Yesterday I asked this question and "juanchopanza" answered my question, but unfortunately I cant caught one of bounded types. Since using a "visitor" is more robust, I'm also wondering of anyone could give me a solution using "visitor"?
I am looking for the best way to filter a vector of the boost variant which has been defined like this:
boost::variant<T1*, T2, T3> Var;
std::vector<Var> Vec;
when I call this vector, what is the best way to filter only T2 bounded type and insert into new vector? or in other way, I want something like this
std::vector<T2> T2Vec =
...(how to filter it from Vec using apply_visitor)...
thanks again!
EDIT: the sulotion by @ ForEveR:
template<typename T>
struct T_visitor : public boost::static_visitor<>
{
T_visitor(std::vector<T>& v) : vec(v) {}
template<typename U>
void operator () (const U&) {}
void operator () (const T& value)
{
vec.push_back(value);
}
private:
std::vector<T>& vec;
};
and:
std::vector<T1> t1vec;
T_visitor<T1> vis(t1vec);
std::for_each(vec.begin(), vec.end(), boost::apply_visitor(vis));
would you please tell me what's wrong here?
struct T2_visitor : public boost::static_visitor<>
{
T2_visitor(std::vector<T2>& v) : vec(v) {}
template<typename T>
void operator () (const T&) {}
void operator () (const T2& value)
{
vec.push_back(value);
}
private:
std::vector<T2>& vec;
};
std::vector<T2> T2Vec;
T2_visitor vis(T2Vec);
std::for_each(Vec.begin(), Vec.end(), boost::apply_visitor(vis));