Stop show with sound  Next slide in show -- Keyboard shortcut: 'n'  2 minutes, 41 secondsLecture 4 - slide 5 : 34
Program 2
1> (define first (make-selector-function 1 "first"))

2> (first '(a b c))
a

3> (first '())
The selector function first: 
The list () is is too short for selection. 
It must have at least 1 elements.
> 

4> (define (make-person-record firstname lastname department) 
      (list 'person-record firstname lastname department))

5> (define person-record 
      (make-person-record "Kurt" "Normark" "Computer Science"))

6> (define first-name-of 
           (make-selector-function 2 "first-name-of"))

7> (define last-name-of 
           (make-selector-function 3 "last-name-of"))

8> (last-name-of person-record)
"Normark"

9> (first-name-of person-record)
"Kurt"