|
| Data.FiniteMap | | Portability | portable | | Stability | provisional | | Maintainer | libraries@haskell.org |
|
|
|
|
| Contents |
- The FiniteMap type
- Construction
- Lookup operations
- Adding elements
- Deleting elements
- Combination
- Extracting information
- Other operations
|
|
| Description |
| A finite map implementation, derived from the paper:
Efficient sets: a balancing act, S. Adams,
Journal of functional programming 3(4) Oct 1993, pp553-562
|
|
| Synopsis |
|
|
|
|
| The FiniteMap type |
|
| data FiniteMap key elt |
| A mapping from keys to elts. | | Instances | |
|
|
| Construction |
|
| emptyFM :: FiniteMap key elt |
| An empty FiniteMap. |
|
| unitFM :: key -> elt -> FiniteMap key elt |
| A FiniteMap containing a single mapping |
|
| listToFM :: (Ord key) => [(key, elt)] -> FiniteMap key elt |
| Makes a FiniteMap from a list of (key,value) pairs. In the
case of duplicates, the last is taken |
|
| Lookup operations |
|
| lookupFM :: (Ord key) => FiniteMap key elt -> key -> Maybe elt |
| Looks up a key in a FiniteMap, returning Just v if the key
was found with value v, or Nothing otherwise. |
|
| lookupWithDefaultFM :: (Ord key) => FiniteMap key elt -> elt -> key -> elt |
| Looks up a key in a FiniteMap, returning elt if the specified
key was not found. |
|
| elemFM :: (Ord key) => key -> FiniteMap key elt -> Bool |
| Returns True if the specified key has a mapping in this
FiniteMap, or False otherwise. |
|
| Adding elements |
|
| addToFM :: (Ord key) => FiniteMap key elt -> key -> elt -> FiniteMap key elt |
| Adds an element to a FiniteMap. Any previous mapping with the same
key is overwritten. |
|
| addToFM_C :: (Ord key) => (elt -> elt -> elt) -> FiniteMap key elt -> key -> elt -> FiniteMap key elt |
| Adds an element to a FiniteMap. If there is already an element
with the same key, then the specified combination function is used
to calculate the new value. |
|
| addListToFM :: (Ord key) => FiniteMap key elt -> [(key, elt)] -> FiniteMap key elt |
| Adds a list of elements to a FiniteMap, in the order given in
the list. Overwrites previous mappings. |
|
| addListToFM_C :: (Ord key) => (elt -> elt -> elt) -> FiniteMap key elt -> [(key, elt)] -> FiniteMap key elt |
| A list version of addToFM_C. The elements are added in the
order given in the list. |
|
| Deleting elements |
|
| delFromFM :: (Ord key) => FiniteMap key elt -> key -> FiniteMap key elt |
| Deletes an element from a FiniteMap. If there is no element with
the specified key, then the original FiniteMap is returned. |
|
| delListFromFM :: (Ord key) => FiniteMap key elt -> [key] -> FiniteMap key elt |
| List version of delFromFM. |
|
| Combination |
|
| plusFM :: (Ord key) => FiniteMap key elt -> FiniteMap key elt -> FiniteMap key elt |
| Combine two FiniteMaps. Mappings in the second argument shadow
those in the first. |
|
| plusFM_C :: (Ord key) => (elt -> elt -> elt) -> FiniteMap key elt -> FiniteMap key elt -> FiniteMap key elt |
| Combine two FiniteMaps. The specified combination function is
used to calculate the new value when there are two elements with
the same key. |
|
| Extracting information |
|
| fmToList :: FiniteMap key elt -> [(key, elt)] |
| Convert a FiniteMap to a [(key, elt)] sorted by Ord key
|
|
| keysFM :: FiniteMap key elt -> [key] |
Extract the keys from a FiniteMap, in the order of the keys, so keysFM == map fst . fmToList
|
|
| eltsFM :: FiniteMap key elt -> [elt] |
Extract the elements from a FiniteMap, in the order of the keys, so eltsFM == map snd . fmToList
|
|
| sizeFM :: FiniteMap key elt -> Int |
|
| isEmptyFM :: FiniteMap key elt -> Bool |
|
| Other operations |
|
| minusFM :: (Ord key) => FiniteMap key elt -> FiniteMap key elt -> FiniteMap key elt |
| (minusFM a1 a2) deletes from a1 any mappings which are bound in a2 |
|
| foldFM :: (key -> elt -> a -> a) -> a -> FiniteMap key elt -> a |
|
| intersectFM :: (Ord key) => FiniteMap key elt -> FiniteMap key elt -> FiniteMap key elt |
| (intersectFM a1 a2) returns a new FiniteMap containing
mappings from a1 for which a2 also has a mapping with the same
key. |
|
| intersectFM_C :: (Ord key) => (elt1 -> elt2 -> elt3) -> FiniteMap key elt1 -> FiniteMap key elt2 -> FiniteMap key elt3 |
| Returns the interesction of two mappings, using the specified
combination function to combine values. |
|
| mapFM :: (key -> elt1 -> elt2) -> FiniteMap key elt1 -> FiniteMap key elt2 |
|
| filterFM :: (Ord key) => (key -> elt -> Bool) -> FiniteMap key elt -> FiniteMap key elt |
|
| Produced by Haddock version 0.3 |
