A bit late for a reply, but...

Very nice job on handling the call-back. You make it look so simple that I'm ashamed that I never got that far when I had this challenge. (: I guess it gets trickier if you have one call-back per object and need to pass the object in to the call-back function, which is what I was doing, but that still sounds doable based on what you did.

Anyway, I was really replying to mention the FFI module that supports building call-backs at run time, usually for use with dynamic libraries. I haven't actually gotten to use it since I found out about it, but I've heard good things about it.

        - tye (but my friends call me "Tye")