From bf4a469f369f1b8c6b1c2d7cc6907177405603f4 Mon Sep 17 00:00:00 2001
From: Tom Smeding <tom@tomsmeding.com>
Date: Wed, 13 Nov 2024 20:20:30 +0100
Subject: Add withKnownSh{S,X}
---
src/Data/Array/Nested/Internal/Shape.hs | 4 ++++
1 file changed, 4 insertions(+)
(limited to 'src/Data/Array/Nested')
diff --git a/src/Data/Array/Nested/Internal/Shape.hs b/src/Data/Array/Nested/Internal/Shape.hs
index b7bbf4c..59f2c9a 100644
--- a/src/Data/Array/Nested/Internal/Shape.hs
+++ b/src/Data/Array/Nested/Internal/Shape.hs
@@ -34,6 +34,7 @@ import Data.Kind (Type, Constraint)
import Data.Monoid (Sum(..))
import Data.Proxy
import Data.Type.Equality
+import GHC.Exts (withDict)
import GHC.IsList (IsList)
import GHC.IsList qualified as IsList
import GHC.TypeLits
@@ -558,6 +559,9 @@ class KnownShS sh where knownShS :: ShS sh
instance KnownShS '[] where knownShS = ZSS
instance (KnownNat n, KnownShS sh) => KnownShS (n : sh) where knownShS = natSing :$$ knownShS
+withKnownShS :: forall sh r. ShS sh -> (KnownShS sh => r) -> r
+withKnownShS sh = withDict @(KnownShS sh) sh
+
shsKnownShS :: ShS sh -> Dict KnownShS sh
shsKnownShS ZSS = Dict
shsKnownShS (SNat :$$ sh) | Dict <- shsKnownShS sh = Dict
--
cgit v1.2.3-70-g09d2