CODEWITHSUNDEEP
c++templatesmetaprogramming
kreuzerkrieg
kreuzerkrieg

Reputation: 3219

typelist-like (?) template class

I'm trying to achieve following: create template class which uses its template arguments to create instance of template type and use it somewhere in the, for example constructor. Consider following example:

template <typename T>
class foo
{
public:
    explicit foo(const T& data) : m_data(data) {}
    T m_data;
};

template <typename T01, typename T02>
class bar
{
public:
    explicit bar(int data) : m_storage(T01(data), T02(data)) {}
    void print() { boost::fusion::for_each(m_storage, printer()); }

private:
    boost::fusion::vector<T01, T02> m_storage;
};

and usage:

bar<foo<int>, foo<int>> b(5);
    b.print();

but what if I want flexibility in the bar class and I want number of these T01, T02 classes varying? example:

bar<foo<int>, foo<int>> b(5);
b.print();
bar<foo<int>, foo<int>>, foo<int>> c(6);
c.print();

Something like using argument pack maybe?

EDIT001:
Final working version on coliru.

Upvotes: 1

Views: 62

Answers (1)

Jarod42
Jarod42

Reputation: 217075

You are looking for variadic template (available since C++11)

template <typename ... Ts>
class bar
{
public:
    explicit bar(int data) : m_storage(Ts(data)...) {}
    void print() { boost::fusion::for_each(m_storage, printer()); }

private:
    boost::fusion::vector<Ts...> m_storage;
};

Upvotes: 4

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