Before the lab

• Read FICS Section 5.1, 5.2

Setup

• make a directory labs/L05 inside your ~/cs2613 git repository
• All of your work from today should be committed in that directory (and pushed before you leave).

Substitute in a list

Complete FICS Exercise 13.

Recall the template for structural recursion.

(define (my-list-fn lst)
  (cond
    [(empty? lst) ...]
    [(cons? lst) ... (first lst) ...
                 ... (my-list-fn (rest lst)) ...]))

Here is a test case based on the linked test

(check-expect
 (substitute 3 "three" (list "four" 3 4 "three" 3))
 (list "four" "three" 4 "three" "three"))

Uniquifying lists

Complete FICS Exercise 15. Although probably not intended by the original question, use the built-in BSL function member? to simplify your solution. Otherwise use only the constructs specified in Exercise 14, and structural recursion. Here is one test case derived from the linked text.

(check-expect
 (unique-right
  (list 1 4 2 1 5 4))
 (list 2 1 5 4))

Add an element to all lists

Recall the template for structural recursion on lists

(define (my-list-fn lst)
  (cond
    [(empty? lst) ...]
    [(cons? lst) ... (first lst) ...
                 ... (my-list-fn (rest lst)) ...])

Use this template to write a function cons-all that adds a given element to the front of each given sublist. The following test case illustrates the use of cons-all. You will need to use the language #lang htdp/bsl+ or "Beginning Student with List Abbreviations" or replace the use of ' in the following.

(check-expect (cons-all 3 '((2 4) () (5)))
              '((3 2 4) (3) (3 5)))

Before next lab