Hi Francis,
On Sat, Aug 30, 2014 at 1:34 PM, Francis Avila <franci...@gmail.com> wrote: > It would probably help if you said more about the source of this > atom-holding object. Is it a plain Java class? A deftype/defrecord? Is it > final? > It's not an atom-holding object. The only guarantee is that this object extends one (or two) of these protocols: http://clecs.muhuk.com/api/0.2.1/clecs.world.html Other than that, it can be anything. A Java class, or a type or a record... > > > If you can control the construction of this object and its class is not > final, you can subclass it and add an IObj implementation. (Note that most, > maybe all clojure ways of creating classes create final classes, so this > technique won't work.) The easiest way to subclass is with `proxy`: > > (defn meta-AtomHolder [atom-value metadata] > (proxy [AtomHolderClass clojure.lang.IObj] ;; [superclass, new > interfaces] > [atom-value] ;; constructor args > (meta [] metadata) ;; subclass method > (withMeta [newmeta] (meta-AtomHolder newmeta)))) > => (var user/meta-AtomHolder) > (meta-AtomHolder (atom "x") {}) > => #<AtomHolderClass$IObj$40298964 > user.proxy$AtomHolderClass$IObj$40298964@302c28cc> > (meta (meta-AtomHolder (atom "x") {})) > => {} > (meta (with-meta (meta-AtomHolder (atom "x") {}) {:a 1})) > => {:a 1} > This is really cool. So I can do (deref (meta-AtomHolder (atom "x") {})) and it would return "x", right? I have actually managed to solve it using vars, had to move things around a bit: https://github.com/muhuk/clecs/blob/master/src/clecs/world/check.clj#L73 > > If the parent class is final or you can't construct the object yourself, > you need to delegate method calls from one instance to this object > instance. I think this is hard-but-not-impossible in java, but I'm not sure. > > (Clojurescript has `specify`, which does exactly what you want, but only > exists because delegation between instances in javascript is trivial.) > > On Friday, August 29, 2014 10:16:05 PM UTC-5, Atamert Ölçgen wrote: >> >> Obviously I can't. >> >> But I need to add this capability to an object. During testing I attach >> meta to this object that contains an atom. Then I pass this object to other >> functions, known in runtime. I can't use a dynamic var because all this >> happens within a mock function that may be retried and run in different >> threads. >> >> I have seen this: http://stackoverflow.com/questions/20724219/ >> simplest-possible-clojure-object-that-can-accept-a-primitive-and-metadata >> but can't deref it since I can't change the functions that will use it >> later. If I wrap this object I need to be able to delegate all of its >> functionality to the original object. >> >> I hope this all is not too vague. The code I'm working on is not online >> yet. But it's for clecs (https://github.com/muhuk/clecs/), I'm adding >> quickcheck to compare different world implementations. >> >> >> -- >> Kind Regards, >> Atamert Ölçgen >> >> -+- >> --+ >> +++ >> >> www.muhuk.com >> > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- Kind Regards, Atamert Ölçgen -+- --+ +++ www.muhuk.com -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
