1 files changed, 38 insertions, 0 deletions
diff --git a/src/Data/Array/Nested/Internal/Shape.hs b/src/Data/Array/Nested/Internal/Shape.hs
index 5d5f8e3..82b7966 100644
--- a/src/Data/Array/Nested/Internal/Shape.hs
+++ b/src/Data/Array/Nested/Internal/Shape.hs
@@ -32,6 +32,7 @@ import Data.Array.Mixed.Types
 import Data.Coerce (coerce)
 import Data.Foldable qualified as Foldable
 import Data.Functor.Const
+import Data.Functor.Product qualified as Fun
 import Data.Kind (Type, Constraint)
 import Data.Monoid (Sum(..))
 import Data.Proxy
@@ -135,6 +136,18 @@ listrIndex SZ (x ::: _) = x
 listrIndex (SS i) (_ ::: xs) | Refl <- lemLeqSuccSucc (Proxy @k) (Proxy @n) = listrIndex i xs
 listrIndex _ ZR = error "k + 1 <= 0"
 
+listrZip :: ListR n i -> ListR n j -> ListR n (i, j)
+listrZip ZR ZR = ZR
+listrZip (i ::: irest) (j ::: jrest) = (i, j) ::: listrZip irest jrest
+listrZip _ _ = error "listrZip: impossible pattern needlessly required"
+
+listrZipWith :: (i -> j -> k) -> ListR n i -> ListR n j -> ListR n k
+listrZipWith _ ZR ZR = ZR
+listrZipWith f (i ::: irest) (j ::: jrest) =
+  f i j ::: listrZipWith f irest jrest
+listrZipWith _ _ _ =
+  error "listrZipWith: impossible pattern needlessly required"
+
 listrPermutePrefix :: forall i n. [Int] -> ListR n i -> ListR n i
 listrPermutePrefix = \perm sh ->
   listrFromList perm $ \sperm ->
@@ -222,6 +235,12 @@ ixrLast (IxR list) = listrLast list
 ixrAppend :: forall n m i. IxR n i -> IxR m i -> IxR (n + m) i
 ixrAppend = coerce (listrAppend @_ @i)
 
+ixrZip :: IxR n i -> IxR n j -> IxR n (i, j)
+ixrZip (IxR l1) (IxR l2) = IxR $ listrZip l1 l2
+
+ixrZipWith :: (i -> j -> k) -> IxR n i -> IxR n j -> IxR n k
+ixrZipWith f (IxR l1) (IxR l2) = IxR $ listrZipWith f l1 l2
+
 ixrPermutePrefix :: forall n i. [Int] -> IxR n i -> IxR n i
 ixrPermutePrefix = coerce (listrPermutePrefix @i)
 
@@ -434,6 +453,17 @@ listsAppend :: ListS sh f -> ListS sh' f -> ListS (sh ++ sh') f
 listsAppend ZS idx' = idx'
 listsAppend (i ::$ idx) idx' = i ::$ listsAppend idx idx'
 
+listsZip :: ListS sh f -> ListS sh g -> ListS sh (Fun.Product f g)
+listsZip ZS ZS = ZS
+listsZip (i ::$ is) (j ::$ js) =
+  Fun.Pair i j ::$ listsZip is js
+
+listsZipWith :: (forall a. f a -> g a -> h a) -> ListS sh f -> ListS sh g
+             -> ListS sh h
+listsZipWith _ ZS ZS = ZS
+listsZipWith f (i ::$ is) (j ::$ js) =
+  f i j ::$ listsZipWith f is js
+
 listsTakeLenPerm :: forall f is sh. Perm is -> ListS sh f -> ListS (TakeLen is sh) f
 listsTakeLenPerm PNil _ = ZS
 listsTakeLenPerm (_ `PCons` is) (n ::$ sh) = n ::$ listsTakeLenPerm is sh
@@ -530,6 +560,14 @@ ixsLast (IxS list) = getConst (listsLast list)
 ixsAppend :: forall sh sh' i. IxS sh i -> IxS sh' i -> IxS (sh ++ sh') i
 ixsAppend = coerce (listsAppend @_ @(Const i))
 
+ixsZip :: IxS n i -> IxS n j -> IxS n (i, j)
+ixsZip ZIS ZIS = ZIS
+ixsZip (i :.$ is) (j :.$ js) = (i, j) :.$ ixsZip is js
+
+ixsZipWith :: (i -> j -> k) -> IxS n i -> IxS n j -> IxS n k
+ixsZipWith _ ZIS ZIS = ZIS
+ixsZipWith f (i :.$ is) (j :.$ js) = f i j :.$ ixsZipWith f is js
+
 ixsPermutePrefix :: forall i is sh. Perm is -> IxS sh i -> IxS (PermutePrefix is sh) i
 ixsPermutePrefix = coerce (listsPermutePrefix @(Const i))