On Wed, Jun 29, 2011 at 1:19 PM, Alastair Rankine
Given a bidirectional range R, is it possible to select at compile time whether we want to iterate forwards or backwards?
Below is a test app. At the commented line, I would like to transparently construct a forward or reverse range, ie either [begin(range), end(range)] or [rbegin(range), rend(range)] respectively, depending on the definition of the Reversed template parameter.
Just to be clear, the desired output is:
forward: abc reversed: abc
Surely you mean ha the reversed output would be: cba ?
I can make this work by using a functor class with partial specialisation to construct the iterator_range, using begin/end or rbegin/rend respectively. But it's a bit ugly and it would seem like something that boost range would provide anyway?
(Note that boost::reverse() is NOT what I am after.)
What you are looking for is a reversing adaptor, hence you probably should look at boost::adaptors::reversed, please see http://www.boost.org/doc/libs/1_46_1/libs/range/doc/html/range/reference/ada.... Note that you could also use the reversed_range class directly. Regards, Neil Groves