Due: Tuesday, Sept 6th by 11:59 PM

In this assignment you will practice using Scheme expressions and values.

Use Racket to type expressions and see the resulting values. Make sure you use #lang eopl.

Record your answers in a plain text file. (Suggestion: use Notepad++.)

Question 1 [20 points]: What values are the results of the following Scheme expressions?

(+ 2 (* 3 4))
(* 2 (+ 3 4))
(integer? 4/5)
(* 4/5 5)
(integer? (* 4/5 5))
(cons 'go '())
(cons 'go (cons 'west '()))
(cons 'west (cons 'go '()))
(cons 'go 'west)
(pair? (cons 'go 'west))
(list? (cons 'go 'west))

Question 2 [40 points]: Create expressions which, when evaluated, will result in the following values. Important: you may not use quoting except to specify literal symbols (e.g., 'a) and the empty list ('()).

Note that values of the form #( ... ) are vectors.

(a b c)
(a (b) c)
((a) (b) (c))
#(a b c)
#(#(a b) #(c))
#((a b) (c))
(a #(b) c)

In Questions 3-6, there is a pair of expressions and an expected value for each expression. In each expression, a variable f is used.

For each pair of expressions, give a definition of f that will cause each expression to evaluate to its expected value.

For example:

Expression Expected value
(f 2 3) 5
(f 4 5) 9

A definition of f that causes the expressions to yield their expected values is

(define f
  (lambda (x y)
    (+ x y)))

Question 3 [10 points]:

Expression Expected value
(f '(a b c)) b
(f '(1 2 3)) 2

Question 4 [10 points]:

Expression Expected value
(f '(a b)) (b a)
(f '(17 42)) (42 17)

Question 5 [10 points]:

Expression Expected value
(f car '(a b)) a
(f cdr '(1 2 3)) (2 3)

Question 6 [10 points]:

Expression Expected value
((f 2) 3) 5
((f 5) 6) 11


Submit your answers as a plain text file to Marmoset as assign1:


Do not submit a Word or OpenOffice document.

IMPORTANT: after uploading, you should download a copy of your submission and double-check it to make sure that it contains the correct file(s). You are responsible for making sure your submission is correct. You may receive a grade of 0 for an incorrectly submitted assignment.