How do you prefer to define class methods in Ruby?

Question

John Nunemaker recently blogged about the various ways to define class methods in Ruby, giving these three alternatives:

# Way 1
class Foo
  def self.bar
    puts 'class method'
  end
end

# Way 2
class Foo
  class << self
    def bar
      puts 'class method'
    end
  end
end

# Way 3
class Foo; end
def Foo.bar
  puts 'class method'
end

• What's your preferred way to do this?
• Do you prefer something other than those above?
• If you use more than one way, under what circumstances do you use them?

Answer 1

I consistently use Way 1:

class Foo
  def self.bar
    puts 'class method'
  end
end

It's not verbose, and it keeps the method in the same context of the class.

Answer 2

I generally prefer def self.foo for single methods, and class << self for long stretches of class methods. I feel it makes the distinction between the class method part and the instance method part of the class definition.