Data.Semigroup.Reducer

A c-Reducer is a Semigroup with a canonical mapping from c to the Semigroup.

Documentation

class Semigroup m => Reducer c m where

This type may be best read infix. A c Reducer m is a Semigroup m that maps values of type c through unit to values of type m. A c-Reducer may also supply operations which tack-on another c to an existing Monoid m on the left or right. These specialized reductions may be more efficient in some scenarios and are used when appropriate by a Generator. The names cons and snoc work by analogy to the synonymous operations in the list monoid.

This class deliberately avoids functional-dependencies, so that () can be a c-Reducer for all c, and so many common reducers can work over multiple types, for instance, First and Last may reduce both a and Maybe a. Since a Generator has a fixed element type, the input to the reducer is generally known and extracting from the monoid usually is sufficient to fix the result type. Combinators are available for most scenarios where this is not the case, and the few remaining cases can be handled by using an explicit type annotation.

Minimal definition: unit

Minimal complete definition

unit

Methods

unit :: c -> m

Convert a value into a Semigroup

snoc :: m -> c -> m

Append a value to a Semigroup for use in left-to-right reduction

cons :: c -> m -> m

Prepend a value onto a Semigroup for use during right-to-left reduction

Instances

Reducer Bool All

Defined in Data.Semigroup.Reducer

Methods

unit :: Bool -> All

snoc :: All -> Bool -> All

cons :: Bool -> All -> All

Reducer Bool Any

Defined in Data.Semigroup.Reducer

Methods

unit :: Bool -> Any

snoc :: Any -> Bool -> Any

cons :: Bool -> Any -> Any

Reducer Int IntSet

Defined in Data.Semigroup.Reducer

Methods

unit :: Int -> IntSet

snoc :: IntSet -> Int -> IntSet

cons :: Int -> IntSet -> IntSet

Reducer a Count

Defined in Data.Semigroup.Reducer

Methods

unit :: a -> Count

snoc :: Count -> a -> Count

cons :: a -> Count -> Count

Reducer c ()

Defined in Data.Semigroup.Reducer

Methods

unit :: c -> ()

snoc :: () -> c -> ()

cons :: c -> () -> ()

Reducer a (First a)

Defined in Data.Semigroup.Reducer

Methods

unit :: a -> First a

snoc :: First a -> a -> First a

cons :: a -> First a -> First a

Reducer a (Last a)

Defined in Data.Semigroup.Reducer

Methods

unit :: a -> Last a

snoc :: Last a -> a -> Last a

cons :: a -> Last a -> Last a

Ord a => Reducer a (Max a)

Defined in Data.Semigroup.Reducer

Methods

unit :: a -> Max a

snoc :: Max a -> a -> Max a

cons :: a -> Max a -> Max a

Ord a => Reducer a (Min a)

Defined in Data.Semigroup.Reducer

Methods

unit :: a -> Min a

snoc :: Min a -> a -> Min a

cons :: a -> Min a -> Min a

Semigroup a => Reducer a (Dual a)

Defined in Data.Semigroup.Reducer

Methods

unit :: a -> Dual a

snoc :: Dual a -> a -> Dual a

cons :: a -> Dual a -> Dual a

Num a => Reducer a (Product a)

Defined in Data.Semigroup.Reducer

Methods

unit :: a -> Product a

snoc :: Product a -> a -> Product a

cons :: a -> Product a -> Product a

Num a => Reducer a (Sum a)

Defined in Data.Semigroup.Reducer

Methods

unit :: a -> Sum a

snoc :: Sum a -> a -> Sum a

cons :: a -> Sum a -> Sum a

Reducer a (Seq a)

Defined in Data.Semigroup.Reducer

Methods

unit :: a -> Seq a

snoc :: Seq a -> a -> Seq a

cons :: a -> Seq a -> Seq a

Ord a => Reducer a (Set a)

Defined in Data.Semigroup.Reducer

Methods

unit :: a -> Set a

snoc :: Set a -> a -> Set a

cons :: a -> Set a -> Set a

Reducer c [c]

Defined in Data.Semigroup.Reducer

Methods

unit :: c -> [c]

snoc :: [c] -> c -> [c]

cons :: c -> [c] -> [c]

HasUnion f => Reducer f (Union f)

Defined in Data.Semigroup.Union

Methods

unit :: f -> Union f

snoc :: Union f -> f -> Union f

cons :: f -> Union f -> Union f

Monoid m => Reducer m (WrappedMonoid m)

Defined in Data.Semigroup.Reducer

Methods

unit :: m -> WrappedMonoid m

snoc :: WrappedMonoid m -> m -> WrappedMonoid m

cons :: m -> WrappedMonoid m -> WrappedMonoid m

Semigroup m => Reducer m (Self m)

Defined in Data.Semigroup.Self

Methods

unit :: m -> Self m

snoc :: Self m -> m -> Self m

cons :: m -> Self m -> Self m

Measured v a => Reducer a (FingerTree v a)

Defined in Data.Semigroup.Reducer

Methods

unit :: a -> FingerTree v a

snoc :: FingerTree v a -> a -> FingerTree v a

cons :: a -> FingerTree v a -> FingerTree v a

(Reducer c m, Reducer c n) => Reducer c (m, n)

Defined in Data.Semigroup.Reducer

Methods

unit :: c -> (m, n)

snoc :: (m, n) -> c -> (m, n)

cons :: c -> (m, n) -> (m, n)

(Reducer c m, Reducer c n, Reducer c o) => Reducer c (m, n, o)

Defined in Data.Semigroup.Reducer

Methods

unit :: c -> (m, n, o)

snoc :: (m, n, o) -> c -> (m, n, o)

cons :: c -> (m, n, o) -> (m, n, o)

(Reducer c m, Reducer c n, Reducer c o, Reducer c p) => Reducer c (m, n, o, p)

Defined in Data.Semigroup.Reducer

Methods

unit :: c -> (m, n, o, p)

snoc :: (m, n, o, p) -> c -> (m, n, o, p)

cons :: c -> (m, n, o, p) -> (m, n, o, p)

Reducer (Maybe a) (First a)

Defined in Data.Semigroup.Reducer

Methods

unit :: Maybe a -> First a

snoc :: First a -> Maybe a -> First a

cons :: Maybe a -> First a -> First a

Reducer (Maybe a) (Last a)

Defined in Data.Semigroup.Reducer

Methods

unit :: Maybe a -> Last a

snoc :: Last a -> Maybe a -> Last a

cons :: Maybe a -> Last a -> Last a

Applicative f => Reducer (f a) (Traversal f)

Defined in Data.Semigroup.Applicative

Methods

unit :: f a -> Traversal f

snoc :: Traversal f -> f a -> Traversal f

cons :: f a -> Traversal f -> Traversal f

Apply f => Reducer (f a) (Trav f)

Defined in Data.Semigroup.Apply

Methods

unit :: f a -> Trav f

snoc :: Trav f -> f a -> Trav f

cons :: f a -> Trav f -> Trav f

Monad f => Reducer (f a) (Action f)

Defined in Data.Semigroup.Monad

Methods

unit :: f a -> Action f

snoc :: Action f -> f a -> Action f

cons :: f a -> Action f -> Action f

Alt f => Reducer (f a) (Alter f a)

Defined in Data.Semigroup.Alt

Methods

unit :: f a -> Alter f a

snoc :: Alter f a -> f a -> Alter f a

cons :: f a -> Alter f a -> Alter f a

Alternative f => Reducer (f a) (Alternate f a)

Defined in Data.Semigroup.Alternative

Methods

unit :: f a -> Alternate f a

snoc :: Alternate f a -> f a -> Alternate f a

cons :: f a -> Alternate f a -> Alternate f a

MonadPlus f => Reducer (f a) (MonadSum f a)

Defined in Data.Semigroup.MonadPlus

Methods

unit :: f a -> MonadSum f a

snoc :: MonadSum f a -> f a -> MonadSum f a

cons :: f a -> MonadSum f a -> MonadSum f a

(Applicative f, Reducer c m) => Reducer (f c) (Ap f m)

Defined in Data.Semigroup.Applicative

Methods

unit :: f c -> Ap f m

snoc :: Ap f m -> f c -> Ap f m

cons :: f c -> Ap f m -> Ap f m

(Apply f, Reducer c m) => Reducer (f c) (App f m)

Defined in Data.Semigroup.Apply

Methods

unit :: f c -> App f m

snoc :: App f m -> f c -> App f m

cons :: f c -> App f m -> App f m

(Monad f, Reducer c m) => Reducer (f c) (Mon f m)

Defined in Data.Semigroup.Monad

Methods

unit :: f c -> Mon f m

snoc :: Mon f m -> f c -> Mon f m

cons :: f c -> Mon f m -> Mon f m

(HasUnionWith f, Semigroup m, Monoid m) => Reducer (f m) (UnionWith f m)

Defined in Data.Semigroup.Union

Methods

unit :: f m -> UnionWith f m

snoc :: UnionWith f m -> f m -> UnionWith f m

cons :: f m -> UnionWith f m -> UnionWith f m

Reducer c m => Reducer (WithReducer m c) m

Defined in Data.Semigroup.Reducer.With

Methods

unit :: WithReducer m c -> m

snoc :: m -> WithReducer m c -> m

cons :: WithReducer m c -> m -> m

Reducer (Int, v) (IntMap v)

Defined in Data.Semigroup.Reducer

Methods

unit :: (Int, v) -> IntMap v

snoc :: IntMap v -> (Int, v) -> IntMap v

cons :: (Int, v) -> IntMap v -> IntMap v

Reducer (a -> a) (Endo a)

Defined in Data.Semigroup.Reducer

Methods

unit :: (a -> a) -> Endo a

snoc :: Endo a -> (a -> a) -> Endo a

cons :: (a -> a) -> Endo a -> Endo a

Ord k => Reducer (k, v) (Map k v)

Defined in Data.Semigroup.Reducer

Methods

unit :: (k, v) -> Map k v

snoc :: Map k v -> (k, v) -> Map k v

cons :: (k, v) -> Map k v -> Map k v

(Eq k, Hashable k) => Reducer (k, v) (HashMap k v)

Defined in Data.Semigroup.Reducer

Methods

unit :: (k, v) -> HashMap k v

snoc :: HashMap k v -> (k, v) -> HashMap k v

cons :: (k, v) -> HashMap k v -> HashMap k v

foldMapReduce :: (Foldable f, Monoid m, Reducer e m) => (a -> e) -> f a -> m

Apply a Reducer to a Foldable container, after mapping the contents into a suitable form for reduction.

foldMapReduce1 :: (Foldable1 f, Reducer e m) => (a -> e) -> f a -> m

foldReduce :: (Foldable f, Monoid m, Reducer e m) => f e -> m

Apply a Reducer to a Foldable mapping each element through unit

foldReduce1 :: (Foldable1 f, Reducer e m) => f e -> m

Apply a Reducer to a Foldable1 mapping each element through unit

pureUnit :: (Applicative f, Reducer c n) => c -> f n

returnUnit :: (Monad m, Reducer c n) => c -> m n

newtype Count

Constructors

Count

Fields

• getCount :: Int

Instances

Data Count

Defined in Data.Semigroup.Reducer

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Count -> c Count

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Count

toConstr :: Count -> Constr

dataTypeOf :: Count -> DataType

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Count)

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Count)

gmapT :: (forall b. Data b => b -> b) -> Count -> Count

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Count -> r

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Count -> r

gmapQ :: (forall d. Data d => d -> u) -> Count -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> Count -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Count -> m Count

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Count -> m Count

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Count -> m Count

Monoid Count

Defined in Data.Semigroup.Reducer

Methods

mempty :: Count

mappend :: Count -> Count -> Count

mconcat :: [Count] -> Count

Semigroup Count

Defined in Data.Semigroup.Reducer

Methods

(<>) :: Count -> Count -> Count

sconcat :: NonEmpty Count -> Count

stimes :: Integral b => b -> Count -> Count

Read Count

Defined in Data.Semigroup.Reducer

Methods

readsPrec :: Int -> ReadS Count

readList :: ReadS [Count]

readPrec :: ReadPrec Count

readListPrec :: ReadPrec [Count]

Show Count

Defined in Data.Semigroup.Reducer

Methods

showsPrec :: Int -> Count -> ShowS

show :: Count -> String

showList :: [Count] -> ShowS

Eq Count

Defined in Data.Semigroup.Reducer

Methods

(==) :: Count -> Count -> Bool

(/=) :: Count -> Count -> Bool

Ord Count

Defined in Data.Semigroup.Reducer

Methods

compare :: Count -> Count -> Ordering

(<) :: Count -> Count -> Bool

(<=) :: Count -> Count -> Bool

(>) :: Count -> Count -> Bool

(>=) :: Count -> Count -> Bool

max :: Count -> Count -> Count

min :: Count -> Count -> Count

Hashable Count

Defined in Data.Semigroup.Reducer

Methods

hashWithSalt :: Int -> Count -> Int

hash :: Count -> Int

Reducer a Count

Defined in Data.Semigroup.Reducer

Methods

unit :: a -> Count

snoc :: Count -> a -> Count

cons :: a -> Count -> Count