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Within LTS Haskell 24.66 (ghc-9.10.3)
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contramapMaybe :: (a -> Maybe b) -> OutputStream b -> IO (OutputStream a)io-streams System.IO.Streams.Combinators Contravariant counterpart to contramapMaybe. contramap f s passes all input to s through the function f. Discards all the elements for which f returns Nothing. Since: 1.2.1.0
class
BiPolyMap (map :: Type -> Type -> Type)mono-traversable Data.Containers A Map type polymorphic in both its key and value.
class (MonoTraversable map, SetContainer map) =>
IsMap mapmono-traversable Data.Containers Polymorphic typeclass for interacting with different map types
class
PolyMap (map :: Type -> Type)mono-traversable Data.Containers A guaranteed-polymorphic Map, which allows for more polymorphic versions of functions.
adjustMap :: IsMap map => (MapValue map -> MapValue map) -> ContainerKey map -> map -> mapmono-traversable Data.Containers Apply a function to the value of a given key. Returns the input map when the key-value pair does not exist.
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mono-traversable Data.Containers Update/Delete the value of a given key. Applies a function to previous value of a given key, if it results in Nothing delete the key-value pair from the map, otherwise replace the previous value with the new value.
deleteMap :: IsMap map => ContainerKey map -> map -> mapmono-traversable Data.Containers Delete a key-value pair of a map using a specified key.
differenceMap :: PolyMap map => map value1 -> map value2 -> map value1mono-traversable Data.Containers Get the difference between two maps, using the left map's values.
filterMap :: IsMap map => (MapValue map -> Bool) -> map -> mapmono-traversable Data.Containers Filter values in a map.
insertMap :: IsMap map => ContainerKey map -> MapValue map -> map -> mapmono-traversable Data.Containers Insert a key-value pair into a map.