`select parseDateTimeBestEffort('01/12/2017, 18:31:44')`

It is confused by a comma - should be easy to fix.
{
            num_digits = readDigits(digits, sizeof(digits), in);
            if (num_digits == 13 && !year && !has_time)
            {
                
                readDecimalNumber<10>(res, digits);
                if (fractional)
                {
                    fractional->digits = 3;
                    readDecimalNumber<3>(fractional->value, digits + 10);
                }
                return ReturnType(true);
            }
            else if (num_digits == 10 && !year && !has_time)
            {
                
                readDecimalNumber<10>(res, digits);
                return ReturnType(true);
            }
            else if (num_digits == 9 && !year && !has_time)
            {
                
                readDecimalNumber<9>(res, digits);
                return ReturnType(true);
            }
            else if (num_digits == 14 && !year && !has_time)
            {
                
                readDecimalNumber<4>(year, digits);
                readDecimalNumber<2>(month, digits + 4);