Safe Haskell | Safe-Inferred |
---|---|
Language | Haskell2010 |
Additional functions for association lists.
Synopsis
- type AssocList k v = [(k, v)]
- apply :: Ord k => AssocList k v -> k -> Maybe v
- insert :: k -> v -> AssocList k v -> AssocList k v
- delete :: Eq k => k -> AssocList k v -> AssocList k v
- keys :: AssocList k v -> [k]
- update :: Eq k => k -> v -> AssocList k v -> AssocList k v
- mapWithKey :: (k -> v -> v) -> AssocList k v -> AssocList k v
- mapKeysMonotonic :: (k -> k') -> AssocList k v -> AssocList k' v
- updateAt :: Eq k => k -> (v -> v) -> AssocList k v -> AssocList k v
- mapWithKeyM :: Applicative m => (k -> v -> m v) -> AssocList k v -> m (AssocList k v)
- lookup :: Eq a => a -> [(a, b)] -> Maybe b
Documentation
type AssocList k v = [(k, v)] Source #
A finite map, represented as a set of pairs.
Invariant: at most one value per key.
apply :: Ord k => AssocList k v -> k -> Maybe v Source #
Lookup keys in the same association list often.
Use partially applied to create partial function
apply m :: k -> Maybe v
.
- First time:
O(n log n)
in the worst case. - Subsequently:
O(log n)
.
Specification: apply m == (
.lookup
m)
insert :: k -> v -> AssocList k v -> AssocList k v Source #
O(1). Add a new binding. Assumes the binding is not yet in the list.
delete :: Eq k => k -> AssocList k v -> AssocList k v Source #
O(n). Delete a binding. The key must be in the domain of the finite map. Otherwise, an internal error is raised.
update :: Eq k => k -> v -> AssocList k v -> AssocList k v Source #
O(n). Update the value at a key. The key must be in the domain of the finite map. Otherwise, an internal error is raised.
mapWithKey :: (k -> v -> v) -> AssocList k v -> AssocList k v Source #
O(n). Map over an association list, preserving the order.
mapKeysMonotonic :: (k -> k') -> AssocList k v -> AssocList k' v Source #
O(n).
Named in analogy to mapKeysMonotonic
.
To preserve the invariant, it is sufficient that the key
transformation is injective (rather than monotonic).
updateAt :: Eq k => k -> (v -> v) -> AssocList k v -> AssocList k v Source #
O(n). Update the value at a key with a certain function. The key must be in the domain of the finite map. Otherwise, an internal error is raised.
mapWithKeyM :: Applicative m => (k -> v -> m v) -> AssocList k v -> m (AssocList k v) Source #
O(n). If called with a effect-producing function, violation of the invariant could matter here (duplicating effects).