Safe Haskell | Trustworthy |
---|

This module provides finite maps that only grow. It is based on a
*concurrent skip list* implementation of maps.

This module is usually a more efficient alternative to
`PureMap`

, and provides almost the same interface. However,
it's always good to test multiple data structures if you have a
performance-critical use case.

- data IMap k s v
- newEmptyMap :: Ord k => Par e s (IMap k s v)
- newMap :: Ord k => Map k v -> Par e s (IMap k s v)
- newFromList :: (Ord k, Eq v) => [(k, v)] -> Par e s (IMap k s v)
- insert :: (Ord k, Eq v, HasPut e) => k -> v -> IMap k s v -> Par e s ()
- getKey :: (HasGet e, Ord k) => k -> IMap k s v -> Par e s v
- waitSize :: HasGet e => Int -> IMap k s v -> Par e s ()
- waitValue :: (HasGet e, Ord k, Eq v) => v -> IMap k s v -> Par e s ()
- modify :: forall f a b e s key. (Ord key, LVarData1 f, Show key, Ord a, HasPut e) => IMap key s (f s a) -> key -> Par e s (f s a) -> (f s a -> Par e s b) -> Par e s b
- gmodify :: forall f a b e s key. (Ord key, LVarData1 f, LVarWBottom f, LVContents f a, Show key, Ord a, HasPut e) => IMap key s (f s a) -> key -> (f s a -> Par e s b) -> Par e s b
- getOrInit :: forall f a b e s key. (Ord key, LVarData1 f, LVarWBottom f, LVContents f a, Show key, Ord a, HasPut e) => key -> IMap key s (f s a) -> Par e s (f s a)
- freezeMap :: (HasFreeze e, Ord k) => IMap k s v -> Par e s (IMap k Frzn v)
- fromIMap :: IMap k Frzn a -> Map k a
- traverseFrzn_ :: Ord k => (k -> a -> Par e s ()) -> IMap k Frzn a -> Par e s ()
- forEach :: IMap k s v -> (k -> v -> Par e s ()) -> Par e s ()
- forEachHP :: Maybe HandlerPool -> IMap k s v -> (k -> v -> Par e s ()) -> Par e s ()
- withCallbacksThenFreeze :: forall k v b s e. (HasPut e, HasGet e, HasFreeze e, Eq b) => IMap k s v -> (k -> v -> Par e s ()) -> Par e s b -> Par e s b
- copy :: (Ord k, Eq v, HasPut e) => IMap k s v -> Par e s (IMap k s v)
- traverseMap :: (Ord k, Eq b, HasPut e) => (k -> a -> Par e s b) -> IMap k s a -> Par e s (IMap k s b)
- traverseMap_ :: (Ord k, Eq b, HasPut e) => (k -> a -> Par e s b) -> IMap k s a -> IMap k s b -> Par e s ()
- traverseMapHP :: (Ord k, Eq b, HasPut e) => Maybe HandlerPool -> (k -> a -> Par e s b) -> IMap k s a -> Par e s (IMap k s b)
- traverseMapHP_ :: (Ord k, Eq b, HasPut e) => Maybe HandlerPool -> (k -> a -> Par e s b) -> IMap k s a -> IMap k s b -> Par e s ()
- unionHP :: (Ord k, Eq a, HasPut e) => Maybe HandlerPool -> IMap k s a -> IMap k s a -> Par e s (IMap k s a)
- levelCounts :: IMap k s a -> IO [Int]

# The type and its basic operations

data IMap k s v

The map datatype itself. Like all other LVars, it has an `s`

parameter (think
`STRef`

) in addition to the `a`

parameter that describes the type of elements
in the set.

Performance note: this data structure reduces contention between parallel
computations inserting into the map, but all *blocking* computations are not as
scalable. All continuations waiting for not-yet-present elements will currently
share a single queue [2013.09.26].

LVarData1 (IMap k) | An |

OrderedLVarData1 (IMap k) | The |

Foldable (IMap k Trvrsbl) | |

Foldable (IMap k Frzn) | |

Eq (IMap k s v) | Equality is physical equality, as with |

(Show k, Show a) => Show (IMap k Trvrsbl a) | For convenience only; the user could define this. |

(Show k, Show a) => Show (IMap k Frzn a) | |

Generator (IMap k Frzn a) | |

Show k => ParFoldable (IMap k Frzn a) | |

DeepFrz a => DeepFrz (IMap k s a) |

newEmptyMap :: Ord k => Par e s (IMap k s v)

Create a fresh map with nothing in it.

newFromList :: (Ord k, Eq v) => [(k, v)] -> Par e s (IMap k s v)

Create a new map drawing initial elements from an existing list.

insert :: (Ord k, Eq v, HasPut e) => k -> v -> IMap k s v -> Par e s ()

Put a single entry into the map. (WHNF) Strict in the key and value.

getKey :: (HasGet e, Ord k) => k -> IMap k s v -> Par e s v

Wait for the map to contain a specified key, and return the associated value.

waitSize :: HasGet e => Int -> IMap k s v -> Par e s ()

Wait on the SIZE of the map, not its contents.

waitValue :: (HasGet e, Ord k, Eq v) => v -> IMap k s v -> Par e s ()

Wait until the map contains a certain value (on any key).

:: forall f a b e s key . (Ord key, LVarData1 f, Show key, Ord a, HasPut e) | |

=> IMap key s (f s a) | |

-> key | The key to lookup. |

-> Par e s (f s a) | Create a new "bottom" element whenever an entry is not present. |

-> (f s a -> Par e s b) | The computation to apply on the right-hand side of the keyed entry. |

-> Par e s b |

# Generic routines and convenient aliases

:: forall f a b e s key . (Ord key, LVarData1 f, LVarWBottom f, LVContents f a, Show key, Ord a, HasPut e) | |

=> IMap key s (f s a) | |

-> key | The key to lookup. |

-> (f s a -> Par e s b) | The computation to apply on the right-hand side of the keyed entry. |

-> Par e s b |

getOrInit :: forall f a b e s key. (Ord key, LVarData1 f, LVarWBottom f, LVContents f a, Show key, Ord a, HasPut e) => key -> IMap key s (f s a) -> Par e s (f s a)

Return the preexisting value for a key if it exists, and otherwise return

This is a convenience routine that can easily be defined in terms of `gmodify`

# Quasi-deterministic operations

freezeMap :: (HasFreeze e, Ord k) => IMap k s v -> Par e s (IMap k Frzn v)

Get the exact contents of the map. As with any
quasi-deterministic operation, using `freezeMap`

may cause your
program to exhibit a limited form of nondeterminism: it will never
return the wrong answer, but it may include synchronization bugs
that can (nondeterministically) cause exceptions.

This is an *O(1)* operation that doesn't copy the in-memory representation of the
IMap.

fromIMap :: IMap k Frzn a -> Map k a

*O(N)*: Convert from an `IMap`

to a plain `Map`

. This is only permitted
when the `IMap`

has already been frozen. This is useful for processing the
result of `runParThenFreeze`

, using standard library
functions.

traverseFrzn_ :: Ord k => (k -> a -> Par e s ()) -> IMap k Frzn a -> Par e s ()

Traverse a frozen map for side effect. This is useful (in comparison with more generic operations) because the function passed in may see the key as well as the value.

# Iteration and callbacks

forEach :: IMap k s v -> (k -> v -> Par e s ()) -> Par e s ()

Add an (asynchronous) callback that listens for all new new key/value pairs added to the map.

:: Maybe HandlerPool | optional pool to enroll in |

-> IMap k s v | Map to listen to |

-> (k -> v -> Par e s ()) | callback |

-> Par e s () |

Add an (asynchronous) callback that listens for all new key/value pairs added to the map, optionally tied to a handler pool.

withCallbacksThenFreeze :: forall k v b s e. (HasPut e, HasGet e, HasFreeze e, Eq b) => IMap k s v -> (k -> v -> Par e s ()) -> Par e s b -> Par e s b

Register a per-element callback, then run an action in this context, and freeze when all (recursive) invocations of the callback are complete. Returns the final value of the provided action.

# Higher-level derived operations

copy :: (Ord k, Eq v, HasPut e) => IMap k s v -> Par e s (IMap k s v)

Return a fresh map which will contain strictly more elements than the input. That is, things put in the former go in the latter, but not vice versa.

traverseMap :: (Ord k, Eq b, HasPut e) => (k -> a -> Par e s b) -> IMap k s a -> Par e s (IMap k s b)

Establish a monotonic map between the input and output map Produce a new result based on each element, while leaving the keys the same.

traverseMap_ :: (Ord k, Eq b, HasPut e) => (k -> a -> Par e s b) -> IMap k s a -> IMap k s b -> Par e s ()

An imperative-style, in-place version of `traverseMap`

that takes the output map
as an argument.

# Alternate versions of derived ops that expose `HandlerPool`

s they create

traverseMapHP :: (Ord k, Eq b, HasPut e) => Maybe HandlerPool -> (k -> a -> Par e s b) -> IMap k s a -> Par e s (IMap k s b)

Variant of `traverseMap`

that optionally ties the handlers to a pool.

traverseMapHP_ :: (Ord k, Eq b, HasPut e) => Maybe HandlerPool -> (k -> a -> Par e s b) -> IMap k s a -> IMap k s b -> Par e s ()

Variant of `traverseMap_`

that optionally ties the handlers to a pool.

unionHP :: (Ord k, Eq a, HasPut e) => Maybe HandlerPool -> IMap k s a -> IMap k s a -> Par e s (IMap k s a)

Return a new map which will (ultimately) contain everything in either input map. Conflicting entries will result in a multiple put exception. Optionally ties the handlers to a pool.

# Debugging Helpers

levelCounts :: IMap k s a -> IO [Int]