An example of aliasing in a singleton class copying a method definition

gistfile1.rb

class MyClass
  def my_instance_method
    :some_value
  end
end

instance = MyClass.new

singleton_class = class << instance; self; end

puts singleton_class.instance_method(:my_instance_method) == MyClass.instance_method(:my_instance_method)

class << instance
  alias_method :temporary_method, :my_instance_method
  alias_method :my_instance_method, :temporary_method
end

class MyClass
  def my_instance_method
    :some_other_value
  end
end

# Singleton class now has the original version of the method
puts singleton_class.instance_method(:my_instance_method) == MyClass.instance_method(:my_instance_method)

singleton_class.instance_method(:my_instance_method).bind(instance).call  # :some_value
MyClass.instance_method(:my_instance_method).bind(instance).call          # :some_other_value