From d6fec1856d02e38fd64769284265bb833b57593d Mon Sep 17 00:00:00 2001
From: Mikolaj Konarski <mikolaj.konarski@funktory.com>
Date: Mon, 9 Feb 2026 20:49:26 +0100
Subject: Add mslice to be typing-wise a counterpart of mappend

---
 src/Data/Array/Nested/Mixed.hs | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'src/Data/Array/Nested/Mixed.hs')

diff --git a/src/Data/Array/Nested/Mixed.hs b/src/Data/Array/Nested/Mixed.hs
index 0cab44f..7510a4c 100644
--- a/src/Data/Array/Nested/Mixed.hs
+++ b/src/Data/Array/Nested/Mixed.hs
@@ -1033,6 +1033,14 @@ msliceSN i n arr =
   let _ :$% sh = mshape arr
   in mlift (SKnown n :!% ssxFromShX sh) (\_ -> X.slice i n) arr
 
+mslice :: forall i n k sh a. Elt a
+       => SMayNat Int i -> SMayNat Int n -> SMayNat Int k -> Mixed (AddMaybe (AddMaybe i n) k : sh) a -> Mixed (n : sh) a
+mslice i n k arr =
+  let _ :$% sh = mshape arr
+      uarr = mcastPartial (ssxFromShX $ smnAddMaybe (smnAddMaybe i n) k :$% ZSX) (SUnknown () :!% ZKX) Proxy arr
+  in mcastPartial (SUnknown () :!% ZKX) (ssxFromShX $ n :$% ZSX) Proxy
+     $ mlift (SUnknown () :!% ssxFromShX sh) (\_ -> X.sliceU (fromSMayNat' i) (fromSMayNat' n)) uarr
+
 mrev1 :: Elt a => Mixed (n : sh) a -> Mixed (n : sh) a
 mrev1 arr = mlift (ssxFromShX (mshape arr)) (\_ -> X.rev1) arr
 
-- 
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