in ruby what's the difference between self.method and a method within class << self

Question

class Foo

  def self.one; 1 end

  class << self
    def two; 2 end
  end

end
puts Foo.singleton_methods.inspect # => [\"two\", \"one\"]

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Answer 1

I strongly recommend you to read "Metaprogramming Ruby". This book explains about Ruby's object model, including singleton method and singleton class.

http://pragprog.com/titles/ppmetr/metaprogramming-ruby

This article also explains same topic.

http://www.contextualdevelopment.com/articles/2008/ruby-singleton