class ActionView::Helpers::Tags::RadioButton

def checked?(value)
  value.to_s == @tag_value.to_s
end

def initialize(object_name, method_name, template_object, tag_value, options)
  @tag_value = tag_value
  super(object_name, method_name, template_object, options)
end

def render
  options = @options.stringify_keys
  options["type"]     = "radio"
  options["value"]    = @tag_value
  options["checked"] = "checked" if input_checked?(options)
  add_default_name_and_id_for_value(@tag_value, options)
  tag("input", options)
end