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nonempty-containers Data.IntMap.NonEmpty.Internal A non-empty (by construction) map from integer keys to values a. At least one key-value pair exists in an NEIntMap v at all times. Functions that take an NEIntMap can safely operate on it with the assumption that it has at least one key-value pair. Functions that return an NEIntMap provide an assurance that the result has at least one key-value pair. Data.IntMap.NonEmpty re-exports the API of Data.IntMap, faithfully reproducing asymptotics, typeclass constraints, and semantics. Functions that ensure that input and output maps are both non-empty (like insert) return NEIntMap, but functions that might potentially return an empty map (like delete) return a IntMap instead. You can directly construct an NEIntMap with the API from Data.IntMap.NonEmpty; it's more or less the same as constructing a normal IntMap, except you don't have access to empty. There are also a few ways to construct an NEIntMap from a IntMap:
- The nonEmptyMap smart constructor will convert a IntMap k a into a Maybe (NEIntMap k a), returning Nothing if the original IntMap was empty.
- You can use the insertIntMap family of functions to insert a value into a IntMap to create a guaranteed NEIntMap.
- You can use the IsNonEmpty and IsEmpty patterns to "pattern match" on a IntMap to reveal it as either containing a NEIntMap or an empty map.
- withNonEmpty offers a continuation-based interface for deconstructing a IntMap and treating it as if it were an NEIntMap.
NEIntMap :: Key -> a -> !IntMap a -> NEIntMap anonempty-containers Data.IntMap.NonEmpty.Internal No documentation available.
foldMapWithKey :: Semigroup m => (Key -> a -> m) -> NEIntMap a -> mnonempty-containers Data.IntMap.NonEmpty.Internal O(n). Fold the keys and values in the map using the given semigroup, such that
foldMapWithKey f = fold1 . mapWithKey f
WARNING: Differs from Data.IntMap.foldMapWithKey, which traverses positive items first, then negative items. This can be an asymptotically faster than foldrWithKey or foldlWithKey for some monoids.insertMaxMap :: Key -> a -> IntMap a -> IntMap anonempty-containers Data.IntMap.NonEmpty.Internal O(log n). Insert new key and value into a map where keys are strictly less than the new key. That is, the new key must be strictly greater than all keys present in the IntMap. /The precondition is not checked./ At the moment this is simply an alias for Data.IntSet.insert, but it's left here as a placeholder in case this eventually gets implemented in a more efficient way.
insertMinMap :: Key -> a -> IntMap a -> IntMap anonempty-containers Data.IntMap.NonEmpty.Internal O(log n). Insert new key and value into a map where keys are strictly greater than the new key. That is, the new key must be strictly less than all keys present in the IntMap. /The precondition is not checked./ At the moment this is simply an alias for Data.IntSet.insert, but it's left here as a placeholder in case this eventually gets implemented in a more efficient way.
neimIntMap :: NEIntMap a -> !IntMap anonempty-containers Data.IntMap.NonEmpty.Internal No documentation available.
nonEmptyMap :: IntMap a -> Maybe (NEIntMap a)nonempty-containers Data.IntMap.NonEmpty.Internal O(log n). Smart constructor for an NEIntMap from a IntMap. Returns Nothing if the IntMap was originally actually empty, and Just n with an NEIntMap, if the IntMap was not empty. nonEmptyMap and maybe empty toMap form an isomorphism: they are perfect structure-preserving inverses of eachother. See IsNonEmpty for a pattern synonym that lets you "match on" the possiblity of a IntMap being an NEIntMap.
nonEmptyMap (Data.IntMap.fromList [(3,"a"), (5,"b")]) == Just (fromList ((3,"a") :| [(5,"b")]))
toMap :: NEIntMap a -> IntMap anonempty-containers Data.IntMap.NonEmpty.Internal O(log n). Convert a non-empty map back into a normal possibly-empty map, for usage with functions that expect IntMap. Can be thought of as "obscuring" the non-emptiness of the map in its type. See the IsNotEmpty pattern. nonEmptyMap and maybe empty toMap form an isomorphism: they are perfect structure-preserving inverses of eachother.
toMap (fromList ((3,"a") :| [(5,"b")])) == Data.IntMap.fromList [(3,"a"), (5,"b")]
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nonempty-containers Data.Map.NonEmpty A non-empty (by construction) map from keys k to values a. At least one key-value pair exists in an NEMap k v at all times. Functions that take an NEMap can safely operate on it with the assumption that it has at least one key-value pair. Functions that return an NEMap provide an assurance that the result has at least one key-value pair. Data.Map.NonEmpty re-exports the API of Data.Map, faithfully reproducing asymptotics, typeclass constraints, and semantics. Functions that ensure that input and output maps are both non-empty (like insert) return NEMap, but functions that might potentially return an empty map (like delete) return a Map instead. You can directly construct an NEMap with the API from Data.Map.NonEmpty; it's more or less the same as constructing a normal Map, except you don't have access to empty. There are also a few ways to construct an NEMap from a Map:
- The nonEmptyMap smart constructor will convert a Map k a into a Maybe (NEMap k a), returning Nothing if the original Map was empty.
- You can use the insertMap family of functions to insert a value into a Map to create a guaranteed NEMap.
- You can use the IsNonEmpty and IsEmpty patterns to "pattern match" on a Map to reveal it as either containing a NEMap or an empty map.
- withNonEmpty offers a continuation-based interface for deconstructing a Map and treating it as if it were an NEMap.
absurdNEMap :: NEMap Void a -> bnonempty-containers Data.Map.NonEmpty Special property of non-empty maps: The type of non-empty maps over uninhabited keys is itself uninhabited. This property also exists for values inside a non-empty container (like for NESet, NESeq, and NEIntMap); this can be witnessed using the function absurd . fold1.