your project is an effort to add those remaining features to Boost Ranges?
I mean to.
I don't understand the "|+" usage at all.
"|+" is oven::regular() function's syntax sugar version. regular() is needed when using lambda(C++0x and BLL) in Range adaptor. Lambda is NonDefaultConstructible and NonCopyAssignable. regular() convert lambda into DefaultConstructible and CopyAssignable. Lambda becomes a problem in the following case: template <class Iterator, class F> F for_each(Iterator first, Iterator last, F f) { Iterator it; // DefaultConstruct it = first; // CopyAssign for (; it != last; ++it) f(*it); return f; } template <class Range, class F> F for_each(const Range& r, F f) { return for_each(boost::begin(r), boost::end(r), f); } for_each(v | filtered(_1 % 2 == 0)); // error! filter_iterator is NonDefaultConstructible and NonCopyAssignable This problem solve by regular() : for_each(v | filtered(regular(_1 % 2 == 0))); // OK, but verbose... But since regular() was verbose, it prepared the short notation: "operator|+" for_each(v |+ filtered(_1 % 2 == 0)); // OK
======================== Akira Takahashi mailto : faithandbrave@gmail.com blog : http://d.hatena.ne.jp/faith_and_brave/