From 6f41fd676865a14572ef4570919632fbfb4a04f1 Mon Sep 17 00:00:00 2001
From: Mikolaj Konarski <mikolaj.konarski@funktory.com>
Date: Sun, 11 May 2025 20:14:10 +0200
Subject: Add zip and zipWith for sized lists

---
 src/Data/Array/Mixed/Shape.hs           | 19 +++++++++++++++++
 src/Data/Array/Nested/Internal/Shape.hs | 37 +++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)

(limited to 'src/Data/Array')

diff --git a/src/Data/Array/Mixed/Shape.hs b/src/Data/Array/Mixed/Shape.hs
index b49e005..4dd0aa6 100644
--- a/src/Data/Array/Mixed/Shape.hs
+++ b/src/Data/Array/Mixed/Shape.hs
@@ -152,6 +152,19 @@ listxLast :: forall f n sh. ListX (n : sh) f -> f (Last (n : sh))
 listxLast (_ ::% sh@(_ ::% _)) = listxLast sh
 listxLast (x ::% ZX) = x
 
+listxZip :: ListX sh (Const i) -> ListX sh (Const j) -> ListX sh (Const (i, j))
+listxZip ZX ZX = ZX
+listxZip (Const i ::% irest) (Const j ::% jrest) =
+  Const (i, j) ::% listxZip irest jrest
+--listxZip _ _ = error "listxZip: impossible pattern needlessly required"
+
+listxZipWith :: (i -> j -> k) -> ListX sh (Const i) -> ListX sh (Const j)
+             -> ListX sh (Const k)
+listxZipWith _ ZX ZX = ZX
+listxZipWith f (Const i ::% irest) (Const j ::% jrest) =
+  Const (f i j) ::% listxZipWith f irest jrest
+--listxZipWith _ _ _ = error "listxZipWith: impossible pattern needlessly required"
+
 
 -- * Mixed indices
 
@@ -222,6 +235,12 @@ ixxInit = coerce (listxInit @(Const i))
 ixxLast :: forall n sh i. IxX (n : sh) i -> i
 ixxLast = coerce (listxLast @(Const i))
 
+ixxZip :: IxX n i -> IxX n j -> IxX n (i, j)
+ixxZip (IxX l1) (IxX l2) = IxX $ listxZip l1 l2
+
+ixxZipWith :: (i -> j -> k) -> IxX n i -> IxX n j -> IxX n k
+ixxZipWith f (IxX l1) (IxX l2) = IxX $ listxZipWith f l1 l2
+
 ixxFromLinear :: IShX sh -> Int -> IIxX sh
 ixxFromLinear = \sh i -> case go sh i of
   (idx, 0) -> idx
diff --git a/src/Data/Array/Nested/Internal/Shape.hs b/src/Data/Array/Nested/Internal/Shape.hs
index 5d5f8e3..102d9d8 100644
--- a/src/Data/Array/Nested/Internal/Shape.hs
+++ b/src/Data/Array/Nested/Internal/Shape.hs
@@ -135,6 +135,18 @@ 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 +234,12 @@ 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 +452,19 @@ 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 (Const i) -> ListS sh (Const j) -> ListS sh (Const (i, j))
+listsZip ZS ZS = ZS
+listsZip (Const i ::$ irest) (Const j ::$ jrest) =
+  Const (i, j) ::$ listsZip irest jrest
+--listsZip _ _ = error "listsZip: impossible pattern needlessly required"
+
+listsZipWith :: (i -> j -> k) -> ListS sh (Const i) -> ListS sh (Const j)
+             -> ListS sh (Const k)
+listsZipWith _ ZS ZS = ZS
+listsZipWith f (Const i ::$ irest) (Const j ::$ jrest) =
+  Const (f i j) ::$ listsZipWith f irest jrest
+--listsZipWith _ _ _ = error "listsZipWith: impossible pattern needlessly required"
+
 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 +561,12 @@ 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 (IxS l1) (IxS l2) = IxS $ listsZip l1 l2
+
+ixsZipWith :: (i -> j -> k) -> IxS n i -> IxS n j -> IxS n k
+ixsZipWith f (IxS l1) (IxS l2) = IxS $ listsZipWith f l1 l2
+
 ixsPermutePrefix :: forall i is sh. Perm is -> IxS sh i -> IxS (PermutePrefix is sh) i
 ixsPermutePrefix = coerce (listsPermutePrefix @(Const i))
 
-- 
cgit v1.2.3-70-g09d2