data::grove::parent(3pm)
NAME
Data::Grove::Parent - provide parent properties to Data::Grove objects
SYNOPSIS
use Data::Grove::Parent; $root = $object->root; $rootpath = $object->rootpath; $tied = $object->add_magic([ $parent ]); $node = Data::Grove::Parent->new($hash [, $parent]); $node_list = Data::Grove::ParentList->new($array [, $parent]);
DESCRIPTION
Data::Grove::Parent is an extension to Data::Grove that adds `"Parent"'
and `"Raw"' properties to Data::Grove objects and methods for returning
the root node of a grove, a list of nodes between and including the
root node and the current node, and a method that creates parented
nodes.
Data::Grove::Parent works by creating a Perl ``tied'' object that
contains a parent reference (`"Parent"') and a reference to the
original Data::Grove object (`"Raw"'). Tying-magic is used so that
every time you reference the Data::Grove::Parent object it actually
references the underlying raw object.
When you retrieve a list or a property of the Raw object,
Data::Grove::Parent automatically adds magic to the returned list or
node. This means you only call `add_magic()' once to create the first
Data::Grove::Parent object and then use the grove objects like you
normally would.
The most obvious use of this is so you don't have to call a `"delete"'
method when you want to release a grove or part of a grove; since
Data::Grove and Data::Grove::Parent objects have no cyclic references,
Perl can garbage collect them normally.
A secondary use is to allow you to reuse grove or property set
fragments in multiple trees. WARNING: Data::Grove currently does not
protect you from creating your own cyclic references! This could lead
to infinite loops if you don't take care to avoid them.
METHODS
- $object->root()
$object->rootpath() - `"root()"' returns the root node if `$object' is a
`"Data::Grove::Parent"' object. `"rootpath()"' returns an array of all the nodes between and including the root node and `$object'. - $tied = $object->add_magic([ $parent ])
- `"add_magic()"' returns a "Data::Grove::Parent" object with
`$object' as it's `"Raw"' object. If `$parent' is given, that
becomes the tied object's parent object.
AUTHOR
Ken MacLeod, ken@bitsko.slc.ut.us