GHC.Arr
| Copyright | (c) The University of Glasgow 1994-2000 |
|---|---|
| License | see libraries/base/LICENSE |
| Maintainer | [email protected] |
| Stability | internal |
| Portability | non-portable (GHC extensions) |
| Safe Haskell | Unsafe |
| Language | Haskell2010 |
Contents
Description
GHC's array implementation.
class Ord a => Ix a where Source
The Ix class is used to map a contiguous subrange of values in a type onto integers. It is used primarily for array indexing (see the array package).
The first argument (l,u) of each of these operations is a pair specifying the lower and upper bounds of a contiguous subrange of values.
An implementation is entitled to assume the following laws about these operations:
-
inRange (l,u) i == elem i (range (l,u)) -
range (l,u) !! index (l,u) i == i, wheninRange (l,u) i -
map (index (l,u)) (range (l,u))) == [0..rangeSize (l,u)-1] -
rangeSize (l,u) == length (range (l,u))
Minimal complete definition
range, (index | unsafeIndex), inRange
Methods
The list of values in the subrange defined by a bounding pair.
index :: (a, a) -> a -> Int Source
The position of a subscript in the subrange.
unsafeIndex :: (a, a) -> a -> Int Source
Like index, but without checking that the value is in range.
inRange :: (a, a) -> a -> Bool Source
Returns True the given subscript lies in the range defined the bounding pair.
rangeSize :: (a, a) -> Int Source
The size of the subrange defined by a bounding pair.
unsafeRangeSize :: (a, a) -> Int Source
like rangeSize, but without checking that the upper bound is in range.
Instances
The type of immutable non-strict (boxed) arrays with indices in i and elements in e.
Instances
| Functor (Array i) | Since: base-2.1 |
| Foldable (Array i) | Since: base-4.8.0.0 |
Defined in Data.Foldable Methodsfold :: Monoid m => Array i m -> m Source foldMap :: Monoid m => (a -> m) -> Array i a -> m Source foldMap' :: Monoid m => (a -> m) -> Array i a -> m Source foldr :: (a -> b -> b) -> b -> Array i a -> b Source foldr' :: (a -> b -> b) -> b -> Array i a -> b Source foldl :: (b -> a -> b) -> b -> Array i a -> b Source foldl' :: (b -> a -> b) -> b -> Array i a -> b Source foldr1 :: (a -> a -> a) -> Array i a -> a Source foldl1 :: (a -> a -> a) -> Array i a -> a Source toList :: Array i a -> [a] Source null :: Array i a -> Bool Source length :: Array i a -> Int Source elem :: Eq a => a -> Array i a -> Bool Source maximum :: Ord a => Array i a -> a Source minimum :: Ord a => Array i a -> a Source | |
| Ix i => Traversable (Array i) | Since: base-2.1 |
Defined in Data.Traversable | |
| (Ix i, Eq e) => Eq (Array i e) | Since: base-2.1 |
| (Data a, Data b, Ix a) => Data (Array a b) | Since: base-4.8.0.0 |
Defined in Data.Data Methodsgfoldl :: (forall d b0. Data d => c (d -> b0) -> d -> c b0) -> (forall g. g -> c g) -> Array a b -> c (Array a b) Source gunfold :: (forall b0 r. Data b0 => c (b0 -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Array a b) Source toConstr :: Array a b -> Constr Source dataTypeOf :: Array a b -> DataType Source dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Array a b)) Source dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Array a b)) Source gmapT :: (forall b0. Data b0 => b0 -> b0) -> Array a b -> Array a b Source gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Array a b -> r Source gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Array a b -> r Source gmapQ :: (forall d. Data d => d -> u) -> Array a b -> [u] Source gmapQi :: Int -> (forall d. Data d => d -> u) -> Array a b -> u Source gmapM :: Monad m => (forall d. Data d => d -> m d) -> Array a b -> m (Array a b) Source gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Array a b -> m (Array a b) Source gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Array a b -> m (Array a b) Source | |
| (Ix i, Ord e) => Ord (Array i e) | Since: base-2.1 |
Defined in GHC.Arr | |
| (Ix a, Read a, Read b) => Read (Array a b) | Since: base-2.1 |
| (Ix a, Show a, Show b) => Show (Array a b) | Since: base-2.1 |
Mutable, boxed, non-strict arrays in the ST monad. The type arguments are as follows:
-
s: the state variable argument for theSTtype -
i: the index type of the array (should be an instance ofIx) -
e: the element type of the array.
Constructors
| STArray !i !i !Int (MutableArray# s e) |
Instances
arrEleBottom :: a Source
Arguments
| :: Ix i | |
| => (i, i) | a pair of bounds, each of the index type of the array. These bounds are the lowest and highest indices in the array, in that order. For example, a one-origin vector of length |
| -> [(i, e)] | a list of associations of the form (index, value). Typically, this list will be expressed as a comprehension. An association |
| -> Array i e |
Construct an array with the specified bounds and containing values for given indices within these bounds.
The array is undefined (i.e. bottom) if any index in the list is out of bounds. The Haskell 2010 Report further specifies that if any two associations in the list have the same index, the value at that index is undefined (i.e. bottom). However in GHC's implementation, the value at such an index is the value part of the last association with that index in the list.
Because the indices must be checked for these errors, array is strict in the bounds argument and in the indices of the association list, but non-strict in the values. Thus, recurrences such as the following are possible:
a = array (1,100) ((1,1) : [(i, i * a!(i-1)) | i <- [2..100]])
Not every index within the bounds of the array need appear in the association list, but the values associated with indices that do not appear will be undefined (i.e. bottom).
If, in any dimension, the lower bound is greater than the upper bound, then the array is legal, but empty. Indexing an empty array always gives an array-bounds error, but bounds still yields the bounds with which the array was constructed.
listArray :: Ix i => (i, i) -> [e] -> Array i e Source
Construct an array from a pair of bounds and a list of values in index order.
(!) :: Ix i => Array i e -> i -> e infixl 9 Source
The value at the given index in an array.
safeRangeSize :: Ix i => (i, i) -> Int Source
safeIndex :: Ix i => (i, i) -> Int -> i -> Int Source
badSafeIndex :: Int -> Int -> Int Source
bounds :: Array i e -> (i, i) Source
The bounds with which an array was constructed.
numElements :: Array i e -> Int Source
The number of elements in the array.
numElementsSTArray :: STArray s i e -> Int Source
indices :: Ix i => Array i e -> [i] Source
The list of indices of an array in ascending order.
elems :: Array i e -> [e] Source
The list of elements of an array in index order.
assocs :: Ix i => Array i e -> [(i, e)] Source
The list of associations of an array in index order.
Arguments
| :: Ix i | |
| => (e -> a -> e) | accumulating function |
| -> e | initial value |
| -> (i, i) | bounds of the array |
| -> [(i, a)] | association list |
| -> Array i e |
The accumArray function deals with repeated indices in the association list using an accumulating function which combines the values of associations with the same index.
For example, given a list of values of some index type, hist produces a histogram of the number of occurrences of each index within a specified range:
hist :: (Ix a, Num b) => (a,a) -> [a] -> Array a b hist bnds is = accumArray (+) 0 bnds [(i, 1) | i<-is, inRange bnds i]
accumArray is strict in each result of applying the accumulating function, although it is lazy in the initial value. Thus, unlike arrays built with array, accumulated arrays should not in general be recursive.
adjust :: (e -> a -> e) -> MutableArray# s e -> (Int, a) -> STRep s b -> STRep s b Source
(//) :: Ix i => Array i e -> [(i, e)] -> Array i e infixl 9 Source
Constructs an array identical to the first argument except that it has been updated by the associations in the right argument. For example, if m is a 1-origin, n by n matrix, then
m//[((i,i), 0) | i <- [1..n]]
is the same matrix, except with the diagonal zeroed.
Repeated indices in the association list are handled as for array: Haskell 2010 specifies that the resulting array is undefined (i.e. bottom), but GHC's implementation uses the last association for each index.
accum :: Ix i => (e -> a -> e) -> Array i e -> [(i, a)] -> Array i e Source
accum f takes an array and an association list and accumulates pairs from the list into the array with the accumulating function f. Thus accumArray can be defined using accum:
accumArray f z b = accum f (array b [(i, z) | i <- range b])
accum is strict in all the results of applying the accumulation. However, it is lazy in the initial values of the array.
amap :: (a -> b) -> Array i a -> Array i b Source
ixmap :: (Ix i, Ix j) => (i, i) -> (i -> j) -> Array j e -> Array i e Source
ixmap allows for transformations on array indices. It may be thought of as providing function composition on the right with the mapping that the original array embodies.
A similar transformation of array values may be achieved using fmap from the Array instance of the Functor class.
eqArray :: (Ix i, Eq e) => Array i e -> Array i e -> Bool Source
cmpArray :: (Ix i, Ord e) => Array i e -> Array i e -> Ordering Source
cmpIntArray :: Ord e => Array Int e -> Array Int e -> Ordering Source
newSTArray :: Ix i => (i, i) -> e -> ST s (STArray s i e) Source
boundsSTArray :: STArray s i e -> (i, i) Source
readSTArray :: Ix i => STArray s i e -> i -> ST s e Source
writeSTArray :: Ix i => STArray s i e -> i -> e -> ST s () Source
freezeSTArray :: STArray s i e -> ST s (Array i e) Source
thawSTArray :: Array i e -> ST s (STArray s i e) Source
foldlElems :: (b -> a -> b) -> b -> Array i a -> b Source
A left fold over the elements
foldlElems' :: (b -> a -> b) -> b -> Array i a -> b Source
A strict left fold over the elements
foldl1Elems :: (a -> a -> a) -> Array i a -> a Source
A left fold over the elements with no starting value
foldrElems :: (a -> b -> b) -> b -> Array i a -> b Source
A right fold over the elements
foldrElems' :: (a -> b -> b) -> b -> Array i a -> b Source
A strict right fold over the elements
foldr1Elems :: (a -> a -> a) -> Array i a -> a Source
A right fold over the elements with no starting value
Unsafe operations
fill :: MutableArray# s e -> (Int, e) -> STRep s a -> STRep s a Source
done :: i -> i -> Int -> MutableArray# s e -> STRep s (Array i e) Source
unsafeArray :: Ix i => (i, i) -> [(Int, e)] -> Array i e Source
unsafeArray' :: (i, i) -> Int -> [(Int, e)] -> Array i e Source
lessSafeIndex :: Ix i => (i, i) -> Int -> i -> Int Source
unsafeAt :: Array i e -> Int -> e Source
unsafeReplace :: Array i e -> [(Int, e)] -> Array i e Source
unsafeAccumArray :: Ix i => (e -> a -> e) -> e -> (i, i) -> [(Int, a)] -> Array i e Source
unsafeAccumArray' :: (e -> a -> e) -> e -> (i, i) -> Int -> [(Int, a)] -> Array i e Source
unsafeAccum :: (e -> a -> e) -> Array i e -> [(Int, a)] -> Array i e Source
unsafeReadSTArray :: STArray s i e -> Int -> ST s e Source
unsafeWriteSTArray :: STArray s i e -> Int -> e -> ST s () Source
unsafeFreezeSTArray :: STArray s i e -> ST s (Array i e) Source
unsafeThawSTArray :: Array i e -> ST s (STArray s i e) Source
© The University of Glasgow and others
Licensed under a BSD-style license (see top of the page).
https://downloads.haskell.org/~ghc/8.10.2/docs/html/libraries/base-4.14.1.0/GHC-Arr.html