Some useful data structures for collections of data

Provide indexing for a list. Inner properties can be used for keys, and keys can be tuples of properties.

Same as Index, but includes checks and optimization to ensure members' keys are unique.

A Queue is a list, with add() and pop(). It ensures members in the queue are not duplicated by not adding the ones already found in the queue.

A multidimensional grid of values that can be used like a Mapping from a-tuple-of-coordinates to the value at that coordinate. Plus a few other convenience methods.

This is a naive implementation. The hope it is a simple facade to a faster implementation.

Store the many-to-many relations between two domains