Function parse_key

Rapfi/external/cpptoml/include/cpptoml.h:2179–2210

    template <class KeyEndFinder, class KeyPartHandler>
    std::string
    parse_key(std::string::iterator& it, const std::string::iterator& end,
              KeyEndFinder&& key_end, KeyPartHandler&& key_part_handler)
    {
        // parse the key as a series of one or more simple-keys joined with '.'
        while (it != end && !key_end(*it))
        {
            auto part = parse_simple_key(it, end);
            consume_whitespace(it, end);

            if (it == end || key_end(*it))
            {
                return part;
            }

            if (*it != '.')
            {
                std::string errmsg{"Unexpected character in key: "};
                errmsg += '"';
                errmsg += *it;
                errmsg += '"';
                throw_parse_exception(errmsg);
            }

            key_part_handler(part);

            // consume the dot
            ++it;
        }

        throw_parse_exception("Unexpected end of key");
    }

    std::string parse_simple_key(std::string::iterator& it,
                                 const std::string::iterator& end)