module ActionView::Layouts

def _layout_for_option(name)
  case name
  when String     then _normalize_layout(name)
  when Proc       then name
  when true       then Proc.new { |lookup_context, formats| _default_layout(lookup_context, formats, true)  }
  when :default   then Proc.new { |lookup_context, formats| _default_layout(lookup_context, formats, false) }
  when false, nil then nil
  else
    raise ArgumentError,
      "String, Proc, :default, true, or false, expected for `layout'; you passed #{name.inspect}"
  end
end