> (list-ref '(a b c) 1)
'b
> (filter positive? '(1 0 -2 -3 4))
'(1 4)
> (assq 3 '((1 2) (3 4) (5 6)))
'(3 4)
> (assq 'a '((b 3) (c 4) (a 5)))
'(a 5)
> (set-car! '(2 3 4) 'a)
. . set-car!: undefined;
 cannot reference an identifier before its definition
> (set-mcar? '(2 3 4) 'a)
. . set-mcar?: undefined;
 cannot reference an identifier before its definition
> (set-mcar! '(2 3 4) 'a)
. . set-mcar!: contract violation
  expected: mpair?
  given: '(2 3 4)
> (define foo (mcons '2 (mcons 3 (mcons 4 '()))))
> foo
(mcons 2 (mcons 3 (mcons 4 '())))
> (set-mcar! foo 'a)
> foo
(mcons 'a (mcons 3 (mcons 4 '())))
> (lambda (x) (lambda (y) (+ y x)))
#<procedure>
> (lambda (x) (display "Ernie") (lambda (y) (+ y x)))
#<procedure>
> ((lambda (x) (display "Ernie") (lambda (y) (+ y x))) 3)
Ernie#<procedure>
> ((lambda (x) (display "Ernie") (lambda (y) (display "Bert ") (+ y x))) 3)
Ernie#<procedure>
> (((lambda (x) (display "Ernie") (lambda (y) (display "Bert ") (+ y x))) 3) 4)
ErnieBert 7
> 
> (add-generator 42)
#<procedure>
> (define add42 (add-generator 42))
> add42
#<procedure>
> (add42 3)
45
> (define add7 (add-generator 7))
> (add7 3)
10
>