class documentation

Generic "Visitor" abstract superclass, for simple traversals. Unless overridden, each ``visit_...`` method calls `default_visit()`, and each ``depart_...`` method (when using `Node.walkabout()`) calls `default_departure()`. `default_visit()` (and `default_departure()`) must be overridden in subclasses. Define fully generic visitors by overriding `default_visit()` (and `default_departure()`) only. Define semi-generic visitors by overriding individual ``visit_...()`` (and ``depart_...()``) methods also. `NodeVisitor.unknown_visit()` (`NodeVisitor.unknown_departure()`) should be overridden for default behavior.

Method default_departure Override for generic, uniform traversals.
Method default_visit Override for generic, uniform traversals.

Inherited from NodeVisitor:

Method __init__ Undocumented
Method dispatch_departure Call self."``depart_`` + node class name" with `node` as parameter. If the ``depart_...`` method does not exist, call self.unknown_departure.
Method dispatch_visit Call self."``visit_`` + node class name" with `node` as parameter. If the ``visit_...`` method does not exist, call self.unknown_visit.
Method unknown_departure Called before exiting unknown `Node` types.
Method unknown_visit Called when entering unknown `Node` types.
Class Variable optional Tuple containing node class names (as strings).
Instance Variable document Undocumented