Lab 4:

FIRST: finish prior labs.  Ask questions.

NEXT: in the Language > Choose Language ... dialog, enable coverage testing.
Try it out by adding a bogus unused def'n to your code:

(define (unused) (+ 3 4 5))

click run. See unevaluated expression highlighted.


THEN:

Develop the 'doublemap' function, that consumes a function and a list and
returns the list formed by applying the function twice to each element of the
original list.

Develop the 'zip' function, that consumes two lists of the same length and
returns a new list of lists where each element of the new list is a list
containing both of the corresponding elements from the original list.

Develop the 'quicksort' function, that conumes a list of numbers and sorts them
like this: the empty list is already sorted.  Any other list is sorted by
appending the result of sorting all elements smaller than or equal to the first
element to the result of sorting all elements greater than the first element.
(You may already know this algorithm, as... quicksort).  You will definitely
need some helper functions for this. Nevertheless, it's a straightforward
structural recursion.

Time left? Write foldl.