1 files changed, 36 insertions, 0 deletions
diff --git a/src/AST.hs b/src/AST.hs
index bcbb19a..99c0681 100644
--- a/src/AST.hs
+++ b/src/AST.hs
@@ -256,6 +256,42 @@ typeOf = \case
 
   EError _ t _ -> t
 
+extOf :: Expr x env t -> x t
+extOf = \case
+  EVar x _ _ -> x
+  ELet x _ _ -> x
+  EPair x _ _ -> x
+  EFst x _ -> x
+  ESnd x _ -> x
+  ENil x -> x
+  EInl x _ _ -> x
+  EInr x _ _ -> x
+  ECase x _ _ _ -> x
+  ENothing x _ -> x
+  EJust x _ -> x
+  EMaybe x _ _ _ -> x
+  EConstArr x _ _ _ -> x
+  EBuild x _ _ _ -> x
+  EFold1Inner x _ _ _ -> x
+  ESum1Inner x _ -> x
+  EUnit x _ -> x
+  EReplicate1Inner x _ _ -> x
+  EMaximum1Inner x _ -> x
+  EMinimum1Inner x _ -> x
+  EConst x _ _ -> x
+  EIdx0 x _ -> x
+  EIdx1 x _ _ -> x
+  EIdx x _ _ -> x
+  EShape x _ -> x
+  EOp x _ _ -> x
+  ECustom x _ _ _ _ _ _ _ _ -> x
+  EWith x _ _ -> x
+  EAccum x _ _ _ _ -> x
+  EZero x _ -> x
+  EPlus x _ _ _ -> x
+  EOneHot x _ _ _ _ -> x
+  EError x _ _ -> x
+
 -- unSNat :: SNat n -> Nat
 -- unSNat SZ = Z
 -- unSNat (SS n) = S (unSNat n)