1 files changed, 14 insertions, 14 deletions
diff --git a/src/Data/Array/Nested/Convert.hs b/src/Data/Array/Nested/Convert.hs
index cdd2b6d..17ccc4d 100644
--- a/src/Data/Array/Nested/Convert.hs
+++ b/src/Data/Array/Nested/Convert.hs
@@ -5,12 +5,22 @@
 {-# LANGUAGE TypeAbstractions #-}
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE TypeOperators #-}
-module Data.Array.Nested.Convert where
+module Data.Array.Nested.Convert (
+  castCastable,
+  Castable(..),
+
+  -- * Special cases
+  --
+  -- | These functions can all be implemented using 'castCastable' in some way,
+  -- but some have fewer constraints.
+  rtoMixed, rcastToMixed, rcastToShaped,
+  stoMixed, scastToMixed, stoRanked,
+  mcast, mcastToShaped, mtoRanked,
+) where
 
 import Control.Category
 import Data.Proxy
 import Data.Type.Equality
-import GHC.TypeLits (Nat)
 
 import Data.Array.Mixed.Lemmas
 import Data.Array.Mixed.Types
@@ -30,15 +40,7 @@ mcast ssh2 arr
   = mcastPartial (ssxFromShape (mshape arr)) ssh2 (Proxy @'[]) arr
 
 mtoRanked :: forall sh a. Elt a => Mixed sh a -> Ranked (Rank sh) a
-mtoRanked arr
-  | Refl <- lemRankReplicate (shxRank (mshape arr))
-  = Ranked (mcast (ssxFromShape (convSh (mshape arr))) arr)
-  where
-    convSh :: IShX sh' -> IShX (Replicate (Rank sh') Nothing)
-    convSh ZSX = ZSX
-    convSh (smn :$% (sh :: IShX sh'T))
-      | Refl <- lemReplicateSucc @(Nothing @Nat) @(Rank sh'T)
-      = SUnknown (fromSMayNat' smn) :$% convSh sh
+mtoRanked = castCastable (CastXR CastId)
 
 rtoMixed :: forall n a. Ranked n a -> Mixed (Replicate n Nothing) a
 rtoMixed (Ranked arr) = arr
@@ -52,9 +54,7 @@ rcastToMixed sshx rarr@(Ranked arr)
 
 mcastToShaped :: forall sh sh' a. (Elt a, Rank sh ~ Rank sh')
               => Mixed sh a -> ShS sh' -> Shaped sh' a
-mcastToShaped arr targetsh
-  | Refl <- lemRankMapJust targetsh
-  = Shaped (mcast (ssxFromShape (shCvtSX targetsh)) arr)
+mcastToShaped arr targetsh = castCastable (CastXS' targetsh CastId) arr
 
 stoMixed :: forall sh a. Shaped sh a -> Mixed (MapJust sh) a
 stoMixed (Shaped arr) = arr