Comments on: On the Existence of Struct::Group in Rails

By: Trevor

Trevor — Sun, 16 Nov 2008 07:22:08 +0000

Maybe I should say… surprising? In my case, I didn’t expect that calling Group.find from within a Struct would be any different from calling it elsewhere in my app. The fact that Struct::Group already existed came from way out in left field, to me at least.

By: Matt Todd

Matt Todd — Sun, 16 Nov 2008 02:31:48 +0000

Not weird at all, it’s just a scoping issue… if you’re asking for Group inside of a scope that has it defined, it will return the first one instead of the one outside of the first scope checked (which is usually always the local scope).

When you prefix two colons like ::Group you’re actually saying Object::Group which tells Ruby to look in the scope of the Object class which will see the right class because the other one is only local inside of the Struct class object.

If I can clarify further, let me know.

Matt

By: Trevor

Trevor — Sat, 15 Nov 2008 22:20:32 +0000

I believe if you did it that way, you'd need to define the initialize method as well, so that you could pass in your variables. That's fine, but it would be a bit more code.

By: Mark Wilden

Mark Wilden — Sat, 15 Nov 2008 21:38:22 +0000

Thanks for the heads-up.

How is

class NewsletterJob < Struct.new(:text, :emails)
end

different from

class NewsletterJob
attr_accessor :text, :emails
end