On 02/07/09 13:58, Larry Evans wrote:
On 02/07/09 13:29, vicente.botet wrote: [snip]
After suggestion of I don't remember who, I have implemented it as
/* Calculate the mlp::and_ of a sequence of nullary logical metafunctions.*/ template <typename Seq> struct and_seq : boost::is_same<typename mpl::find_if<Seq, mpl::not_<mpl::_> >::type, typename mpl::end<Seq>::type> {}; [snip]
If there are better ways to do that, you don't tink that this must be encapsulated in the library? Why not add these metafunctions in Boost.MPL?
Thanks,
OOPS. I misread the post. I was just thinking of and_ and or_. I missed the "sequence of nullary logical metafunctions". Sorry for noise. It just seemed so similar I neglected any differences.
Aren't true_ and false_ nullary logical metafunctions. If so then I think what you're requiring is someway to "unpack" the args from Seq<T1,T2,...Tn> into and_<T1,T2,...,Tn> or or_<T1,T2,...,Tn>. Could: http://www.boost.org/doc/libs/1_37_0/libs/mpl/doc/refmanual/unpack-args.html be used to do that? If not, then it's pretty easy to do that with the variadic version of mpl since all Sequences are derived from package<T1,T2,...,Tn> so: template<typename... T> or_seq<package<T...> > : or_<T...> {}; A prototype variadic version of mpl is in the boost vault.