Miscellanea

iteration_utilities provides some general utilities that were useful in some of the implementations. Some of these might even be useful in other contexts, so these are summarized here.

• ItemIdxKey(), a class to facilitate stable sorting supporting reverse and key.

• Seen(), a class that wraps a set and a list supporting in operations and a contains_add() method to facilitate keeping track of already seen objects (even if they are unhashable).