diff --git a/app/Builtins.hs b/app/Builtins.hs
index 898d664..9db5386 100644
--- a/app/Builtins.hs
+++ b/app/Builtins.hs
@@ -32,11 +32,11 @@ bi = Builtin
 
 showTerm itos heap = runIdentity . heapStruct atom struct hrec heap
   where
-    atom (Atom a) = pure $ itos M.! a
+    atom (Atom a) = pure $ "'" ++ itos M.! a ++ "'"
     atom (Number n) = pure (show n)
     atom VoidRef = pure "_"
     struct (Struct (IR.Id h _)) args =
-      pure $ itos M.! h ++ "(" ++ intercalate "," args ++ ")"
+      pure $ "'" ++ itos M.! h ++ "'(" ++ intercalate "," args ++ ")"
     hrec (HeapRef hr) ref =
       pure $
       (if hr == ref