Copyright	(c) 2020 Composewell Technologies
License	BSD-3-Clause
Maintainer	streamly@composewell.com
Stability	experimental
Portability	GHC
Safe Haskell	None
Language	Haskell2010

Streamly.Internal.Data.Fold.Tee

Description

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

Synopsis

newtype Tee m a b = Tee {
- unTee :: Fold m a b
}
toFold :: Tee m a b -> Fold m a b

Documentation

newtype Tee m a b Source #

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

Instances details

Functor m => Functor (Tee m a) Source #
Instance details 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 #
Monad m => Applicative (Tee m a) Source #	`<*>` distributes the input to both the argument `Tee`s and combines their outputs using function application.
Instance details 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 #
(Monad m, Floating b) => Floating (Tee m a b) Source #	Binary `Floating` operations distribute the input to both the argument `Tee`s and combine their outputs using the `Floating` instance of the output type.
Instance details 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, Fractional b) => Fractional (Tee m a b) Source #	Binary `Fractional` operations distribute the input to both the argument `Tee`s and combine their outputs using the `Fractional` instance of the output type.
Instance details 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 #
(Monad m, Num b) => Num (Tee m a b) Source #	Binary `Num` operations distribute the input to both the argument `Tee`s and combine their outputs using the `Num` instance of the output type.
Instance details 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 #
(Semigroup b, Monad m) => Semigroup (Tee m a b) Source #	`<>` distributes the input to both the argument `Tee`s and combines their outputs using the `Semigroup` instance of the output type.
Instance details 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 #
(Semigroup b, Monoid b, Monad m) => Monoid (Tee m a b) Source #	`<>` distributes the input to both the argument `Tee`s and combines their outputs using the `Monoid` instance of the output type.
Instance details 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 #

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

Deprecated: Please use unTee instead.