Rails class << self
this
module Utility class Options #:nodoc: class << self # we are inside Options's singleton class def parse(args) end end endendis equivalent to:
module Utility class Options #:nodoc: def Options.parse(args) end endendA couple examples to help you understand :
class A HELLO = 'world' def self.foo puts "class method A::foo, HELLO #{HELLO}" end def A.bar puts "class method A::bar, HELLO #{HELLO}" end class << self HELLO = 'universe' def zim puts "class method A::zim, HELLO #{HELLO}" end endendA.fooA.barA.zimputs "A::HELLO #{A::HELLO}"# Output# class method A::foo, HELLO world# class method A::bar, HELLO world# class method A::zim, HELLO universe# A::HELLO world