plopp.core.Node

class plopp.core.Node(func, *parents, **kwparents)

A node that can have parent and children nodes, to create a graph. A node can be constructed from a callable func, or a raw object. In the case of a raw object, a node wrapping the object will be created.

Nodes can have views attached to them, which are instances of View. Views can be notified when the node’s data changes. When this happens, the view typically requests data from its parent nodes, who in-turn request data from their parents, traversing the graph from bottom to top.

Caching is used to avoid traversing the graph multiple times when data is requested multiple times without any changes to the graph.

Leaf nodes are nodes that have neither children nor views. When such nodes are notified of changes, they will call their func to ensure any side effects are executed.

Parameters:

• func (Any) – The callable that is called when data is requested from the node. This can also be a raw object, in which case this becomes a callable that returns the object.

• *parents (Any) – Positional arguments that represent the positional arguments of the function func.

• *kwparents (Any) – Keyword arguments that represent the keyword arguments of the function func.

__init__(func, *parents, **kwparents)

Methods

__init__(func, *parents, **kwparents)
add_kwparents(**parents)	Add one or more keyword parents to the node.
add_parents(*parents)	Add one or more parents to the node.
add_view(view)	Add a view to the node.
is_leaf()	Whether the node is a leaf node (i.e. has neither children nor views).
notify_children(message)	Notify all of the node's children with message.
notify_views(message)	Notify the node's views with message.
remove()	Remove the node from the graph.
request_data()	Request data from the node.

Attributes

id	The unique uuid of the node.
input_value	The input value of the node, if it is an input node.
is_input_node	Whether the node is an input node.