From 17dd9271a64ff47abb551179a6ab61dff1f9ed6f Mon Sep 17 00:00:00 2001
From: Tom Smeding <tom@tomsmeding.com>
Date: Mon, 27 May 2024 17:25:58 +0200
Subject: Re-add KnownNatList for convenience with transpose functions

---
 src/Data/Array/Mixed.hs  | 4 ++++
 src/Data/Array/Nested.hs | 1 +
 2 files changed, 5 insertions(+)

(limited to 'src/Data')

diff --git a/src/Data/Array/Mixed.hs b/src/Data/Array/Mixed.hs
index d61969f..bc392ad 100644
--- a/src/Data/Array/Mixed.hs
+++ b/src/Data/Array/Mixed.hs
@@ -777,6 +777,10 @@ shIndex p1 p2 = coerce (listxIndex @(SMayNat Int SNat) p1 p2)
 shPermutePrefix :: HList SNat is -> IShX sh -> IShX (PermutePrefix is sh)
 shPermutePrefix = coerce (listxPermutePrefix @(SMayNat Int SNat))
 
+class KnownNatList l where makeNatList :: HList SNat l
+instance KnownNatList '[] where makeNatList = HNil
+instance (KnownNat n, KnownNatList l) => KnownNatList (n : l) where makeNatList = natSing `HCons` makeNatList
+
 -- | The list argument gives indices into the original dimension list.
 transpose :: forall is sh a. (Permutation is, Rank is <= Rank sh)
           => StaticShX sh
diff --git a/src/Data/Array/Nested.hs b/src/Data/Array/Nested.hs
index 968ea18..6f9a56d 100644
--- a/src/Data/Array/Nested.hs
+++ b/src/Data/Array/Nested.hs
@@ -60,6 +60,7 @@ module Data.Array.Nested (
   SNat, pattern SNat,
   HList,
   Permutation,
+  KnownNatList(..),
   listSToList,
   shSToList,
 ) where
-- 
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