| Copyright | (c) Fumiaki Kinoshita 2015 |
|---|---|
| License | BSD3 |
| Maintainer | Fumiaki Kinoshita <fumiexcel@gmail.com> |
| Stability | provisional |
| Portability | non-portable |
| Safe Haskell | Trustworthy |
| Language | Haskell2010 |
Data.Witherable
Description
Synopsis
- class Functor f => Filterable f where
- (<$?>) :: Filterable f => (a -> Maybe b) -> f a -> f b
- (<&?>) :: Filterable f => f a -> (a -> Maybe b) -> f b
- class (Traversable t, Filterable t) => Witherable t where
- wither :: Applicative f => (a -> f (Maybe b)) -> t a -> f (t b)
- witherM :: Monad m => (a -> m (Maybe b)) -> t a -> m (t b)
- filterA :: Applicative f => (a -> f Bool) -> t a -> f (t a)
- ordNub :: (Witherable t, Ord a) => t a -> t a
- hashNub :: (Witherable t, Eq a, Hashable a) => t a -> t a
- forMaybe :: (Witherable t, Applicative f) => t a -> (a -> f (Maybe b)) -> f (t b)
- class (FunctorWithIndex i t, Filterable t) => FilterableWithIndex i t | t -> i where
- class (TraversableWithIndex i t, Witherable t) => WitherableWithIndex i t | t -> i where
- iwither :: Applicative f => (i -> a -> f (Maybe b)) -> t a -> f (t b)
- iwitherM :: Monad m => (i -> a -> m (Maybe b)) -> t a -> m (t b)
- ifilterA :: Applicative f => (i -> a -> f Bool) -> t a -> f (t a)
- type FilterLike f s t a b = (a -> f (Maybe b)) -> s -> f t
- type Filter s t a b = forall f. Applicative f => FilterLike f s t a b
- type FilterLike' f s a = FilterLike f s s a a
- type Filter' s a = forall f. Applicative f => FilterLike' f s a
- witherOf :: FilterLike f s t a b -> (a -> f (Maybe b)) -> s -> f t
- forMaybeOf :: FilterLike f s t a b -> s -> (a -> f (Maybe b)) -> f t
- mapMaybeOf :: FilterLike Identity s t a b -> (a -> Maybe b) -> s -> t
- catMaybesOf :: FilterLike Identity s t (Maybe a) a -> s -> t
- filterAOf :: Functor f => FilterLike' f s a -> (a -> f Bool) -> s -> f s
- filterOf :: FilterLike' Identity s a -> (a -> Bool) -> s -> s
- ordNubOf :: Ord a => FilterLike' (State (Set a)) s a -> s -> s
- hashNubOf :: (Eq a, Hashable a) => FilterLike' (State (HashSet a)) s a -> s -> s
- cloneFilter :: FilterLike (Peat a b) s t a b -> Filter s t a b
- newtype Peat a b t = Peat {
- runPeat :: forall f. Applicative f => (a -> f (Maybe b)) -> f t
- newtype WrappedFoldable f a = WrapFilterable {
- unwrapFoldable :: f a
Documentation
class Functor f => Filterable f where Source #
Like Functor, but you can remove elements instead of updating them.
Formally, the class Filterable represents a functor from Kleisli Maybe to Hask.
A definition of mapMaybe must satisfy the following laws:
Methods
mapMaybe :: (a -> Maybe b) -> f a -> f b Source #
Like mapMaybe.
catMaybes :: f (Maybe a) -> f a Source #
filter :: (a -> Bool) -> f a -> f a Source #
Filterablef .Filterableg ≡ filter (liftA2(&&) f g)
Instances
(<$?>) :: Filterable f => (a -> Maybe b) -> f a -> f b infixl 4 Source #
(<&?>) :: Filterable f => f a -> (a -> Maybe b) -> f b infixl 1 Source #
class (Traversable t, Filterable t) => Witherable t where Source #
An enhancement of Traversable with Filterable
A definition of wither must satisfy the following laws:
- conservation
wither(fmapJust. f) ≡traversef- composition
Compose.fmap(witherf) .witherg ≡wither(Compose.fmap(witherf) . g)
Parametricity implies the naturality law:
t .witherf ≡wither(t . f)
Minimal complete definition
Nothing
Methods
wither :: Applicative f => (a -> f (Maybe b)) -> t a -> f (t b) Source #
witherM :: Monad m => (a -> m (Maybe b)) -> t a -> m (t b) Source #
Monadic variant of wither. This may have more efficient implementation.filterA :: Applicative f => (a -> f Bool) -> t a -> f (t a) Source #
Instances
ordNub :: (Witherable t, Ord a) => t a -> t a Source #
forMaybe :: (Witherable t, Applicative f) => t a -> (a -> f (Maybe b)) -> f (t b) Source #
Indexed variants
class (FunctorWithIndex i t, Filterable t) => FilterableWithIndex i t | t -> i where Source #
Indexed variant of Filterable.
Minimal complete definition
Nothing
Instances
class (TraversableWithIndex i t, Witherable t) => WitherableWithIndex i t | t -> i where Source #
Indexed variant of Witherable.
Minimal complete definition
Nothing
Methods
iwither :: Applicative f => (i -> a -> f (Maybe b)) -> t a -> f (t b) Source #
iwitherM :: Monad m => (i -> a -> m (Maybe b)) -> t a -> m (t b) Source #
Monadic variant of wither. This may have more efficient implementation.ifilterA :: Applicative f => (i -> a -> f Bool) -> t a -> f (t a) Source #
Instances
Generalization
type FilterLike f s t a b = (a -> f (Maybe b)) -> s -> f t Source #
This type allows combinators to take a Filter specializing the parameter f.
type Filter s t a b = forall f. Applicative f => FilterLike f s t a b Source #
type FilterLike' f s a = FilterLike f s s a a Source #
A simple FilterLike.
type Filter' s a = forall f. Applicative f => FilterLike' f s a Source #
A simple Filter.
witherOf :: FilterLike f s t a b -> (a -> f (Maybe b)) -> s -> f t Source #
forMaybeOf :: FilterLike f s t a b -> s -> (a -> f (Maybe b)) -> f t Source #
mapMaybeOf :: FilterLike Identity s t a b -> (a -> Maybe b) -> s -> t Source #
mapMaybe through a filter.
catMaybesOf :: FilterLike Identity s t (Maybe a) a -> s -> t Source #
catMaybes through a filter.
filterAOf :: Functor f => FilterLike' f s a -> (a -> f Bool) -> s -> f s Source #
filterA through a filter.
filterOf :: FilterLike' Identity s a -> (a -> Bool) -> s -> s Source #
Filter each element of a structure targeted by a Filter.
ordNubOf :: Ord a => FilterLike' (State (Set a)) s a -> s -> s Source #
Remove the duplicate elements through a filter.
hashNubOf :: (Eq a, Hashable a) => FilterLike' (State (HashSet a)) s a -> s -> s Source #
Remove the duplicate elements through a filter.
It is often faster than ordNubOf, especially when the comparison is expensive.
Cloning
cloneFilter :: FilterLike (Peat a b) s t a b -> Filter s t a b Source #
Reconstitute a Filter from its monomorphic form.
This is used to characterize and clone a Filter.
Since FilterLike (Peat a b) s t a b is monomorphic, it can be used to store a filter in a container.
Constructors
| Peat | |
Fields
| |
Wrapper
newtype WrappedFoldable f a Source #
Constructors
| WrapFilterable | |
Fields
| |