[racket] How to get arity of make-object?

I’m just wondering, would it be possible to make a class be a function that would be equivalent to (make-object % arg …)?  

Is there a way to attach structure-type properties to classes, instead of to instances of classes?  

Because if there is, then procedure-arity could work on the class.  

My first instinct was to do this: (I know why it doesn’t work)
#lang racket

(define with-constructor%
  (interface* ()
              ([prop:procedure (lambda (this . args)
                                 (send/apply this constructor args))])
              constructor
              ))

(define point%
  (class* object% (with-constructor%)
    (super-new) (inspect #f)
    (init-field [x 0] [y 0])
    (define/public (constructor . args) 
      (apply make-object this% args))
    ))

(define p (point% 1 2))

But this doesn’t work because it attaches the structure type properties to instances of the class instead of to the class itself.

Is there a way to attach structure-type properties to classes, instead of to instances of classes?  

On Jun 5, 2014, at 11:32 AM, Roman Klochkov <kalimehtar at mail.ru> wrote:

> For any procedure I can use procedure-arity. But how to get the number of init arguments for a class?
> 
> Or maybe there are any other way to make a contract, like in Guide 7.3.9, where one can compare number of arguments and arity of the function, but when using (make-object someclass ...)
> instead of the function.
> 
> 
> -- 
> Roman Klochkov
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