[Smtk-developers] Iterator class

[David Thompson]

Hi all,

Due to popular demand, SMTK now has an iterator class for traversing model entities:

  https://github.com/Kitware/SMTK/blob/master/smtk/model/EntityIterator.h
  https://github.com/Kitware/SMTK/blob/master/smtk/model/testing/cxx/unitIterators.cxx

The iterator can traverse
* a fixed set of EntityRefs you provide,
* the children of all the items in a set you provide (without repetition), or
* the children of all the models of all the items in a set you provide (without repetition).
The unit test above illustrates how to use it.

To avoid revisiting entities and for robustness against cycles (such as a model owning itself), the iterator maintains a set of entities it has traversed. This also allows for multiple passes to be performed simply (by recycling the list of traversed entities as the source list on the next pass).

	David