Question 1 @ 2021-11-09 18:27
What can you say about a language that fulfils the following test:
(test (map (+ 2) '(1 2 3)) => '(3 4 5))
Choose the best answer.
-
It cannot be compiled
-
It is dynamically scoped
-
It is Schlac
-
It is Schlac, extended by all of the encodings we’ve seen in
class
-
It cannot be a statically typed language (like #lang pl)
-
It is an auto-curried language
Question 2 @ 2021-11-09 18:30
Can you write a blank definition in Racket
so the following test succeeds?
(test (* blank blank) => 660)
-
Yes, (define blank (sqrt 660))
-
No; sqrt would produce a floating point, so it’ll return 660.0
-
Yes, using exact rationals
-
Yes, using mutation
Question 3 @ 2021-11-09 18:33
How would you write a blank definition in Racket
so the following test succeeds?
(test (* (blank) (blank)) => 660)
Choose the best answer.
-
(define (blank)
(let ([b (box #f)])
(set-box! b (not (unbox b)))
(if (unbox b) 1 660)))
-
(define blank
(let ([b (box #f)])
(lambda ()
(set-box! b (not (unbox b)))
(if (unbox b) 1 660))))
-
(define (blank)
(let ([b (box #f)])
(lambda ()
(set-box! b (not (unbox b)))
(if (unbox b) 1 660))))
-
(define (blank)
(let ([b (box #t)])
(define result (if (unbox b) 660 1))
(set-box! b #f)
result))
-
(define blank
(let ([b (box #t)])
(lambda ()
(define result (if (unbox b) 660 1))
(set-box! b #f)
result)))
-
(define (blank)
(let ([b (box #t)])
(lambda ()
(define result (if (unbox b) 660 1))
(set-box! b #f)
result)))
Question 4 @ 2021-11-09 18:39
Consider a function of type A -> B,
and another function of type T -> T .
Which of the following condition will make the first function be a
subtype of the second? That is, which of these will make
A -> B ⊆ T -> T
?
-
A ⊆ T
-
T ⊆ A
-
B ⊆ T
-
T ⊆ B