;;(require (lib "datatype.ss" "eopl"))
(require (lib "eopl.ss" "eopl"))

(define-datatype BusRoute BusRoute?
  (a-BusRoute
    (name symbol?)
    (buses (list-of Bus?))
    (towns (list-of Town?))))

(define-datatype Bus Bus?
  (a-Bus
    (name symbol?)
    (passengers (list-of Person?))))

(define-datatype Town Town?
  (a-Town
     (name symbol?)
     (busStops (list-of BusStop?))))

(define-datatype BusStop BusStop?
    (a-BusStop
      (name symbol?)
      (waiting (list-of Person?))))

(define-datatype Person Person?
   (a-Person
      (name symbol?)))

(define (trav br)
  (cases BusRoute br
    (a-BusRoute (name buses towns) (+ (trav-buses buses) (trav-towns towns)))))
(define (trav-buses lob)
  (foldl + 0 (map trav-bus lob)))
(define (trav-bus b)
  (cases Bus b
    (a-Bus (name passengers) (trav-passengers passengers))))
(define (trav-passengers lop)
  (foldl + 0 (map trav-person lop)))
(define (trav-person p)
  (cases Person p
    (a-Person (name) 1)))
(define (trav-towns lot)
  0)

(define br1 (a-BusRoute 'Route1 
            (list (a-Bus 'B45 (list 
                               (a-Person 'Dimitrios)
                               (a-Person 'Viera)))) 
            (list (a-Town 'Cambridge (list
                                      (a-BusStop 'CentralSquare 
                                                 (list
                                                  (a-Person 'Jesse)
                                                  (a-Person 'Matthias))))))))
(trav br1)