Re: [boost] Re: [MPL] Type detection

From: Joel de Guzman (joel_at_[hidden])
Date: 2003-10-23 04:54:24

David B. Held <dheld_at_[hidden]> wrote:
> Ok, now I want to create an mpl::vector of std::vectors,
> instantiated over the types in my sequence.  I think this
> is what I want, but I want to make sure it's the best way:
> 
> template <typename T>
> struct make_vector
> {
>     typedef std::vector<T> type;
> };
> 
> template <typename T>
> struct foo
> {
>     typedef typename as_sequence<T>::type seq;
>     typedef typename transform<seq, make_vector<_1> >::type my_vec;
> 
>     tuple<elements_of_my_vec> v;
> };
> 
> foo f;
> 
> get<3>(f.v);
> 
> Obviously, my problem is making a tuple from an mpl::vector.
> I sure hope this is possible and easy, because it would totally
> rock if it is.

The Fusion lib (in the sandbox) hopefully to replace the old tuple lib
can do that easily (example):

        typedef boost::mpl::list<int, double, X, int> mpl_list1;
        type_sequence<mpl_list1> view;
        std::cout << generate(view) << std::endl;

generate(view) creates a tuple from the view.

Cheers,
-- 
Joel de Guzman
http://www.boost-consulting.com
http://spirit.sf.net