Copyright	(c) Edward Kmett 2009
License	BSD3
Maintainer	ekmett@gmail.com
Stability	experimental
Portability	non-portable (MPTCs)
Safe Haskell	Trustworthy
Language	Haskell98

Data.Semigroup.Reducer

Description

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

Synopsis

class Semigroup m => Reducer c m where
- unit :: c -> m
- snoc :: m -> c -> m
- cons :: c -> m -> m
foldMapReduce :: (Foldable f, Monoid m, Reducer e m) => (a -> e) -> f a -> m
foldMapReduce1 :: (Foldable1 f, Reducer e m) => (a -> e) -> f a -> m
foldReduce :: (Foldable f, Monoid m, Reducer e m) => f e -> m
foldReduce1 :: (Foldable1 f, Reducer e m) => f e -> m
pureUnit :: (Applicative f, Reducer c n) => c -> f n
returnUnit :: (Monad m, Reducer c n) => c -> m n
newtype Count = Count {
- getCount :: Int
}

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 #
Instance details Defined in Data.Semigroup.Reducer Methods unit :: Bool -> All # snoc :: All -> Bool -> All # cons :: Bool -> All -> All #
Reducer Bool Any #
Instance details Defined in Data.Semigroup.Reducer Methods unit :: Bool -> Any # snoc :: Any -> Bool -> Any # cons :: Bool -> Any -> Any #
Reducer Int IntSet #
Instance details Defined in Data.Semigroup.Reducer Methods unit :: Int -> IntSet # snoc :: IntSet -> Int -> IntSet # cons :: Int -> IntSet -> IntSet #
Reducer c () #
Instance details Defined in Data.Semigroup.Reducer Methods unit :: c -> () # snoc :: () -> c -> () # cons :: c -> () -> () #
Reducer a Count #
Instance details Defined in Data.Semigroup.Reducer Methods unit :: a -> Count # snoc :: Count -> a -> Count # cons :: a -> Count -> Count #
Monoid m => Reducer m (WrappedMonoid m) #
Instance details Defined in Data.Semigroup.Reducer Methods unit :: m -> WrappedMonoid m # snoc :: WrappedMonoid m -> m -> WrappedMonoid m # cons :: m -> WrappedMonoid m -> WrappedMonoid m #
Ord a => Reducer a (Set a) #
Instance details Defined in Data.Semigroup.Reducer Methods unit :: a -> Set a # snoc :: Set a -> a -> Set a # cons :: a -> Set a -> Set a #
Reducer a (Seq a) #
Instance details Defined in Data.Semigroup.Reducer Methods unit :: a -> Seq a # snoc :: Seq a -> a -> Seq a # cons :: a -> Seq a -> Seq a #
Reducer a (Last a) #
Instance details Defined in Data.Semigroup.Reducer Methods unit :: a -> Last a # snoc :: Last a -> a -> Last a # cons :: a -> Last a -> Last a #
Reducer a (First a) #
Instance details Defined in Data.Semigroup.Reducer Methods unit :: a -> First a # snoc :: First a -> a -> First a # cons :: a -> First a -> First a #
Ord a => Reducer a (Max a) #
Instance details 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) #
Instance details Defined in Data.Semigroup.Reducer Methods unit :: a -> Min a # snoc :: Min a -> a -> Min a # cons :: a -> Min a -> Min a #
Num a => Reducer a (Product a) #
Instance details 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) #
Instance details Defined in Data.Semigroup.Reducer Methods unit :: a -> Sum a # snoc :: Sum a -> a -> Sum a # cons :: a -> Sum a -> Sum a #
Semigroup a => Reducer a (Dual a) #
Instance details Defined in Data.Semigroup.Reducer Methods unit :: a -> Dual a # snoc :: Dual a -> a -> Dual a # cons :: a -> Dual a -> Dual a #
Reducer c [c] #
Instance details Defined in Data.Semigroup.Reducer Methods unit :: c -> [c] # snoc :: [c] -> c -> [c] # cons :: c -> [c] -> [c] #
Semigroup m => Reducer m (Self m) #
Instance details Defined in Data.Semigroup.Self Methods unit :: m -> Self m # snoc :: Self m -> m -> Self m # cons :: m -> Self m -> Self m #
HasUnion f => Reducer f (Union f) #
Instance details Defined in Data.Semigroup.Union Methods unit :: f -> Union f # snoc :: Union f -> f -> Union f # cons :: f -> Union f -> Union f #
Measured v a => Reducer a (FingerTree v a) #
Instance details 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) #
Instance details 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) #
Instance details 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) #
Instance details 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) (Last a) #
Instance details 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 #
Reducer (Maybe a) (First a) #
Instance details 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 #
Monad f => Reducer (f a) (Action f) #
Instance details 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 #
Apply f => Reducer (f a) (Trav f) #
Instance details 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 #
Applicative f => Reducer (f a) (Traversal f) #
Instance details 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 #
MonadPlus f => Reducer (f a) (MonadSum f a) #
Instance details 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 #
(Monad f, Reducer c m) => Reducer (f c) (Mon f m) #
Instance details 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 #
(Apply f, Reducer c m) => Reducer (f c) (App f m) #
Instance details 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 #
(Applicative f, Reducer c m) => Reducer (f c) (Ap f m) #
Instance details 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 #
Alternative f => Reducer (f a) (Alternate f a) #
Instance details 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 #
Alt f => Reducer (f a) (Alter f a) #
Instance details 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 #
(HasUnionWith f, Semigroup m, Monoid m) => Reducer (f m) (UnionWith f m) #
Instance details 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 #
Instance details 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 (a -> a) (Endo a) #
Instance details 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 #
Reducer (Int, v) (IntMap v) #
Instance details 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 #
(Eq k, Hashable k) => Reducer (k, v) (HashMap k v) #
Instance details 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 #
Ord k => Reducer (k, v) (Map k v) #
Instance details 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 #

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

Eq Count #
Instance details Defined in Data.Semigroup.Reducer Methods (==) :: Count -> Count -> Bool # (/=) :: Count -> Count -> Bool #
Data Count #
Instance details 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 :: (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 #
Ord Count #
Instance details 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 #
Read Count #
Instance details Defined in Data.Semigroup.Reducer Methods readsPrec :: Int -> ReadS Count # readList :: ReadS [Count] # readPrec :: ReadPrec Count # readListPrec :: ReadPrec [Count] #
Show Count #
Instance details Defined in Data.Semigroup.Reducer Methods showsPrec :: Int -> Count -> ShowS # show :: Count -> String # showList :: [Count] -> ShowS #
Semigroup Count #
Instance details Defined in Data.Semigroup.Reducer Methods (<>) :: Count -> Count -> Count # sconcat :: NonEmpty Count -> Count # stimes :: Integral b => b -> Count -> Count #
Monoid Count #
Instance details Defined in Data.Semigroup.Reducer Methods mempty :: Count # mappend :: Count -> Count -> Count # mconcat :: [Count] -> Count #
Hashable Count #
Instance details Defined in Data.Semigroup.Reducer Methods hashWithSalt :: Int -> Count -> Int # hash :: Count -> Int #
Reducer a Count #
Instance details Defined in Data.Semigroup.Reducer Methods unit :: a -> Count # snoc :: Count -> a -> Count # cons :: a -> Count -> Count #