summer 0.3.2.0 → 0.3.4.0

raw patch · 2 files changed

+20/−2 lines, 2 filesdep +profunctors

Dependencies added: profunctors

Files

• src/Data/Summer.hs +18/−0
• summer.cabal +2/−2

@@ -36,6 +36,7 @@   , inspect   , consider   , considerFirst+  , variant   , Match(match, override, unmatch)   , Unmatch   -- * Type families@@ -64,11 +65,28 @@ import Control.Monad (unless) import Generics.SOP (Generic(..)) import qualified Generics.SOP as SOP+import Data.Profunctor (Profunctor(dimap), Choice(..)) import Data.ForAll (type ForAll)  -- | The extensible sum type, allowing inhabitants to be of any of the -- types in the given type list. data Sum (xs :: [*]) = UnsafeInj {-# UNPACK #-} !Word Any++-- | A prism which operates on a chosen variant of a 'Sum'+variant :: forall a b xs p f. (a `HasTagIn` xs, Applicative f, Choice p) => p a (f b) -> p (Sum xs) (f (Sum (Replace a b xs)))+variant p = dimap try replace (left' p) where+  try :: Sum xs -> Either a (Sum (Replace a b xs))+  try (UnsafeInj t x) = if t == tag @a @xs then Left (unsafeCoerce x) else Right (UnsafeInj t x)+  replace :: Either (f b) (Sum (Replace a b xs)) -> f (Sum (Replace a b xs))+  replace = \case+    Left fb -> fmap (UnsafeInj (tag @a @xs) . unsafeCoerce) fb+    Right s -> pure s++-- | Type family for replacing one type in a type level list with another+type family Replace x y xs where+  Replace x y (x ': xs) = y ': xs+  Replace x y (z ': xs) = z ': Replace x y xs+  Replace x y '[] = '[]  instance Generic (Sum '[]) where   type Code (Sum '[]) = '[]

@@ -1,6 +1,6 @@ cabal-version:       2.4 name:                summer-version:             0.3.2.0+version:             0.3.4.0 synopsis:            An implementation of extensible products and sums description:         An implementation of extensible products and sums. license:             MIT@@ -21,7 +21,7 @@ library   exposed-modules:     Data.Summer, Data.Prodder   other-modules:       Data.ForAll-  build-depends:       base >=4.12 && <4.16, vector >=0.12, generics-sop >=0.5+  build-depends:       base >=4.12 && <4.16, vector >=0.12, generics-sop >=0.5, profunctors >=5.6   hs-source-dirs:      src   default-language:    Haskell2010