Add Distributive and Representable instances to Vec n (#2829)

changelog/2024-11-02T17_43_16+08_00_distributive_representative_vec

@@ -0,0 +1 @@
+ADDED: `Distributive` and `Representable` instances for `Vec`

clash-prelude/clash-prelude.cabal

@@ -317,7 +317,8 @@ Library
                       TypeFamilies
                       UndecidableInstances
 
-  Build-depends:      array                     >= 0.5.1.0 && < 0.6,
+  Build-depends:      adjunctions               >= 4.0     && < 5.0,
+                      array                     >= 0.5.1.0 && < 0.6,
                       arrows                    >= 0.4     && < 0.5,
                       base                      >= 4.11    && < 5,
                       binary                    >= 0.8.5   && < 0.11,
@@ -327,6 +328,7 @@ Library
                       data-binary-ieee754       >= 0.4.4   && < 0.6,
                       data-default-class        >= 0.1.2   && < 0.2,
                       deepseq                   >= 1.4.1.0 && < 1.6,
+                      distributive              >= 0.1     && < 1.0,
                       extra                     >= 1.6.17  && < 1.8,
                       ghc-prim                  >= 0.5.1.0 && < 0.12,
                       ghc-typelits-extra        >= 0.4     && < 0.5,

clash-prelude/src/Clash/Sized/Vector.hs

@@ -108,6 +108,8 @@ import Data.Constraint.Nat        (leZero)
 import Data.Data
   (Data (..), Constr, DataType, Fixity (..), Typeable, mkConstr, mkDataType)
 import Data.Either                (isLeft)
+import Data.Distributive
+import Data.Functor.Rep
 #if MIN_VERSION_base(4,18,0)
 import qualified Data.Foldable1   as F1
 #endif
@@ -2776,3 +2778,16 @@ type instance Lens.Index   (Vec n a) = Index n
 type instance Lens.IxValue (Vec n a) = a
 instance KnownNat n => Lens.Ixed (Vec n a) where
   ix i f xs = replace_int xs (fromEnum i) <$> f (index_int xs (fromEnum i))
+
+instance KnownNat n => Distributive (Vec n) where
+    distribute fxs = tabulate $ \i -> fmap (!! i) fxs
+    {-# INLINE distribute #-}
+
+instance KnownNat n => Representable (Vec n) where
+    type Rep (Vec n) = Index n
+
+    tabulate f = map f indicesI
+    {-# INLINE tabulate #-}
+
+    index = (!!)
+    {-# INLINE index #-}