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NAME ^

Reflex - Class library for flexible, reactive programs.

VERSION ^

This document describes version 0.099, released on April 21, 2013.

SYNOPSIS ^

The distribution includes a few different versions of this synopsis. See eg/eg-18-synopsis-no-moose.pl if you don't like Moose. See eg/eg-32-promise-tiny.pl if you prefer promises (condvar-like). See eg/eg-36-coderefs-tiny.pl if you prefer coderefs and/or closures.

        {
                package App;
                use Moose;
                extends 'Reflex::Base';
                use Reflex::Interval;
                use Reflex::Trait::Watched qw(watches);

                watches ticker => (
                        isa   => 'Reflex::Interval',
                        setup => { interval => 1, auto_repeat => 1 },
                );

                sub on_ticker_tick {
                        print "tick at ", scalar(localtime), "...\n";
                }
        }

        exit App->new()->run_all();

DESCRIPTION ^

Reflex is a class library that assists with writing reactive (AKA event-driven) programs. Reflex uses Moose internally, but it doesn't enforce programs to use Moose's syntax.

Those who enjoy Moose should find useful Reflex's comprehensive suite of reactive roles.

Reflex is considered "reactive" because it's an implementation of the reactor pattern. http://en.wikipedia.org/wiki/Reactor_pattern

About Reactive Objects

Reactive objects provide responses to interesting (to them) stimuli. For example, an object might be waiting for input from a client, a signal from an administrator, a particular time of day, and so on. The App object in the SYNOPSIS is waiting for timer tick events. It generates console messages in response to those events.

Example Reactive Objects

Here an Echoer class emits "pong" events in response to ping() commands. It uses Moose's extends(), but it could about as easily use warnings, strict, and base instead. Reflex::Base gets its emit() method from Reflex::Role::Reactive.

        package Echoer;
        use Moose;
        extends 'Reflex::Base';

        sub ping {
                my ($self, $args) = @_;
                print "Echoer was pinged!\n";
                $self->emit( -name => "pong" );
        }

The next object uses Echoer. It creates an Echoer and pings it to get started. It also reacts to "pong" events by pinging the Echoer again. Reflex::Trait::Watched (via its exported watches() declarative syntax) implicitly watches the object in echoer(), mapping its "pong" event to the on_echoer_pong() method.

        package Pinger;
        use Moose;
        extends 'Reflex::Base';
        use Reflex::Trait::Watched qw(watches);

        watches echoer => (
                isa     => 'Echoer',
                default => sub { Echoer->new() },
        );

        sub BUILD {
                my $self = shift;
                $self->echoer->ping();
        }

        sub on_echoer_pong {
                my $self = shift;
                print "Pinger got echoer's pong!\n";
                $self->echoer->ping();
        }

Then the Pinger would be created and run.

        Pinger->new()->run_all();

A complete, runnable version of this example is in the distribution as eg/eg-37-ping-pong.pl.

Coderef Callbacks

Reflex supports any conceivable callback type, even the simple ones: plain old coderefs. You don't need to write objects to handle events.

Here we'll start a periodic timer and handle its ticks with a simple callback. The program is still reactive. Every second it prints "timer ticked" in response Reflex::Interval's events.

        my $t = Reflex::Interval->new(
                interval    => 1,
                auto_repeat => 1,
                on_tick     => sub { say "timer ticked" },
        );

        $t->run_all();

A complete, runnable version of the above example is available as eg/eg-36-tiny-coderefs.pl in the distribution.

Promises Instead of Callbacks

Callback haters are not left out. Reflex objects may also be used as asynchronous event generators. The following example is identical in function to the previous coderef callback example, but it doesn't use callbacks at all.

It may not be obvious that the same emit() method drives all of Reflex's forms of callback. The same Reflex::Interval class can be used in many different ways.

        use Reflex::Interval;

        my $t = Reflex::Interval->new(
                interval    => 1,
                auto_repeat => 1,
        );

        while (my $event = $t->next()) {
                say "next() returned an event (@$event)";
        }

PUBLIC METHODS ^

Reflex itself contains some convenience methods for cleaner semantics.

run_all

Run all active Reflex objects until they destruct.

        # (Omitted: First you'll need to create some Reflex objects.)

        Reflex->run_all();
        exit;

BUNDLED MODULES AND DOCUMENTATION INDEX ^

Reflex bundles a number of helpful base classes to get things started.

Core Modules

The basic modules upon which most everything else is built.

Reflex - You're reading it!

Reflex::Base - A base class for reactive (aka, event driven) objects.

Reflex::Role - Define a new Reflex parameterized role.

Reflex::Role::Reactive - Add non-blocking reactive behavior to a class.

Callback Adapters

Reflex provides adapters for nearly every kind of callback that exists, including condvar-like promises that allow Reflex objects to be used inline without callbacks at all.

Reflex::Callback - A base class for callback adapters.

Reflex::Callback::CodeRef - Implement plain coderef callbacks.

Reflex::Callback::Method - Implement class and object method callbacks.

Reflex::Callback::Promise - Return events procedurally rather than via callbacks.

Reflex::Callbacks - Convenience functions to creating and use callbacks.

POE Adapters

POE provides over 400 modules for various useful things. Reflex can work with them using these adapters.

Reflex::POE::Event - Communicate with POE components that expect command events.

Reflex::POE::Postback - Communicate with POE components that respond via postbacks.

Reflex::POE::Session - Communicate with POE components that expect to talk to POE sessions.

Reflex::POE::Wheel - A generic POE::Wheel adapter to use them in Reflex.

Reflex::POE::Wheel::Run - Adapt POE::Wheel::Run by wrapping it in a Reflex class.

Object Collections

It's often useful to manage collections of like-typed modules, such as connections or jobs.

Reflex::Collection - Automatically manage a collection of collectible objects.

Reflex::Role::Collectible - Allow objects to be managed by Reflex::Collection.

Reflex::Sender - API to access the objects an event has passed through.

I/O

Event driven programs most often react to I/O of some sort. These modules provide reactive I/O support.

Reflex::Acceptor - A non-blocking server (client socket acceptor).

Reflex::Client - A non-blocking socket client.

Reflex::Connector - A non-blocking client socket connector.

Reflex::Role::Accepting - Add non-blocking connection accepting to a role.

Reflex::Role::Connecting - Add non-blocking client connecting to a class.

Reflex::Role::InStreaming - Add non-blocking streaming input behavior to a class.

Reflex::Role::OutStreaming - Add non-blocking streaming output behavior to a class.

Reflex::Role::Readable - Add non-blocking readable-watching behavior to a class.

Reflex::Role::Reading - Add standard non-blocking sysread() behavior to a class.

Reflex::Role::Recving - Add standard non-blocking send/recv behavior to a class.

Reflex::Role::Streaming - Add non-blocking streaming I/O behavior to a class.

Reflex::Role::Writable - Add non-blocking writable-watching behavior to a class.

Reflex::Role::Writing - Add standard non-blocking syswrite() behavior to a class.

Reflex::Stream - A non-blocking, buffered and translated I/O stream.

Reflex::UdpPeer - A base class for non-blocking UDP networking peers.

Signals and Child Processes

Modules that provide signal support, including SIGCHLD for child process management.

Reflex::PID - A non-blocking SIGCHLD watcher for a specific process.

Reflex::Role::PidCatcher - Add non-blocking SIGCHLD watching to a class.

Reflex::Role::SigCatcher - Add non-blocking signal handling behavior to a class.

Reflex::Signal - A non-blocking signal watcher.

Timers

Timer management has been relatively overlooked so far. We'll get to it eventually, and you're welcome to help.

Reflex::Interval - A non-blocking periodic interval timer.

Reflex::Role::Interval - Add non-blocking periodic callbacks to a class.

Reflex::Role::Timeout - Add non-blocking timeout timer behavior to a class.

Reflex::Role::Wakeup - Add non-blocking wakeup alarm behavior to a class.

Reflex::Timeout - A non-blocking single-shot delayed timer.

Reflex::Wakeup - A non-blocking single-shot alarm for a specific time.

Breadboarding Traits

Reflex also implements signal/slot style object interaction, through emit() and watch() methods. These traits were inspired by Smalltalk's watchable object attributes.

Reflex::Trait::EmitsOnChange - Cause a Moose attribute to emit() an event when it changes.

Reflex::Trait::Observed - (Deprecated. See Reflex::Trait::Watched.)

Reflex::Trait::Watched - Automatically watch a Reactive object stored in a Moose attribute.

ASSISTANCE ^

Thank you for volunteering to assist with this project. You can find like-minded people in a few places, in descending order of preference. Or, oh, wait, maybe you wanted assistance using it? We'll help you, too. :)

See irc.perl.org #reflex for help with Reflex.

See irc.perl.org #poe for help with POE and Reflex.

See irc.perl.org #moose for help with Moose.

Support is officially available from POE's mailing list as well. Send a blank message to poe-subscribe@perl.org to join.

The Reflex package also has helpful examples which may serve as a tutorial until Reflex is documented more.

BUGS ^

We appreciate your feedback, bug reports, feature requests, patches and kudos. You may enter them into our request tracker by following the instructions at https://rt.cpan.org/Dist/Display.html?&Queue=Reflex.

We also accept e-mail at bug-Reflex@rt.cpan.org.

AUTHORS ^

Rocco Caputo, RCAPUTO on CPAN.

CONTRIBUTORS

Reflex is open source, and we welcome involvement.

Chris Fedde, CFEDDE on CPAN

TODO ^

Please browse the source for the TODO marker. Some are visible in the documentation, and others are sprinlked around in the code's comments.

Also see "TODO.otl" in docs in the distribution. This is a Vim Outliner file with the current roadmap and progress.

Set up Dist::Zilla to reduce technical debt and make releasing code fun again.

COPYRIGHT AND LICENSE ^

Copyright 2009-2011 by Rocco Caputo.

Reflex is free software. You may redistribute and/or modify it under the same terms as Perl itself.

SEE ALSO ^

Please see those modules/websites for more information related to this module.

SUPPORT ^

Perldoc

You can find documentation for this module with the perldoc command.

  perldoc Reflex

Websites

The following websites have more information about this module, and may be of help to you. As always, in addition to those websites please use your favorite search engine to discover more resources.

Email

You can email the author of this module at poe-subscribe@perl.org asking for help with any problems you have.

Internet Relay Chat

You can get live help by using IRC ( Internet Relay Chat ). If you don't know what IRC is, please read this excellent guide: http://en.wikipedia.org/wiki/Internet_Relay_Chat. Please be courteous and patient when talking to us, as we might be busy or sleeping! You can join those networks/channels and get help:

Bugs / Feature Requests

Please report any bugs or feature requests by email to bug-reflex at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Reflex. You will be automatically notified of any progress on the request by the system.

Source Code

The code is open to the world, and available for you to hack on. Please feel free to browse it and play with it, or whatever. If you want to contribute patches, please send me a diff or prod me to pull from your repository :)

http://github.com/rcaputo/reflex

  git clone git://github.com/rcaputo/reflex.git

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>

ACKNOWLEDGEMENTS ^

irc.perl.org channel #moose and #poe. The former for assisting in learning their fine libraries, sometimes against everyone's better judgement. The latter for putting up with lengthy and sometimes irrelevant design discussion for oh so long.

COPYRIGHT AND LICENSE ^

This software is copyright (c) 2013 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 ^

BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR, OR CORRECTION.

IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

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