module Symantic.Reader where

import Data.Function ((.), const)

import Symantic.Classes hiding (const, (.))
import Symantic.Derive

-- * Type 'Reader'
-- | An intermediate interpreter exposing an environment.
newtype Reader r sem a = Reader { unReader :: r -> sem a }

type instance Derived (Reader r sem) = sem
instance LiftDerived (Reader r sem) where
  liftDerived = Reader . const
instance LiftDerived1 (Reader r sem) where
  liftDerived1 f a = Reader (f . unReader a)
instance LiftDerived2 (Reader r sem) where
  liftDerived2 f a b = Reader (\r -> f (unReader a r) (unReader b r))
instance LiftDerived3 (Reader r sem) where
  liftDerived3 f a b c = Reader (\r -> f (unReader a r) (unReader b r) (unReader c r))
instance LiftDerived4 (Reader r sem) where
  liftDerived4 f a b c d = Reader (\r -> f (unReader a r) (unReader b r) (unReader c r) (unReader d r))

instance Abstractable sem => Abstractable (Reader r sem) where
  lam f = Reader (\r -> lam ((`unReader` r) . f . liftDerived))
  lam1 f = Reader (\r -> lam1 ((`unReader` r) . f . liftDerived))
instance Functionable sem => Functionable (Reader r sem)
instance Anythingable sem => Anythingable (Reader r sem)
instance Constantable c sem => Constantable c (Reader r sem)
instance Eitherable sem => Eitherable (Reader r sem)
instance Equalable sem => Equalable (Reader r sem)
instance IfThenElseable sem => IfThenElseable (Reader r sem)
-- Using 'Inferable' with a specific @a@ and keeping @sem@ polymorphic
-- is more usual; hence commenting this instance that would overlap.
--instance Inferable a sem => Inferable a (Reader r sem)
instance Listable sem => Listable (Reader r sem)
instance Maybeable sem => Maybeable (Reader r sem)
instance IsoFunctor sem => IsoFunctor (Reader r sem)
instance (ProductFunctor sem, IsoFunctor sem) => ProductFunctor (Reader r sem)
instance (SumFunctor sem, IsoFunctor sem) => SumFunctor (Reader r sem)
instance AlternativeFunctor sem => AlternativeFunctor (Reader r sem)
instance Dicurryable sem => Dicurryable (Reader r sem)
instance Emptyable sem => Emptyable (Reader r sem)
instance Semigroupable sem => Semigroupable (Reader r sem)
instance Optionable sem => Optionable (Reader r sem)
instance Repeatable sem => Repeatable (Reader r sem)
-- instance Permutable sem => Permutable (Reader r sem)
instance Routable sem => Routable (Reader r sem)
instance Voidable sem => Voidable (Reader r sem)
instance Substractable sem => Substractable (Reader r sem)