1 files changed, 7 insertions, 0 deletions
diff --git a/src/AST.hs b/src/AST.hs
index b1f3e5d..7c5de11 100644
--- a/src/AST.hs
+++ b/src/AST.hs
@@ -13,6 +13,8 @@
 {-# LANGUAGE DeriveFoldable #-}
 module AST (module AST, module AST.Weaken) where
 
+import Data.Functor.Const
+
 import Data.Kind (Type)
 import Data.Int
 
@@ -126,6 +128,11 @@ data Expr x env t where
   EError :: STy a -> String -> Expr x env a
 deriving instance (forall ty. Show (x ty)) => Show (Expr x env t)
 
+type Ex = Expr (Const ())
+
+ext :: Const () a
+ext = Const ()
+
 type SOp :: Ty -> Ty -> Type
 data SOp a t where
   OAdd :: SScalTy a -> SOp (TPair (TScal a) (TScal a)) (TScal a)