Reflex::Trait::EmitsOnChange - Emit an event when an attribute's value changes.
This document describes version 0.099, released on April 21, 2013.
# Not a complete program. See examples eg-09-emitter-trait.pl # and eg-10-setup.pl for working examples. package Counter; use Moose; extends 'Reflex::Base'; use Reflex::Trait::EmitsOnChange; emits count => ( isa => 'Int', default => 0, );
An equivalent alternative:
has count => ( traits => ['Reflex::Trait::EmitsOnChange'], isa => 'Int', is => 'rw', default => 0, );
An attribute with the Reflex::Trait::EmitsOnChange trait emit an event on behalf of its object whenever its value changes. The event will be named after the attribute by default. It will be accompanied by a "value" parameter, the value of which is the attribute's new value at the time of the change.
In the SYNOPSIS example, changes to count() cause its Counter object to emit "count" events.
The "default" option can be used to override the default event emitted by the Reflex::Trait::EmitsOnChange trait. That default, by the way, is the name of the attribute.
The "setup" option provides default constructor parameters for the attribute. In the above example, clock() will by default contain
Reflex::Interval->new(interval => 1, auto_repeat => 1);
In other words, it will emit the Reflex::Interval event ("tick") once per second until destroyed.
Reflex::Trait::EmitsOnChange exports a declarative emits() function, which acts almost identically to Moose's has() but with a couple convenient defaults: The EmitsOnChange trait is added, and the attribute is "rw" to allow changes.
The "setup" option is a work-around for unfortunate default timing. It will be deprecated if default can be made to work instead.
Please see those modules/websites for more information related to this module.
You can make new bug reports, and view existing ones, through the web interface at http://rt.cpan.org/Public/Dist/Display.html?Name=Reflex.
Rocco Caputo <firstname.lastname@example.org>
This software is copyright (c) 2013 by Rocco Caputo.
The latest version of this module is available from the Comprehensive Perl Archive Network (CPAN). Visit http://www.perl.com/CPAN/ to find a CPAN site near you, or see https://metacpan.org/module/Reflex/.
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