On Monday, 6 July 2015 at 20:50:19 UTC, Gary Willoughby wrote:
The problem is when I call the save method of the forward range
interface I don't get a copy I only get another view to the
same state. So when i remove nodes from the original list the
range becomes invalid.
This is why modifying a sequence while iterating over it is
generally forbidden; there's no good way to make it work. You
could duplicate the entire list for each range, but that's
expensive for the usual case of simply reading the list.
Forward ranges don't require that ranges be independent of the
data they iterate over [1]:
Saving a range is not duplicating it; in the example above, r1
and r2 still refer to the same underlying data. They just
navigate that data independently.
IMO your implementation is fine.
[1]:
http://dlang.org/phobos/std_range_primitives.html#isForwardRange
