This gem provides support for creating tree data structures. The structure of the tree is defined with dot delimited paths on each node. This has a couple of advantages over the acts_as_tree plugin.
Each node gets a unique character identifier that has semantic qualities and indicates the structure in the tree.
Queries for all ancestors or all descendants are far more efficient.
Out of the box the code works with ActiveRecord, but it can easily be made to work with other ORM's if they implement just a few methods.
See PathTree for more details.