On Thu, 17 May 2007 16:04:57 -0300, JOAQUIN LOPEZ MU?Z <joaquin@tid.es> wrote:
More than a year ago a request was made for Boost.MultiIndx to provide the ability to get an iterator to an element x from x alone:
iterator iterator_to(const value_type& x);
It was me, I think.
I can provide this functionality in constant time, and the internal implementation is trivial, but I got thinking about the potential use cases for such capability and cannot come up with something convincing.
Do you see usefulness in having iterator_to()? Can you describe a potential usage scenario? At first blush, seems like this is at least as useful as the homonym functionality in Boost.Intrusive, but if you think about the obvious scenarios applying to B.I, it turns out they do not immediately translate to B.MI.
Yes. My use case was http://thread.gmane.org/gmane.comp.lib.boost.devel/136418/focus=136955 However, now that I look at it, it seems iterator_to is not a solution to that problem. I still think the feature is usefull. For example, you may be forced to pass a raw pointer to a C interface. With iterator_to you can get the position of the element in a collection without overhead. Bruno