Safe Haskell | None |
---|---|

Language | Haskell98 |

Additional functions for association lists.

- type AssocList k v = [(k, v)]
- lookup :: Eq k => k -> AssocList k v -> Maybe v
- keys :: AssocList k v -> [k]
- insert :: k -> v -> AssocList k v -> AssocList k v
- update :: Eq k => k -> v -> AssocList k v -> AssocList k v
- updateAt :: Eq k => k -> (v -> v) -> AssocList k v -> AssocList k v
- mapWithKey :: (k -> v -> v) -> AssocList k v -> AssocList k v
- mapWithKeyM :: Applicative m => (k -> v -> m v) -> AssocList k v -> m (AssocList k v)
- mapKeysMonotonic :: (k -> k') -> AssocList k v -> AssocList k' v

# Documentation

type AssocList k v = [(k, v)] Source #

A finite map, represented as a set of pairs.

Invariant: at most one value per key.

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.

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.

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.

mapWithKey :: (k -> v -> v) -> AssocList k v -> AssocList k v Source #

O(n). Map over an association list, preserving the order.

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).

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).