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package Tree::Simple::Visitor::PreOrderTraversal;
use strict;
use warnings;
our $VERSION = '0.16';
use base qw(Tree::Simple::Visitor);
# make sure we use the "new" interface
# so we enforce it here
sub new {
my ($_class) = @_;
my $class = ref($_class) || $_class;
my $visitor = $class->SUPER::new();
return $visitor;
}
1;
__END__
=head1 NAME
Tree::Simple::Visitor::PreOrderTraversal - A Visitor for pre-order traversal a Tree::Simple hierarchy
=head1 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 ", " => $visitor->getResults();
# this will print this:
# 1 1.1 1.1.1 1.2 2 2.1 3 3.1
# assuming your tree is like this:
# 1
# 1.1
# 1.1.1
# 1.2
# 2
# 2.1
# 3
# 3.1
=head1 DESCRIPTION
Pre-order traversal is a depth-first traversal method in which the sub-tree's are processed I<after> the parent. It is essentially a wrapper around the base Tree::Simple::Visitor class, and is a separate module here for completeness. (If you have a post-order, you should have a pre-order too).
=head1 METHODS
=over 4
=item B<new>
There are no arguments to the constructor the object will be in its default state. You can use the C<setNodeFilter> method to customize its behavior.
=item B<includeTrunk ($boolean)>
Based upon the value of C<$boolean>, this will tell the visitor to include the trunk of the tree in the traversal as well.
=item B<setNodeFilter ($filter_function)>
This method accepts a CODE reference as its C<$filter_function> argument and throws an exception if it is not a code reference. This code reference is used to filter the tree nodes as they are collected. This can be used to customize output, or to gather specific information from a more complex tree node. The filter function should accept a single argument, which is the current Tree::Simple object.
=item B<visit ($tree)>
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.
=item B<getResults>
This method returns the accumulated results of the application of the node filter to the tree.
=back
=head1 Repository
L<https://github.com/ronsavage/Tree-Simple-VisitorFactory>
=head1 SUPPORT
Bugs should be reported via the CPAN bug tracker at
L<https://github.com/ronsavage/Tree-Simple-VisitorFactory/issues>
=head1 CODE COVERAGE
See the B<CODE COVERAGE> section in L<Tree::Simple::VisitorFactory> for more information.
=head1 SEE ALSO
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.
=head1 AUTHOR
stevan little, E<lt>stevan@iinteractive.comE<gt>
=head1 COPYRIGHT AND LICENSE
Copyright 2004, 2005 by Infinity Interactive, Inc.
L<http://www.iinteractive.com>
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=cut
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