gistfile1.cpp

token tryId(std::string str)
{
    token result ("INVALID", "");
    int state = 0;

    for(auto x : str)
    {
        switch(state)
        {
            case 0:
                if((x >= 'A' && x <= 'Z') || (x >= 'a' && x <= 'z') || x == '_')
                {
                    result.text.push_back(x);
                    state = 1;
                } else return result;
                break;
            case 1:
                if((x >= 'A' && x <= 'Z') || (x >= 'a' && x <= 'z') || x == '_' || (x >= '0' && x <= '9'))
                {
                    result.text.push_back(x);
                } else return result;
                break;
        }
    }

    result.type = "ID";
    return result;
}