From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2010-11-07T18:35:10+09:00
Subject: Re: Meaning of ::

On Sun, Nov 7, 2010 at 9:37 AM, Zhi-Qiang Lei <zhiqiang.lei@gmail.com> wrote:
> What about code like:
>
> ::Digest::MD5.hexdigest "xxx"
>
> Why is the :: before Digest module nothing?

That means to refer to the top most Digest constant, to avoid
referencing the wrong one in cases like this:

module Test
  module Digest
    # my own Digest module
  end

  class TestClass
    Digest # refers to my own module
    ::Digest # refers to the Digest module defined at the top level
  end
end

Jesus.