gistfile1.txt

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

    for(auto x : str)
    {
        switch(state)
        {
            case 0:
                if(x == '.')
                {
                    result.text.push_back(x);
                    state = 1;
                }
                else if(x == '-')
                {
                    result.text.push_back(x);
                    state = 3;
                }
                else if(x >= '0' && x <= '9')
                {
                    result.text.push_back(x);
                    state = 4;
                } else return result;
                break;
            case 1:
                if(x >= '0' && x <= '9')
                {
                    result.text.push_back(x);
                    state = 2;
                    result.type = "FLOAT";
                } else return result;
                break;
            case 2:
                if(x >= '0' && x <= '9')
                {
                    result.text.push_back(x);
                }
                else if(x == 'e' || x == 'E')
                {
                    result.text.push_back(x);
                    state = 5;
                }
                else return result;
                break;
            case 3:
                if(x == '.')
                {
                    result.text.push_back(x);
                    state = 2;
                }
                else if(x >= '0' && x <= '9')
                {
                    result.text.push_back(x);
                    state = 4;
                } else return result;
                break;
            case 4:
                if(x >= '0' && x <= '9')
                {
                    result.text.push_back(x);
                }
                else if(x == '.')
                {
                    result.text.push_back(x);
                    state = 2;
                    result.type = "FLOAT";
                }
                else if(x == 'e' || x == 'E')
                {
                    result.text.push_back(x);
                    state = 5;
                } else return result;
                break;
            case 5:
                result.type = "INVALID";
                if(x >= '0' && x <= '9')
                {
                    result.text.push_back(x);
                    state = 7;
                    result.type = "FLOAT";
                }
                else if(x == '+' || x == '-')
                {
                    result.text.push_back(x);
                    state = 6;
                } else return result;
                break;
            case 6:
                if(x >= '0' && x <= '9')
                {
                    result.text.push_back(x);
                    state = 7;
                    result.type = "FLOAT";
                } else return result;
                break;
            case 7:
                if(x >= '0' && x <= '9')
                {
                    result.text.push_back(x);
                } else return result;
                break;
        }
    }

    return result;
}