template <class T>
class StringCache {
public:
    static int get(const std::string &value) {
        return Type(_values.insert(std::make_pair(value, _values.size() + 1)).first->second);
    }
    static int find(const std::string &value) {
        auto it =_values.find(value);
        return it != _values.end() ? it->second : 0;
    }
private:
    static std::map<std::string,int> _values;
};
template <class T>
std::map<std::string,int> StringCache<T,int>::_values;