This package is the successor of zodict.

Data structures could be described as tree. Some are by nature treeish, like XML documents, LDAP directories or filesystem directory trees, while others could be treaten as. Consider SQL as example. A Database has tables, these contain rows which contain columns.

Next, python has elegant ways for customizing all sorts of datamodel related API. The dictionary container type fits almost completely the purpose of representing a node of a tree. The same API is also described in zope.interface.common.mapping.IFullMapping. Additionaly a node must provide hierarchy information. In this case the contract of zope.location.interfaces.ILocation is used.

Having data structures as such trees has some advantages:

• Unified data access API to different data models and/or sources
• Trees are traversable in both directions
• Once in memory, node trees are fast to deal with
• Software working on node trees may not need to know about internal data structures, as long as the node tree implementation provides the correct interface contracts

node ships with some "ready-to-import-and-use" nodes.

An unordered node. This can be used as base for trees where oder of items doesn't matter.:

>>> from node.base import BaseNode
>>> root = BaseNode(name='root')
>>> root['child'] = BaseNode()
>>> root.printtree()
<class 'node.base.BaseNode'>: root
  <class 'node.base.BaseNode'>: child

An ordered node. Order of items is preserved.:

>>> from node.base import OrderedNode
>>> root = OrderedNode(name='orderedroot')
>>> root['foo'] = OrderedNode()
>>> root['bar'] = OrderedNode()
>>> root.printtree()
<class 'node.base.OrderedNode'>: orderedroot
  <class 'node.base.OrderedNode'>: foo
  <class 'node.base.OrderedNode'>: bar

>>> root.items()
[('foo', <OrderedNode object 'foo' at ...>), 
('bar', <OrderedNode object 'bar' at ...>)]

A full API desctiption of the node interface can be found at node.interfaces.INode.

Nodes are implemented using the plumber package. If you want to write your own Node implementations read the plumber documentation first to understand the syntax and look at node.parts sources for blueprints.

• Robert Niederreiter <rnix@squarewave.at>
• Florian Friesdorf <flo@chaoflow.net>
• Jens Klein <jens@bluedynamics.com>

• Make it work [rnix, chaoflow, et al]