Concatenation of arrays for M and R

What should the type of sconcat be?

1 files changed, 10 insertions, 0 deletions

diff --git a/src/Data/Array/Mixed/XArray.hs b/src/Data/Array/Mixed/XArray.hs
index e93ffca..20f5c7a 100644
--- a/src/Data/Array/Mixed/XArray.hs
+++ b/src/Data/Array/Mixed/XArray.hs
@@ -18,7 +18,9 @@ import Control.DeepSeq (NFData(..))
 import Data.Array.Ranked qualified as ORB
 import Data.Array.RankedS qualified as S
 import Data.Coerce
+import Data.Foldable (toList)
 import Data.Kind
+import Data.List.NonEmpty (NonEmpty)
 import Data.Proxy
 import Data.Type.Equality
 import Data.Type.Ord
@@ -117,6 +119,14 @@ append ssh (XArray a) (XArray b)
   | Dict <- lemKnownNatRankSSX ssh
   = XArray (S.append a b)
 
+-- | All arrays must have the same shape, except possibly for the outermost
+-- dimension.
+concat :: Storable a
+       => StaticShX sh -> NonEmpty (XArray (Nothing : sh) a) -> XArray (Nothing : sh) a
+concat ssh l
+  | Dict <- lemKnownNatRankSSX ssh
+  = XArray (S.concatOuter (coerce (toList l)))
+
 -- | If the prefix of the shape of the input array (@sh@) is empty (i.e.
 -- contains a zero), then there is no way to deduce the full shape of the output
 -- array (more precisely, the @sh2@ part): that could only come from calling