2 package Tree::Simple::Visitor::PreOrderTraversal;
9 use base qw(Tree::Simple::Visitor);
11 # make sure we use the "new" interface
12 # so we enforce it here
15 my $class = ref($_class) || $_class;
16 my $visitor = $class->SUPER::new();
26 Tree::Simple::Visitor::PreOrderTraversal - A Visitor for pre-order traversal a Tree::Simple hierarchy
30 use Tree::Simple::Visitor::PreOrderTraversal;
33 my $visitor = Tree::Simple::Visitor::PreOrderTraversal->new();
35 # pass our visitor to the tree
36 $tree->accept($visitor);
39 print join ", " => $visitor->getResults();
41 # this will print this:
42 # 1 1.1 1.1.1 1.2 2 2.1 3 3.1
43 # assuming your tree is like this:
55 Pre-order traversal is a depth-first traversal method in which the sub-tree's are processed I<after> the parent. It is essentially a wrapper around the base Tree::Simple::Visitor class, and is a seperate module here for completeness. (If you have a post-order, you should have a pre-order too).
63 There are no arguments to the constructor the object will be in its default state. You can use the C<setNodeFilter> method to customize its behavior.
65 =item B<includeTrunk ($boolean)>
67 Based upon the value of C<$boolean>, this will tell the visitor to include the trunk of the tree in the traversal as well.
69 =item B<setNodeFilter ($filter_function)>
71 This method accepts a CODE reference as its C<$filter_function> argument and throws an exception if it is not a code reference. This code reference is used to filter the tree nodes as they are collected. This can be used to customize output, or to gather specific information from a more complex tree node. The filter function should accept a single argument, which is the current Tree::Simple object.
73 =item B<visit ($tree)>
75 This is the method that is used by Tree::Simple's C<accept> method. It can also be used on its own, it requires the C<$tree> argument to be a Tree::Simple object (or derived from a Tree::Simple object), and will throw and exception otherwise.
79 This method returns the accumulated results of the application of the node filter to the tree.
85 None that I am aware of. Of course, if you find a bug, let me know, and I will be sure to fix it.
89 See the B<CODE COVERAGE> section in L<Tree::Simple::VisitorFactory> for more inforamtion.
93 These Visitor classes are all subclasses of B<Tree::Simple::Visitor>, which can be found in the B<Tree::Simple> module, you should refer to that module for more information.
97 stevan little, E<lt>stevan@iinteractive.comE<gt>
99 =head1 COPYRIGHT AND LICENSE
101 Copyright 2004, 2005 by Infinity Interactive, Inc.
103 L<http://www.iinteractive.com>
105 This library is free software; you can redistribute it and/or modify
106 it under the same terms as Perl itself.