NAME
Reflex::Trait::EmitsOnChange - Emit an event when an attribute's value changes.
VERSION
This document describes version 0.100, released on April 02, 2017.
SYNOPSIS
# 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,
);DESCRIPTION
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.
event
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.
setup
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.
Declarative Syntax
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.
CAVEATS
The "setup" option is a work-around for unfortunate default timing. It will be deprecated if default can be made to work instead.
SEE ALSO
Please see those modules/websites for more information related to this module.
BUGS AND LIMITATIONS
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.
AUTHOR
Rocco Caputo <rcaputo@cpan.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2017 by Rocco Caputo.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.
AVAILABILITY
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/.
DISCLAIMER OF WARRANTY
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