Joel de Guzman <joel@boost-consulting.com> on Thu, 26 Jul 2007 06:59:46 +0800
- bind expression with tuple becomes a nightmare
Why? Ah access to the members?
It's a nightmare indeed. I'd say boost::get is not bindable at all. typedef tuple<int, double> two; vector<two> src; vector<int> dst; // ouch const int & (*get_first)(const cons<two::head_type, two::tail_type> &) = get<0>; transform(src.begin(), src.end(), dst.begin(), get_first); Would not it be cool to write something like this instead? transform(src.begin(), src.end(), dst.begin(), get<0>()); And it's not hard to implement it. namespace boost { namespace tuples { template <int N> struct getter { template <class HT, class TT> typename access_traits< typename element<N, cons<HT, TT> >::type >::non_const_type operator()(cons<HT, TT> & c) const { return get<N>(c); } template <class HT, class TT> typename access_traits< typename element<N, cons<HT, TT> >::type >::const_type operator()(const cons<HT, TT> & c) const { return get<N>(c); } }; } template <int N> tuples::getter<N> get() { return tuples::getter<N>(); } } Does fusion have something like this? Regards, Roman Perepelitsa Deutsche Bank Moscow +7 (495) 660-74-08 --- This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and delete this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden. Please refer to http://www.db.com/en/content/eu_disclosures.htm for additional EU corporate and regulatory disclosures.