3 files changed, 26 insertions, 0 deletions
diff --git a/src/Data/Array/Nested/Internal/Mixed.hs b/src/Data/Array/Nested/Internal/Mixed.hs
index 6d601b8..b799190 100644
--- a/src/Data/Array/Nested/Internal/Mixed.hs
+++ b/src/Data/Array/Nested/Internal/Mixed.hs
@@ -686,6 +686,12 @@ mfromListPrimLinear sh l =
 munScalar :: Elt a => Mixed '[] a -> a
 munScalar arr = mindex arr ZIX
 
+mnest :: forall sh sh' a. Elt a => StaticShX sh -> Mixed (sh ++ sh') a -> Mixed sh (Mixed sh' a)
+mnest ssh arr = M_Nest (fst (shxSplitApp (Proxy @sh') ssh (mshape arr))) arr
+
+munNest :: Mixed sh (Mixed sh' a) -> Mixed (sh ++ sh') a
+munNest (M_Nest _ arr) = arr
+
 mrerankP :: forall sh1 sh2 sh a b. (Storable a, Storable b)
          => StaticShX sh -> IShX sh2
          -> (Mixed sh1 (Primitive a) -> Mixed sh2 (Primitive b))
diff --git a/src/Data/Array/Nested/Internal/Ranked.hs b/src/Data/Array/Nested/Internal/Ranked.hs
index 3e911ac..d6e05e6 100644
--- a/src/Data/Array/Nested/Internal/Ranked.hs
+++ b/src/Data/Array/Nested/Internal/Ranked.hs
@@ -349,6 +349,16 @@ rtoOrthotope (rtoPrimitive -> Ranked (M_Primitive sh (XArray arr)))
 runScalar :: Elt a => Ranked 0 a -> a
 runScalar arr = rindex arr ZIR
 
+rnest :: forall n m a. Elt a => SNat n -> Ranked (n + m) a -> Ranked n (Ranked m a)
+rnest n arr
+  | Refl <- lemReplicatePlusApp n (Proxy @m) (Proxy @(Nothing @Nat))
+  = coerce (mnest (ssxFromSNat n) (coerce arr))
+
+runNest :: forall n m a. Elt a => Ranked n (Ranked m a) -> Ranked (n + m) a
+runNest rarr@(Ranked (M_Ranked (M_Nest _ arr)))
+  | Refl <- lemReplicatePlusApp (rrank rarr) (Proxy @m) (Proxy @(Nothing @Nat))
+  = Ranked arr
+
 rrerankP :: forall n1 n2 n a b. (Storable a, Storable b)
          => SNat n -> IShR n2
          -> (Ranked n1 (Primitive a) -> Ranked n2 (Primitive b))
diff --git a/src/Data/Array/Nested/Internal/Shaped.hs b/src/Data/Array/Nested/Internal/Shaped.hs
index 7d523b0..d1881c1 100644
--- a/src/Data/Array/Nested/Internal/Shaped.hs
+++ b/src/Data/Array/Nested/Internal/Shaped.hs
@@ -310,6 +310,16 @@ sfromListPrimLinear sh l =
 sunScalar :: Elt a => Shaped '[] a -> a
 sunScalar arr = sindex arr ZIS
 
+snest :: forall sh sh' a. Elt a => ShS sh -> Shaped (sh ++ sh') a -> Shaped sh (Shaped sh' a)
+snest sh arr
+  | Refl <- lemMapJustApp sh (Proxy @sh')
+  = coerce (mnest (ssxFromShape (shCvtSX sh)) (coerce arr))
+
+sunNest :: forall sh sh' a. Elt a => Shaped sh (Shaped sh' a) -> Shaped (sh ++ sh') a
+sunNest sarr@(Shaped (M_Shaped (M_Nest _ arr)))
+  | Refl <- lemMapJustApp (sshape sarr) (Proxy @sh')
+  = Shaped arr
+
 srerankP :: forall sh1 sh2 sh a b. (Storable a, Storable b)
          => ShS sh -> ShS sh2
          -> (Shaped sh1 (Primitive a) -> Shaped sh2 (Primitive b))