Method char_set_parser

include/boost/parser/parser.hpp:7325–7336

    struct char_set_parser
    {
        BOOST_PARSER_ALGO_CONSTEXPR char_set_parser()
        {
            auto const & chars = detail::char_set<Tag>::chars;
            auto const first = std::begin(chars);
            auto const last = std::end(chars);
            auto it = std::upper_bound(first, last, 0x100, [](auto x, auto y){
                using common_t = std::common_type_t<decltype(x), decltype(x)>;
                return (common_t)x < (common_t)y;
            });
            if (it != last)
                one_byte_offset_ = int(it - first);
        }

        template<typename T>
        using attribute_type = std::decay_t<T>;