Function.hs

{- |
Module      : Antelude.Function
Description : Contains some functional functions and symbols.
Maintainer  : dneavesdev@pm.me

I realized after-the-fact that the arrows (which I was taking inspiration from Elm) is essentially part of what the 'flow' package does.
-}
module Antelude.Function
    ( constant
    , identity
      -- | Reexport from 'Data.Function'
    , Prelude.flip
      -- | Reexport from 'Prelude'
    , Prelude.asTypeOf
      -- | Reexport from 'Prelude'
    , Prelude.seq
      -- operators
    , (.>)
    , (<.)
    , (<|)
    , (|>)
    ) where

import safe qualified Prelude


-- | Re-return the first argument. Can be surprisingly useful.
identity :: a -> a
identity = Prelude.id


-- | Always return the first argument.
constant :: a -> b -> a
constant = Prelude.const


infixr 0 <|


-- | Equivalent to '($)' from 'Data.Function', but like Elm. Can be slightly clearer for unfamiliar developers.
(<|) :: (a -> b) -> a -> b
a <| b = a b

infixl 0 |>


-- | Equivalent to '(&)' from 'Data.Function', but like Elm. Can be slightly clearer for unfamiliar developers.
(|>) :: a -> (a -> b) -> b
a |> b = b a


infixl 9 <.


{- |
   Equivalent to '(.)' from 'Data.Function', but in an arrowhead format.

   Since '(<<)' would be confused with 'flip (>>)', '(<.)' was decided as it's `(.)` but with a direction.
-}
(<.) :: (b -> c) -> (a -> b) -> a -> c
a <. b = \x -> a <| b x


infixr 9 .>


{- |
   Equivalent to 'flip (.)', but in an arrowhead format.

   Since '(>>)' is already a typeclass-locked Haskell symbol for `Monad`, '(.>)' was decided as was decided as it's `(.)` but with a direction.
-}
(.>) :: (a -> b) -> (b -> c) -> a -> c
a .> b = \x -> b <| a x