linfo2335-programming-paradigms/project-2/step0.rkt

;Auhors:Dubois Brieuc, Dubois Simon
;Addapted from the example given in the assignment. Major change are:
;   function directly defined in dispatch
;   = changed to eq? to take symbol as input
;   eror message added

;Class definition
(define (point x y)
  (define (dispatch m)
    (cond ((eq? m 'getx) x)
          ((eq? m 'gety) y)
          ((eq? m 'type) 'point)
          ((eq? m 'info) (list 'point x y))
          (else (display (string-append "point as no method: " (symbol->string m) "\n")))))
  dispatch)

;Usage example 
(define p (point 1 2))
(p 'getx) ; 1
(p 'gety) ; 2
(p 'type) ; point
(p 'info) ; (point 1 2)
(p 'foo) ; display "point as no method: foo"