class RBS::Writer

def attribute(kind, attr)
  visibility =
    case attr.visibility
    when :public
      "public "
    when :private
      "private "
    else
      ""
    end
  var = case attr.ivar_name
        when nil
          ""
        when false
          "()"
        else
          "(#{attr.ivar_name})"
        end
  receiver = case attr.kind
             when :singleton
               "self."
             when :instance
               ""
             end
  "#{visibility}attr_#{kind} #{receiver}#{attr.name}#{var}: #{attr.type}"
end