---
name: "Tree::Simple::Visitor::ToNestedHash"
section: "3pm"
platform: "linux"
package: "libtree-simple-visitorfactory-perl"
version: "0.16-3"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Tree::Simple::Visitor::ToNestedHash"
---

# Tree::Simple::Visitor::ToNestedHash(3pm)

A Visitor for creating nested hash trees from Tree::Simple objects.

## NAME

Tree::Simple::Visitor::ToNestedHash - A Visitor for creating nested hash trees from Tree::Simple objects.

## SYNOPSIS

```
  use Tree::Simple::Visitor::ToNestedHash;
  my $visitor = Tree::Simple::Visitor::ToNestedHash->new();
  # given this Tree::Simple tree
  my $tree = Tree::Simple->new("Root")
                ->addChildren(
                    Tree::Simple->new("Child1")
                        ->addChildren(
                            Tree::Simple->new("GrandChild1"),
                            Tree::Simple->new("GrandChild2")
                        ),
                    Tree::Simple->new("Child2"),
                );
  $tree->accept($visitor);
  my $array_tree = $visitor->getResults();
  # this then creates the equivalent nested array tree:
  # {
  # Root => {
  #         Child1 => {
  #                 GrandChild1 => {},
  #                 GrandChild2 => {}
  #                 },
  #         Child2 => {}
  #         }
  # }
```

## DESCRIPTION

Given a tree constructed from a Tree::Simple hierarchy, this Visitor will create the equivalent tree of nested hashes.

## METHODS

- **new**

  There are no arguments to the constructor the object will be in its default state. You can use the `"setNodeFilter"` and `"includTrunk"` methods to customize its behavior.

- **includTrunk ($boolean)**

  Setting the `$boolean` value to true (`1`) will cause the node value of the tree's root to be included in the nested hash output, setting it to false will do the opposite.

- **setNodeFilter ($filter\_function)**

  This method accepts a CODE reference as its `$filter_function` argument and throws an exception if it is not a code reference. This code reference is used to filter the tree nodes as they are placed into the hash tree. The `$filter_function` is passed a Tree::Simple object, and is expected to return the value desired for inclusion into the hash tree.

- **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 will return the hash tree constructed.

## Repository

\<https://github.com/ronsavage/Tree-Simple-VisitorFactory\>

## SUPPORT

Bugs should be reported via the CPAN bug tracker at

\<https://github.com/ronsavage/Tree-Simple-VisitorFactory/issues\>

## 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.