YAML::Node(3) User Contributed Perl Documentation YAML::Node(3)
NAME
YAML::Node - A generic data node that encapsulates YAML information
SYNOPSIS
use YAML;
use YAML::Node;
my $ynode = YAML::Node->new({}, 'ingerson.com/fruit');
%$ynode = qw(orange orange apple red grape green);
print Dump $ynode;
yields:
--- !ingerson.com/fruit
orange: orange
apple: red
grape: green
DESCRIPTION
A generic node in YAML is similar to a plain hash, array, or scalar node
in Perl except that it must also keep track of its type. The type is a
URI called the YAML type tag.
YAML::Node is a class for generating and manipulating these containers. A
YAML node (or ynode) is a tied hash, array or scalar. In most ways it
behaves just like the plain thing. But you can assign and retrieve and
YAML type tag URI to it. For the hash flavor, you can also assign the
order that the keys will be retrieved in. By default a ynode will offer
its keys in the same order that they were assigned.
YAML::Node has a class method call new() that will return a ynode. You
pass it a regular node and an optional type tag. After that you can use
it like a normal Perl node, but when you YAML::Dump it, the magical
properties will be honored.
This is how you can control the sort order of hash keys during a YAML
serialization. By default, YAML sorts keys alphabetically. But notice in
the above example that the keys were Dumped in the same order they were
assigned.
YAML::Node exports a function called ynode(). This function returns the
tied object so that you can call special methods on it like ->keys().
keys() works like this:
use YAML;
use YAML::Node;
%$node = qw(orange orange apple red grape green);
$ynode = YAML::Node->new($node);
ynode($ynode)->keys(['grape', 'apple']);
print Dump $ynode;
produces:
---
grape: green
apple: red
It tells the ynode which keys and what order to use.
ynodes will play a very important role in how programs use YAML. They are
the foundation of how a Perl class can marshall the Loading and Dumping
of its objects.
The upcoming versions of YAML.pm will have much more information on this.
AUTHOR
Ingy dot Net <ingy@cpan.org>
COPYRIGHT
Copyright 2001-2014. Ingy dot Net
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
See <http://www.perl.com/perl/misc/Artistic.html>
perl v5.34.0 2020-01-27 YAML::Node(3)
yaml 1.300.0 - Generated Thu Aug 18 13:04:49 CDT 2022