module Agda.Utils.Three where
data Three
= One
| Two
| Three
deriving (Eq, Ord, Show, Bounded, Enum)
partition3 :: (a -> Three) -> [a] -> ([a], [a], [a])
partition3 f = loop where
loop [] = ([], [], [])
loop (x:xs) = case f x of
One -> (x:as, bs, cs)
Two -> (as, x:bs, cs)
Three -> (as, bs, x:cs)
where (as, bs, cs) = loop xs
data Either3 a b c
= In1 a
| In2 b
| In3 c
deriving (Eq, Ord, Show)
partitionEithers3 :: [Either3 a b c] -> ([a], [b], [c])
partitionEithers3 = \case
[] -> ([], [], [])
(x:xs) -> case x of
In1 a -> (a:as, bs, cs)
In2 b -> (as, b:bs, cs)
In3 c -> (as, bs, c:cs)
where (as, bs, cs) = partitionEithers3 xs
mapEither3M :: Applicative m => (a -> m (Either3 b c d)) -> [a] -> m ([b], [c], [d])
mapEither3M f xs = partitionEithers3 <$> traverse f xs
forEither3M :: Applicative m => [a] -> (a -> m (Either3 b c d)) -> m ([b], [c], [d])
forEither3M = flip mapEither3M