Class NodeVisitor

Known Subclasses:

GenericNodeVisitor, HTMLTranslator, LaTeXTranslator, SparseNodeVisitor

"Visitor" pattern [GoF95] abstract superclass implementation for document tree traversals.

Each node class has corresponding methods, doing nothing by default; override individual methods for specific and useful behaviour. The "visit_ + node class name" method is called by Node.walk() upon entering a node. Node.walkabout() also calls the "depart_ + node class name" method before exiting a node.

This is a base class for visitors whose visit_... & depart_... methods should be implemented for all node types encountered (such as for docutils.writers.Writer subclasses). Unimplemented methods will raise exceptions.

For sparse traversals, where only certain node types are of interest, subclass SparseNodeVisitor instead. When (mostly or entirely) uniform processing is desired, subclass GenericNodeVisitor.