On Thu, Mar 6, 2008 at 8:12 PM, vicente.botet <vicente.botet@wanadoo.fr> wrote:
From: "Steven Watanabe" <watanabesj@gmail.com>
AMDG
vicente.botet wrote:
Hello,
I needs calculate the mlp::or_ of a sequence of nullary logical metafunction.
This seams quite simple. I have do the following: <code> template <typename Seq> struct or_seq;
template <typename Seq, long N> struct or_seq_aux : mpl::or_< typename mpl::front<Seq>::type, or_seq<typename mpl::pop_front<Seq>::type>
{};
template <typename Seq> struct or_seq_aux<Seq, 1> : mpl::front<Seq>::type {};
template <typename Seq> struct or_seq : or_seq_aux<Seq, mpl::size<Seq>::value> {}; </code>
Is there a boost or_seq like logical metafunction? Is there a better way to do it?
I would be extremely interested in any suggestions.
not_<is_same<typename find_if<Seq, _>::type, typename end<Seq>::type> >?
In Christ, Steven Watanabe
I have tested your much more compact solution and it works as expected. Here it is with the mpl namespace:
template <typename Seq> struct or_seq : mpl::not_< boost::is_same<typename mpl::find_if<Seq, mpl::_>::type, typename mpl::end<Seq>::type> > {};
It seems a perfect application for fold: template<typename Seq> struct or_seq : mpl::apply< mpl::fold<mpl::_1, mpl::false_, mpl::quote2<mpl::or_> > , Seq > {}; template<typename Seq> struct and_seq : mpl::apply< mpl::fold<mpl::_1, mpl::true_, mpl::quote2<mpl::and_> > , Seq > {}; -- gpd