Small event handling module

[airstruck]

This module provides a simple way to register multiple handlers for events.

The module has no knowledge of Love's API, so the first step (in main.lua) is this:

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local Event = require 'event'
Event.injectDispatchers(love.handlers)
Event.injectDispatchers(love, { 'load', 'update', 'draw' })

This "hijacks" all standard Love events, as well as the love.load, love.update and love.draw callbacks.

Now instead of defining (for example) love.update, you can do something like this:

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Event.on('update', function (dt)
    myGame:updateStuff(dt)
end)

The benefit here is that you can register as many handlers as you like for this "update" event; all of them will fire.

If you need to unregister an event handler at some point, save the return value from Event.on and call :remove() on it later.

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local keyHandler = Event.on('keypressed', function (b, s, r)
    myGame:mashButtons(b, s, r)
end)
-- later...
keyHandler:remove()

You can also dispatch your own events if you like. These are not Love events, they are produced and consumed within this module.

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Event.dispatch('pebkac', keyboard, chair)

That's pretty much it, do whatever you want with it. Any input on API or implementation is welcome.

https://gist.github.com/airstruck/9c07256b06ef5925c540

[FruityLark]

Reminds me of javascript EventListeners or jquery binds. I like it.
Is this common in other languages?

[airstruck]

Reminds me of javascript EventListeners or jquery binds. I like it.

Thanks, it's partly inspired by EventListeners and partly by "DOM 0" events (in that you can return false from within a handler to stop other handlers from processing the event, forgot to mention that).

Is this common in other languages?

I think it's very common to have some way of hooking up multiple handlers to events, yeah. I understand why Love doesn't do this by default, keeps things simple and it's easy enough to override the behavior. For anything more than very simple applications it's probably cleaner to have something like this, though.