Data.Monoid.Flux

Flux is a monoid which detects the number of times a value changes across a sequence

getFlux $ foldMap flux ["a", "b", "b", "a"]
2
getFlux $ foldMap flux ["a", "b", "b", "a", "c", "c", "c"]
3

Documentation

data Flux a

Flux is a monoid which counts the number of times an element changes (according to its Eq instance) This is useful for gaining associativity (and its associated performance improvements) for tasks where you'd otherwise use group or groupBy

It also allows usage of change-detection semantics in situations where a Monoid is required; e.g. in a FingerTree

Constructors

Flux

Fields

• sides :: Maybe (a, a)
• getFlux :: Int

Instances

Eq a => Eq (Flux a)

Methods

(==) :: Flux a -> Flux a -> Bool

(/=) :: Flux a -> Flux a -> Bool

Show a => Show (Flux a)

Methods

showsPrec :: Int -> Flux a -> ShowS

show :: Flux a -> String

showList :: [Flux a] -> ShowS

Eq a => Monoid (Flux a)

Methods

mempty :: Flux a

mappend :: Flux a -> Flux a -> Flux a

mconcat :: [Flux a] -> Flux a

flux :: a -> Flux a

Embed a single value into a Flux; number of changes starts at 0.