Re: [Boost-users] [tuple][mpl][fusion] How to "prune" or "collapse" a tuple?

Subject: Re: [Boost-users] [tuple][mpl][fusion] How to "prune" or "collapse" a tuple?
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2010-08-13 17:09:58

AMDG

AJG wrote:
> // Collapse code:
>
> template <typename Sequence>
> struct tuple_from_sequence :
>     mpl::reverse_fold
>         < Sequence
>         , tuples::null_type
>         , tuples::cons<mpl::_2, mpl::_1>
>         > {};
>
> template <typename T0, typename T1, typename T2, typename T3, typename T4,
>           typename T5, typename T6, typename T7, typename T8, typename T9>
> struct collapse <tuple<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9> > {
>     typedef tuple<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9> original;
>     typedef mpl::list<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9> sequence;
>
>     typedef typename mpl::remove<sequence, tuples::null_type>::type removed;
>     typedef typename tuple_from_sequence<removed>::type type;
>
>     static type construct(original const& t) {
>         // return ???;
>     }
> };
>   

Try using fusion::remove
http://www.boost.org/libs/fusion/doc/html/fusion/algorithm/transformation/functions/remove.html

In Christ,
Steven Watanabe