Tree::Simple::Visitor::PreOrderTraversal - A Visitor for pre-order traversal a Tree::Simple hierarchy

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 seperate 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 the Tree::Simple::VisitorFactory manpage for more inforamtion.

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.

 Tree::Simple::Visitor::PreOrderTraversal - A Visitor for pre-order traversal a Tree::Simple hierarchy