1 define A = { .a -> do write("A"); .theAnswer; _ -> .other };

2

3 -- define B = rec { .a -> do write("IN"); do self.b; write("OUT") } |extends ({.b -> A.a} |extends A);

4 define B = rec { .a -> self.b; .b -> A.a } |extends A;

5

6 define debugTrace x -> rec {

7 selector -> do write(selector);

8 do write("IN");

9 let result = self |as x selector;

10 do write(selector);

11 do write("OUT");

12 result

13 };

14