On Sat, Jul 14, 2012 at 12:25 PM, Nathan Ridge <zeratul976@hotmail.com> wrote:
Hm.
Why not follow this design:
http://www.boost.org/doc/libs/1_50_0/libs/range/doc/html/range/reference/ran...
The implementation would be more elegant, but the user would have to write:
BOOST_FOREACH(directory_entry& x, directory_range(directory_iterator(".")))
instead of the simpler:
BOOST_FOREACH(directory_entry& x, directory_iterator("."))
I verified the above with an actual implementation and test.
I don't see why that's the case. In the posted link, the function istream_range() takes an argument of type istream&, which is the same argument type that the constructor of istream_iterator takes. Notice that istream_range() does *not* take an actual istream_iterator as its constructor argument.
Similarly, I would expect directory_range() to take a path argument, and return something like make_iterator_range(directory_iterator(p), directory_iterator()).
The make_iterator_range template requires ForwardIterators, but directory_iterator only meets InputIterator requirements. Perhaps someone familiar with Boost.Range can come up with a workaround. For C++11 range-based for statement use, this works: class directory_range { public: directory_range(const path& p) : m_iter(p) {} directory_iterator begin() const { return m_iter; } directory_iterator end() const { return directory_iterator(); } private: directory_iterator m_iter; }; I'll ask the C++ committee's Filesystem Study Group if they prefer the above over the non-member begin()/end() approach. It is a bit less efficient, although that's probably swamped by operating system overhead. Thanks, --Beman