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| Data.Array.Diff | | Portability | non-portable | | Stability | experimental | | Maintainer | libraries@haskell.org |
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| Description |
| Functional arrays with constant-time update.
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| Synopsis |
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| Diff array types |
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Diff arrays have an immutable interface, but rely on internal
updates in place to provide fast functional update operator
//.
When the // operator is applied to a diff array, its contents
are physically updated in place. The old array silently changes
its representation without changing the visible behavior:
it stores a link to the new current array along with the
difference to be applied to get the old contents.
So if a diff array is used in a single-threaded style,
i.e. after // application the old version is no longer used,
a'!'i takes O(1) time and a // d takes O(length d).
Accessing elements of older versions gradually becomes slower.
Updating an array which is not current makes a physical copy.
The resulting array is unlinked from the old family. So you
can obtain a version which is guaranteed to be current and
thus have fast element access by a // []. |
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| data IOToDiffArray a i e |
| An arbitrary MArray type living in the IO monad can be converted
to a diff array. | | Instances | |
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| Type synonyms for the two most important IO array types. |
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| type DiffArray = IOToDiffArray IOArray |
| Fully polymorphic lazy boxed diff array. |
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| type DiffUArray = IOToDiffArray IOUArray |
| Strict unboxed diff array, working only for elements
of primitive types but more compact and usually faster than DiffArray. |
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| Overloaded immutable array interface |
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| Module Data.Array.IArray provides the interface of diff arrays.
They are instances of class IArray. |
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| module Data.Array.IArray |
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| Low-level interface |
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| These are really internal functions, but you will need them
to make further IArray instances of various diff array types
(for either more MArray types or more unboxed element types). |
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| newDiffArray :: (MArray a e IO, Ix i) => (i, i) -> [(Int, e)] -> IO (IOToDiffArray a i e) |
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| readDiffArray :: (MArray a e IO, Ix i) => IOToDiffArray a i e -> Int -> IO e |
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| replaceDiffArray :: (MArray a e IO, Ix i) => IOToDiffArray a i e -> [(Int, e)] -> IO (IOToDiffArray a i e) |
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| Produced by Haddock version 0.6 |
