Hey guys!
Can anyone tell me why this code doesn't work? I've just started using assignment. My "mover" procedure is supposed to add 1 to the variable "position" each time it's called (each calling using the newly set position). It sets it right the first time but then it doesn't changes with further calls.

(define (make-mover position)
(define north
(begin (set! position (+ position 1))
position))
(define (dispatch direction)
(cond ((eq? direction 'north) north)))
dispatch)

(define position1 0)

(define mover ((make-mover position1) 'north))

Question

Hey guys!
Can anyone tell me why this code doesn't work? I've just started using assignment. My "mover" procedure is supposed to add 1 to the variable "position" each time it's called (each calling using the newly set position). It sets it right the first time but then it doesn't changes with further calls.

(define (make-mover position)
  (define north
      (begin (set! position (+ position 1))
             position))
  (define (dispatch direction)
    (cond ((eq? direction 'north) north)))
  dispatch)

(define position1 0)

(define mover ((make-mover position1) 'north))

anonymous · Answer

It's weird because it works fine if "mover" has an argument like distance.

anonymous · Answer

Note: it looks a bit odd because a few parts have just been deleted...