On Wed, Jun 24, 2015 at 10:21:44PM +0200, Michael Tiedtke wrote: > (use-modules (oop goops)) > > GOOPS has some nice features (you can even use unexported methods with > generics in 1.8) but there is no message passing paradigm.
Guile's GOOPS is a (rather impressive) clone of CLOS, the Common Lisp Object System. I such a system functions/methods don't "belong" to a class. > Objective-C has > /tell/ Racket has /send/ but Guile/GOOPS is missing /call/. Message passing only exists in object systems where methods belong to a class/object. Generic functions don't "belong" to a class/object. If you really want to use a far inferior OO system you might want to port Common Lisp's Flavour system :-) > > This is a first "raw" definition where the parameter /message/ has to be a > quoted symbol. > > (define-method (call (receiver <object>) message . arguments) > (apply (slot-ref receiver message) arguments)) > > > The class definition still looks like traditional GOOPS but it works. > > An example: > > (define-class <receiver> () > (msg #:init-value (lambda () 'hello-world))) > > (define r (make <receiver>)) > (call r 'msg) => 'hello-world > > > Now I'd like to have an easier syntax for describing the slot. The > definition might be: > > (define-syntax define-message > (syntax-rules () > ((_ (message-name arguments ... ) body ...) > (message-name #:init-value (lambda (arguments ...) body ...))))) > > But the following example doesn't work in 1.8: > > (define-class <house> () > (define-message (phone n) > (repeat n (lambda () (bell) 'rang)) )) > > GOOPS complains about malformed slots and *seems* to see the unexpanded > form.* Here: $ guile-1.8 guile> (use-modules (oop goops)) guile> define-class #<macro! define-class> Why would you expect a macro to evaluate its arguments? :-) > I could use a little help here, anyone?* Even for the naming scheme: /send/ > is already used by unix sockets and methods are part of the implementation > of generics. Perhaps /message/ isn't that bad. That's what modules are for. guile> (define-module (ios) #:export (send)) ; ios = Inferior Object System and then: guile> (ios:send ....) > [...] > PS > Perhaps it's better to recreate a clean object model without 3,000 lines of > C code like GOOPS. But then GOOPS really creates the illusion of an object > oriented environment with a MOP ... Why, 3000 lines of C code seems like a rather lean codebase for an objet system. Just my 0.2 $ Ralf Mattes
