Data::Grove::Parent - provide parent properties to Data::Grove objects
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]);
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.
- $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.
Ken MacLeod, ken@bitsko.slc.ut.us
perl(1), Data::Grove(3)
