Petite Chez Scheme Version 9.5.4
Copyright 1984-2020 Cisco Systems, Inc.

> (define a '(3 4 5))
> (cdr a)
(4 5)
> (cddr a)
(5)
> (cdddr a)
()
> (cddddr a)
Exception in cddddr: incorrect list structure (3 4 5)
> (cdddddr a)
Exception: variable cdddddr is not bound
> a
(3 4 5)
> (define f '((a (b (c))) d))
> (cadar f) ; want output b
(b (c))
> (caadar f) ; want output b
b
> /
#<procedure />
> (define / *)
> (/ 3 4)
12
> (let ([* +])
     (* 4 7))
11
> (* 4 7)
28
> (max 3 5 7 2)
7
> (max 3)
3
> (max)
Exception: incorrect argument count in call (max)
> a
(3 4 5)
> (max a)
Exception in max: (3 4 5) is not a real number
> (apply max a)
5
> (max 3 4 5)
5
> (if 0 1 2)
1
> (if '() 1 2)
1
> (if #f 1 2)
2
> (if #f 1)
> (list (if #f 1))
(#<void>)
> (void)
> (list (void))
(#<void>)
> (if (void) 1 2)
1
> (if (< 3 5) 2 4)
2
> (define letter-to-number
    (lambda (letter)
      (if (eq? letter 'A)
	  4.0
	  (if (eq? letter 'B+)
	      3.5
	      3.0))))
(define letter-to-number
    (lambda (letter)
      (if (eq? letter 'A)
	  4.0
	  (if (eq? letter 'B+)
	      3.5
	      3.0))))
)	      
)))
Exception: invalid syntax (if (eq? letter (quote B)) (eq? letter (quote B+)) 3.5 (define letter-to-number (lambda (...) (...))))
> (define letter-to-number
    (lambda (letter)
      (if (eq? letter 'A)
	  4.0
	  (if (eq? letter 'B+)
	      3.5
	      3.0))))
> (letter-to-number 'B+)
3.5
> (letter-to-number 't)
3.0
> (length a)
3
> (length '(2 4 5))
3
> (define len (lambda (x) (length x)))
> (len a)
3
>