| Portability | portable |
|---|---|
| Stability | experimental |
| Maintainer | wren@community.haskell.org |
Data.Trie.Convenience
Contents
Description
Additional convenience functions. In order to keep Data.Trie concise, non-essential and uncommonly used functions have been moved here. Most of these functions simplify the generic functions from Data.Trie, following after the interface for Data.Map and Data.IntMap.
- fromListL :: [(ByteString, a)] -> Trie a
- fromListR :: [(ByteString, a)] -> Trie a
- fromListS :: [(ByteString, a)] -> Trie a
- fromListWith :: (a -> a -> a) -> [(ByteString, a)] -> Trie a
- fromListWith' :: (a -> a -> a) -> [(ByteString, a)] -> Trie a
- fromListWithL :: (a -> a -> a) -> [(ByteString, a)] -> Trie a
- fromListWithL' :: (a -> a -> a) -> [(ByteString, a)] -> Trie a
- lookupWithDefault :: a -> ByteString -> Trie a -> a
- insertIfAbsent :: ByteString -> a -> Trie a -> Trie a
- insertWith :: (a -> a -> a) -> ByteString -> a -> Trie a -> Trie a
- insertWith' :: (a -> a -> a) -> ByteString -> a -> Trie a -> Trie a
- insertWithKey :: (ByteString -> a -> a -> a) -> ByteString -> a -> Trie a -> Trie a
- insertWithKey' :: (ByteString -> a -> a -> a) -> ByteString -> a -> Trie a -> Trie a
- adjustWithKey :: (ByteString -> a -> a) -> ByteString -> Trie a -> Trie a
- update :: (a -> Maybe a) -> ByteString -> Trie a -> Trie a
- updateWithKey :: (ByteString -> a -> Maybe a) -> ByteString -> Trie a -> Trie a
- disunion :: Trie a -> Trie a -> Trie a
- unionWith :: (a -> a -> a) -> Trie a -> Trie a -> Trie a
- unionWith' :: (a -> a -> a) -> Trie a -> Trie a -> Trie a
Conversion functions (fromList variants)
Just like fromList all of these functions convert an association
list into a trie, with earlier values shadowing later ones when
keys conflict. Depending on the order of keys in the list, there
can be as much as 5x speed difference between the left and right
variants. Yet, performance is about the same when matching
best-case to best-case and worst-case to worst-case (which is
which is swapped when reversing the list or changing which
function is used).
fromListL :: [(ByteString, a)] -> Trie aSource
fromListR :: [(ByteString, a)] -> Trie aSource
fromListS :: [(ByteString, a)] -> Trie aSource
This variant sorts the list before folding over it. This adds O(n log n) overhead and requires the whole list be in memory at once, but it ensures that the list is in best-case order. The benefits generally outweigh the costs.
fromListWith :: (a -> a -> a) -> [(ByteString, a)] -> Trie aSource
A variant of fromListR that takes a function for combining
values on conflict. The first argument to the combining function
is the `new' value from the initial portion of the list; the
second argument is the value that has been accumulated into the
trie from the tail of the list (just like the first argument to
foldr). Thus, fromList = fromListWith const.
fromListWith' :: (a -> a -> a) -> [(ByteString, a)] -> Trie aSource
A variant of fromListWith which applies the combining
function strictly. This function is a good consumer for list
fusion. If you need list fusion and are running into stack
overflow problems with fromListWith, then this function may
solve the problem.
fromListWithL :: (a -> a -> a) -> [(ByteString, a)] -> Trie aSource
A left-fold variant of fromListWith. Note that the arguments
to the combining function are swapped: the first is the value
in the trie which has been accumulated from the initial part of
the list; the second argument is the `new' value from the
remaining tail of the list (just like the first argument to
foldl). Thus, fromListL = fromListWithL const.
fromListWithL' :: (a -> a -> a) -> [(ByteString, a)] -> Trie aSource
A variant of fromListWithL which applies the combining
function strictly.
Query functions (lookupBy variants)
lookupWithDefault :: a -> ByteString -> Trie a -> aSource
Lookup a key, returning a default value if it's not found.
Inserting values (alterBy variants)
insertIfAbsent :: ByteString -> a -> Trie a -> Trie aSource
Insert a new key, retaining old value on conflict.
insertWith :: (a -> a -> a) -> ByteString -> a -> Trie a -> Trie aSource
Insert a new key, with a function to resolve conflicts.
insertWith' :: (a -> a -> a) -> ByteString -> a -> Trie a -> Trie aSource
A variant of insertWith which applies the combining function
strictly.
insertWithKey :: (ByteString -> a -> a -> a) -> ByteString -> a -> Trie a -> Trie aSource
A variant of insertWith which also provides the key to the
combining function.
insertWithKey' :: (ByteString -> a -> a -> a) -> ByteString -> a -> Trie a -> Trie aSource
A variant of insertWithKey which applies the combining
function strictly.
Updating and adjusting values (alterBy and adjustBy variants)
adjustWithKey :: (ByteString -> a -> a) -> ByteString -> Trie a -> Trie aSource
Apply a function to change the value at a key.
update :: (a -> Maybe a) -> ByteString -> Trie a -> Trie aSource
Apply a function to the value at a key, possibly removing it.
updateWithKey :: (ByteString -> a -> Maybe a) -> ByteString -> Trie a -> Trie aSource
A variant of update which also provides the key to the function.
Combining tries (mergeBy variants)
disunion :: Trie a -> Trie a -> Trie aSource
Combine two tries, a la symmetric difference. If they define the same key, it is removed; otherwise it is retained with the value it has in whichever trie.