Anatoli Tubman wrote:
Another option is to write
for (crange<int>& r = mkrange(d); r; ++r) { ... } Small correction for (crange<int> *const* & r = mkrange(d); r; ++r) { ... }
where mkrange returns crange_impl<int, d_array> which is derived from crange<int>. Slicing problem should be solved because it's easy to forget & between crange<int> and r. I wish we were able to typedef a reference to 'crange_impl<int, d_array> const' as crange<int>.
This doesn't need heap allocation, but still needs virtual operator++ and virtual operator*. A smart compiler could in theory inline them anyway, but I wouldn't count on it. I hope they will follow if we ever decided to accept the approach ;-)
Later this approach could be changed either to for (auto r = mkrange(d); r; ++r) { ... } // TODO: correct the idea if auto strip top-level reference off or direct compiler support of foreach construct. -- Alexander Nasonov Independent Developer and Consultant