Function ltrim

src/include/common/string_utils.h:39–44

    static bool CharacterIsDigit(char c) { return c >= '0' && c <= '9'; }

    static std::string ltrim(const std::string& input) {
        auto s = input;
        s.erase(s.begin(),
            find_if(s.begin(), s.end(), [](unsigned char ch) { return !isspace(ch); }));
        return s;
    }
    static std::string_view ltrim(std::string_view input) {
        auto begin = 0u;
        while (begin < input.size() && isspace(input[begin])) {