From: Aaron Patterson <aaron@...>
Date: 2009-03-01T09:42:29+09:00
Subject: Re: double colons in class def

On Sun, Mar 01, 2009 at 07:54:03AM +0900, matt neuburg wrote:
> In this phrase:
> 
> class IterString < ::String
>   # whatever
> end
> 
> what do the double-colons do? Thx - m.

It's explicitly telling ruby where to find the "String" constant.

For example:

  module Foo
    class String
      def hello
        "world"
      end
    end
  
    class Bar < String
    end
  
    class Baz < ::String
    end
  end
  
  puts Foo::Bar.new.hello
  puts Foo::Baz.new.hello # => (NoMethodError)

The double colons make sure that ruby looks at the top level for the constant.

-- 
Aaron Patterson
http://tenderlovemaking.com/