Title is misleading. What I see presented in the article is a single technique, "implement the same interface." What I expected instead was to see methods for getting ruby core objects to present themselves as more complex objects or so on. In that case, I'd expect to see references to SimpleDelegate, Forwardable, duping the metaclass, extending the singleton class of the instantiated objects and so forth.
I don't know how to edit titles on HN, otherwise I'd change it to "A Technique For ..."
As for the rest of the ideas here, they're all good, and if you want to write up a post about them, I'd be happy to run it on RBP Blog. We'll be opening up third party contributions soon anyway. Or if you post somewhere else, I can link this post back to it.
While delegation is interesting on its own, it isn't too interesting when it comes to duck typing in the abstract sense because it by definition chains you to implementation details. Of course, it is nice to make an array-like thing act like an array by just delegating the relevant calls, or something similar.
Of course, things do get more exciting when you do something like this:
a = [1,2,3]
a.extend(ActLikeAFoo)
expect_a_foo(a)
So thanks for pointing this out. It's a great technique for certain needs and hopefully it'll get coverage soon on the blog.
