Streamly.Internal.Data.Fold.Tee

A newtype wrapper over the Fold type providing distributing Applicative, Semigroup, Monoid, Num, Floating and Fractional instances.

Documentation

newtype Tee m a b

Tee is a newtype wrapper over the Fold type providing distributing Applicative, Semigroup, Monoid, Num, Floating and Fractional instances.

The input received by the composed Tee is replicated and distributed to the constituent folds of the Tee.

For example, to compute the average of numbers in a stream without going through the stream twice:

>>> avg = (/) <$> (Tee Fold.sum) <*> (Tee $ fmap fromIntegral Fold.length)
>>> Stream.fold (unTee avg) $ Stream.fromList [1.0..100.0]
50.5

Similarly, the Semigroup and Monoid instances of Tee distribute the input to both the folds and combine the outputs using Monoid or Semigroup instances of the output types:

>>> import Data.Monoid (Sum(..))
>>> t = Tee Fold.one <> Tee Fold.latest
>>> Stream.fold (unTee t) (fmap Sum $ Stream.enumerateFromTo 1.0 100.0)
Just (Sum {getSum = 101.0})

The Num, Floating, and Fractional instances work in the same way.

Constructors

Tee

Fields

• unTee :: Fold m a b

Instances

Monad m => Applicative (Tee m a)

<*> distributes the input to both the argument Tees and combines their outputs using function application.

Defined in Streamly.Internal.Data.Fold.Tee

Methods

pure :: a0 -> Tee m a a0

(<*>) :: Tee m a (a0 -> b) -> Tee m a a0 -> Tee m a b

liftA2 :: (a0 -> b -> c) -> Tee m a a0 -> Tee m a b -> Tee m a c

(*>) :: Tee m a a0 -> Tee m a b -> Tee m a b

(<*) :: Tee m a a0 -> Tee m a b -> Tee m a a0

Functor m => Functor (Tee m a)

Defined in Streamly.Internal.Data.Fold.Tee

Methods

fmap :: (a0 -> b) -> Tee m a a0 -> Tee m a b

(<$) :: a0 -> Tee m a b -> Tee m a a0

(Semigroup b, Monoid b, Monad m) => Monoid (Tee m a b)

<> distributes the input to both the argument Tees and combines their outputs using the Monoid instance of the output type.

Defined in Streamly.Internal.Data.Fold.Tee

Methods

mempty :: Tee m a b

mappend :: Tee m a b -> Tee m a b -> Tee m a b

mconcat :: [Tee m a b] -> Tee m a b

(Semigroup b, Monad m) => Semigroup (Tee m a b)

<> distributes the input to both the argument Tees and combines their outputs using the Semigroup instance of the output type.

Defined in Streamly.Internal.Data.Fold.Tee

Methods

(<>) :: Tee m a b -> Tee m a b -> Tee m a b

sconcat :: NonEmpty (Tee m a b) -> Tee m a b

stimes :: Integral b0 => b0 -> Tee m a b -> Tee m a b

(Monad m, Floating b) => Floating (Tee m a b)

Binary Floating operations distribute the input to both the argument Tees and combine their outputs using the Floating instance of the output type.

Defined in Streamly.Internal.Data.Fold.Tee

Methods

pi :: Tee m a b

exp :: Tee m a b -> Tee m a b

log :: Tee m a b -> Tee m a b

sqrt :: Tee m a b -> Tee m a b

(**) :: Tee m a b -> Tee m a b -> Tee m a b

logBase :: Tee m a b -> Tee m a b -> Tee m a b

sin :: Tee m a b -> Tee m a b

cos :: Tee m a b -> Tee m a b

tan :: Tee m a b -> Tee m a b

asin :: Tee m a b -> Tee m a b

acos :: Tee m a b -> Tee m a b

atan :: Tee m a b -> Tee m a b

sinh :: Tee m a b -> Tee m a b

cosh :: Tee m a b -> Tee m a b

tanh :: Tee m a b -> Tee m a b

asinh :: Tee m a b -> Tee m a b

acosh :: Tee m a b -> Tee m a b

atanh :: Tee m a b -> Tee m a b

log1p :: Tee m a b -> Tee m a b

expm1 :: Tee m a b -> Tee m a b

log1pexp :: Tee m a b -> Tee m a b

log1mexp :: Tee m a b -> Tee m a b

(Monad m, Num b) => Num (Tee m a b)

Binary Num operations distribute the input to both the argument Tees and combine their outputs using the Num instance of the output type.

Defined in Streamly.Internal.Data.Fold.Tee

Methods

(+) :: Tee m a b -> Tee m a b -> Tee m a b

(-) :: Tee m a b -> Tee m a b -> Tee m a b

(*) :: Tee m a b -> Tee m a b -> Tee m a b

negate :: Tee m a b -> Tee m a b

abs :: Tee m a b -> Tee m a b

signum :: Tee m a b -> Tee m a b

fromInteger :: Integer -> Tee m a b

(Monad m, Fractional b) => Fractional (Tee m a b)

Binary Fractional operations distribute the input to both the argument Tees and combine their outputs using the Fractional instance of the output type.

Defined in Streamly.Internal.Data.Fold.Tee

Methods

(/) :: Tee m a b -> Tee m a b -> Tee m a b

recip :: Tee m a b -> Tee m a b

fromRational :: Rational -> Tee m a b

toFold :: Tee m a b -> Fold m a b

Deprecated: Please use unTee instead.