On Tue, Nov 25, 2008 at 8:41 AM, Matt Wynne <[EMAIL PROTECTED]> wrote: > Sorry, I know this is off-topic, but I'd really like to know what the > revered ruby-hackers who read this list think. > > See > http://ozmm.org/posts/class__self_is_harmful.html > > I have adopted class << self, partly from reading RSpec and Cucumber's code > as I learn Ruby. I personally think of class methods (or 'static' methods) > as being in a kind of 'holding pen' waiting to be factored off onto a proper > class of their own, so I rather like the clear way you can group them in a > 'nameless' metaclass ready for the exit door. > > I also really like the clarity of seeing the invisible metaclass for what it > is. > > What do people think? How can this be harmful?
I think the issue is that people are using class << self to access the virtual class when they don't need it. I've seen code where you have to scroll to see all of the methods implemented inside of class << self. Adding methods to a virtual class does make method dispatching in ruby less efficient, but I don't think enough to render it non-usable. The virtual class of an object (class or instance alike) gives you the ability to modify the object in ways that a simple class method usually does not allow. For example, if you want to break down a class method into a couple of methods, but you don't want to support all of the methods as a public API. Here you can use class << self to privately scope some of those helper methods that you just decomposed. My rule of thumb is to use it when I can't easily achieve the same result using other mechanisms, but not to use it just cause'. -- Zach Dennis http://www.continuousthinking.com http://www.mutuallyhuman.com _______________________________________________ rspec-users mailing list rspec-users@rubyforge.org http://rubyforge.org/mailman/listinfo/rspec-users
