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module Hakyll.Alias where
import Prolog
import Data.HashSet qualified as HS
newtype Aliased a x = Aliased { unAliased :: Either a x }
deriving newtype (Binary, Eq, Foldable, Functor, Generic, Generic1, Hashable, Ord, Show, Traversable)
class (Eq a, Hashable a) => ToAliases x a where
toAliases :: x -> HashSet a
instance Hashable a => ToAliases a a where
toAliases = HM.singleton
instance (Eq a, Hashable a) => ToAliases (HashSet a) a where
toAliases = id
instance ToAliases x a => ToAliases [x] a where
toAliases = foldMap toAliases
class FromAlias a x where
fromAlias :: MonadThrow m => a -> m x
instance FromAlias a a where
fromAlias = pure
instance (FromAlias a x, FromAlias b x) => FromAlias (Either a b) x where
fromAlias = either fromAlias fromAlias
instance FromAlias a x => FromAlias (Aliased a x) x where
fromAlias = fromAlias . unAliased
newtype NoAlias a =NoAlias a
deriving (Eq, Show)
instance Show a => Exception (NoAlias a) where
displayException (NoAlias a) = show a <> " is not an alias"
missingAlias :: MonadThrow m => a -> m b
missingAlias = throwM . NoAlias
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