subscribed 1.2.1

subscribe.d

A minimalistic event and event machine library.

There are two modules in the package (both are publicly imported using import subscribed:

Documentation

A ddox-generated documentation with example usage can be found here.

modules

subscribed.event

An event structure representing a one-to-many function/delegate relationship. Events are basically collections of listeners (either functions or delegates) that have the same signature. Events are called like functions (via opCall) and return arrays, corresponding to the return values of individual listeners.

Use case

The module provides C#-like events for managing proper change propagation between different components of a program.

subscribed.event_machine

A structure representing a complete finite automaton with a singleton alphabet - any state (except for the initial one) can be reached from any other state at any time. Each state has an event that is triggered upon transitioning to it.

Use case

The module is intended for simplifying development of persistently running applications. Most components of a long-running program have multiple possible states and implementing switching between states without some publish-subscribe mechanism generally does not scale well. Consider the case bellow:

Simple example

void playMusic()
{
    // Magic
}

void showLyrics()
{
    // Magic
}

void exit()
{
    // Magic
}

EventMachine!(["Play", "Stop"], void function()) player;
player.subscribe(player.State.Play, &playMusic);
player.subscribeToPlay(&showLyrics);
player.subscribeToStop(&exit);

// To start the player
player.goToPlay();

// To stop the player
player.goToStop();

pub-sub

The initial version of the subscribe.d included a pub-sub module. It provided a unified interface for calling events via scoped publish and subscribe functions. It provided no real benefit over using events directly, except for a little syntax sugar.

The module was removed in version 1.2.

TODO

• Make events synchronize across multiple threads.