NAME¶
Tree::Simple::Visitor::PreOrderTraversal - A Visitor for pre-order traversal a
Tree::Simple hierarchy
SYNOPSIS¶
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 ", " => $visitor->getResults();
# this will print this:
# 1 1.1 1.1.1 1.2 2 2.1 3 3.1
# assuming your tree is like this:
# 1
# 1.1
# 1.1.1
# 1.2
# 2
# 2.1
# 3
# 3.1
DESCRIPTION¶
Pre-order traversal is a depth-first traversal method in which the sub-tree's
are processed
after the parent. It is essentially a wrapper around the
base Tree::Simple::Visitor class, and is a separate module here for
completeness. (If you have a post-order, you should have a pre-order too).
METHODS¶
- new
- There are no arguments to the constructor the object will be in its
default state. You can use the "setNodeFilter" method to
customize its behavior.
- includeTrunk ($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 $filter_function argument and
throws an exception if it is not a code reference. This code reference is
used to filter the tree nodes as they are collected. This can be used to
customize output, or to gather specific information from a more complex
tree node. The filter function should accept a single argument, which is
the current Tree::Simple object.
- visit ($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.
- getResults
- This method returns the accumulated results of the application of the node
filter to the tree.
BUGS¶
None that I am aware of. Of course, if you find a bug, let me know, and I will
be sure to fix it.
CODE COVERAGE¶
See the
CODE COVERAGE section in Tree::Simple::VisitorFactory for more
information.
SEE ALSO¶
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.
AUTHOR¶
stevan little, <stevan@iinteractive.com>
COPYRIGHT AND LICENSE¶
Copyright 2004, 2005 by Infinity Interactive, Inc.
<
http://www.iinteractive.com>
This library is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.