<div class="gmail_quote">On Wed, Sep 15, 2010 at 15:59, Matthias Felleisen <<a href="mailto:matthias@ccs.neu.edu">matthias@ccs.neu.edu</a>> wrote: <blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> Where do you want to bind them? In the current namespace? Scope? </blockquote><div> Module scope, in the current namespace, runtime phase. (I think, if I understand all these terms correctly). Here is the same code as the previous one, but this time working (still only for a%): <a.rkt> #lang racket (provide a%) (define a% (class object% (super-new) (init-field val) (define/public (get-the-val) val) )) <singleton.rkt> #lang racket (require (for-syntax racket/class) "a.rkt" (for-syntax "a.rkt") ) (define-syntax-rule (define-singleton-sender func obj meth) (begin (printf "define-sender: ~s ~s ~s\n" 'func 'obj 'meth) (define (func . args) (send/apply (obj) meth args)))) (define-syntax (class->singleton stx) (syntax-case stx () [(_ cl obj) (with-syntax ([(name ...) (map (λ(n)(datum->syntax #'cl n)) (interface->method-names (class->interface a%)))]) ; only for a% *** #'(begin (define-singleton-sender name obj name) ...))])) (define current-a (make-parameter (new a% [val 3]))) (class->singleton a% current-a) (get-the-val) I really only need to pass some class to the class->singleton macro. There must be some simple answer ; I'd be very surprised if this was not possible. Thanks a lot for the time you take to answer. </div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> <div><div></div><div class="h5"> On Sep 15, 2010, at 9:47 AM, Laurent wrote: > > > On Wed, Sep 15, 2010 at 15:29, Matthias Felleisen <<a href="mailto:matthias@ccs.neu.edu">matthias@ccs.neu.edu</a>> wrote: > > > Would this help you: > > #lang racket > > (define a% > (class object% > (init-field this.x) > (define/public (foo x) > (set! this.x x)) > (define/public (bar) > this.x) > (super-new))) > > (new a% [this.x 10]) > > (define (generic-methods class%) > (map (lambda (name) (list name (make-generic class% name))) > (interface->method-names (class->interface class%)))) > > (generic-methods a%) > > If I could pass the latter result to a macro that binds the names with the function automatically, yes, > but this seems to be exactly my initial problem, I think. > > > > > > On Sep 15, 2010, at 9:10 AM, Laurent wrote: > > > > > > > On Wed, Sep 15, 2010 at 14:57, Matthias Felleisen <<a href="mailto:matthias@ccs.neu.edu">matthias@ccs.neu.edu</a>> wrote: > > > > Can we start from something simpler? > > > > The name of your macro suggests that you want something like this: > > > > (define one-and-only-one-instance > > (new (class my-super% ...))) > > > > This creates a class and creates a single instance. Because class is nested > > in the call to new, there is no way to get another instance. > > > > Would this be what you want? > > > > Okay, let me explain what I want to do (the name is not really set in stone yet). > > > > There is a class a% defined somewhere, and an instance parameter > > current-a%-object of class a%. > > Suppose a% has methods foo and bar. > > > > Then I call: > > (class->singleton a% current-a%-object) > > > > This is supposed to define the forms (foo ....) and (bar ....) so that they act like > > (send (current-a%-object) foo ....), etc. > > > > I want to build these definitions automatically from the methods of the class. > > > > Anyway, beside the intended goal, I'd still like to know how solve the macro issue. > > > > </div></div></blockquote></div>