add toc

diff --git a/topics/week7_untyped_evaluator.mdwn b/topics/week7_untyped_evaluator.mdwn
index 119a730..760068b 100644 (file)
--- a/topics/week7_untyped_evaluator.mdwn
+++ b/topics/week7_untyped_evaluator.mdwn
@@ -1,5 +1,7 @@
-A program that interprets untyped lambda terms (and more)
-=========================================================
+[[!toc levels=2]]
+
+Datatypes and complications
+---------------------------
 
 Let's start with an OCaml datatype for untyped lambda terms: