From: Jeff Rose <rosejn@...>
Date: 2006-05-11T19:52:10+09:00
Subject: Re: class << self

I asked the same question yesterday...

It is just another way add singleton methods to the outer scope 
(probably saw this in a module?).  So this:

module Foo
   class << self
     def a; end
     def b; end
   end
end

is the same as:

module Foo
   def Foo.a; end
   def Foo.b; end
end

I guess people use this style to organize sets of singleton methods so 
that they are clearly separated from the rest of the module.  (Since 
methods defined regularly won't be used until the module is mixed in 
somewhere...)  Saves you from having to write the "Foo." part before 
every method too...

-Jeff

Tim Uckun wrote:
> I was reading through the source code of the DBI module and I saw this
> line there.
> 
> class << self
> 
> What does this statement do?