class Roda::RodaPlugins::PermissionsPolicy::Policy

def header_value
  return @header_value if @header_value
  s = String.new
  @opts.each do |k, vs|
    s << k << "="
    if vs == :all
      s << '*, '
    else
      s << '('
      vs.each{|v| append_formatted_value(s, v)}
      s.chop! unless vs.empty?
      s << '), '
    end
  end
  s.chop!
  s.chop!
  @header_value = s
end