This is a nested hash / unbalance tree structure which iterates over all of its available values in insertion order.
##Like a Normal Hash?
Exactly like a normal hash. Althought with a standard Ruby Hash it's impossible to
know whether or not
hash["a"]["b"] was inserted before or after
because each individual Hash maintains it's own insertion order.
Now you can know. If you need to. The main thing you gain with this over an Array is the ability to prune or transplant multiple values at the same time by cutting on one of the branches.
Each value is actually stored in a proxy object which maintains a unique id.
This is necessary so that if you insert three
4s into the tree you can tell
which one came first. This wouldn't actually be necessary in a C implementation,
or in one based on WeakRefs, but it works okay here.
You can generally treat the OrderTree exactly like a nested hash, but be aware that the first and last methods (as well as the #each iterator) actually return an OrderTreeNode and not the actual object stored at that location. (You can get at it by using #orig on the returned value.