Opening act

Getting some great questions.

  • What else?

HW Grades – still working at.

Recap

Let's go wild!

CPS me :-)

(lambda (f)
  ((lambda (x) (x x))
   (lambda (x) (f (lambda (y) ((x x) y))))))

call/cc example program

Complete the following definition of last-non-zero, a function which takes a list of numbers and return the last cdr whose car is 0. In other words, when starting from the right of the list, it should be all numbers before the first 0 is reached. Your solution should be naturally recursive, and should not contain any calls to member-like operations, nor should you be reversing the list.

Don't CPS anything, don't use empty-k, etc.

(define last-non-zero
  (lambda (ls)
    (let/cc k
      (letrec
    ((last-non-zero
       (lambda (ls)
         (cond
           ;; fill in lines here
           ))))
    (last-non-zero ls)))))

> (last-non-zero '(0))
()
> (last-non-zero '(1 2 3 0 4 5))
(4 5)
> (last-non-zero '(1 0 2 3 0 4 5))
(4 5)
> (last-non-zero '(1 2 3 4 5))
(1 2 3 4 5)
>

CPS something.

Updated: