alias_method_chain_source.rb

class Module

  def alias_method_chain(target, feature)
    aliased_target, punctuation = target.to_s.sub(/([?!=])$/, ''), $1
    yield(aliased_target, punctuation) if block_given?

    alias_method without_method, target
    alias_method target, with_method
    case
      when public_method_defined?(without_method)
        public target
      when protected_method_defined?(without_method)
        protected target
      when private_method_defined?(without_method)
        private target
    end
  end
end