throw an exception). For instance:

data Box a = Box a
...

f sa = case indexSmallArrayM sa 0 of
  Box x -> ...

x is not a closure that references sa as it would be if we instead wrote:

let x = indexSmallArray sa 0

And does not prevent sa from being garbage collected.

Note that Identity is not adequate for this use, as it is a newtype, and cannot be evaluated without evaluating the element.

indexSmallArray## :: SmallArray a -> Int -> (#a#)

Read a value from the immutable array at the given index, returning the result in an unboxed unary tuple. This is currently used to implement folds.

cloneSmallArray

Arguments

:: SmallArray a

source

-> Int

offset

-> Int

length

-> SmallArray a

Create a copy of a slice of an immutable array.

cloneSmallMutableArray

Arguments

:: PrimMonad m

=> SmallMutableArray (PrimState m) a

source

-> Int

offset

-> Int

length

-> m (SmallMutableArray (PrimState m) a)

Create a copy of a slice of a mutable array.

freezeSmallArray

Arguments

:: PrimMonad m

=> SmallMutableArray (PrimState m) a

source

-> Int

offset

-> Int

length

-> m (SmallArray a)

Create an immutable array corresponding to a slice of a mutable array.

This operation copies the portion of the array to be frozen.

unsafeFreezeSmallArray :: PrimMonad m => SmallMutableArray (PrimState m) a -> m (SmallArray a)

Render a mutable array immutable.

This operation performs no copying, so care must be taken not to modify the input array after freezing.

thawSmallArray

Arguments

:: PrimMonad m

=> SmallArray a

source

-> Int

offset

-> Int

length

-> m (SmallMutableArray (PrimState m) a)

Create a mutable array corresponding to a slice of an immutable array.

This operation copies the portion of the array to be thawed.

runSmallArray :: (forall s. ST s (SmallMutableArray s a)) -> SmallArray a

unsafeThawSmallArray :: PrimMonad m => SmallArray a -> m (SmallMutableArray (PrimState m) a)

Render an immutable array mutable.

This operation performs no copying, so care must be taken with its use.

sizeofSmallArray :: SmallArray a -> Int

sizeofSmallMutableArray :: SmallMutableArray s a -> Int

smallArrayFromList :: [a] -> SmallArray a

Create a SmallArray from a list.

smallArrayFromListN :: Int -> [a] -> SmallArray a

Create a SmallArray from a list of a known length. If the length of the list does not match the given length, this throws an exception.

mapSmallArray' :: (a -> b) -> SmallArray a -> SmallArray b

Strict map over the elements of the array.

traverseSmallArrayP :: PrimMonad m => (a -> m b) -> SmallArray a -> m (SmallArray b)

This is the fastest, most straightforward way to traverse an array, but it only works correctly with a sufficiently "affine" PrimMonad instance. In particular, it must only produce *one* result array. ListT-transformed monads, for example, will not work right at all.