{-# LANGUAGE Safe #-}
{-# LANGUAGE NoImplicitPrelude #-}

module Protolude.Applicative
  ( orAlt,
    orEmpty,
    eitherA,
    purer,
    liftAA2,
    (<<*>>),
  )
where

import Control.Applicative
import Data.Bool (Bool)
import Data.Either (Either (Left, Right))
import Data.Function ((.))
import Data.Monoid (Monoid (mempty))

orAlt :: (Alternative f, Monoid a) => f a -> f a
orAlt :: forall (f :: * -> *) a. (Alternative f, Monoid a) => f a -> f a
orAlt f a
f = f a
f forall (f :: * -> *) a. Alternative f => f a -> f a -> f a
<|> forall (f :: * -> *) a. Applicative f => a -> f a
pure forall a. Monoid a => a
mempty

orEmpty :: Alternative f => Bool -> a -> f a
orEmpty :: forall (f :: * -> *) a. Alternative f => Bool -> a -> f a
orEmpty Bool
b a
a = if Bool
b then forall (f :: * -> *) a. Applicative f => a -> f a
pure a
a else forall (f :: * -> *) a. Alternative f => f a
empty

eitherA :: (Alternative f) => f a -> f b -> f (Either a b)
eitherA :: forall (f :: * -> *) a b.
Alternative f =>
f a -> f b -> f (Either a b)
eitherA f a
a f b
b = (forall a b. a -> Either a b
Left forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> f a
a) forall (f :: * -> *) a. Alternative f => f a -> f a -> f a
<|> (forall a b. b -> Either a b
Right forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> f b
b)

purer :: (Applicative f, Applicative g) => a -> f (g a)
purer :: forall (f :: * -> *) (g :: * -> *) a.
(Applicative f, Applicative g) =>
a -> f (g a)
purer = forall (f :: * -> *) a. Applicative f => a -> f a
pure forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall (f :: * -> *) a. Applicative f => a -> f a
pure

liftAA2 :: (Applicative f, Applicative g) => (a -> b -> c) -> f (g a) -> f (g b) -> f (g c)
liftAA2 :: forall (f :: * -> *) (g :: * -> *) a b c.
(Applicative f, Applicative g) =>
(a -> b -> c) -> f (g a) -> f (g b) -> f (g c)
liftAA2 = forall (f :: * -> *) a b c.
Applicative f =>
(a -> b -> c) -> f a -> f b -> f c
liftA2 forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall (f :: * -> *) a b c.
Applicative f =>
(a -> b -> c) -> f a -> f b -> f c
liftA2

infixl 4 <<*>>

(<<*>>) :: (Applicative f, Applicative g) => f (g (a -> b)) -> f (g a) -> f (g b)
<<*>> :: forall (f :: * -> *) (g :: * -> *) a b.
(Applicative f, Applicative g) =>
f (g (a -> b)) -> f (g a) -> f (g b)
(<<*>>) = forall (f :: * -> *) a b c.
Applicative f =>
(a -> b -> c) -> f a -> f b -> f c
liftA2 forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
(<*>)