Attachment: A callback helper for LÖVE

Attachment is a callback helper utility for the LÖVE framework. When initialized, Attachment will register all existing LÖVE callbacks with itself and then replace all of LÖVE's callbacks with its own. In addition, Attachment has its own event system so you can easily register all of your game's modules with LÖVE's callbacks.

Usage

To use Attachment, require it into your project, create an event handler, and attach some functions to it.

Creating an Event Handler

Creating a Attachment event handler is as simple as calling the Attachment table.

local attachment = require("attachment")
local handler = attachment()

For simplicity, you may want to do this instead:

local attachment = require("attachment")()

attaching

The function for attaching functions is used like this

attachment:attach("event name", function)

local attachment = require("attachment")()

attachment:attach("draw", function()
  love.graphics.setFont(love.graphics.newFont(12))
  love.graphics.setColor(0, 255, 0)
  love.graphics.print("Hello, World!", 0, 0)
end)

The attach function returns the function that was added so that you may detach it later, if necessary.

With Attachment, you can also add all of an object or module's callbacks to a Attachment event handler by calling attachment:attachObject

local attachment = require("attachment")()
local othermodule = require("othermodule")

attachment:attachObject(othermodule)

This will have Attachment run through the object and register anything that looks like a LÖVE callback.

Unattaching

To detach a function from an event, do

attachment:detach("event name", function)

This will run through the event called "event name" and remove the given function if it is found.

Calling

You can register your own events with Attachment if you'd like. To do so, simply attach a function to the desired event and then call the event somewhere in your code. For example:

local attachment = require("attachment")()
attachment:attach("foo", function() print("bar") end)
attachment:call("foo") -- Outputs "bar"

Other Environments

If, for some reason, your main environment is not love, you can pass your environment to Attachment as the first argument when creating your Attachment event handler.

local environment = require("environment")
local attachment = require("attachment")(environment)

This can be useful if, for example, you don't want Attachment to consume LÖVE's callbacks.

local attachment = require("attachment")({})