Fold.Nonempty

Type

data NonemptyFold a b

Processes at least one input of type a and results in a value of type b

Constructors

forall x. NonemptyFold

Fields

• initial :: a -> x
• step :: x -> a -> x
• extract :: x -> b

Instances

Applicative (NonemptyFold a)

Defined in Fold.Nonempty.Type

Methods

pure :: a0 -> NonemptyFold a a0

(<*>) :: NonemptyFold a (a0 -> b) -> NonemptyFold a a0 -> NonemptyFold a b

liftA2 :: (a0 -> b -> c) -> NonemptyFold a a0 -> NonemptyFold a b -> NonemptyFold a c

(*>) :: NonemptyFold a a0 -> NonemptyFold a b -> NonemptyFold a b

(<*) :: NonemptyFold a a0 -> NonemptyFold a b -> NonemptyFold a a0

Functor (NonemptyFold a)

Defined in Fold.Nonempty.Type

Methods

fmap :: (a0 -> b) -> NonemptyFold a a0 -> NonemptyFold a b

(<$) :: a0 -> NonemptyFold a b -> NonemptyFold a a0

Monoid b => Monoid (NonemptyFold a b)

Defined in Fold.Nonempty.Type

Methods

mempty :: NonemptyFold a b

mappend :: NonemptyFold a b -> NonemptyFold a b -> NonemptyFold a b

mconcat :: [NonemptyFold a b] -> NonemptyFold a b

Semigroup b => Semigroup (NonemptyFold a b)

Defined in Fold.Nonempty.Type

Methods

(<>) :: NonemptyFold a b -> NonemptyFold a b -> NonemptyFold a b

sconcat :: NonEmpty (NonemptyFold a b) -> NonemptyFold a b

stimes :: Integral b0 => b0 -> NonemptyFold a b -> NonemptyFold a b

Run

run :: NonemptyFold a b -> NonEmpty a -> b

Fold a nonempty listlike container to a single summary result

Examples

General

magma :: (a -> a -> a) -> NonemptyFold a a

Start with the first input, append each new input on the right with the given function

semigroup :: Semigroup a => NonemptyFold a a

Append each new input on the right with (<>)

monoid :: Monoid a => NonemptyFold a a

Start with mempty, append each input on the right with (<>)

Endpoints

first :: NonemptyFold a a

The first input

last :: NonemptyFold a a

The last input

Extrema

maximum :: Ord a => NonemptyFold a a

The greatest input

minimum :: Ord a => NonemptyFold a a

The least input

maximumBy :: (a -> a -> Ordering) -> NonemptyFold a a

The greatest input with respect to the given comparison function

minimumBy :: (a -> a -> Ordering) -> NonemptyFold a a

The least input with respect to the given comparison function

Length

length :: NonemptyFold a Natural

The number of inputs

Boolean

and :: NonemptyFold Bool Bool

True if all inputs are True

or :: NonemptyFold Bool Bool

True if any input is True

all :: (a -> Bool) -> NonemptyFold a Bool

True if all inputs satisfy the predicate

any :: (a -> Bool) -> NonemptyFold a Bool

True if any input satisfies the predicate

Numeric

sum :: Num a => NonemptyFold a a

Adds the inputs

product :: Num a => NonemptyFold a a

Multiplies the inputs

mean :: Fractional a => NonemptyFold a a

Numerically stable arithmetic mean of the inputs

variance :: Fractional a => NonemptyFold a a

Numerically stable (population) variance over the inputs

standardDeviation :: Floating a => NonemptyFold a a

Numerically stable (population) standard deviation over the inputs

Search

element :: Eq a => a -> NonemptyFold a Bool

True if any input is equal to the given value

notElement :: Eq a => a -> NonemptyFold a Bool

False if any input is equal to the given value

find :: (a -> Bool) -> NonemptyFold a (Maybe a)

The first input that satisfies the predicate, if any

lookup :: Eq a => a -> NonemptyFold (a, b) (Maybe b)

The b from the first tuple where a equals the given value, if any

Index

index :: Natural -> NonemptyFold a (Maybe a)

The nth input, where n=0 is the first input, if the index is in bounds

findIndex :: (a -> Bool) -> NonemptyFold a (Maybe Natural)

The index of the first input that satisfies the predicate, if any

elementIndex :: Eq a => a -> NonemptyFold a (Maybe Natural)

The index of the first input that matches the given value, if any

List

list :: NonemptyFold a (NonEmpty a)

All the inputs

reverseList :: NonemptyFold a (NonEmpty a)

All the inputs in reverse order

Conversion

fold :: Fold a b -> NonemptyFold a b

Turn a regular fold that allows empty input into a fold that requires at least one input

effectfulFold :: EffectfulFold Identity a b -> NonemptyFold a b

Turn an effectful fold into a pure fold that requires at least one input

shortcutFold :: ShortcutFold a b -> NonemptyFold a b

shortcutNonemptyFold :: ShortcutNonemptyFold a b -> NonemptyFold a b

Utilities

duplicate :: NonemptyFold a b -> NonemptyFold a (Fold a b)

Allows to continue feeding a fold even after passing it to a function that closes it

premap :: (a -> b) -> NonemptyFold b r -> NonemptyFold a r

(premap f folder) returns a new fold where f is applied at each step

nest :: Applicative f => NonemptyFold a b -> NonemptyFold (f a) (f b)

Nest a fold in an applicative