Ron Savage > Tree-Simple-VisitorFactory > Tree::Simple::Visitor::GetAllDescendents



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Tree::Simple::Visitor::GetAllDescendents - A Visitor for fetching all the descendents of a Tree::Simple object


  use Tree::Simple::Visitor::GetAllDescendents;

  # create an instance of our visitor
  my $visitor = Tree::Simple::Visitor::GetAllDescendents->new();

  # pass the visitor to a Tree::Simple object

  # you can also get the descendents
  # back as an array of node values
  my @descendents = $visitor->getDescendents();

  # for more complex node objects, you can specify
  # a node filter which will be used to extract the
  # information desired from each node
  $visitor->setNodeFilter(sub {
                my ($t) = @_;
                return $t->getNodeValue()->description();


Given a Tree::Simple instance this Visitor will return all the descendents recursively on down the hierarchy.



There are no arguments to the constructor the object will be in its default state. You can use the setNodeFilter method to customize its behavior.

setTraversalMethod ($visitor)

By default we will use Tree::Simple's built in depth-first (pre-order) traverse method. If however, you desire the descendents to be returned in a different ordering, this can be accomplished using a different traversal method, you can supply a $visitor object implementing that traversal type to this method (See Tree::Simple::Visitor::BreadthFirstTraversal, Tree::Simple::Visitor::PreOrderTraversal and Tree::Simple::Visitor::PostOrderTraversal).

setNodeFilter ($filter_function)

This method accepts a CODE reference as its $filter_function argument and throws an exception if it is not a code reference. This code reference is used to filter the tree nodes as they are collected. This can be used to customize output, or to gather specific information from a more complex tree node. The filter function should accept a single argument, which is the current Tree::Simple object.

visit ($tree)

This is the method that is used by Tree::Simple's accept method. It can also be used on its own, it requires the $tree argument to be a Tree::Simple object (or derived from a Tree::Simple object), and will throw and exception otherwise.


This method will give back and array of descendents in depth-first order (pre-order) or in the order specified by the setTraversalMethod. If called in scalar context it will give an array reference, in list context it will return a regular array. This method is the same as calling getResults.


None that I am aware of. Of course, if you find a bug, let me know, and I will be sure to fix it.


See the CODE COVERAGE section in Tree::Simple::VisitorFactory for more information.


These Visitor classes are all subclasses of Tree::Simple::Visitor, which can be found in the Tree::Simple module, you should refer to that module for more information.


stevan little, <>


Copyright 2004, 2005 by Infinity Interactive, Inc.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

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