Data::Grove(3pm) User Contributed Perl Documentation Data::Grove(3pm)
NAME
Data::Grove -- support for deeply nested structures
SYNOPSIS
use Data::Grove;
$object = MyPackage->new;
package MyPackage;
@ISA = qw{Data::Grove};
DESCRIPTION
"Data::Grove" provides support for deeply nested tree or graph
structures. "Data::Grove" is intended primarily for Perl module
authors writing modules with many types or classes of objects that need
to be manipulated and extended in a consistent and flexible way.
"Data::Grove" is best used by creating a core set of ``data'' classes
and then incrementally adding functionality to the core data classes by
using ``extension'' modules. One reason for this design is so that the
data classes can be swapped out and the extension modules can work with
new data sources. For example, these other data sources could be disk-
based, network-based or built on top of a relational database.
Two extension modules that come with "Data::Grove" are
"Data::Grove::Parent" and "Data::Grove::Visitor".
"Data::Grove::Parent" adds a `"Parent"' property to grove objects and
implements a `"root"' method to grove objects to return the root node
of the tree from anywhere in the tree and a `"rootpath"' method to
return a list of nodes between the root node and ``this'' node.
"Data::Grove::Visitor" adds callback methods `"accept"' and
`"accept_name"' that call your handler or receiver module back by
object type name or the object's name.
"Data::Grove" objects do not contain parent references, Perl garbage
collection will delete them when no longer referenced and sub-
structures can be shared among several structures.
"Data::Grove::Parent" is used to create temporary objects with parent
pointers.
Properties of data classes are accessed directly using Perl's hash
functions (i.e. `"$object->{Property}"'). Extension modules may also
define properties that they support or use, for example
Data::Grove::Parent adds `"Parent"' and `"Raw"' properties and Visitor
depends on `"Name"' and `"Content"' properties.
See the module "XML::Grove" for an example implementation of
"Data::Grove".
METHODS
new( PROPERTIES )
Return a new object blessed into the SubClass, with the given
properties. PROPERTIES may either be a list of key/value pairs, a
single hash containing key/value pairs, or an existing
"Data::Grove" object. If an existing "Data::Grove" is passed to
`"new()"', a shallow copy of that object will be returned. A
shallow copy means that you are returned a new object, but all of
the objects underneath still refer to the original objects.
AUTHOR
Ken MacLeod, ken@bitsko.slc.ut.us
SEE ALSO
perl(1)
perl v5.36.0 2022-12-13 Data::Grove(3pm)
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