data-effects-core 0.4.2.0 → 0.4.3.0

raw patch · 4 files changed

+65/−4 lines, 4 filesPVP ok

version bump matches the API change (PVP)

API changes (from Hackage documentation)

Files

• ChangeLog.md +5/−0
• data-effects-core.cabal +1/−1
• src/Data/Effect.hs +28/−1
• src/Data/Effect/OpenUnion.hs +31/−2

@@ -15,3 +15,8 @@ * The new v4 interface.     * Unified first-order and higher-order effect interfaces.     * Added a generic `Eff` carrier type.++## 0.4.3.0 -- 2025-05-21++* Add type classes for weaving+* Fix the missing type role specification in `Data.Effect.OpenUnion`

@@ -1,6 +1,6 @@ cabal-version:      3.0 name:               data-effects-core-version:            0.4.2.0+version:            0.4.3.0  -- A short (one-line) description of the package. synopsis: A basic framework for effect systems based on effects represented by GADTs.

@@ -44,8 +44,35 @@     ) =>     FirstOrder (e :: Effect) --- | A higher-order polynomial functor.+{- | A higher-order polynomial functor.++Prevents resources from escaping the scope through unlift operations.+-} class (FormOf e ~ 'Polynomial) => PolyHFunctor (e :: Effect)++{- | Enables algebraic handling even in the presence of higher-order effects.+In such cases, the scope of higher-order effects behaves according to a semantics similar to @mtl@,+where it may or may not become transactional depending on the order of the effect stack.++This follows the "weave" approach described in the *Effect Handlers in Scope* paper,+and is the method used in libraries such as @fused-effects@ and @polysemy@.++https://doi.org/10.1145/2633357.2633358+-}+class Weave (e :: Effect) where+    -- | The @weave@ method from the *Effect Handlers in Scope* paper.+    --+    --   https://doi.org/10.1145/2633357.2633358+    --+    --   To accommodate the effect representation used by @data-effects@ (which is generally not a @Functor@),+    --   the types have been transformed based on a Church encoding of @Coyoneda@.+    weave+        :: (Functor ctx)+        => ctx ()+        -> (forall x. ctx (m x) -> n (ctx x))+        -> (forall x. e n x -> (x -> ctx a) -> r)+        -> e m a+        -> r  -- * Nop Effect 

@@ -1,5 +1,6 @@ {-# LANGUAGE AllowAmbiguousTypes #-} {-# LANGUAGE PatternSynonyms #-}+{-# LANGUAGE RoleAnnotations #-} {-# LANGUAGE UndecidableInstances #-} {-# LANGUAGE ViewPatterns #-} {-# OPTIONS_GHC -Wno-redundant-constraints #-}@@ -16,13 +17,14 @@ import Control.Arrow ((&&&)) import Data.Coerce (coerce) import Data.Data (Proxy (Proxy), (:~:) (Refl))-import Data.Effect (Effect, EffectForm (Exponential, Polynomial), EffectOrder (FirstOrder, HigherOrder), FirstOrder, FormCase, FormOf, LabelOf, OrderCase, OrderOf, PolyHFunctor)+import Data.Effect (Effect, EffectForm (Exponential, Polynomial), EffectOrder (FirstOrder, HigherOrder), FirstOrder, FormCase, FormOf, LabelOf, OrderCase, OrderOf, PolyHFunctor, Weave, weave) import Data.Effect.HFunctor (HFunctor, hfmap) import Data.Effect.Tag (type (#)) import Data.Kind (Constraint, Type) import GHC.TypeLits (ErrorMessage (ShowType, Text, (:$$:), (:<>:)), KnownNat, Natural, Symbol, TypeError, natVal, type (+), type (-)) import Unsafe.Coerce (unsafeCoerce) +type role Union representational representational nominal data Union (es :: [Effect]) (f :: Type -> Type) (a :: Type) where     UnsafeUnion         :: {-# UNPACK #-} !Int@@ -58,12 +60,39 @@ instance PolyHFunctors '[] instance (PolyHFunctor e, PolyHFunctors es) => PolyHFunctors (e ': es) +-- | The list @es@ consists only of weavable effects.+class (Weave (Union es)) => Weaves (es :: [Effect])++instance Weaves '[]+instance (Weave e, Weaves es, KnownOrder e) => Weaves (e ': es)++weaveUnion+    :: (Weaves es, Functor ctx)+    => ctx ()+    -> (forall x. ctx (m x) -> n (ctx x))+    -> (forall x. Union es n x -> (x -> ctx a) -> r)+    -> Union es m a+    -> r+weaveUnion = weave+{-# INLINE weaveUnion #-}++instance Weave (Union '[]) where+    weave _ _ _ = nil+    {-# INLINE weave #-}++instance (Weave e, Weave (Union es), KnownOrder e) => Weave (Union (e ': es)) where+    weave ctx distrib f =+        weave ctx distrib (f . inject Here)+            !: weave ctx distrib (f . weaken)+    {-# INLINE weave #-}+ coerceFOEs :: (FOEs es) => Union es f a -> Union es g a coerceFOEs = unsafeCoerce {-# INLINE coerceFOEs #-}  type instance OrderOf (Union es) = 'HigherOrder +type role Membership representational representational newtype Membership (e :: Effect) (es :: [Effect]) = UnsafeMembership {unMembership :: Int}     deriving stock (Eq, Show) @@ -339,7 +368,7 @@ nil _ = error "Effect system internal error: nil - An empty effect union, which should not be possible to create, has been created."  nilMembership :: Membership e '[] -> r-nilMembership _ = error "Effect system internal error: nil - An empty effect union membership, which should not be possible to create, has been created."+nilMembership _ = error "Effect system internal error: nilMmebership - An empty effect union membership, which should not be possible to create, has been created."  weakensFor :: forall es es' e. (Suffix es es') => Membership e es -> Membership e es' weakensFor (UnsafeMembership n) = UnsafeMembership $ n + prefixLen @es @es'