template<class T>
std::vector<std::string> MapEvaluator<T>::extractVariables(std::string expression) {

    expression = expression + " ";
    std::vector<std::string> variables = {};
    std::string substring;
    size_t consecutiveCharsCaps = 0;
    bool previousCharCaps = false;

    for (size_t i = 0; i < expression.length(); i++)
    {
        if (isCapital(expression[i]))
        {
            consecutiveCharsCaps++;
            previousCharCaps = true;
        }
        else {
            if(previousCharCaps) {
                substring = expression.substr(i - consecutiveCharsCaps, consecutiveCharsCaps);
                variables.push_back(substring);
                consecutiveCharsCaps = 0;
                previousCharCaps = false;
            }
        }
    }

    unique(variables);
    return variables;
}

template <class T>
void MapEvaluator<T>::unique(std::vector<std::string> &vec)
{
    auto end = vec.end();
    for (auto it = vec.begin(); it != end; ++it) {
        end = std::remove(it + 1, end, *it);
    }
    vec.erase(end, vec.end());
}

template<class T>
bool MapEvaluator<T>::isCapital(char c) {
    return (c >='A' && c <= 'Z');
}