Function HexDigit

library/cpp/yson/writer.cpp:18–24

    // Copied from <util/string/escape.cpp>
    namespace {
        inline char HexDigit(char value) {
            Y_ASSERT(value < 16);
            if (value < 10)
                return '0' + value;
            else
                return 'A' + value - 10;
        }

        inline char OctDigit(char value) {
            Y_ASSERT(value < 8);