Re: HAMT iterator

[Bruno Haible]

Marc Nieper-Wißkirchen wrote:
> > > /* Return an independent copy of ITER that is initially in the same
> > >    state.  */
> > > extern Hamt_iterator *hamt_iterator_copy (Hamt_iterator *iter);
> >
> > Then a copy function is not needed, because the user's program can do
> >
> >   Hamt_iterator iter_clone = iter;
> 
> The hamt itself has to be copied (to increase the reference counter).

Then the comment should clarify what "independent" means. I thought it
means that both iterators (the original one and the copy) can be used
simultaneously, as long as the HAMT does not change. Do you mean
something broader?
  - If someone creates a derivative of the HAMT, the iterator won't
    be affected, right? ("persistence")
  - If someone makes destructive modifications to the HAMT (through the
    *_x functions), the iterator will be affected if it has not yet
    passed the point of modification, right?
So, what is the scenario where increasing the reference count will make
a difference?

Bruno