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/Mixed/Shape.hs           | 4 ++++
 src/Data/Array/Nested/Internal/Shape.hs | 4 ++++
 2 files changed, 8 insertions(+)

(limited to 'src/Data/Array')

diff --git a/src/Data/Array/Mixed/Shape.hs b/src/Data/Array/Mixed/Shape.hs
index 1d3e60a..b5a4cb9 100644
--- a/src/Data/Array/Mixed/Shape.hs
+++ b/src/Data/Array/Mixed/Shape.hs
@@ -31,6 +31,7 @@ import Data.Kind (Type, Constraint)
 import Data.Monoid (Sum(..))
 import Data.Proxy
 import Data.Type.Equality
+import GHC.Exts (withDict)
 import GHC.Generics (Generic)
 import GHC.IsList (IsList)
 import GHC.IsList qualified as IsList
@@ -469,6 +470,9 @@ instance KnownShX '[] where knownShX = ZKX
 instance (KnownNat n, KnownShX sh) => KnownShX (Just n : sh) where knownShX = SKnown natSing :!% knownShX
 instance KnownShX sh => KnownShX (Nothing : sh) where knownShX = SUnknown () :!% knownShX
 
+withKnownShX :: forall sh r. StaticShX sh -> (KnownShX sh => r) -> r
+withKnownShX sh = withDict @(KnownShX sh) sh
+
 
 -- * Flattening
 
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