(define point%
  (class object%
    (super-new)
    (init-field x y)

    (public normalize)

    (define (normalize)
      (let* ([x x]
             [y y]
             [scale (sqrt (+ (* x x) (* y y)))])
        (new point%
             [x (/ x scale)]
             [y (/ y scale)])))))

(define P (send (new point% [x 1.0] [y 1.0]) normalize))