1 files changed, 26 insertions, 10 deletions
diff --git a/src/AST/Accum.hs b/src/AST/Accum.hs
index 1101cc0..158b4d9 100644
--- a/src/AST/Accum.hs
+++ b/src/AST/Accum.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE StandaloneDeriving #-}
+{-# LANGUAGE TypeData #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE UndecidableInstances #-}
 module AST.Accum where
@@ -32,21 +33,36 @@ data SAcPrj (p :: AcPrj) (a :: Ty) (b :: Ty) where
   -- SAPArrSlice :: SNat m -> SAcPrj (APArrSlice m) (TArr n t) (TArr (n - m) t)
 deriving instance Show (SAcPrj p a b)
 
-type family AcIdx p t where
-  AcIdx APHere t = TNil
-  AcIdx (APFst p) (TPair a b) = TPair (AcIdx p a) (ZeroInfo b)
-  AcIdx (APSnd p) (TPair a b) = TPair (ZeroInfo a) (AcIdx p b)
-  AcIdx (APLeft p) (TLEither a b) = AcIdx p a
-  AcIdx (APRight p) (TLEither a b) = AcIdx p b
-  AcIdx (APJust p) (TMaybe a) = AcIdx p a
-  AcIdx (APArrIdx p) (TArr n a) =
+type data StillDense = AI_D | AI_S
+data SStillDense dense where
+  SAI_D :: SStillDense AI_D
+  SAI_S :: SStillDense AI_S
+deriving instance Show (SStillDense dense)
+
+type family AcIdx dense p t where
+  AcIdx dense APHere t = TNil
+  AcIdx AI_D (APFst p) (TPair a b) = AcIdx AI_D p a
+  AcIdx AI_D (APSnd p) (TPair a b) = AcIdx AI_D p b
+  AcIdx AI_S (APFst p) (TPair a b) = TPair (AcIdx AI_S p a) (ZeroInfo b)
+  AcIdx AI_S (APSnd p) (TPair a b) = TPair (ZeroInfo a) (AcIdx AI_S p b)
+  AcIdx dense (APLeft p) (TLEither a b) = AcIdx AI_S p a
+  AcIdx dense (APRight p) (TLEither a b) = AcIdx AI_S p b
+  AcIdx dense (APJust p) (TMaybe a) = AcIdx AI_S p a
+  AcIdx AI_D (APArrIdx p) (TArr n a) = TPair (Tup (Replicate n TIx)) (AcIdx AI_D p a)
+  AcIdx AI_S (APArrIdx p) (TArr n a) =
     -- ((index, shapes info), recursive info)
     TPair (TPair (Tup (Replicate n TIx)) (ZeroInfo (TArr n a)))
-          (AcIdx p a)
-  -- AcIdx (APArrSlice m) (TArr n a) =
+          (AcIdx AI_S p a)
+  -- AcIdx AI_D (APArrSlice m) (TArr n a) =
+  --   -- index
+  --   Tup (Replicate m TIx)
+  -- AcIdx AI_S (APArrSlice m) (TArr n a) =
   --   -- (index, array shape)
   --   TPair (Tup (Replicate m TIx)) (Tup (Replicate n TIx))
 
+type AcIdxD p t = AcIdx AI_D p t
+type AcIdxS p t = AcIdx AI_S p t
+
 acPrjTy :: SAcPrj p a b -> SMTy a -> SMTy b
 acPrjTy SAPHere t = t
 acPrjTy (SAPFst prj) (SMTPair t _) = acPrjTy prj t