Tree::Simple::Visitor::PreOrderTraversal - A Visitor for pre-order traversal a Tree::Simple hierarchy
use Tree::Simple::Visitor::PreOrderTraversal; # create an visitor my $visitor = Tree::Simple::Visitor::PreOrderTraversal->new(); # pass our visitor to the tree $tree->accept($visitor); # print our results print join ", " => $visitor->getResults(); # this will print this: # 1 1.1 1.1.1 1.2 2 2.1 3 3.1 # assuming your tree is like this: # 1 # 1.1 # 1.1.1 # 1.2 # 2 # 2.1 # 3 # 3.1
Pre-order traversal is a depth-first traversal method in which the sub-tree's are processed after the parent. It is essentially a wrapper around the base Tree::Simple::Visitor class, and is a separate module here for completeness. (If you have a post-order, you should have a pre-order too).
There are no arguments to the constructor the object will be in its default state. You can use the
setNodeFiltermethod to customize its behavior.
- includeTrunk ($boolean)
Based upon the value of
$boolean, this will tell the visitor to include the trunk of the tree in the traversal as well.
- setNodeFilter ($filter_function)
This method accepts a CODE reference as its
$filter_functionargument and throws an exception if it is not a code reference. This code reference is used to filter the tree nodes as they are collected. This can be used to customize output, or to gather specific information from a more complex tree node. The filter function should accept a single argument, which is the current Tree::Simple object.
- visit ($tree)
This is the method that is used by Tree::Simple's
acceptmethod. It can also be used on its own, it requires the
$treeargument to be a Tree::Simple object (or derived from a Tree::Simple object), and will throw and exception otherwise.
This method returns the accumulated results of the application of the node filter to the tree.
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, <firstname.lastname@example.org>
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.