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 doet Net <ingy@cpan.org>
COPYRIGHT¶
Copyright 2001-2014. Ingy doet 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>