8.12
Lecture 13: More self-reference
This assignment is due on Sunday, February 18 at 11:59pm. Submit it using Handin as assignment lecture13.
; A Doll is one of: ; - (make-small-doll String) ; - (make-larger-doll Doll) (define-struct small-doll (color)) (define-struct larger-doll (smaller))
Exercise 1.
Design the function green-doll which takes a
Doll and returns a similar Doll, but the small
Doll at the center has the color "green".
Here’s an example:
(check-expect (green-doll (make-larger-doll (make-small-doll "red"))) (make-larger-doll (make-small-doll "green")))
Exercise 2.
Recall from Who can name the bigger number? by Aaronson
that “5 tetrated to the 3” means 5 raised to its own power 3 times.
That is (expt 5 (expt 5 5)) = (expt 5 (expt 5 (expt 5 1))),
a number with 2185 digits.
Design a function tetrated-5 that takes a NaturalNumber and
returns 5 tetrated to it.
Use the data definition of NaturalNumber at the end of the video above.