Ex-2.74

a:We can give each division's personnel record file a tag and that is the division's name itself.
(

define (get-record file employee-name)
  ((get 'get-record (get-division file))
   file employee-name)) 

b:Each employee record is also given a tag and that is the the division's name itself.

(define (get-salary employee-record)
  ((get 'get-salary (get-division employee-record))
   employee-record)) 

c:

(define (find-employee-record files name)
  (cond
   ((null? files) nil)
   ((null? (get-record (car files) name))
    (find-employee-record (cdr files) name))
   (else
    (get-record (car files) name)))) 

d:A new division needs to be added with its appropriate procedures into the type-operations table.