/ 
MooseX-TrackDirty-Attributes-2.001
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/ MooseX::TrackDirty::Attributes

NAME

MooseX::TrackDirty::Attributes - Track dirtied attributes

VERSION

This document describes version 2.001 of MooseX::TrackDirty::Attributes - released July 19, 2012 as part of MooseX-TrackDirty-Attributes.

SYNOPSIS

package Foo;
use Moose;
use MooseX::TrackDirty::Attributes;

# tracking accessor is not automagically applied
has foo => (is => 'rw');

# one_is_dirty() is generated by default
has one => (traits => [ TrackDirty ], is => 'rw');

# dirtyness "accessor" is generated as two_isnt_clean()
has two      => (
    traits   => [ TrackDirty ],
    is       => 'rw',
    is_dirty => 'two_isnt_clean',
);

# three_is_dirty() and original_value_of_three() are generated
has three => (
    traits         => [ TrackDirty ],
    is             => 'rw',
    original_value => 'original_value_of_three',
);

# ...meanwhile, at the bat-cave

package main;
my $foo = Foo->new();

$foo->one_is_dirty; # false

DESCRIPTION

MooseX::TrackDirty::Attributes does the necessary metaclass fiddling to track if attributes are dirty; that is, if they're set to some value and then set again, to another value. (The setting can be done by the constructor, builder, default, accessor, etc.)

An attribute can be returned to a clean state by invoking its clearer.

CAVEAT

Note that with one (significant) exceptions we can only track dirtiness at the very first level. That is, if you have an attribute that is a HashRef, we can tell that the _attribute_ is dirty if and only if the actual ref changes, but not if the HashRef's keys/values change. e.g.

$self->hashref({ new => 'hash' })

would render the 'hashref' attribute dirty, but

$self->hashref->{foo} = 'bar'

would not.

In plainer language: we can only tell if an attribute's value is dirty if our accessors are used to modify its values.

The exception to this is...

IMPLICATIONS FOR NATIVE TRAITS

We now track when a native trait accessor is used to change the contents of the attribute; this is considered to make the attribute value dirty.

This is still new and experimental, so feedback is quite welcome :)

ATTRIBUTE OPTIONS

To track a given attribute, the trait must be applied. This package exports a "TrackDirty" function that returns the full (ridiculously long) package name of the trait.

Once applied, we have two additional options that can be passed to the attribute constructor (usually via 'has'):

is_dirty => method_name

is_dirty controls what the name of the "is this attribute's value dirty?" accessor is (returning true on dirty; false otherwise):

By default, the accessor is installed as "{attribute_name}_is_dirty";

If a legal method name is passed, the accessor is installed under that name;

Otherwise we blow up.

original_value => method_name

original_value controls what the name for the original value accessor is installed (returns the original value if dirty, undef otherwise):

By default, we do not install an original_value accessor;

If a legal method name is passed, the accessor is installed under that name;

Otherwise we blow up.

cleaner => method_name

cleaner controls what the name for the cleaner accessor is installed (marks a dirty attribute as clean without clearing):

By default, we do not install an original_value accessor;

If a legal method name is passed, the accessor is installed under that name;

Otherwise we blow up.

SOURCE

The development version is on github at http://github.com/RsrchBoy/moosex-trackdirty-attributes and may be cloned from git://github.com/RsrchBoy/moosex-trackdirty-attributes.git

BUGS

Please report any bugs or feature requests on the bugtracker website https://github.com/RsrchBoy/moosex-trackdirty-attributes/issues

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.

AUTHOR

Chris Weyl <cweyl@alumni.drew.edu>

COPYRIGHT AND LICENSE

This software is Copyright (c) 2011 by Chris Weyl.

This is free software, licensed under:

The GNU Lesser General Public License, Version 2.1, February 1999