Modulerelude-1.2.0.0Haskell2010

Relude.Extra.Foldable

SPDX-License-Identifier : MIT Maintainer : Kowainik xrom.xkov@gmail.com Stability : Stable Portability : Portable

Contains utility functions for working with tuples.

2 values

Packagerelude-1.2.0.0
Exports2
LanguageHaskell2010
LicenceMIT
SourceFoldable.hs

valuefoldlSC :: Foldable t => (b -> a -> Either b b) -> b -> t a -> b

A left-associative fold that's tail-recursive but can still short-circuit. Returning a Left short-circuits and immediately returns the value inside. Returning a Right continues the fold as usual with the value inside.

Example2 expressions

>>> foldlSC (\acc x -> if x == 0 then Left 0 else Right $! acc * x) 1 [1..6]720>>> foldlSC (\acc x -> if x == 0 then Left 0 else Right $! acc * x) 1 (0:error "Short-circuiting should keep this from happening")0

valueaverage :: (Foldable f, Fractional a) => f a -> Maybe a

Given a Foldable of Fractional elements, computes the average if possible and returns Maybe element.

Example4 expressions

>>> average [42]Just 42.0>>> average @Double [1, 2, 3, 4]Just 2.5>>> average @Float [1.5, 2.5, 3 ,4]Just 2.75>>> average []Nothing