[boost] append_iterator

From: Jason Hise (0xchaos_at_[hidden])
Date: 2006-10-26 12:24:39

Does boost provide any sort of iterator adapter which can be used as a
forward iterator through a collection, but which will act like an
output iterator upon reaching the end and push back new values?  I am
looking for something which will allow me to build a collection as
though I was using an output iterator, but will also allow me to save
copies of the current iterator so that I can modify the values they
point to later.

If there isn't, should I roll my own, or is there a better way to do
what I want?

If I do roll my own, would people be interested in seeing it developed
into a boost library?

Sidenote: This iterator adapter would require push_back to not
invalidate existing iterators (other than end).  Therefore, a special
iterator might need to be specified when wrapping certain collections.
 For instance, random access containers (vector and deque) would
probably need iterators that stored an integer index and a pointer to
the container, because push_back would be likely to result in memory
reallocations.