{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeApplications #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE AllowAmbiguousTypes #-}
{-# LANGUAGE PatternSynonyms #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE UndecidableInstances #-}
{-# LANGUAGE ConstraintKinds #-}
module Haskus.Utils.EADT
( VariantF (..)
, ApplyAll
, pattern FV
, appendVariantF
, toVariantFHead
, toVariantFTail
, popVariantFHead
, popVariantF
, mapVariantF
, variantFToValue
, LiftableF
, liftVariantF
, EADT
, (:<:)
, pattern VF
, appendEADT
, liftEADT
, popEADT
, module Haskus.Utils.Functor
)
where
import Haskus.Utils.Variant
import Haskus.Utils.Functor
import Haskus.Utils.Types.List
import Haskus.Utils.Types
newtype VariantF (xs :: [* -> *]) e
= VariantF (V (ApplyAll e xs))
type family ApplyAll e (xs :: [* -> *]) :: [*] where
ApplyAll e '[] = '[]
ApplyAll e (f ': fs) = f e ': ApplyAll e fs
instance (Show (V (ApplyAll e xs))) => Show (VariantF xs e) where
show (VariantF x) = show x
deriving instance (Eq (V (ApplyAll e xs))) => Eq (VariantF xs e)
deriving instance (Ord (V (ApplyAll e xs))) => Ord (VariantF xs e)
instance Functor (VariantF '[]) where
fmap _ = undefined
instance (Functor (VariantF fs), Functor f) => Functor (VariantF (f ': fs)) where
fmap f (VariantF v) = case popVariantHead v of
Right x -> toVariantFHead (fmap f x)
Left xs -> toVariantFTail (fmap f (VariantF xs))
pattern FV :: forall c cs e. Popable c (ApplyAll e cs) => c -> VariantF cs e
pattern FV x = VariantF (V x)
variantFToValue :: VariantF '[f] e -> f e
variantFToValue (VariantF v) = variantToValue v
appendVariantF :: forall (ys :: [* -> *]) (xs :: [* -> *]) e.
( ApplyAll e (Concat xs ys) ~ Concat (ApplyAll e xs) (ApplyAll e ys)
) => VariantF xs e -> VariantF (Concat xs ys) e
appendVariantF (VariantF v) = VariantF (appendVariant @(ApplyAll e ys) v)
toVariantFHead :: forall x xs e. x e -> VariantF (x ': xs) e
{-# INLINE toVariantFHead #-}
toVariantFHead v = VariantF (toVariantHead @(x e) @(ApplyAll e xs) v)
toVariantFTail :: forall x xs e. VariantF xs e -> VariantF (x ': xs) e
{-# INLINE toVariantFTail #-}
toVariantFTail (VariantF v) = VariantF (toVariantTail @(x e) @(ApplyAll e xs) v)
popVariantFHead :: forall x xs e. VariantF (x ': xs) e -> Either (VariantF xs e) (x e)
{-# INLINE popVariantFHead #-}
popVariantFHead (VariantF v) = case popVariantHead v of
Right x -> Right x
Left xs -> Left (VariantF xs)
popVariantF :: forall x xs ys e.
( Popable (x e) (ApplyAll e xs)
, Filter (x e) (ApplyAll e xs) ~ ApplyAll e ys
) => VariantF xs e -> Either (VariantF ys e) (x e)
{-# INLINE popVariantF #-}
popVariantF (VariantF v) = case popVariant v of
Right x -> Right x
Left xs -> Left (VariantF xs)
mapVariantF :: forall a b cs e ds as.
( MappableVariant (a e) (b e) as
, ds ~ ReplaceNS (IndexesOf a cs) b cs
, as ~ ApplyAll e cs
, ApplyAll e ds ~ ReplaceNS (IndexesOf (a e) as) (b e) as
) => (a e -> b e) -> VariantF cs e -> VariantF ds e
mapVariantF f (VariantF v) = VariantF (mapVariant @(a e) @(b e) @as f v)
type LiftableF e xs ys =
( IsSubset xs ys ~ 'True
, LiftVariant (ApplyAll e xs) (ApplyAll e ys)
)
liftVariantF :: forall e as bs.
( LiftableF e as bs
) => VariantF as e -> VariantF bs e
liftVariantF (VariantF v) = VariantF (liftVariant' v)
type EADT xs = Fix (VariantF xs)
type family f :<: xs where
f :<: xs = EADTF' f (EADT xs) xs
type EADTF' f e cs =
( Member' f cs
, Index (IndexOf (f e) (ApplyAll e cs)) (ApplyAll e cs) ~ f e
, PopVariant (f e) (ApplyAll e cs)
, KnownNat (IndexOf (f e) (ApplyAll e cs))
)
pattern VF :: forall e f cs.
( e ~ EADT cs
, f :<: cs
) => f (EADT cs) -> EADT cs
pattern VF x = Fix (VariantF (V' x))
appendEADT :: forall ys xs zs.
( zs ~ Concat xs ys
, ApplyAll (EADT zs) zs ~ Concat (ApplyAll (EADT zs) xs) (ApplyAll (EADT zs) ys)
, Functor (VariantF xs)
) => EADT xs -> EADT zs
appendEADT (Fix v) = Fix (appendVariantF @ys (fmap (appendEADT @ys) v))
liftEADT :: forall e as bs.
( e ~ Fix (VariantF bs)
, LiftableF e as bs
, Functor (VariantF as)
) => EADT as -> EADT bs
liftEADT = cata (Fix . liftVariantF)
popEADT :: forall xs f e.
( f :<: xs
, e ~ EADT xs
, Popable (f e) (ApplyAll e xs)
, Filter (f e) (ApplyAll e xs) ~ ApplyAll e (Filter f xs)
) => EADT xs -> Either (VariantF (Filter f xs) (EADT xs)) (f (EADT xs))
popEADT (Fix v) = popVariantF v