This strategy has to introduce a new kind of structure, called a `Closure`, to handle
binding to terms that have locally free variables in them. Let's
see how this works. For exposition, I'll pretend that the code you're working with has
-primitive numbers in it, though [[the homework assignment|/exercises/assignment6-7]] doesn't.
+primitive numbers in it, though [[the homework assignment|/exercises/assignment7]] doesn't.
(But [[the fuller code|/topics/week7_untyped_evaluator]] it's simplified from does.)
Now consider: